Lessons

The Microscope in Cell Studies

know the ultrastructure of prokaryotic cells: cell wall, capsule, plasmid, flagellum, pili, ribosomes, circular DNA, and the function of each · know how magnification and resolution can be achieved using light and electron microscopy; understand the importance of staining specimens · CORE PRACTICAL 5: use a light microscope to make observations and labelled drawings of suitable animal cells; use a graticule to make measurements and understand scale

Eukaryotic Cell Structure: Animal Cell Ultrastructure

know the ultrastructure of eukaryotic cells: nucleus, nucleolus, ribosomes, rough and smooth ER, mitochondria, centrioles, lysosomes, Golgi apparatus · understand the function of each organelle listed above · understand the role of the rough ER and Golgi apparatus in protein transport, including formation of extracellular enzymes · recognise these organelles in electron microscope (EM) images

Plant Cell Ultrastructure and Comparing Plant & Animal Cells

know the structure and ultrastructure of plant cells including cell wall, chloroplast, amyloplast, vacuole, tonoplast, plasmodesmata, pits and middle lamella; compare with animal cells · understand the function of each plant-cell structure listed above · recognise plant organelles in electron microscope (EM) images

Prokaryotic Cells and Viruses

know the ultrastructure of prokaryotic cells: cell wall, capsule, plasmid, flagellum, pili, ribosomes, circular DNA, and the function of each · know how magnification and resolution can be achieved using light and electron microscopy; understand the importance of staining specimens · CORE PRACTICAL 5: use a light microscope to make observations and labelled drawings of suitable animal cells; use a graticule to make measurements and understand scale

Biochemical Tests for Biological Molecules

understand the importance of water as a solvent in transport, including its dipole nature · know the differences between monosaccharides, disaccharides and polysaccharides (glycogen, amylose, amylopectin); relate structures to roles in energy supply and storage (β-glucose and cellulose not required in this topic) · know how monosaccharides (glucose, fructose, galactose) join to form disaccharides (maltose, sucrose, lactose) and polysaccharides via condensation/glycosidic bonds, and how these split via hydrolysis · know how triglycerides are synthesised by ester bonds between glycerol and three fatty acids; saturated vs unsaturated lipids · CORE PRACTICAL 1: semi-quantitative Benedict's test for reducing sugars and iodine test for starch using colour standards

Carbohydrates

understand the importance of water as a solvent in transport, including its dipole nature · know the differences between monosaccharides, disaccharides and polysaccharides (glycogen, amylose, amylopectin); relate structures to roles in energy supply and storage (β-glucose and cellulose not required in this topic) · know how monosaccharides (glucose, fructose, galactose) join to form disaccharides (maltose, sucrose, lactose) and polysaccharides via condensation/glycosidic bonds, and how these split via hydrolysis · know how triglycerides are synthesised by ester bonds between glycerol and three fatty acids; saturated vs unsaturated lipids · CORE PRACTICAL 1: semi-quantitative Benedict's test for reducing sugars and iodine test for starch using colour standards

Lipids and Water

understand the importance of water as a solvent in transport, including its dipole nature · know the differences between monosaccharides, disaccharides and polysaccharides (glycogen, amylose, amylopectin); relate structures to roles in energy supply and storage (β-glucose and cellulose not required in this topic) · know how monosaccharides (glucose, fructose, galactose) join to form disaccharides (maltose, sucrose, lactose) and polysaccharides via condensation/glycosidic bonds, and how these split via hydrolysis · know how triglycerides are synthesised by ester bonds between glycerol and three fatty acids; saturated vs unsaturated lipids · CORE PRACTICAL 1: semi-quantitative Benedict's test for reducing sugars and iodine test for starch using colour standards

Proteins

know the basic structure of an amino acid (structures of specific amino acids are not required) · understand how polypeptides and proteins form via condensation/peptide bonds · understand how primary structure determines secondary and tertiary structure; differences between globular and fibrous proteins and the bonds involved · know the molecular structure of a globular and a fibrous protein (haemoglobin, collagen) and how their structures relate to their functions

Mode of Action of Enzymes

understand enzyme action and specificity in terms of three-dimensional structure · understand that enzymes are biological catalysts that lower activation energy · know that intracellular enzymes catalyse reactions inside cells and extracellular enzymes catalyse reactions outside cells · CORE PRACTICAL 4: investigate the effects of temperature, pH, enzyme concentration and substrate concentration on the initial rate of enzyme-catalysed reactions

