Biology Plant and Animal Cells •
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Microscopes (invented 1600s) allowed seeing cells. Robert Hooke was the first to describe cells in 1663 Cell = building blocks of life, every living organism – basic unit of life for all living things Takes in nutrients and releases waste products, Use electron microscopes An organelle is a small cell part that that maintains life processes of the cell All cells have cell membrane – protective barrier of double layer of fat lipids. Substances move through it through processes such as diffusion. Based on different concentrations of substances. Move from high to low concentration until equilibrium. Cytoplasm – jellylike substance fills inside of cell. Carries nutrients required for life and organelles suspended in it, allowing movement. Nucleus is the control center of the th e cell, controls growth/reproduction. Surrounded by a nuclear envelope (contains pores to allow movement of materials). Typically has a nucleolus. Nucleolus contains nearly all of a cell’s DNA (which is bound to proteins and appears as chromatin) When a cell divides, chromatin condenses into chromosomes. Vacuoles and vesicles (transport substances throughout cell) – membrane bound organelles that store nutrients, wastes and other substances. Plant cells have a large center vacuole which stores water (causing the vacuole to fill and become firm. Mitochondria – organelles which supply the cell energy through chemical reactions and produce sugar. Lysosomes - organelles for digestion, filled with enzymes (a protein which can speed up chemical reactions in a cell). Also break down invading bacteria and damaged organelles. Golgi apparatus – receives proteins from endoplasmic reticulum which they modify, sort and package. Stack of flattened membranes Endoplasmic Reticulum – organelle of interconnected tubes that carry material through cell. Rough endoplasmic reticulum related to making proteins. Ribosomes – small dense organelles may be attached to rough endo.ret. or free in cytoplasm. Where proteins are assembled. Closely associated with amino acid bonding. Smooth endoplasmic reticulum – associated with fats and oils (no ribosomes) Cytoskeleton, Cytoskeleton, internal network of fibres (made of protein filaments) Cell wall – only found in plant cells; rigid frame, provides support and protection. Chloroplasts – only found in plant cells. Contain chlorophyll and are vital from photosynthesis. Thylakoids are little sacs that make up chloroplasts. A stack of thylakoids is a granum. granum. Thylakoids collect solar energy and help transform it into carbohydrates.
Difference between Plant and Animal Cells: • • •
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Plant cells contain chlorophyll (and chloroplasts) which allow photosynthesis Plant cells have a large center vacuole Some plant cells store energy in starch or oils. Animal cells store energy in the form of glycogen (carbohydrate) or lipids Some animal cells have special compounds such as haemoglobin in red blood cells or cholesterol Only animal cells have centrioles which are paired structures that are involved in cell division.
M3 Biology: Reviewing Cell Theory Historical Introduction: Introduction: Robert Hooke observed thin slices of cork under a microscope in 1665 and called the spaces he found (see figure to the right) cells because they reminded him of the rooms in which monks lived. With developments in microscopy, other scientists in Europe studied plant and animal cells and began to identify organelles (structures within cells) and how cells moved, grew and divided. Based on these studies, Theodore Schwann and Matthias Schleiden put forward the cell theory in 1839. Rudolf Virchow added the idea of cell division to the cell theory in 1858. Classical Cell Theory: All life forms are made from one or more more cells. Cells only arise from pre-existing pre- existing cells. The cell is the smallest form of life. • • •
Modern Cell Theory: 1. All known known livi living ng things things are are made made up of cells cells.. 2. The cell cell is structur structural al & functional functional unit unit of all all living living things. things. 3. All cells cells come from pre-existi pre-existing ng cells by division division.. (Spontaneous (Spontaneous Generation Generation does does not occur). 4. Cells contain contain heredita hereditary ry information information which which is passed passed from cell cell to cell during during cell division. 5. All cells cells are are basicall basically y the same same in chemic chemical al composit composition. ion. 6. All energy energy flow (metabolis (metabolism m & biochemistr biochemistry) y) of life occurs occurs within within cells. cells.
Cell Cycle, Cell Division and Mitosis: The cell grows and prepares for cell division. This is because a cell’s volume increases 4 times faster than the surface area. This means that the cell can’t absorb materials or expel wastes quickly enough. When a cell reaches this size it is healthier to undergo division. •
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A cell spends 90% of its its time in Interphase, preparing for division There are three stages of Interphase. o G1 phase; phase; period of growth, production of proteins and organelles. o S phase; phase; the cell creates a copy of its DNA. Proteins associated with chromatin are also produced o G2 phase; cell grows organelles needed for cell division. Shortest stage of interphase. Mitosis (or M phase); phase); creating an identical cell. Mitosis has five stages. o Prophase; Prophase; chromatin condenses to form chromosomes (sister chromatids joined together by a centromere). Nuclear structures and nuclear nuclear envelope disintegrate to allow motion. Mitotic spindles form to move the chromatids. In animal cells, centrioles move to opposite ends forming the poles of the mitotic spindle. o Metaphase; Metaphase; each chromosome becomes completely condensed and line up in the middle of a cell. The mitotic spindle is completely formed. Anaphase; the sister chromatids separate at the centromere, forming two full o Anaphase; chromosomes. The separated chromosomes are pulled to opposite ends. cytokinesis; the cell divides into two new daughter cells. The o Telophase and cytokinesis; cell membrane pinches inward, splitting into two cells. Two nuclei form and mitotic spindles disappear. The cell cycle is repeated. Apoptosis & Necrosis; Necrosis; cells die when they suffer injury or are damaged beyond repair (may absorb poison and die). This is called cell necrosis. A cell might die as a normal part of a healthy organism through apoptosis, when a cell is no longer useful or have lost their efficiency. Chromosomes; Chromosomes; A long coiled piece of DNA and proteins. A human cell has 46 chromosomes. Chromosomes are only visible during cell division, otherwise it is chromatin.
Plant Tissues All plant cells originate from one of two types of unspecialized unspecialized meristamatic tissue. Histology: Histology: the study of tissues. The three common ways of getting tissue cuts are (A) transverse; (B) longitudinal; (C) tangential. Apical Meristem: Completely undifferentiated meristematic tissue Found in the (apical) buds and growing tips of roots in plants. begins growth of new (specialized) cells in young seedlings It is capable of dividing by mitosis and is found in several locations in the plant. • • • •
Vascular Cambium: It’s a lateral meristem It’s responsible for moving water/food throughout the plant. • •
Three types of plant tissue: Def Definition
Examples
Dermal Tissue Prote otects the the inner ti tissue. Prevents water loss and controls gas exchange.
Ground Tissue Photosynthesis, offers food storage, support and protection
Vascular Tissue Transports food, minerals, nutrients and water throughout the plant.
Epidermis Bark, leaves
Parenchyma tissue Collenchyma tissue Sclerenchyma tissue Roots
Xylem tissue Phloem tissue
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Dermal Tissue: Root Hair Cells: They are thin elongated structures on the surface of the roots which increase water intake by increasing the surface area of the cell. Leaf Hair Cells: Similarly, they are thin elongated structures on the surface of leaves. They are responsible for lowering water loss by decreasing the flow of air over the leaf. Stomata and Guard Cells: Guard cells contain chloroplasts and regulate gas exchange between the leaf and the environment. The stomata are pores in the leaf’s surface for gas exchange needed for photosynthesis. However, they make the leaf more vulnerable to water loss. Ground Tissue: Parenchyma (chlorenchyma, transfer cells): They are spherical cells responsible for photosynthesis, food storage and regeneration. Cholernchyma have a high density of chloroplasts which enable photosynthesis. They have a high efficiency in providing support with very little metabolic effort due to prominent intercellular spaces.
