Sugars ○ Monosaccharides vs polysaccharides ○ Glycosidic bond – Stru Struct ctur ure e – Condensati Condensation/hy on/hydroly drolysis sis ○ Disaccharide formation Glucose ○ Alpha- and beta-Glucose Starch ○ Amylose and amylopectin ○ Long chain a-Glucose polymers ○ Stored in chloroplasts Glycogen ○ Multibranched a-Glucose polymer ○ Stored in muscles and liver ○ Hydrolysed to glucose as energy substrate Cellulose ○ Unbranched B-glucose polymer ○ Contributes to cell wall strength
•
•
•
• • •
•
•
TOPIC 2 Lipids •
•
Triglycerides ○ 1 glycerol + 3 FA ○ Ester bond ○ Can be saturated or unsaturated ○ Fats are solid at room temp, oils are liquid Phospholipids ○ Like triglyceride, but one FA replaced with phosphoric acid group ○ Polar head, hydrophobic tails ○ Main component of plasma membranes
•
•
•
20 dierent R groups = 20 dierent amino acids Dipeptide vs polypeptide Peptide bonds ○ Formed in condensation reactions Primary structure ○ Amino acid sequence ○ Unique to gene Secondary structure ○ B-pleated sheet or a-helix ○ Interactions of amino acid in same polypeptide ○ Result of hydrogen bonds Tertiary structure ○ Further coils/folds ○ Interactions between R groups Quaternary structure ○ Two or more polypeptides ○ E.g. Haemoglobin, collagen ○ Fibrous or globular
•
•
•
•
TOPIC 4
○ Double-stranded Complementary base pairing ○ A-T; C-G ○ Hydrogen bonds ○ 2 strands in double helix Transfer RNA (tRNA) ○ Transports amino acids to ribosome ○ Codon vs anticodon Transcription = copying RNA from DNA ○ RNA synthase forms mRNA Translation = form polypeptides based on mRNA ○ Ribosomes on rough ER ○ Active process involving tRNA ○ Stop codon Genetic code ○ 1 triplet = 1 amino acid ○ Degenerate ○ No triplet overlaps Types of gene mutations ○ Substitution – Nucleo Nucleotid tide e replaced replaced ○ Insertion – Causes Causes frames frameshif hiftt ○ Deletion – Causes Causes frames frameshif hiftt Consequences of gene mutations ○ Neutral ○ Harmful ○ Beneficial Point mutation ○ Only one base is affected ○ Silent vs missense vs nonsense mutations ○ E.g. Sickle cell anaemia
DNA and protein synthesis
TOPIC 5
G, T, C, A, (U) ○ Purines vs pyramidines
Enzymes
•
•
Enzymes = globular proteins
AS-LEVEL BIOLOGY MODULE 1: Biological Molecules
•
•
• •
Induced fit hypothesis ○ Enzymes are specific to substrate ○ Enzyme-substrate complex formation ○ Lowers activation energy ○ Enzyme-product complex unbinds Enzyme activity affected by ○ pH different from optimal pH ○ Temp different from optimal temperature ○ Enzymes become denatured ○ Enzyme concentration ○ Substrate concentration – Reaction rate reaches Vmax – Active sites can become saturated Competitive vs non-competitive inhibitors Reversible vs irreversible inhibitors
TOPIC 6 INORGANIC IONS • • • •
Nitrate ions for DNA/amino acids Calcium ions for calcium pectate Magnesium ions for chlorophyll Phosphate ions for ATP/ADP
TOPIC 7 WATER • • •
Water molecules are polar Water involves covalent and hydrogen bonds Properties of water ○ Polar solvent ○ High specific heat capacity ○ Cohesion ○ Incompressibility/density at 4 degrees
This summary is intentionally blurred, to view the full document buy now!
BUY NOW
This summary is intentionally blurred, to view the full document buy now!
BUY NOW
This summary is intentionally blurred, to view the full document buy now!
BUY NOW
This summary is intentionally blurred, to view the full document buy now!
BUY NOW
This summary is intentionally blurred, to view the full document buy now!
BUY NOW
This summary is intentionally blurred, to view the full document buy now!