Factors Affecting the Rate of Enzyme Action

understand enzyme action and specificity in terms of three-dimensional structure · understand that enzymes are biological catalysts that lower activation energy · know that intracellular enzymes catalyse reactions inside cells and extracellular enzymes catalyse reactions outside cells · CORE PRACTICAL 4: investigate the effects of temperature, pH, enzyme concentration and substrate concentration on the initial rate of enzyme-catalysed reactions

Enzyme Kinetics, Inhibitors and Immobilised Enzymes

explain that the maximum rate of reaction (Vmax) is used to derive the Michaelis-Menten constant (Km), and that Km is used to compare the affinity of different enzymes for their substrates (3.2.2) · explain the effects of reversible inhibitors, both competitive and non-competitive, on enzyme activity, including their effects on Vmax and Km (3.2.3) · investigate the difference in activity between an enzyme immobilised in alginate and the same enzyme free in solution, and state the advantages of using immobilised enzymes (3.2.4)

Fluid Mosaic Membranes and Cell Signalling

know the structure and properties of cell membranes · understand how models such as the fluid mosaic model are interpretations of data on membrane structure and properties · CORE PRACTICAL 3: investigate membrane properties including the effects of alcohol and temperature on membrane permeability · understand osmosis in terms of free water movement through a partially permeable membrane down a water potential gradient · understand passive transport (diffusion, facilitated diffusion), active transport (ATP-driven, including endocytosis and exocytosis), and the roles of carrier and channel proteins

Movement Into and Out of Cells

know the structure and properties of cell membranes · understand how models such as the fluid mosaic model are interpretations of data on membrane structure and properties · CORE PRACTICAL 3: investigate membrane properties including the effects of alcohol and temperature on membrane permeability · understand osmosis in terms of free water movement through a partially permeable membrane down a water potential gradient · understand passive transport (diffusion, facilitated diffusion), active transport (ATP-driven, including endocytosis and exocytosis), and the roles of carrier and channel proteins

Chromosomes, the Cell Cycle and Mitosis

understand the role of mitosis and the cell cycle in producing genetically identical daughter cells for growth and asexual reproduction · CORE PRACTICAL 6: prepare and stain a root tip squash to observe the stages of mitosis · calculate mitotic indices

Stem Cells, Cell Replacement and Cancer

understand the terms stem cell, pluripotent, totipotent, morula and blastocyst; discuss societal uses of stem-cell knowledge in medical therapies · understand how cells become specialised through differential gene expression, producing active mRNA that drives synthesis of proteins controlling cell processes or structure · understand how one gene can give rise to more than one protein via post-transcriptional changes to mRNA

Structure of nucleic acids and replication of DNA

know the basic structure of mononucleotides (deoxyribose or ribose + phosphate + base: thymine, uracil, adenine, cytosine or guanine) and the structure of DNA and RNA (polynucleotides linked by phosphodiester bonds) · know how complementary base pairing and hydrogen bonding form the DNA double helix · understand DNA replication and the role of DNA polymerase · understand how Meselson and Stahl's classic experiment supported the accepted theory of DNA replication · understand the nature of the genetic code (triplet, non-overlapping, degenerate); know that a gene is a base sequence on DNA coding for a polypeptide

Protein synthesis

understand protein synthesis (transcription and translation); roles of RNA polymerase, mRNA, tRNA, ribosomes, start and stop codons; the antisense template strand, codons on mRNA, anticodons on tRNA · understand how errors in DNA replication can give rise to mutations (substitution, insertion, deletion) · know that some mutations cause cancer or genetic disorders, but many have no observable effect

Structure of plant transport tissues (xylem, phloem and companion cells)

understand the structure and function of starch and cellulose, including the role of hydrogen bonds between β-glucose molecules in cellulose microfibrils · understand how the arrangement of cellulose microfibrils and secondary thickening in plant cell walls contributes to the physical properties of xylem vessels and sclerenchyma fibres · know the similarities and differences between sclerenchyma fibres (support), xylem vessels (support and water/mineral transport) and phloem (translocation of organic solutes), and their positions in the stem · CORE PRACTICAL 7: use a light microscope to make labelled plan diagrams of transverse sections of roots, stems and leaves; identify sclerenchyma fibres, phloem, sieve tubes and xylem vessels