Specialized for short distance transfer of solutes between cells have inner walls wa lls which increase surface area. Collenchyma: It offers structural support, especially for young, developing plants. Sclerenchyma (sclereids and fibres): It offers rigid support and protection (similar to our skeletal system). Vascular tissue: Xylem (vessels, tracheids) They are meant to transport water and dissolved minerals or nutrients to the rest of the plant or as food storage (not main function though). They also give support. It is mostly made of already dead cells (large diameter but hollow to allow a rapid water flow). Predominate in conifers, water moves upward from tracheid to tracheid and prevents gas build up in winter and thus the plant can keep the leaves without having to lose them Phloem (sieve and companion cells) They are used for transporting food and organic matter (glucose amino acids, hormones, and RNAs) to the rest of the plant. They also give support. It is found in tree bark (comes from Greek word meaning bark). It is mostly made of living cells.
Animal Tissues The different parts of an animal are formed from division and differentiation of animal cells. Cells which give rise to animal tissues are called stem cells: Stem cells: It is an unspecialized animal cell that can divide (through mitosis) and differentiate into diverse specialized cell types. It’s similar to the meristamatic tissue in plants. Animal Tissues are classified classified generally into four types: Epithelial (integumentary): Forms a protective barrier to protect against external contaminants Forms glands Lines the body cavities and on the outer surface up with densely packed cells to form a protective barrier. It may be one cell thick or consist of several layers. • • •
External skin: It is made of flat, squamous cells which offer protection from UV radiation, dehydration and bacterial infections. It also acts as a sensory receptor warning and informing us of our surroundings. Internal skin: It forms the lining of the stomach and intestines. It’s responsible for sensory reception and secreting mucus to keep a smooth surface. Certain parts are specialized depending on their system.
Glands: Glands: Goblet cells secrete and synthesize certain substances such as enzymes, hormones, milk, mucus, sweat or saliva depending on their system. Connective: It is used to join oth er tissues together. There are different types such as tendons, ligaments, bones, cartilage, and blood. Adipose: Adipose: Round cells of body fat which stores energy in the form of lipids, It’s also an important endocrine organ. Bone: Forms the skeletal system and is the main source of structural support in the body. Blood: It has many functions such as transporting nutrients, regulating body temperature, healing the body (moving antibodies, clotting if there’s a cut). Without it, no other systems could function. Nervous: It is made up of different types of nervous cells, which work together to respond to stimuli, transmit and store messages throughout the body. Neurons: Neurons react to stimuli and conduct the impulses. The stimuli are integrated for appropriate results. Glia: Glia provide neural support, stability and protection (by supplying nutrients and killing pathogens).
Muscular: It consists of three types of muscles which allow both voluntary and involuntary movement. Smooth Smooth muscle controls slow involuntary movement. It also regulates b lood pressure ad the flow of blood. Striated Striated muscles control co-ordinated movements such as breathin g. Cardiac There is only one cardiac muscle: the heart. It is involuntary even though it’s striated. It controls the contraction of the atria and ventricles to allow a regular beating. It responds to your movements (faster pulse when running, etc.)
Human Organ Systems Human Skeletal System Main Functions: Framework and support Protection Storage Axial and appendicular skeleton Bone structure Joints and ligaments The skeleton forms a sturdy internal framework of 206 bones and associated tissues – cartilage, tendons, and ligaments. Bones Bones provide the base to which muscles attach attach and also the leverage required to accomplish external movement. The skeleton protects vital organs such as the brain, spinal cord, heart and lungs. As a living, dynamic tissue, bone stores vitamins and minerals (especially calcium and phosphorus) and houses red bone marrow, which produces blood cells. The axial skeleton (upright, or core of the body) includes the skull, ribs, sternum and vertebral column. Comprised of the shoulders, arms, hips and legs, the appendicular skeleton appendicular skeleton forms the appendages that attach to the axial skeleton. The articulation of bones forms joints and provides the skeleton with flexibility, enabling it to be moved as muscles contract, extend and relax. Bone is approximately four times as strong as concrete. Bones are made of a dense outer layer of compact material that surrounds a core of loosely structured spongy bone. The compact layer of bone is covered by a fibrous membrane called the periosteum. Cavities within each bone contain red bone marrow (blood-forming tissue) or yellow bone marrow (fat storage). Movement of the skeleton occurs at the joints where two or more bones meet. There are three categories of joints: Slightly movable joints allow some movement but function mainly as a cushion (eg, joints between the vertebra). Freely movable, or synovial, joints allow a range of movement determined by the structure of the joint. Examples of movable joints are the ball and socket (shoulder), hinge (elbow), pivot (between radius, ulna and humerus), and saddle joint (thumb). A few joints found in the skull skull are non-movable (sutures). Ligaments are inelastic inelastic connective tissues which hold bones together in a joint. Muscular: Functions Movement Warmth Posture Muscle Properties Ability to contract Ability to be stretched stretched Ability to respond to a stimulus stimulus • • •
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Muscle Types Skeletal o Skeletal muscle is attached to the skeleton with tendons and is controlled consciously. Skeletal muscle cells are long, fiber-like and multinucleated o Smooth Movement of smooth muscle tissue, found in internal organs, is usually o involuntary. o The cells of smooth muscle tissue are spindle-shaped and contain a single nucleus. Cardiac o Involuntary muscle. Cardiac muscle tissue contains “gap” junctions that allow the diffusion of o ions and the spread of electrical impulses from one cell to another. As muscle tissue contracts, contracts, energy is used and heat is generated. Muscles also maintain body positions and postures, such as supporting your head or sitting. Muscle is unique in its ability to contract. contract. The functional unit of skeletal muscle tissue is a sarcomere When a muscle contracts, the sarcomere is shortened by actin filaments “sliding” over myosin filaments. Since a muscle fiber moves by shortening (it pulls and cannot push), muscles must work in antagonistic pairs. A flexor contracts flexor contracts and decreases the angle of joint while an extensor is extensor is stretched, increasing the angle of the joint. • •
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Circulatory:
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Why is a transport system needed? 1) To transp transport ort oxygen oxygen and CO2 2) Tran Transp sport ort nutr nutrie ient nts s 3) Get Get rid rid of was waste te pro produ duct cts s 4) To heal heal (help (help the immune immune syst system) em),, defense defense 5) To heat heat (regula (regulate te body body tempera temperatur ture) e) 6) Tran Transp sport ort hormo hormone nes s 7) Store tore ener nergy Transport in single celled organisms (amoeba) and simple animals (Hydra): Through diffusion, no blood Open systems (insects, crayfish): Contain a pump, vessels and blood. Fluids are pumped to the open area where nutrients are exchanged with the cells. Closed systems (worm, frog, human): Also contains a pump, vessels vessels and blood. The blood is always contained contained within the vessels here though. Advantages: More efficient Less stagnation, prevents pooling No contamination between oxygen and deoxygenated blood Can support larger animals as there is sufficient pressure. • • • •
HUMAN Circulatory system The average heart rate ranges from 60 to 70 beats per minute initiated by the sinoatrial node, or pacemaker, which is found in the wall of the heart. William Harvey (an English physician) demonstrated the function of the heart and complete circulation of the blood in 1628, Blood vessels of the circulatory system consist of arteries, veins and capillaries. The largest artery is the aorta and the smallest arteries are arterioles. Arteries transport blood away from the heart, and, with the exception of pulmonary arteries, contain oxygenated blood. Arteries expand and recoil under pressure (creating what we call “pulse”) “pulse”) because of the elastic connective tissue in the walls. Veins are thinner and less muscular than arteries and return blood to the heart. With the exception of the pulmonary veins, veins transport blood low in oxygen. Capillaries are one cell in thickness. This allows for the essential exchange of materials between the blood and cells of the body. Plasma is approximately 90% water and 10% solutes (nutrients, wastes, vitamins, hormones, gases, ions, and plasma proteins, which maintain osmotic pressure). The cellular portion of the blood is made of red blood cells (erythrocytes which contain hemoglobin, iron-containing pigment which binds and transports oxygen), which transport oxygen; white blood cells (leukocytes), which aid in defending the body from infection; and platelets, which are important in blood-clotting reactions. •
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Some of the fluid in blood, along with several plasma proteins, moves into the tissues and is returned back ba ck to normal circulation by the lymphatic system. The lymphatic system consists of a series of vessels and “nodes,” whi ch filter out bacteria and other microorganisms.
