Part B: Short Answer, Matching, Diagrams (choice, 40 marks)
Part C: Extended Answer (choice, 10 marks)
Biochemistry
Chemical principles are important for understanding biological molecules and reactions.
Organic Compounds:
Hydrocarbons: The basic framework for organic molecules. Understand their structure and properties.
Functional Groups: Specific groups of atoms attached to hydrocarbon backbones that determine chemical properties (e.g., hydroxyl, carboxyl, amino groups).
Linkages: How monomers connect to form polymers (e.g., peptide bonds in proteins, glycosidic linkages in carbohydrates, ester linkages in lipids).
Lipids:
Triglycerides: Fats and oils composed of glycerol and three fatty acids. Know their structure and function as energy storage molecules.
Phospholipids: Major components of cell membranes, consisting of a glycerol, two fatty acids, and a phosphate group. Understand their amphipathic nature.
Sterols: Lipids with a characteristic four-ring structure, such as cholesterol. Know their role in membrane structure and as precursors to steroid hormones.
Carbohydrates:
Monosaccharides: Simple sugars like glucose and fructose. Know their structures and roles as energy sources.
Disaccharides: Two monosaccharides joined by a glycosidic linkage (e.g., sucrose, lactose).
Polysaccharides: Polymers of monosaccharides, such as starch, glycogen, and cellulose. Understand their functions in energy storage and structural support.
Proteins:
Amino Acids: The building blocks of proteins, each with a unique R-group. Know the basic structure of an amino acid and the different types of R-groups.
Structure: Primary (amino acid sequence), secondary (alpha-helices and beta-sheets), tertiary (3D structure), and quaternary (multiple polypeptide chains). Understand the forces that maintain protein structure (e.g., hydrogen bonds, hydrophobic interactions).
Enzymes: Biological catalysts that speed up chemical reactions by lowering activation energy. Understand enzyme kinetics, active sites, and factors affecting enzyme activity (e.g., temperature, pH, inhibitors).
Cellular Respiration
Mitochondria: The site of aerobic respiration in eukaryotic cells. Understand its structure (inner and outer membranes, cristae, matrix).
ATP, NAD+, FAD+: Key molecules in energy transfer.
ATP (adenosine triphosphate): The primary energy currency of the cell.
NAD+ and FAD+: Coenzymes that act as electron carriers in redox reactions.
Glycolysis: The breakdown of glucose into pyruvate in the cytoplasm. Know the inputs, outputs, and energy yield (ATP and NADH).
Kreb’s Cycle (Citric Acid Cycle): A series of reactions in the mitochondrial matrix that oxidizes acetyl-CoA, producing ATP, NADH, and FADH2. Understand its role in energy production and carbon metabolism.
Electron Transport Chain (ETC): A series of protein complexes in the inner mitochondrial membrane that use electrons from NADH and FADH2 to pump protons across the membrane, creating an electrochemical gradient.
Fermentation: Anaerobic pathways that regenerate NAD+ from NADH, allowing glycolysis to continue in the absence of oxygen (e.g., lactic acid fermentation, alcohol fermentation).
Fat/Protein Oxidation: The breakdown of fats and proteins to enter cellular respiration. Understand how fatty acids are converted to acetyl-CoA and how amino acids are deaminated and enter the Krebs cycle.
Chemiosmotic Model: The mechanism by which the proton gradient generated by the ETC is used to drive ATP synthesis by ATP synthase.
Control of Respiration: Regulation of cellular respiration based on energy needs and availability of substrates. Understand feedback mechanisms and the role of allosteric enzymes.
Photosynthesis
Chloroplasts, Plant Pigments:
Chloroplasts: The site of photosynthesis in plant cells. Understand their structure (thylakoids, grana, stroma).
Plant Pigments: Molecules that absorb light energy, such as chlorophylls and carotenoids. Know their absorption spectra and roles in capturing light energy.
Light-Dependent Reactions:
Chlorophyll, Light, Water: Reactants required for the light-dependent reactions.