Water uptake, transport and transpiration in plants

state that some mineral ions and organic compounds can be transported within plants dissolved in water (7.2.1) · describe the transport of water from soil to xylem through the apoplast pathway, including the role of lignin and cellulose in cell walls (7.2.2) · describe the transport of water from soil to xylem through the symplast pathway, including the role of the endodermis, the Casparian strip and suberin in directing water into the symplast (7.2.2) · explain that transpiration involves evaporation of water from the internal (mesophyll) surfaces of leaves followed by diffusion of water vapour through stomata to the atmosphere (7.2.3) · explain how hydrogen bonding of water molecules gives cohesion (transpiration pull / cohesion-tension theory) and adhesion to cellulose in xylem cell walls, moving water up the xylem (7.2.4) · make annotated drawings of transverse sections of xerophytic leaves to explain how adaptations (e.g. sunken stomata, rolled leaves, thick waxy cuticle, hairs/trichomes, reduced leaf area) reduce water loss by transpiration (7.2.5)

Translocation: phloem transport from source to sink by mass flow

state that assimilates dissolved in water, such as sucrose and amino acids, move from sources to sinks in phloem sieve tubes (7.2.6) · explain how companion cells actively load assimilates into phloem sieve tubes, with reference to proton (H+) pumps establishing a hydrogen-ion gradient and sucrose-H+ cotransporter proteins (7.2.7) · explain mass flow in phloem sieve tubes down a hydrostatic (turgor) pressure gradient from source to sink, including water entering the sieve tube by osmosis at the source (lowering water potential) and leaving at the sink (7.2.8)

The circulatory system and blood vessels

understand why many animals need a heart and circulation (mass transport overcoming diffusion limits) · understand how the structures of capillaries, arteries and veins relate to their functions · know the cardiac cycle (atrial systole, ventricular systole, cardiac diastole) and the structure/operation of the mammalian heart, including major blood vessels (myogenic detail not required at IAS)

Blood, water and tissue fluid

8.1.5: recognise and draw red blood cells, monocytes, neutrophils and lymphocytes from microscope slides, photomicrographs and electron micrographs · 8.1.6: state that water is the main component of blood and tissue fluid, and relate the properties of water (solvent action and high specific heat capacity) to its role in transport in mammals · 8.1.7: state the functions of tissue fluid and describe the formation of tissue fluid in a capillary network (high hydrostatic pressure at the arterial end forcing fluid out, return at the venous end driven by solute/oncotic potential)

Transport of oxygen and carbon dioxide

understand the role of haemoglobin in transporting oxygen and carbon dioxide · understand the oxygen dissociation curve, the Bohr effect, and the significance of the higher oxygen affinity of fetal haemoglobin compared with adult haemoglobin

The heart and the cardiac cycle

understand why many animals need a heart and circulation (mass transport overcoming diffusion limits) · understand how the structures of capillaries, arteries and veins relate to their functions · know the cardiac cycle (atrial systole, ventricular systole, cardiac diastole) and the structure/operation of the mammalian heart, including major blood vessels (myogenic detail not required at IAS)

Structure of the Human Gas Exchange System

describe the structure of the human gas exchange system, limited to lungs, trachea, bronchi, bronchioles, alveoli and the capillary network (outcome 1) · describe the distribution in the gas exchange system of cartilage, ciliated epithelium, goblet cells, squamous epithelium of alveoli, smooth muscle and capillaries (outcome 2) · recognise cartilage, ciliated epithelium, goblet cells, squamous epithelium of alveoli, smooth muscle and capillaries in microscope slides, photomicrographs and electron micrographs (outcome 3) · recognise trachea, bronchi, bronchioles and alveoli in microscope slides, photomicrographs and electron micrographs, and make plan (tissue-map) diagrams of transverse sections of the walls of the trachea and bronchus (outcome 4)

Functions of Tissues in the Gas Exchange System

describe the functions of ciliated epithelial cells, goblet cells and mucous glands in maintaining the health of the gas exchange system (mucus trapping pathogens/particles, cilia sweeping the mucus escalator toward the throat) (outcome 5) · describe the functions in the gas exchange system of cartilage (holding airways open / preventing collapse while allowing flexibility), smooth muscle (controlling airway diameter), elastic fibres (recoil during expiration and stretch on inspiration) and squamous epithelium (thin surface for short diffusion distance) (outcome 6)