Immune Nonspecific defense responses Skin and mucous membranes Inflammatory response Temperature Proteins White blood cells Specific immune responses Humoral immunity Cell-mediated immunity Defends the body against pathogens. The skin (largest organ of the body) and mucous membranes are the body’s first line of defense, serving as a physical barrier and providing chemical defenses. As pathogens enter the body, the immune immune system’s inflammatory response response initiates the release of histamines and prostaglandins. prostaglandins. This increases blood circulation, circulation, thereby enabling white blood cells to migrate to t he infection site. site. Because many pathogens can exist only in a very narrow temperature range chemicals are released to increase body temperature, temperature, making it more difficult for pathogens to survive and reproduce. Interferon (a protein released by cells infected by viruses) causes surrounding cells to produce an enzyme that prevents viruses from making proteins and RNA. The most important nonspecific defense is mounted by three kinds of white blood cells: neutrophils, macrophages and natural killer cells. If a pathogen is able to survive the body’s nonspecific defenses, specific immune responses are triggered. Specific defenses include humoral immunity and cellmediated immunity. Immunity against pathogens in the blood and lymph is called humoral immunity. B cells (lymphocytes) produce specific proteins, known as antibodies, antibodies, which bind to specific antigens, tagging them for destruction by phagocytes. In cell mediated immunity, killer T cells or cytotoxic T cells (lymphocytes), transfer proteins to a pathogenic cell, causing fluid to leak out of the membrane. The pathogenic cell ruptures and is destroyed. •
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Respiratory Respiration is a chemical reaction inside the mitochondrion from glucose and oxygen into CO2 and water. Breathing is the intake of gases (inhalation and exhalation) Criteria for Gas Exchange: Gas transport (nose to lungs, etc.) Large surface area (alveoli) Gas exchange (capillaries) • • •
Single celled or simple animals (hydra) through diffusion Aquatic Animals: Much larger organisms and it’s not possible for each individual cell to be in contact with the aqueous environment Gills are used Have a capillary bed •
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Insects e.g. Grasshopper • Have a separate system of tubules • Air enters enters body through through tiny holes holes in the abdomen; abdomen; the insect insect can control control the size size of these openings using their muscles. Amphibians Amphibians e.g. frog, frog, salamander salamander -3 breathing organs • skin (moist) • lining of mouth • lungs (small because they have other gas exchange methods) Mammals e.g. rabbit, human • lungs are larger because these are the only site of gas exchange air is pulled into the lungs through a series of tubes • • lungs themselves have many very small sacs called alveoli • these are good for gas exchange because they are moist, have a large surface area (they are squamous epithelial cells) • They are one cell layer, allowing for rapid diffusion.
Digestive Carbohydrates – best energy source Proteins – major functions in animal structure & metabolism Fats – second best energy source, also used for structure and protection Water – Water – makes up more than 75% of most organisms. Is an important dissolving medium & used for transportation Vitamins – Only required in small amounts, made of organic compounds (aid in metabolism, growth and even vision) Minerals – only required in small amounts, made of inorganic compounds Autotrophs – produce their own food Heterotrophs – eat other organisms Digestive tract – a long tube that runs from one end of the organism to the other, with a iin and out opening. Its four major roles: 1. Absorption Absorption of nutrients nutrients,, cell uptakes uptakes 2. Ingestion Ingestion – take in food food 3. Digestion Digestion – physical physical & chemical chemical breakdown breakdown 4. Ejestion Ejestion – eliminates eliminates waste from syste system m Single celled organisms engulf food Tongue: Tongue: used for taste, swallowing, gathering food, thermal regulation and speech
Oral glands: glands: secrete a variety of substances such as saliva (moistens and begins chemical breakdown of carbohydrates through enzymes found in saliva) Pharynx: Pharynx: helps us swallow, transport, prevents p revents choking Esophagus: Esophagus: muscular tube that pushes partially broken down food to the stomach. Stomach Intestine: Intestine: a long tube from the stomach ultimately to the outside of the organism. It’s main role is absorption. absorption. Microvilli and villi: villi: increase surface area and help absorb Excretory Excretion is the removal of metabolic wa stes from the body, including toxic chemicals, excess water, carbon dioxide and salts. Excretory Organs Skin removes water, salts and nitrogen wastes in the form of sweat. o o Lungs eliminate carbon dioxide, water vapor and heat in exhaled air. Kidneys excrete the majority of metabolic waste products from the body. o Each kidney contains about one million functional filtering units called nephrons. Urinary The urinary system, consisting of the kidneys, ureters, urinary bladder and urethra Is responsible for eliminating the majority of metabolic wastes from the body. •
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Reproductive: Produces gametes (eggs and sperm) Fertilization – produce zygote Male Reproductive System Testes o Epididymus, vas deferens, urethra, seminal vesicle, prostate gland, C owper’s o gland Female Reproductive System Ovary o Fallopian tubes, uterus, vagina o The reproductive system is responsible for producing, storing and releasing specialized cells called gametes and then transporting them to a place where fertilization can occur. As the fertilized egg (called a zygote) begins to divide, it becomes an embryo and must be maintained within the body during a critical period of development. • • •
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Endocrine: Endocrine: The endocrine system consists of ductless glands that prod uce hormones. o Hypothalamus, pituitary, pineal, thyroid, parathyroid, thymus, adrenal, pancreas, ovary, testes Hormones are chemical messengers that travel through the blood stream and affect activities throughout the body. o Steroid hormones Nonsteroid hormones o •
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Hypothalamus – coordinates activities of the nervous and endocrine systems and produces hormones to regulate the pituitary gland Pituitary – produces hormones that direct the activities of other endocrine glands Pineal – releases melatonin which is involved in rhythmic or cyclic activities Thyroid – produces hormones that regulate metabolism and development Parathyroid – helps maintain appropriate calcium levels Thymus – involved with immune development during childhood Adrenal – regulates the body’s stress response (epinephrine, norepinephrine, cortisol, aldosterone) Pancreas – controls glucose levels in the blood (insulin, glucagon) Ovary – secretes estrogen and progesterone to regulate reproduction Testes – produces testosterone to control formation of sperm and sexual behavior
Nervous: Controls and coordinates functions throughout the body Neurons are specialized cells that transmit impulses throughout the body. Nervous System Central Nervous System Peripheral Nervous System o Somatic o Autonomic • • •
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Integumentary: Consists of the skin, hair, and nails The word integument is derived from a Latin word meaning “to cover.” The skin serves as a first line of defense for the b ody, protecting against infection and UV radiation. It also helps to regulate temperature and remove wastes. The top layer of skin = the epidermis, contains keratin, making skin more waterproof. The dermis, contains blood vessels, nerves, sense receptors, h air follicles and smooth muscle. The subcutaneous layer is made of connective tissue (mostly fat) and helps to insulate, store energy and protect the body. • • •
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X-ray
It’s easy for a radiX-rays use high energy ologist to identify a radiation which can problem. IT helps cause changes or mutadiagnose cancer in tions in your DNA leadthe cardiovascular ing to cancer and other or respiratory syshealth complications. tem. Mammograms also use x-rays to identify breast cancer. It is quick, painless and non-invasive. Fluoroscopy Studies th the mo move As it uses uses x-ray technotechnoment of organs logy, it may cause radisuch as the digestation-induced injuries to ive system. It is also the skin and underlying used to perform an- tissues (“burns”), and giograms (to show increase the risk of dethe narrowing arter- veloping cancer. Some ies). patients may react to the contrast agent. CT Scan or As you can can see It uses more x-rays than Computed cross sections, it is other forms of diagnosTomography frequently used to is. This leads to a highidentify cancer. It is er risk of cancer, skin irquick, painless ritation/disease. It is while providing very dangerous to have a CT thorough informascan if you are pregnant tion. (may lead to birth defects). Ultrasound It is very safe as it You can’t study bone as doesn’t use radithe waves can’t penetation but sound rate it. You can’t study waves. the intestinal system as gases blur the image. It is used to diagnose other issues such as a fetus or heart abnormalities. Mamm Mammog ogra raph phy y It can can det detec ectt brea breast st While it doesn’t use xcancer early and rays it uses a small prevent the need for dose that does not have chemotherapy. major repercussions.