Cyclic vs. Noncyclic Photophosphorylation: Two pathways of electron flow in the thylakoid membrane that generate ATP and NADPH.
Light-Independent Reactions (Calvin Cycle):
CO2: The carbon source for glucose synthesis.
Fate of Glucose: How glucose produced during photosynthesis is used by the plant (e.g., energy, storage, building materials).
Leaf, Root Structure: Adaptations of leaves and roots for photosynthesis and nutrient uptake.
Photorespiration: A process that occurs when rubisco binds to oxygen instead of carbon dioxide, reducing the efficiency of photosynthesis.
Homeostasis
Membranes: Selective barriers that regulate the movement of substances into and out of cells and organelles. Understand membrane structure (phospholipid bilayer, proteins) and transport mechanisms (e.g., diffusion, osmosis, active transport).
Stimulus/Response Pathway: The sequence of events that allows an organism to detect and respond to changes in its environment.
Kidney:
Gross Anatomy: The overall structure of the kidney, including the cortex, medulla, and renal pelvis.
Nephron: The functional unit of the kidney responsible for filtering blood and producing urine. Understand the structure (glomerulus, Bowman's capsule, tubules) and function (filtration, reabsorption, secretion) of the nephron.
Nervous System:
Neuron: The basic unit of the nervous system, responsible for transmitting nerve impulses. Understand the structure of a neuron (cell body, dendrites, axon) and the types of neurons (sensory, motor, interneurons).
CNS (Brain, Spinal Cord): The central processing center of the nervous system.
PNS (Sensory, Somatic, Autonomic [Para/Sympathetic]): The network of nerves that connect the CNS to the rest of the body.
Nerve Impulse Transmission: The process by which nerve impulses are transmitted along neurons and across synapses.
Neurotransmitters: Chemical messengers that transmit signals across synapses.
Endocrine System:
Glands and Hormones: Glands that secrete hormones into the bloodstream.
Endocrine
Pituitary gland: A master gland that controls many other endocrine glands.
Pancreas: Produces insulin and glucagon, which regulate blood sugar levels.
Thyroid & Parathyroid: Regulate metabolism and calcium levels, respectively.
Adrenal & Pineal glands: Produce hormones involved in stress response, sleep cycles, and other functions.
Reproductive Hormones & Cycles: Hormones involved in reproduction and the menstrual cycle.
Genetics
Nucleic Acids:
Bases: Adenine (A), guanine (G), cytosine (C), and thymine (T) in DNA; uracil (U) replaces thymine in RNA.
Base Pairing: A pairs with T (or U in RNA), and C pairs with G.
DNA/RNA: DNA (deoxyribonucleic acid) stores genetic information; RNA (ribonucleic acid) plays various roles in gene expression.
DNA Replication:
Reasons: To produce identical copies of DNA for cell division.
Enzymes: Helicase (unwinds DNA), DNA polymerase (synthesizes new DNA strands), ligase (joins DNA fragments).
Leading/Lagging Strands: The leading strand is synthesized continuously, while the lagging strand is synthesized in fragments (Okazaki fragments).
Protein Synthesis:
Transcription (Modifications): The process of copying DNA into RNA. Includes pre-mRNA splicing, capping, and tailing.
Ribosomes: The site of protein synthesis.
tRNA, mRNA: Transfer RNA (tRNA) carries amino acids to the ribosome; messenger RNA (mRNA) carries the genetic code from DNA to the ribosome.
Translation (Initiation, Elongation, Termination, Modification): The process of converting mRNA into a protein. Includes initiation (start codon), elongation (amino acid addition), termination (stop codon), and post-translational modification.
Regulation of Gene Expression: Mechanisms that control which genes are expressed and at what level.
Mutations: Changes in the DNA sequence that can lead to altered protein function.
Applications:
DNA Recombination: The process of combining DNA from different sources.
Reverse Transcriptase: Enzyme that synthesizes DNA from an RNA template.
Biotechnology: The use of biological systems to develop new technologies and products.