Gas Exchange at the Alveoli

know the properties of gas exchange surfaces (large surface area to volume ratio, thin surface, concentration gradient) · understand how the rate of diffusion depends on these properties and can be calculated using Fick's Law of Diffusion · understand how the mammalian lung is adapted for rapid gaseous exchange

Infectious Diseases: Pathogens and Transmission

understand how Mycobacterium tuberculosis and human immunodeficiency virus infect human cells, causing symptoms that may result in death · know the major routes pathogens may take when entering the body · understand the role of physical/chemical barriers protecting the body from infection: skin, stomach acid, gut and skin flora

Prevention and Control of Infectious Diseases

discuss the BIOLOGICAL factors in the prevention and control of cholera (clean water supplies, sanitation/sewage treatment, oral rehydration therapy, vaccination), malaria (vector control via insecticides, insecticide-treated bed nets, draining/managing standing water, prophylactic and treatment drugs), TB (BCG vaccination, contact tracing, isolation of infectious cases, full antibiotic courses/DOTS) and HIV (no cure or effective vaccine; barrier protection, screening blood products, needle-exchange schemes, antiretroviral drugs, preventing mother-to-child transmission) · discuss the SOCIAL factors in prevention and control (health education and public-awareness campaigns, behaviour change, contact tracing, cultural and behavioural barriers, stigma, access to and uptake of healthcare and screening) · discuss the ECONOMIC factors in prevention and control (cost of clean-water and sanitation infrastructure, of drugs, vaccines, bed nets and surveillance/monitoring, and the economic burden of the disease on individuals and on developing economies) · relate each prevention/control strategy to the specific mode of transmission of cholera, malaria, TB and HIV (details of the malarial parasite life cycle are not required)

Antibiotics and Antibiotic Resistance

understand how individuals develop immunity (natural, artificial, active and passive) · understand how the evolutionary arms race between pathogens and hosts is supported by pathogen evasion mechanisms · understand the difference between bacteriostatic and bactericidal antibiotics · CORE PRACTICAL 14: investigate the effect of different antibiotics on bacteria · know how understanding the contributory causes of hospital-acquired infections has led to codes of practice on antibiotic prescription and infection control

Phagocytes and the Non-Specific Response

understand the non-specific responses to infection: inflammation, lysozyme action, interferon and phagocytosis

Antigens and the Specific Immune Response

understand the roles of antigens and antibodies in the body's immune response, including plasma cells, macrophages and antigen-presenting cells · understand the differences between B cells (B memory and B effector) and T cells (T helper, T killer, T memory) in the host's immune response

Antibodies and Monoclonal Antibodies

relate the molecular structure of antibodies (immunoglobulins) to their functions: two identical heavy and two identical light polypeptide chains joined by disulfide bonds, variable and constant regions, two antigen-binding sites, and the hinge region; link this structure to specificity and to agglutination, neutralisation and opsonisation (11.2.1) · outline the hybridoma method for producing monoclonal antibodies: immunise a mouse with the antigen, isolate antibody-producing B-lymphocytes/plasma cells, fuse them with myeloma (tumour) cells to form immortal hybridoma cells, then screen, select and culture the single clone producing the desired antibody (11.2.2) · outline the principles of using monoclonal antibodies in the DIAGNOSIS of disease, e.g. pregnancy testing, ELISA/immunoassays, and locating blood clots or tumours using labelled antibodies (11.2.3) · outline the principles of using monoclonal antibodies in the TREATMENT of disease, e.g. targeted delivery of drugs or radioisotopes to cells bearing a specific antigen, such as in cancer therapy (11.2.3)

Immunity Types and Vaccination

understand how individuals develop immunity (natural, artificial, active and passive) · understand how the evolutionary arms race between pathogens and hosts is supported by pathogen evasion mechanisms · understand the difference between bacteriostatic and bactericidal antibiotics · CORE PRACTICAL 14: investigate the effect of different antibiotics on bacteria · know how understanding the contributory causes of hospital-acquired infections has led to codes of practice on antibiotic prescription and infection control

Energy and ATP: the universal energy currency

12.1.1 outline the need for energy in living organisms, as illustrated by active transport, movement and anabolic reactions such as those occurring in DNA replication and protein synthesis · 12.1.2 describe the features of ATP that make it suitable as the universal energy currency (e.g. small, soluble, easily transported, releases a usable amount of energy in a single hydrolysis step, rapidly resynthesised from ADP + Pi) · 12.1.3 state that ATP is synthesised by transfer of phosphate in substrate-linked reactions and by chemiosmosis in the membranes of mitochondria and chloroplasts