Nuclear Medicine
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It is used to diagnose cancer. Radioisotopes can also be used to treat diseases such as thyroid, prostate or breast cancer.
It does use radiation which can cause mutations in the DNA and lead to cancer. However, the radioisotopes will either decay into non-radioactive elements or be excreted by the body.
You bombard an area with high energy radiation which easily penetrate skin and tissue, but not bone or metal. It results in a photograph of that area which is used for diagnosis.
Uses a continuous beam of x-rays to show the movement of organs. The patient may have to ingest a contrast liquid such as barium or iodine.
Uses x-ray technology to generate 3D images of an area.
Uses high frequency sound waves to produce images of tissue or organs. This is done by placing a transducer on top of the skin which emits the sound waves.
It is used to detect breast cancer through x-ray technology.
Doctors use radioisotopes (a radioactive form of an element) to provide images of tissue and organs. You attach the radioisotope to a chemical which the tissue absorbs. A special camera detects the radiation and converts it into an image. X-ra X-ray y is ver very y succ succes essf sful ul in dete detect ctin ing g canc cancer er usi using ng a smal smalll dose dose of of radi radi-ation Fluoroscopy is excellent at detecting cancer in the digestive system as it measures over a period of time. However, the radiation dose is higher, it
Body Systems: Skeletal: Skeletal: The skeletal system consists of bones in the body which are attached to each other a joints using ligaments. It provides structural support and protection, acting as storage of calcium and other minerals. Muscles attached to the bones enable movement. Muscular system: system: Muscles provide movement, warmth and posture. po sture. Muscles can contract (when actin and myosin proteins move past each other), relax or respond to stimuli. Circulatory system: system: It consists of a heart (or pump) which forces the blood through arteries or veins (which return blood to the heart). Lungs help oxygenate the blood as haemoglobin carries oxygen through the blood stream. Humans have two atria and two ventricles in their hearts. Immune System: It acts as the primary defence mechanism in our body, using white blood cells to help fight off infections or viruses. The use of vaccines has improved the human health system by allowing our immune system to create antibodies which help fight. However, there are some diseases which target the immune system such as AIDS. Respiratory: It allows for gas exchange with the environment using lungs and subsequently alveoli (thin containers which expand with air (have a very high surface area). Digestive: This system contains the esophagus, stomach and intestines. Its functions are to breakdown food absorb the nutrients using glands (which secrete enzymes). Peristalsis is the contraction of muscles which allows food to move through the system. Excretory: Consists of kidneys (filter blood and remove waste). The waste is temporarily stored in the bladder and then removed as urine. That’s why it’s important to stay hydrated. Reproductive: Uses different organs to produce a zygote Nervous: It consists of the brain, the spinal cord and nerves. Using these, it controls and coordinates all activity. The neuron is the basic unit of the nervous system which communicates with other neurons using chemical signals.
Endocrine: It consists of glands spread throughout the body which produce hormones, the pituitary gland being the main one. It controls and regulates growth, immune responses and developmental characteristics. Integumentary: It consists of skin, nails and hair which wh ich cover the body. It protects the body from pathogens and helps regulate body temperature.
CHEMISTRY • •
Everything is matter (anything that has mass and occupies space) The Particle Theory of Matter: Particles make up all matter Identical are the particles of the same element or pure substance and they are different from all other particles of a different pure substance Space is between all particles, not air Attraction exists between all particles Motion: all particles are constantly in motion Acronym = PISAM Particles tend to move faster at a higher temperature than at a lower temperature • •
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Classification of Matter Matter can be classified as a: Pure Substance or a Mixture A pure substance is matter that contains only one type of particle A mixture contains more than one kind of particle Pure water is a pure substance while salt water is a mixture of salt and water Oxygen is a pure substance while air is a mixture of nitrogen, oxygen, etc. A Pure Substance can further further be divided as a: Compound or Compound or an Element A compound is a pure substance that is made of two or more different elements that are chemically combined. A compound can be divided into the original elements only through chemical means. Water is a compound made of oxygen and hydrogen o o Separating water into Hydrogen and Oxygen requires electrolysis An element is a pure substance that cannot be broken down further by chemical or physical means. It consists only of one type of particle. All the elements are found in the periodic table of elements. element. o Aluminium is a type of element. Please note that if you were simply to take hydrogen and oxygen and physically mix them into a container, they can also be separated physically. This is known as a mixture •
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Separating Mixtures: One way to separate a mixture is through filters or o r sieves (i.e. coffee filter) •
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Distillation is another form of separating substances Magnetism is another form of separating objects
Physical Properties: There are two types of properties: Qualitative and Quantitative Qualitative properties observed and described without detailed measurements, but with our own five senses. Qualitative things include: colour, odour, state, texture, lustre & malleability Quantitative properties can be measured and assigned a particular value Quantitative properties include: viscosity, melting point, boiling point, solubility, hardness, conductivity and density Solubility is the measure of the ability of a substance to dissolve in another substance. It is typically expressed as a concentration; a substance is highly soluble if large amounts of the substance will dissolve di ssolve in a given amount of solvent. Salt dissolves in water at 39.5/100mL If water is used as the solvent, it is called an aqueous solution. Water is referred to as the universal solvent because most thing s dissolve in water. It dissolves more things than any other liquid. Mohs scale is used to measure hardness (1 to 10). A diamond is the hardest, being measured as ten, and talc one of the softest as a one Density is the ratio of mass of a substance to the volume it occupies. m Density = Mass/Volume, D = v Chemical Properties and Change A chemical property is the ability ability of a substance to react and form new substances. The final substance is substantially different than the initial substance. A new substance is ALWAYS produced. Energy is usually released, but may by required to get the change going One can identify a chemical reaction by a resulting by-product: colour change, gas, light, odour etc. Combustibility (the Combustibility (the ability of a substance to burn in air), stability (the stability (the ability of a substance to remain unchanged) and toxicity (the toxicity (the ability of a substance to cause harmful effects to organisms), reactivity with reactivity with other substances, are all chemical properties Vinegar and baking soda mix to form carbon dioxide. o o Hydrochloric acid reacts with magnesium to form hydrogen gas. • •
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Physical Change: No new substance is produced. The substance remains the same even with a change of state May require additional energy, or there may be a release of energy The outside might look different, but the particles remain unchanged. The particles might rearrange, or have weaker or stronger attraction between particles Ice to water to water vapour o o Mixing sugar and water • • • • •
The Atomic Model 450 BC - The Ancient Greeks (Democritus and Leucippus) thought that matter was made up of small individual particles 1803 – Dalton came up with the atomic theory, in which elements consisted of tiny particles called atoms, which were small, hard and indestructible. The atoms of each element were different from an atom of another element. Compounds consisted of atoms of different elements 1897 – Thomson experimented with cathode rays. He had the “muffin” model, in which the overall atom is neutral, it is made up of positive charge with negatively charged electrons embedded in it 1911 – Rutherford had the gold foil experiment through which he concluded that the atom was mostly empty space occupied by a small central charge that contained all the positive protons in a central NUCLEUS. NUCLEUS. Electrons orbited this core. The nucleus also has the most mass of the atom. 1913 – Bohr Similar Bohr Similar to Rutherford’s model except for the fact that electrons are allowed to jump between certain energy orbits. Atoms radiate energy only when an electron “jumps” between energy orbits Modern View – states that electrons are distributed around the nucleus in certain “probability regions” or atomic orbitals Chadwick got the Nobel prize for discovering neutrons (mass of the nucleus) •
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The ATOM: The proton and neutron have a very similar weight; both are nearly 1840 times heavier than an electron. The neutrons and protons are attracted by the strong force. There are in fact many other sub atomic particles apart from the proton, neutron and electron, such as the quark. Electrons can have shells unfilled and filled with valence electrons. The noble gases are stable because they have no valence electrons. It is hard for them to share or bond with other elements. During a chemical reaction, one atom can join with another atom by gaining/losing/sharing valence electrons. Groups 1 and 17 tend to lose their valence electrons more easily as they only need to lose one in order to have a full valence shell. This makes them much more reactive. The farther the valence electrons are from the nucleus, the easier they can be lost (less gravity and attraction between the electron and nucleus). For example, a sodium atom has one valence electron in the third shell and a potassium atom has a valence electron in the fourth shell. The potassium loses its valence electron faster than the sodium atom, making it more reactive Isotopes: One of the two or more forms of an element that have the same number of protons but a different number of neutrons. •
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Ionic Compounds and Covalent Bonds: And ion is a positively or negatively negatively charged atom or molecule. This can happen when an atom gains or loses electrons, and the balance between protons and electrons no longer exists. • •
If it loses an electron, it is positively charged. If it gains electrons, it is n egative. The charge of an ion is the sum of the charges. Compounds consist of chemical bonds (a chemical link between two atoms which holds them together). One chemical bond is an ionic bond Ionic Compound An ionic bond is a chemical bond formed between between two oppositely charged ions. When an ionic compound forms, one or more electrons from one atom is transferred to another atom. This creates charged ions that are attracted to each other. This creates a neutral balance once more. Ionic compounds are formed between one metal and one non-metal. Metals tend to lose electrons and non metals tend to gain electrons. NaCl is an ionic compound. Ionic compounds tend to be very strong as they exist in a solid arrangement known as a crystal lattice. Because of this strong shape, it requires high amounts of energy to break, so they have a high melting point. Many ionic compounds are also soluble in water. An ionic compound dissolves because the water separates the positive and negative ions, causing the ionic bonds to break. Our body needs aqueous solutions. Conductivity – ionic compounds are good conductors if they are dissolved allowing the ions to move freely. In solid state, the ions are locking in a crystal lattice and are poor conductors. • • •
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Covalent Bonds (Molecular Bonds) A molecular compound is formed when atoms of of two or more elements share electrons. A covalent bond refers to one or more pairs of electrons being shared by two atoms. The atoms remain uncharged. A molecule is the smallest smallest discrete particle of a pure substance substance which has one or more shared pairs of electrons (it can be for elements or compounds, O 2) Water is a molecular compound. It is typically between two or more non metals. The attractions between molecules are much weaker than ionic compounds. Have low melting or boiling points. Plastics are a type of molecular compounds known as polymers. •
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Two-dimensional Models: Bohr-Rutherford Diagrams 2 dimensional models that indicate height and width Useful for showing what happens during formation of ionic and molecular compounds Helpful for showing how ions form and how atoms share electrons When you see an element in the periodic table, it states the mass number and the atomic number. The atomic number is the number of protons while the mass number minus the atomic number is the number of neutrons. The maximum number of electrons in the first shell is two (number of elements in first row) The maximum number for the second shell is 8 (number of elements in 2 nd row) The maximum number for the third shell is 8 (number of elements in 2 nd row) • •
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How to Count Atoms
The symbol of an atom is one atom of that element (e.g. Ca) A subscript is a number written written at the lower right corner beside the symbol of an eleelement If there is more than one atom of the element in the molecule, then a subscript is used to indicate the number of atoms If there is only one atom of an element in a molecule, then no subscript is o written (e.g. N2, H2O) A subscript outside the bracket bracket multiplies all the elements inside inside the bracket E.g. In Ba3(PO4)2 there are 3 barium, 2 phosphorus, and 8 oxygen o A coefficient (makes a compound) compound) is a number written in front of a chemical chemical symbol and indicates the number of atoms of that element (e.g. 3C) A coefficient is a number number written in front of a chemical formula formula and indicates the number of molecules of that compound (a coefficient multiplies the number of atoms of each element in the formula E.g. 2H2O = 2 molecules of water, 4 atoms of hydrogen, 2 atoms of oxygen o E.g. 3FeSO4 = 3 atoms of iron, 3 atoms of sulphur and 12 atoms of oxygen o • •
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Multivalent Elements:
Valence 1 Eleme nt
Valence 2
Ion
Classic al (ous)
Stock
Ion
Classic al (-ic)
Stock
Coppe r Iron
Cu+
cuprous
I
Cu2+
cupric
II
Fe2+
II
Fe3+
Pb2+
II
Pb4+
IV
Gold
Au+
I
Au3+
ferric plumbi c auric
III
Lead
Nickel
Ni2+
II
Ni3+
nickelic
III
Tin
Sn2+
II
Sn4+
stannic
IV
Antim ony
Sb3+
ferrous plumbo us aurous nickelo us stannou s stibinou s
III
Sb5+
stibinic
V
Polyatomic Ions:
III
Ion
Charge
Name
NO3ClO3OHCO32SO42PO43NH4+
1112231+
nitrate chlorate hydroxide carbonate sulphate phosphate ammonium
Diatomic Molecules: These are molecular compounds formed with two atoms, either of the same or of different elements, Some elements naturally combine with themselves to form diatomic elements. Noble gases never form diatomic molecules. 99% of the atmosphere is composed of diatomic gases (nitrogen, oxygen, etc.) •
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Diatomic Element
Formula
hydrogen gas
H2
oxygen gas
O2
nitrogen gas
N2
chlorine gas
Cl2
fluorine gas
F2
bromine liquid
Br2
iodine solid
I2
Magnesium and Aluminum Chloride Mg + AlCl3 = Al + MgCl3 X + AlCl3 = Al + xCl2
Here, A is an element and BC is usually an aqueous ionic compound or an acid (consisting of B + and C- aqueous ions). Element A replaces B in BC, BC, resulting in the formation of a new element element B and a new ionic compound compound or acid, AC. If the new element element B is a metal, it will appear appear as a metallic deposit. If it is a gas, it will will appear as bubbles. An Activit An Activityy Series of elements is often used to determine if A will displace B in a single replacement reaction. An Activity An Activity Series Series is provided provided below. As a rule, if A has a higher activity activity that B, a single replacement replacement reaction reaction will occur. However, However, if A has lower activity than B, a single replacement reaction will not occur.
Naming Compounds and Formulae: First determine the type of compound (ionic or covalent). If it’s IONIC, IONIC, you would simply add the suffix “ide” to the non-metal element. The metal’s name remains unchanged. o Examples: AlCl3 is Aluminium Chlor ide ide MgH2 is Magnesium Hydr ide ide o If it is COVALENT, COVALENT, you would add a prefix to indicate the number of each element. Notes that is the first element has only one you do not write mono in front of it The prefixes are: mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca. You still use the suffix “ide” for the last element. Examples: CO is Carbon monox monoxide ide o N2O5 is di nitrogen pent nitrogen pent oxide oxide o
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How to Draw Lewis Dot Diagrams: • • • •
Scientists typically use Lewis Dot Diagrams to show th e bonding between elements. There are different ways to draw ionic and covalent bonds. Ionic Lewis dot diagrams: Metals will lose electrons, non-metals will gain electrons
[Na]- [ Cl ]+
[Al]3- 3[ Cl ]+
Covalent bonds: H – O – H water
N
N nitrogen gas
1
2
3
4
-3
-2
-1
The metalloids are the brown stair case elements (B, Si, Ge, etc.). These metalloids are semi-conductive and are used for computer chips. The noble gases are found on the right side. They are the most stable elements. The non-metals are the halogens (dark blue), the noble gases, Hydrogen, Helium, Carbon, Nitrogen, Oxygen, Phosphorous, Silicon and Selenium. Halogens are very reactive and highly unstable and corrosive. Alkali metals have low melting melting points and aren’t too hard but highly reactive Alkaline Earth metals are reactive reactive (not as much as alkali). If they are heated, they will burn in the air. They are often used for fireworks. A valence electron is the number number of electrons in the outer shell. This helps helps us learn the ionic charge and form compounds A period represents a row. A group is a column. column. Mendeleyev however found a pattern of the increasing atomic mass. When Mendeleyev arranged the table, he noticed that properties repeated in a pattern that allowed the elements to be organized. This table is also useful for making predictions. Dimitri made several predictions, which turned out to be correct.