Glycolysis and the stages of aerobic respiration

understand the overall reaction of aerobic respiration: splitting of respiratory substrate to release CO₂ and reuniting hydrogen with atmospheric oxygen, releasing large amounts of energy · understand that respiration is a stepped process, each step controlled and catalysed by a specific intracellular enzyme (names of enzymes not required) · understand the role of glycolysis in aerobic and anaerobic respiration: phosphorylation of hexoses, ATP production by substrate-level phosphorylation, reduced coenzyme, pyruvate and lactate (intermediate compound names not required)

The link reaction and the Krebs cycle

understand the role of the link reaction and the Krebs cycle in the complete oxidation of glucose, formation of CO₂ by decarboxylation, ATP by substrate-level phosphorylation, and reduced NAD/FAD by dehydrogenation (other compound names not required); locate these steps in mitochondria vs glycolysis in the cytoplasm

Oxidative phosphorylation and the mitochondrion

understand how ATP is synthesised by oxidative phosphorylation associated with the electron transport chain in mitochondria, including the role of chemiosmosis and ATP synthase

Anaerobic respiration, respiratory substrates and RQ

understand what happens to lactate after anaerobic respiration in animals · understand the term respiratory quotient (RQ) · CORE PRACTICAL 15: use an artificial hydrogen carrier (redox indicator) to investigate respiration in yeast · CORE PRACTICAL 16: use a simple respirometer to determine the rate of respiration and RQ of a suitable material (e.g. germinating seeds or small invertebrates)

Chloroplast Structure, Pigments and Chromatography

understand the structure of chloroplasts in relation to their role in photosynthesis · understand the terms absorption spectrum and action spectrum · understand how chloroplast pigments can be separated using chromatography and identified using R+f values · CORE PRACTICAL 10: investigate the effects of light intensity, light wavelength, temperature and CO₂ availability on the rate of photosynthesis using a suitable aquatic plant

The Light-Dependent Reactions and Photophosphorylation

understand the light-dependent reactions of photosynthesis: light excites electrons in chlorophyll; the role of these electrons in generating ATP, reducing NADP in cyclic and non-cyclic photophosphorylation, and producing O₂ via photolysis of water

The Light-Independent Reactions: The Calvin Cycle

understand the light-independent reactions as reduction of CO₂ using the products of the light-dependent reactions (carbon fixation in the Calvin cycle, roles of GP, GALP, RuBP and RUBISCO) · know that the products are simple sugars used by plants, animals and other organisms in respiration and the synthesis of polysaccharides, amino acids, proteins, lipids and nucleic acids

Limiting Factors and Investigating Photosynthesis

understand the structure of chloroplasts in relation to their role in photosynthesis · understand the terms absorption spectrum and action spectrum · understand how chloroplast pigments can be separated using chromatography and identified using R+f values · CORE PRACTICAL 10: investigate the effects of light intensity, light wavelength, temperature and CO₂ availability on the rate of photosynthesis using a suitable aquatic plant

Homeostasis and Negative Feedback Control

understand negative feedback and positive feedback control · understand the principle of negative feedback in maintaining systems within narrow limits · understand homeostasis and its importance in maintaining dynamic equilibrium during exercise, including the role of the hypothalamus in thermoregulation

The Kidney: Excretion, Urine Formation and Osmoregulation

know the gross and microscopic structure of the mammalian kidney · understand how urea is produced from excess amino acids in the liver (ornithine cycle detail not required) and removed by ultrafiltration · understand selective reabsorption in the proximal tubule and how the loop of Henle acts as a countercurrent multiplier to increase water reabsorption · understand how the pituitary, osmoreceptors in the hypothalamus, and ADH bring about negative feedback control of plasma concentration and blood volume

Cell Signalling and the Control of Blood Glucose

describe the principles of cell signalling using the control of blood glucose by glucagon: hormone binds cell-surface receptor causing conformational change -> activation of G-protein -> stimulation of adenylyl cyclase -> formation of the second messenger cyclic AMP (cAMP) -> activation of protein kinase A -> initiation of an enzyme cascade -> amplification of the signal via successive phosphorylation -> final enzyme catalyses the breakdown of glycogen (9700 14.1.9) · explain how negative feedback control mechanisms regulate blood glucose concentration, with reference to the effects of insulin on muscle cells and liver cells and the effect of glucagon on liver cells (9700 14.1.10) · explain the principles of operation of test strips and biosensors for measuring glucose concentration in blood and urine, with reference to glucose oxidase and peroxidase enzymes (9700 14.1.11)