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However, he had to put a few elements out of order. This problem was solved by the discovery of the proton. The modern periodic table is organized by an increasing atomic number. The ion charge is also included.
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WHMIS:
A - COMPRESSED GAS A compressed compressed gas is a material material which is a gas gas at normal normal room temperature temperature ( 20 C ) and pressure but is packaged as a pressured gas, dissolved gas or gas liquified by compression or refrigeration. The hazard from these materials, aside from their chemical nature, arises from sudden loss of integrity of the container. A compressed gas cylinder is usually quite heavy and when ruptured can become a projectile with the potential to cause significant damage. Stop this by protecting the container and maintaining constant pressure (heat). Acetylene Acetylene and oxygen oxygen are examples examples of of compressed compressed gases. gases. B - FLAMMABLE AND COMBUSTIBLE MATERIAL Flammable or combustible materials will ignite and continue to burn if exposed to a flame or source of ignition. Isolate and take safety measures to minimize risk of combustion. Materials are classified as a flammable gas, flammable aerosol, flammable liquid, combustible liquid, flammable solid, or reactive flammable material. Methane, acetone, aniline, and lithium hydride are examples of flammable materials. C - OXIDIZING MATERIAL An oxidizing oxidizing material material may or may not not burn itself, itself, but will will release oxygen oxygen or ananother oxidizing substance, and thereby causes or contributes to the combustion of another material. Wear protective clothing and ensure good ventilation when using these substances. Ozone, chlorine, and nitrogen dioxide are oxidizing materials. These chemicals will support a fire and are highly reactive. POISONOUS AND INFECTIOUS MATERIAL D1- Materials Causing Immediate and Serious Toxic Effects These materials may be classified as toxic or very toxic based on information such as LD50 or LC50. Wear protective clothing and ensure good ventilation when using these substances. Do not ingest or inhale. Examples: Styrene, hydrogen cyanide are very toxic substances.
D2 - Materials Causing Other Toxic Effects A pure substance substance or mixture mixture that that may be any any one of the following: following: a carcinocarcinogen, teratogen, reproductive toxin, respiratory tract sensitizer, irritant or chronic toxic hazard. Wear protective clothing and ensure good ventilation when using these substances. Do not ingest or inhale. inhale . Examples: Asbestos causes cancer, ammonia is an irritant. D3 - Biohazardous Infectious Material This classification includes any organisms and the toxins produced by these organisms that have been shown to cause disease or are believed to cause disease in either humans or animals. For example, a blood sample containing the Hepatitis B virus is a biohazardous infectious material. It may cause hepatitis in persons exposed to it. Isolate & place in specialized container. Special personnel only have only have access to it. E - CORROSIVE MATERIAL Can cause permanent damage to human tissues such as the skin and eyes on contact. Burning, scarring, and blindness may result from skin or eye contact. Corrosive materials may also cause metal containers or structural materials to become weak and eventually to leak or collapse. Wear protective clothing and ensure good ventilation when using these substances. Do not ingest or inhale. inhale . Constantly check the container for signs of structural decay. Ammonia, Ammonia, fluorine, and and hydrochloric hydrochloric acid are examples examples of corrosive substan substances. ces. F - DANGEROUSLY REACTIVE MATERIAL Dangerously reactive materials may undergo vigorous polymerization, decomposition or condensation. They may react violently under conditions of shock or an increase in pressure or temperature. They may also react vigorously with water to release a toxic gas.
It is important to seal them in specialized containers.
WORKPLACE HAZARDOUS MATERIALS INFORMATIONS SYSTEM
Chemical Reactions, Acids and Bases: Property
Acids
Bases
Ion Present in Solution Water soluble
H+ or [H3O]+
OH-
Yes
Yes
Taste
Sour
Bitter
Feel
NA
Slippery
pH range
1- 7
7-14
Electrical conductivity Corrodes metals
Yes
Yes
Yes
No
Examples of Acids: H2SO4, HCl, vinegar, car battery, oranges, citric acid. Examples of Bases: KOH, NH4OH, milk, soap, draino, liquid plumber. Acids contain Hydrogen and a non-metal. Starts Starts with the prefix hydro (hydrofluoric acid) Acids can contain polyatomic ions with some oxygen atoms. Named after the polyatomic ion with oxygen (Sulphuric acid). Acids can end in COOH (carboxylic acid (vinegar). Butanoic acid (C3H7OOH)
CHEMISTRY Naming Ionic Compounds: Name the metal ion first followed by the non-metal ion with the ending “IDE” Examples: KBr becomes Potassium Bromide. ZnF2 becomes Zinc Fluoride CaS becomes Calcium Sulphide MgCl2 becomes Magnesium Chloride Na3P becomes Sodium Phosphide Naming Molecular Compounds: Use prefixes: mono, di, tri, tetra, penta, hexa, hepta, octa, nona and deca Name the first element, name the second element using the “ide” suffix and add prefixes to indicate the number of each atom. Note that the prefix mono is NOT used for the first element. N2O becomes dinitrogen monoxide PBr3 becomes phosphorus tribromide N2S3 becomes dinitrogen trisulphide
Synthesis: A + B = AB Two or more reactants = a single compound, often the reactants are elements. Zn+ I2 = ZnI2 2Mg + O2 =2MgO Decomposition: A compound breaks down into two or more simpler simpler substances XY =X + Y Hydrolysis 2 H 2O = 2 H2 + O2 Single Displacement: The reactants: compound and a metal element OR compound and a non-metal element The products: compound and a metal element OR compound and a non-metal element AX +B = BX + A 2Li +2 H2O = H2 +2LiOH Some metals react with acids to displace d isplace hydrogens Mg + 2HCl = H 2 +MgCl2 Double displacement: Two aqueous ionic compounds = two ionic compounds AB + CD = AD + CB Use solubility rules. Combustion of hydrocarbons: Hydrogen and carbon in a compound that reacts with oxygen COMPLETE combustion occurs under certain conditions with maximum oxygen amount. The only products are CO2 and H2O. For INCOMPLETE combustion, there is less than maximum oxygen. The products are CO 2, H2O, carbon monoxide and solid carbon. Eg. CH4 + 2 O2 = CO2 +2 +2 H2O
Law of Conservation of Mass: Antoine Lavoisier (1743-1794) In a chemical reaction, the total mass of the reactants is always equal to the total mass of the products.