Homeostasis in Plants: Stomata and Guard Cells

explain that stomata respond to changes in environmental conditions by opening and closing, and that regulation of stomatal aperture balances CO2 uptake by diffusion against minimising water loss by transpiration (9700 14.2.1) · explain that stomata show daily rhythms of opening and closing (9700 14.2.2) · describe the structure and function of guard cells and explain the mechanism by which they open and close stomata, including K+ and water movement and resulting turgor changes (9700 14.2.3) · describe the role of abscisic acid (ABA) in the closure of stomata during times of water stress, including the role of calcium ions as a second messenger (9700 14.2.4)

The Endocrine System and Nervous vs Endocrine Coordination

describe the features of the endocrine system: ductless glands secrete hormones directly into the blood, which transports them to target cells/organs bearing specific receptors, with reference to the hormones ADH (posterior pituitary), glucagon and insulin (pancreatic islet alpha and beta cells) - full action detail cross-refers to Topic 14 (15.1.1). NOTE: the seed al-edx-bio-5.2-lesson-7 contributes only the 'nervous and hormonal coordination' thread; all endocrine-gland content is authored fresh (draws on Topic 14 kidney/ADH and blood-glucose lessons) · compare the features of the nervous system and the endocrine system: nature of signal (electrical impulse vs chemical hormone), pathway (along neurones vs dissolved in blood/transported by circulation), speed of transmission, duration of the effect, and whether the response is localised or widespread (15.1.2)

Neurones and Sensory Reception

know the structure and function of sensory, relay and motor neurones, including Schwann cells and myelination · understand how the nervous system can cause effectors to respond to a stimulus · know the structure and function of a spinal reflex arc, including grey matter and white matter of the spinal cord

The Nerve Impulse: Resting and Action Potentials, Conduction and the Refractory Period

understand how a nerve impulse (action potential) is conducted along an axon, including changes in membrane permeability to sodium and potassium ions · understand the role of myelination in saltatory conduction

The Cholinergic Synapse

know the structure and function of synapses in nerve impulse transmission, including the role of neurotransmitters and acetylcholine · understand how the pupil dilates and contracts

Striated Muscle Structure and the Neuromuscular Junction

describe the ultrastructure of striated (skeletal) muscle with reference to sarcomere structure using electron micrographs and diagrams: A band, I band, H zone, Z line and M line, and the arrangement of actin (thin) and myosin (thick) filaments within the sarcomere (15.1.11). NOTE: seed al-edx-bio-5.1-lesson-5 supplies only generic 'structure of a mammalian skeletal muscle fibre' (its skeleton/tendons/antagonistic-pairs/fast-vs-slow-twitch content is sunk); the EM sarcomere banding can also draw on the sliding-filament clone source al-edx-bio-5.1-lesson-6 · describe the roles of the neuromuscular junction (arrival of the action potential at the motor end plate releasing acetylcholine to depolarise the sarcolemma), the T-tubule system (conducting depolarisation into the fibre) and the sarcoplasmic reticulum (Ca2+ store releasing calcium ions to stimulate contraction) in stimulating contraction in striated muscle (15.1.10) - this outcome is entirely absent from the seed and authored fresh

The Sliding Filament Model of Muscle Contraction

understand the process of skeletal muscle contraction in terms of the sliding filament theory, including the roles of actin, myosin, troponin, tropomyosin, calcium ions (Ca²⁺), ATP and ATPase

Control and Coordination in Plants

understand the term habituation · understand how phytochrome, auxin (IAA) and gibberellins bring about responses in plants, including their effects on transcription · CORE PRACTICAL 18: investigate the production of amylase in germinating cereal grains

Meiosis and the Production of Genetically Different Gametes

know that a locus is the location of a gene on a chromosome; understand the linkage of genes on a chromosome · understand the role of meiosis in producing non-identical gametes via independent assortment in metaphase I and crossing over in prophase I (stage names of prophase not required) · understand how mammalian gametes are specialised for their functions (acrosome in sperm, zona pellucida in the egg)

Monohybrid Genetics: Codominance, Multiple Alleles, Sex Linkage and Test Crosses

understand the terms gene, allele, genotype, phenotype, recessive, dominant, codominance, homozygote, heterozygote · understand patterns of inheritance including monohybrid inheritance and genetic pedigree diagrams · understand sex linkage on the X chromosome (red-green colour blindness) · understand how the cystic fibrosis gene mutation impairs gaseous exchange, digestive and reproductive systems · understand uses of genetic screening (carrier identification, PGD, prenatal testing including amniocentesis and chorionic villus sampling) and the implications of prenatal screening · identify and discuss ethical and social issues relating to genetic screening (religious, moral and social viewpoints)

Dihybrid Crosses, Autosomal Linkage, Epistasis and the Chi-Squared Test

interpret and construct genetic diagrams, including Punnett squares, to predict the results of dihybrid crosses involving dominance, codominance, multiple alleles and sex linkage (16.2.2) · interpret and construct genetic diagrams for dihybrid crosses involving autosomal linkage and epistasis (knowledge of expected epistasis ratios not required) (16.2.3) · interpret and construct genetic diagrams for dihybrid test crosses (16.2.4) · use the chi-squared test to test the significance of differences between observed and expected results, with the formula provided (16.2.5)

Genes, Proteins and Phenotype: Genetic Disorders and Gibberellin

explain the relationship between genes, proteins and phenotype with respect to the four required examples: TYR gene / tyrosinase / albinism; HBB gene / haemoglobin / sickle cell anaemia; F8 gene / factor VIII / haemophilia; HTT gene / huntingtin / Huntington's disease (16.2.6). NOTE: seed al-edx-bio-1.2-lesson-6 contributes only a generic 'mutations cause genetic disorders' sentence (already consumed by the primary derivation al-cie-bio-6-lesson-2); all four named examples are authored fresh · explain the role of gibberellin in stem elongation, including the dominant allele Le coding for a functional enzyme in the gibberellin-synthesis pathway and the recessive allele le coding for a non-functional enzyme, and the effect on phenotype/plant height (16.2.7) - entirely absent from the seed

Gene Control: the lac Operon and Eukaryotic/Plant Gene Regulation

describe the differences between structural genes and regulatory genes, and the differences between repressible enzymes and inducible enzymes (16.3.1) · explain genetic control of protein production in a prokaryote using the lac operon (role of cAMP not required) (16.3.2) · state that transcription factors are proteins that bind to DNA and are involved in controlling eukaryotic gene expression by decreasing or increasing the rate of transcription (16.3.3) · explain how gibberellin activates genes by causing the breakdown of DELLA protein repressors, which normally inhibit factors that promote transcription (16.3.4)

Variation

understand how phenotype results from the interaction of genotype and environment · know how epigenetic modification (DNA methylation, histone modification) can alter gene activation and be passed on following cell division · understand how phenotypes are affected by multiple alleles for the same gene, by polygenic inheritance, and by the environment, giving rise to continuous variation

Natural Selection, Allele Frequencies and the Hardy-Weinberg Principle

understand the concept of niche; discuss adaptations of organisms (behavioural, anatomical, physiological) · understand how the Hardy-Weinberg equation tracks allele frequency changes in a population over time · understand that changes in allele frequency arise from mutation and natural selection · understand that reproductive isolation can lead to accumulation of different genetic information in populations and the formation of new species

Selective Breeding (Artificial Selection)

17.2.6: describe the principles of selective breeding (artificial selection) - humans choosing parents with desirable phenotypes, breeding them, selecting the best offspring, and repeating over many generations to shift allele frequencies in the desired direction · 17.2.7: outline the introduction of disease resistance to varieties of wheat and rice · 17.2.7: outline inbreeding and hybridisation (including hybrid vigour) to produce vigorous, uniform varieties of maize · 17.2.7: outline improving the milk yield of dairy cattle (use of progeny testing / artificial insemination)

Evolution and Speciation

understand how evolution (changes in allele frequency) can come about through gene mutation and natural selection · understand how isolation reduces gene flow between populations, leading to allopatric or sympatric speciation · understand how scientific conclusions on controversial issues (climate change actions, human contribution) can depend on who is reaching the conclusions · understand how reforestation and the use of sustainable resources (including biofuels) manage the conflict between human needs and conservation

Classification: species concepts, three domains and taxonomy

understand that classification organises the variety of life using phenotypic and genotypic differences, built around the species concept · understand the importance of critical evaluation of new data by the scientific community, leading to new taxonomic groupings based on molecular evidence (three-domain system: Archaea, Bacteria, Eukarya) · know that, over time, the variety of life has become extensive but is now being threatened by human activity