Acid Base Indicators: Litmus Plant extract Can be blue or red Red paper turns blue when dipped in basic solution Blue paper turns red when dipped in acidic solution
pH Paper Imbedded with a universal indicator Compare colours to standard colour chart
Phenolphthalein Organic compound Colourless in acids, pink in bases
pH Scale Is a measure of the acidity of a solution Has a range between 0 and 14 Substances that have a low pH have a high concentration of H +, and substances that have a high pH have a low concentration of H + ions, and therefore have a high concentration of OH - ions. Note that pH can only be determined in aqueous form One unit of change on the pH scale represents a 10 times change in actual acidity Acids have have low pH values values and bases have have high pH values values + pH = -log[H ] for each change in 1 pH unit, there is a ten-fold change in the concentration of H + ions H2O H+ + OH-
pH paper and Universal Indicator Unlike litmus paper, universal indicator is capable of distinguishing between strong and weak acids and bases. Strong acid - red Weak acid – orange/yellow Neutral - green Weak base – turquoise/blue Strong base – deep blue/purple
The Properties of Acids and Bases Concentration Refers to the amount of pure acid/base that is dissolved in pure water
Drain cleaner
Percent Ionization Refers to the number of molecules that will ionize for every 100 molecules that are dissolved in water. o Few acids and bases ionize completely in water Strong acids/bases HCl, H2SO4, NaOH, KOH o Those acids/bases that do not ionize completely in water are called weak acids/bases Acetic acid acid (CH3COOH), Ba(OH) 2 o Although Although two acids may may have the the same concen concentration, tration, their their acidity may vary considerably. This is because the concentration of Hydrogen ions is widely different. Sulphuric acid is far stronger than lemon juice for example. example. AlCl3 + 3Na(OH) = Al(OH) 3 + 3NaCl
Cu(NO3) +KBr = CuBr + K(NO3) Metallic ions possess positive charges, non-metals have negatively charged ions 2Na + Br2 = 2NaBr Mg + F2 = 2MgF 2Al + 3Cl2 = AlCl3 H2(SO4) +2NH4(OH) = 2H20 +(NH4) 2(SO4) Benzene combustion: 2C6H6 + 15O2 = 12CO2 + 6H2O
Determine experiment
Determine Procedure
Make Hypothesi s
PROCEDURE GOES HERE
Analyze data
Is hypothesis proven or are more tests needed?
Draw Conclusion
End of experiment, clean up.
Optics A wave is a disturbanc disturbance e that transfers transfers energy energy from one one point to to another, another, without without matter matter transfer. transfer. The three important properties of a wave are: the wave length, amplitude and frequency. Wavelength is the distance from one wave to another (from crest to crest - the highest point of a wave). The wave length is measured in meters and the symbol is a λ (lambda). A trough is the lowest point of the wave. The amplitude is the wave height from the rest position to the crest or to the trough. The larger the amplitude, the more energy is being transferred. The Frequency is the rate of repetition of a wave. Frequency is usually measured in hertz (Hz) which is cycles per second. The symbol is f. The frequency affects what colour of light we see (red, orange, yellow, green, blue and violet). The speed is represented by a v. Therefore, we get that v = f x λ The additive colour theory states that white light is composed of different colours (wavelengths) of light, such as red green and blue (primary colours). Red and blue = magenta Green and Red = yellow Green and blue = cyan The subtractive colour theory states that coloured matter selectively absorbs different colours and that the absorbed colours are “subtracted” from the reflected light that is seen by the eye. A black object absorbs all and a white object reflects all, a blue object reflects blue and absorbs all other colours. The primary colours are (cyan, magenta and yellow) The Electromagnetic Spectrum
Radio waves: Longest wave frequency and lowest frequency. Used for communications mainly (radio stations, television, mines, MRI scans, etc.) Microwaves: Have shorter wavelengths than radio so they have higher frequencies and carry more energy. Microwaves work by eradiating the food with microwaves causing the water molecules to vibrate and heat up. Also used in radar technology as it is not affected by weather or lighting (day/night). (day/night). Infrared waves: We experience infrared as heat although we cannot see it. Burglar alarms and night vision goggles. • •
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VISIBLE LIGHT Ultraviolet Rays: Main source of ultraviolet radiation is the Sun and other stars. A small amount is good for our health. health. In excess can burn your skin or lead to skin cancer. UV radiation is used to disinfect water or in DNA & forensic analysis. X-Rays: Is very high radiation that can be highly dangerous. Used for medical diagnosis or airport security. • •
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Gamma Rays: An extremely high energy radiation that can penetrate penetrate human tissue as well. Used to sterilize medical equipment, treatment o f cancer. Produced mainly by black holes and neutron stars. • • •
Methods to Produce Light: Bioluminescence: The ability of plants/animals/insects to create visible light 90% of all sea creatures are bioluminescent such as the black sea dragon or angler fish Is an internal chemical reaction or use bioluminescent bacteria instead Incandescent: Light that is produced by an object (such as a metal filament) that is heated until it emits light. In an incandescent bulb, electric current flows through the filament, heating it up. Very inefficient, only 5% of electrical energy is converted into light. Fluorescent: Light that is produced when a suitable substance is exposed to electromagnetic radiation. Fluorescent light tubes are filled by gases such as mercury and the inside of the bulb is coated with phosphor, a white powder. Phosphor is a substance that glows after exposure to energized particles. When electric current passes through the tube, the gases emit UV radiation which hits the phosphor and causes it to glow. Phosphorescent Light: The ability to store energy from a source of light and slowly emit it (i.e. glow in the dark) It will eventually fade, but can be quickly recharged when held close to a light source for a few minutes. Chemiluminescence: A light produced by a chemical reaction. reaction. Very efficient as there is very little loss in heat Triboluminescence: Through friction - some crystals can glow if they are rubbed together. Can be created by breaking sugar crystals (Wint-o-green lifesavers) or rubbing a diamond Electric discharge: Electric current passes through air or a gas (like neon), such as lightning • •
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Mirrors and Ray Reflection: Diffuse reflection is when light hits and irregular surface and the light rays are scattered. Thus you can see the object from any angle.
The Law of Reflection: Angle of Incidence = Angle of Reflection The normal is the imaginary line perpendicular to the mirror at the point of reflection.
Image formed
Curved Mirrors: •
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When parallel rays hit a curved surface (concave), all the rays converge in the focal point. The middle point of a curved mirror is a vertex and the principal axis is the line drawn to it, through the focal.
Ray diagrams for Concave Mirrors: The first ray travels parallel to the principal axis from the object. It will then reflect through the focal point of the converging mirror. The second ray will travel through the focal point and reflect parallel. The third ray goes through the center of center of the arc. The point of intersection of these three rays is the place where the image is formed. formed. Magnification h image _ height M = i OR M = ho object _ height
M = −
d i d o OR Image Distance/ Object Distance. The negative sign indicates that it is inverted.
Case 1: The object is located beyond beyond C C The image will always be located between the center of curvature and the focal point. The image will be an inverted image, diminished and real. real. Case 2: the object is located at C The image will also be located at the center of curvature. curvature. The image will be inverted, same size and real .
Case 3: The object is located between C and F The image will be located beyond the beyond the center of curvature. curvature. The image will be inverted, magnified and real. Case 4: The object is located at F NO IMAGE IS FORMED. FORMED. As discussed earlier in Lesson 3, 3, light rays Case 5: The object is located in front of F of F Virtual image, behind mirror, will be upright and magnified magnified;;
SNELL’S LAW: n1 sin θ 1 = n2 sin θ 2 N1 is the index of refraction for the first medium N2 is the index of the refraction for the second medium When the second medium is more optically dense, the light ray will bend towards the normal. When the first medium is more optically dense, the light will bend away from the normal. THEREFORE as the angle of incidence increases when the first medium is MORE optically dense than the second medium, then the angle of refraction will increase to the point where it would pass 90 degrees. d egrees. At that point, the light will start reflecting instead of refracting. This point where the angle of refraction is 90 degrees is where the angle of incidence is the critical angle.
Thin Lens Equation
Convex: The diagrams above show that in each case, the image is: For TWO FOCAL LENGTHS AWAY Diminished, Inverted & Real BETWEEN ONE & TWO FOCAL LENGTH: Magnified, inverted, real LESS THAN ONE FOCAL LENGTH AWAY: Magnified, upright and VIRTUAL
CLIMATE CHANGE: 1. What What happens happens when when solar solar radia radiation tion hits hits the the earth? earth? The sun emits radiation which reaches Earth. Upon entering our atmosphere, 31% is directly reflected back (part by clouds and aerosol and part by the reflective surface of the earth (albedo effect). Part is then absorbed by the surface which emits it as radiation (infrared or heat). Of the surface radiation, only 12% penetrates the atmosphere. The large majority is reflected back (by greenhouse gases) as back radiation. In fact, it is important that only a specific amount of radiation penetrates the atmosphere as that supports life at a comfortable temperature. 2. What would would happen happen to the earth’s earth’s average average temperature temperature without without the natural natural greengreenhouse effect? Without the natural greenhouse effect, Earth would have a much colder temperature as there is nothing to capture the thermal energy around Earth. This would also mean that there would be no life or small bacterial life forms as few things could survive the cold. Our world would be covered with ice instead of having this warm climate.
The Albedo Effect: The percent of incoming solar radiation that the surface reflects • Typically on a scale of 1 – 0 • • For example, snow/ice has a high albedo – reflects 90% of the sunlight • Soil/water –absorbs 90% and has a very low albedo. • Albedo changes changes with seasons seasons and affects affects the radiation radiation budget. budget.
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The above diagram shows the energy coming into our atmosphere and leaving it, such that energy in = energy out (without human involvement) We first get solar radiation (324 W m-2), 33% of which is reflected back by the surface (9%) and clouds (23%) and an additional 20% is absorbed by the atmosphere.
GHG (name) Water
Chemical formula H2O
Carbon dioxide Methane Nitrous oxide (Dinitrogen monoxide)
CO2 CH4 N2O
100-year Global Warming Potential Not calculated because its GWP depends on temperature and there is no way to directly influence % water vapour concentration (could be dangerous to life on earth to try) 1 21 310
Atmospheric Atmospheric lifetime (years) Variable?
Variable 12 120
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The remaining 50% is absorbed by the surface. There is also surface radiation (120%) and thermal/evapo-transpiration (31%) Only 12% of surface radiation makes it through immediately. The surface radiation is over 100% because of back radiation (324 W m-2). Back radiation is radiation reflected back from our atmosphere at Earth and re-absorbed by the surface.
Radiation Budget: • Net radiation budget = incoming radiation – outgoing radiation = ZERO • This is the balance for a stable climate • However, by adding greenhouse gas emissions, we create a change such that the temperature goes up • Latitude also affects radiation budgets- the Polar Regions tend to have less incoming radiation than outgoing and the tropics are the opposite. Modes of Thermal Energy Transfer: Radiation – emission of energy as waves • • Absorbed Absorbed energy increases increases the movement movement of particles particles – increase increase of kinetic kinetic energy – inincrease of temperature. Conduction – transfer of thermal energy through direct contact between the particles of • a substance (requires a solid medium). • Particles with more kinetic energy transfer some of their energy to neighbouring particles. Higher kinetic energy = higher temperature. Convection – transfer of thermal energy through the movement of particles, requiring a • fluid. Example: water in pot over a heater. The water heats and the volume increases, leading • to low density water which rises. It then cools upon contact with the surface and begins to move downwards again, creating cyclic convection currents. • •
Weather refers specifically to the environmental conditions at a specific time and place Climate is global (larger region) and is the average over a long period of time (around 30 years),
Feedback: • Positive feedback means that the output is put back into the input so as to increase output – unsustainable and generally bad. • Negative feedback means that the output is put back into the input, blocking the output – good and more sustainable • Positive and Negative feedbacks balance out Examples of Positive of Positive feedback are: population growth (more people can reproduce • more, while more people = more scientists = more innovations = longer life span – But It Cannot Be Sustained Due To Limited Resources!!!) Positive feedback: feedback : investing: investing : invest money, make profit, reinvest and make profit, • cont. Unsustainable, leads to an economic bubble. Also, the Ponzi scheme: scheme : promise a better profit than simply investing and pay the customers back with the new line of investors and continuing on. Trees dying due to a change in climate, so less CO2 is absorbed, so more trees die, • cont...
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Positive Feedback in Climate : Arctic Methane release, Ice albedo (ice melts, even lower albedo, so more ice melts, cont.), CO2 in the oceans (cooler water can absorb more CO2 than warmer water) Negative Feedback examples : a thermostat. thermostat . When the temperature reaches a certain upper limit the heating is switched off, temp falls. When temp drops to a lower limit, the heating is switched on. Similar control mechanisms are used in cooling systems, such as an air conditioner, a refrigerator, or a freezer. 16th century with invention of the centrifugal governor (used governor (used later in the steam engine). Two heavy rotate at the same speed as the engine. As their speed increases, they swing up and outwards due to the centrifugal force. This causes them to lift a mechanism which closes the steam inlet valve and the engine slows. When the speed of the engine falls too far, the balls will fall by gravity and open the steam valve. Negative feedback CLIMATE: CLIMATE : As the temp goes up, water evaporation goes up, means more low clouds, means higher albedo = temp down = less evaporation = less clouds = lower albedo!!!
Climate Oscillations: • ENSO is a climate pattern that occurs every 3-8 years across the Pacific Ocean. • Southern oscillation refers to the variations in temperature (warming is typically El Nino and cooling is La Nina, however, it is opposite for certain locations) • Toronto would be colder during El Niño and warmer during La Niña. • Rise in surface pressure over the Indian Ocean, Indonesia, and Australia • Fall in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean • Trade winds in the south Pacific weaken or head east • Warm air rises near Peru, causing rain in the northern Peruvian deserts • Warm water spreads from the west Pacific and the Indian Ocean to the east Pacific. It takes the rain with it, causing extensive drought in the western Pacific and rainfall in the normally dry eastern Pacific. • Can affect fishing markets as El Niño brings in warm, nutrient – poor water with few fish instead of the deep, cold mineral rich water.
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Rainfall shifts from the western Pacific toward the Americas, while Indonesia and India
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become drier ENSO is affected by the Pacific Ocean (heat reservoir) and would greatly affect global wind patterns. Winters during El Niño are drier and warmer in Northern US, while Mexico is much wetter. El Niño warmed Vancouver for the 2010 Winter Olympics, such that the area experienced a subtropical-like winter during the games. The North Atlantic Oscillation (NAO) is a major mode of atmospheric variability in the Northern Hemisphere, particularly in winter. The NAO index is calculated based on the difference between the normalized sea level pressures over Gibraltar (or Portugal, or the Azores) (subtropica (subtropicall high) and Southwest Southwest Iceland Iceland (polar (polar low). Positive NAO Index Negative NAO Index More and stronger winter storms crossFewer and weaker winter storms crossing on ing the Atlantic Ocean on a more a more west-east pathway northerly track Warm and wet winters in Europe Moist air into the Mediterranean and cold air to northern Europe Cold and dry winters in northern Canada Milder winter temperatures in Greenland and Greenland US east coast experiences mild and wet US east coast experiences more cold air outwinter conditions breaks and hence snowy weather conditions The following figure shows the winter NAO since 1823 based on Gibraltar. Displaces the Jet Stream through pressure variations.
Thermohaline Currents – the Global Conveyor belt • Water towards the poles is more dense due to the colder temperature • Salinity also affects makes water more dense • This denser water sinks, forming currents • Transports heat and nutrients/gas • It will “overturn” “overturn” with different different pressure and water masses • Causes upwelling (this leads to huge increase in fishing)
When the polar vortex weakens, the polar jet stream slows and meanders in a form that allows the extension of low pressure lobes much farther to the south. These can become stationary for days and block the normal circulation of the atmosphere. The negative AO/NAO is associate associated d with a slowed polar vortex and polar jet stream. When the jet stream slows, it meanders in a waveform pattern (Rossby waves). •
Galilean telescope: Two convex lenses Magnification of up to four times Keplerian telescope: Diverging and Converging Middle magnification Give chromatic aberration: When you make a larger lens and eventually, it becomes thick enough Newtonian telescope: Big concave mirror and secondary plane mirror
CONVERGING LENSES (teardrop) AND MIRRORS (concave): Object is at infinity Position at F Real, Inverted and diminished Object beyond 2F: Position between F & 2F Real, Inverted and diminished Object Between f and 2f Position is beyond 2F Real, Inverted and magnified Object at 2f: Position at 2F Real, Inverted and same size. Object at F: No image formed! Object between F and mirror: Virtual, Erect and magnified Behind the object DIVERGING LENSES AND MIRROR: Virtual, erect and diminished. Between F and lens/mirror BENDS TOWARDS THE NORMAL: from less to denser d enser medium Bends away from the normal: denser to less dense medium