The four eukaryotic kingdoms and classification of viruses

outline the characteristic features of the kingdoms Protoctista, Fungi, Plantae and Animalia (18.1.5) · outline how viruses are classified, limited to the type of nucleic acid (RNA or DNA) and whether this is single stranded or double stranded (18.1.6)

Ecosystems, niches and sampling distribution and abundance

understand the terms population, community, habitat and ecosystem · understand that the numbers and distribution of organisms in a habitat are controlled by biotic and abiotic factors · understand how the concept of niche accounts for distribution and abundance of organisms in a habitat · CORE PRACTICAL 11: study the ecology of a habitat using quadrats and transects; measure relevant abiotic factors

Measuring and analysing biodiversity

understand the terms biodiversity and endemism · know how biodiversity within a habitat is measured using species richness, and within a species using genetic diversity via the heterozygosity index = number of heterozygotes / number of individuals · understand how biodiversity is compared between habitats using the index of diversity D = N(N−1) / Σn(n−1)

Extinction, maintaining biodiversity and conservation methods

explain why populations and species can become extinct as a result of climate change, competition, hunting by humans, and degradation/loss of habitats (18.3.1) - the climate-change driver draws on the sunk al-edx-bio-4.1-lesson-8 climate material; this outcome has NO coverage in the seed · outline reasons for the need to maintain biodiversity (ecological, economic, ethical and aesthetic reasons) (18.3.2) - no coverage in the seed · outline the roles of zoos, botanic gardens, conserved areas (including national parks and marine parks), 'frozen zoos' and seed banks in the conservation of endangered species (18.3.3) - seed al-edx-bio-2.2-lesson-8 covers only the zoos + seed banks fragment; botanic gardens, conserved areas and frozen zoos are authored fresh

Assisted reproduction, invasive species and conservation organisations

describe methods of assisted reproduction used in the conservation of endangered mammals, limited to IVF, embryo transfer and surrogacy (18.3.4) · explain reasons for controlling invasive alien species (18.3.5) · outline the role in conservation of the IUCN and of CITES (18.3.6)

Principles of Genetic Engineering and Recombinant DNA

know how drugs can be produced using genetically modified organisms (plants, animals and microorganisms) · understand how recombinant DNA can be produced, including the roles of restriction endonucleases and DNA ligase · understand how recombinant DNA can be inserted into other cells · understand the risks and benefits associated with the use of genetically modified organisms

Amplifying and Separating DNA: PCR and Gel Electrophoresis

know how DNA can be amplified using the polymerase chain reaction (PCR) · know how gel electrophoresis separates DNA fragments of different length · understand how DNA profiling is used for identification and determining genetic relationships between organisms (plants and animals)

Analysing Genomes: Microarrays and Bioinformatics Databases

know how microarrays can be used to identify active genes · understand the term bioinformatics

Genetic Technology in Medicine: Recombinant Proteins and Gene Therapy

explain the advantages of using recombinant human proteins to treat disease, using insulin (diabetes), factor VIII (haemophilia) and adenosine deaminase (ADA-SCID) · outline how genetic diseases can be treated with gene therapy, using severe combined immunodeficiency (SCID) and inherited eye diseases as examples (somatic vs germ-line) · discuss the social and ethical considerations of using gene therapy in medicine

Genetic Screening and Its Ethics

understand the terms gene, allele, genotype, phenotype, recessive, dominant, codominance, homozygote, heterozygote · understand patterns of inheritance including monohybrid inheritance and genetic pedigree diagrams · understand sex linkage on the X chromosome (red-green colour blindness) · understand how the cystic fibrosis gene mutation impairs gaseous exchange, digestive and reproductive systems · understand uses of genetic screening (carrier identification, PGD, prenatal testing including amniocentesis and chorionic villus sampling) and the implications of prenatal screening · identify and discuss ethical and social issues relating to genetic screening (religious, moral and social viewpoints)

Genetically Modified Organisms in Agriculture

explain how genetic engineering can help meet global food demand by improving the quality and productivity of farmed animals and crop plants, using GM salmon (fast growth), herbicide resistance in soybean, and insect resistance in cotton (Bt cotton) · discuss the ethical and social implications of using genetically modified organisms (GMOs) in food production

Practical Skills: Microscopy, Measurement & Investigation Design