Flashcards

• Describe the sequence of events that results in an action potential in a sensory neurone, using a chemoreceptor cell in a human taste bud as an exampl... View Answer
• Outline the role of sensory receptor cells in detecting stimuli and stimulating the transmission of impulses in sensory neurones... View Answer
• Describe the structure and function of a sensory neurone and a motor neurone and state that intermediate neurones connect sensory neurones and motor n... View Answer
• Explain that stomata respond to changes in environmental conditions by opening and closing and that regulation of stomatal aperture balances the need ... View Answer
• State that Calvin cycle intermediates are used to produce other molecules, limited to GP to produce some amino acids and TP to produce carbohydrates, ... View Answer
• Outline the three main stages of the Calvin cycle: • rubisco catalyses the fixation of carbon dioxide by combination with a molecule of ribulose bisph... View Answer
• Discuss the ethical and social implications of using genetically modified organisms (GMOs) in food production... View Answer
• Explain that genetic engineering may help to solve the global demand for food by improving the quality and productivity of farmed animals and crop pla... View Answer
• Discuss the social and ethical considerations of using genetic screening and gene therapy in medicine... View Answer
• Outline how genetic diseases can be treated with gene therapy, using the examples severe combined immunodeficiency (SCID) and inherited eye diseases... View Answer
• Outline the advantages of genetic screening, using the examples of breast cancer (BRCA1 and BRCA2), Huntington’s disease and cystic fibrosis... View Answer
• Explain the advantages of using recombinant human proteins to treat disease, using the examples insulin, factor VIII and adenosine deaminase... View Answer
• Outline the benefits of using databases that provide information about nucleotide sequences of genes and genomes, and amino acid sequences of proteins... View Answer
• Outline how microarrays are used in the analysis of genomes and in detecting mRNA in studies of gene expression... View Answer
• Describe and explain how gel electrophoresis is used to separate DNA fragments of different lengths... View Answer
• Describe and explain the steps involved in the polymerase chain reaction (PCR) to clone and amplify DNA, including the role of Taq polymerase... View Answer
• Explain that gene editing is a form of genetic engineering involving the insertion, deletion or replacement of DNA at specific sites in the genome... View Answer
• Explain how gene expression may be confirmed by the use of marker genes coding for fluorescent products... View Answer
• Explain why a promoter may have to be transferred into an organism as well as the desired gene... View Answer
• Explain the roles of restriction endonucleases, DNA ligase, plasmids, DNA polymerase and reverse transcriptase in the transfer of a gene into an organ... View Answer
• Explain that genes to be transferred into an organism may be: • extracted from the DNA of a donor organism • synthesised from the mRNA of a donor orga... View Answer
• Explain that genetic engineering is the deliberate manipulation of genetic material to modify specific characteristics of an organism and that this ma... View Answer
• Outline the role in conservation of the International Union for Conservation of Nature (IUCN) and the Convention on International Trade in Endangered ... View Answer
• Explain reasons for controlling invasive alien species View Answer
• Describe methods of assisted reproduction used in the conservation of endangered mammals, limited to IVF, embryo transfer and surrogacy... View Answer
• Outline the roles of zoos, botanic gardens, conserved areas (including national parks and marine parks), ‘frozen zoos’ and seed banks, in the conserva... View Answer
• Outline reasons for the need to maintain biodiversity View Answer
• Explain why populations and species can become extinct as a result of: • climate change • competition • hunting by humans • degradation and loss of ha... View Answer
• Use Simpson’s index of diversity (D) to calculate the biodiversity of an area, and state the significance of different values of D (the formula for Si... View Answer
• Use Spearman’s rank correlation and Pearson’s linear correlation to analyse the relationships between two variables, including how biotic and abiotic ... View Answer
• Describe and use suitable methods to assess the distribution and abundance of organisms in an area, limited to frame quadrats, line transects, belt tr... View Answer
• Explain the importance of random sampling in determining the biodiversity of an area... View Answer
• Explain that biodiversity can be assessed at different levels, including: • the number and range of different ecosystems and habitats • the number of ... View Answer
• Define the terms ecosystem and niche View Answer
• Outline how viruses are classified, limited to the type of nucleic acid (RNA or DNA) and whether this is single stranded or double stranded... View Answer
• Outline the characteristic features of the kingdoms Protoctista, Fungi, Plantae and Animalia... View Answer
• Describe the classification of organisms in the Eukarya domain into the taxonomic hierarchy of kingdom, phylum, class, order, family, genus and specie... View Answer
• State that Archaea and Bacteria are prokaryotes and that there are differences between them, limited to differences in membrane lipids, ribosomal RNA ... View Answer
• Explain how speciation may occur as a result of genetic isolation by: • geographical separation (allopatric speciation) • ecological and behavioural s... View Answer
• Discuss how DNA sequence data can show evolutionary relationships between species... View Answer
• Outline the theory of evolution as a process leading to the formation of new species from pre-existing species over time, as a result of changes to ge... View Answer
• Outline the following examples of selective breeding: • the introduction of disease resistance to varieties of wheat and rice • inbreeding and hybridi... View Answer
• Describe the principles of selective breeding (artificial selection) View Answer
• Use the Hardy–Weinberg principle to calculate allele and genotype frequencies in populations and state the conditions when this principle can be appli... View Answer
• Outline how bacteria become resistant to antibiotics as an example of natural selection... View Answer
• Explain how selection, the founder effect and genetic drift, including the bottleneck effect, may affect allele frequencies in populations... View Answer
• Explain how environmental factors can act as stabilising, disruptive and directional forces of natural selection... View Answer
• Explain that natural selection occurs because populations have the capacity to produce many offspring that compete for resources; in the ‘struggle for... View Answer
• Use the t-test to compare the means of two different samples (the formula for the t-test will be provided, as shown in the Mathematical requirements)... View Answer
• Explain the genetic basis of discontinuous variation and continuous variation View Answer
• Explain what is meant by discontinuous variation and continuous variation View Answer
• Explain, with examples, that phenotypic variation is due to genetic factors or environmental factors or a combination of genetic and environmental fac... View Answer
• Explain how gibberellin activates genes by causing the breakdown of DELLA protein repressors, which normally inhibit factors that promote transcriptio... View Answer
• State that transcription factors are proteins that bind to DNA and are involved in the control of gene expression in eukaryotes by decreasing or incre... View Answer
• Explain genetic control of protein production in a prokaryote using the lac operon (knowledge of the role of cAMP is not expected)... View Answer
• Describe the differences between structural genes and regulatory genes and the differences between repressible enzymes and inducible enzymes... View Answer
• Explain the role of gibberellin in stem elongation including the role of the dominant allele, Le, that codes for a functional enzyme in the gibberelli... View Answer
• Explain the relationship between genes, proteins and phenotype with respect to the: • TYR gene, tyrosinase and albinism • HBB gene, haemoglobin and si... View Answer
• Use the chi-squared test to test the significance of differences between observed and expected results (the formula for the chi-squared test will be p... View Answer
• Interpret and construct genetic diagrams, including Punnett squares, to explain and predict the results of test crosses... View Answer
• Interpret and construct genetic diagrams, including Punnett squares, to explain and predict the results of dihybrid crosses that involve autosomal lin... View Answer
• Interpret and construct genetic diagrams, including Punnett squares, to explain and predict the results of monohybrid crosses and dihybrid crosses tha... View Answer
• Explain the terms gene, locus, allele, dominant, recessive, codominant, linkage, test cross, F1, F2, phenotype, genotype, homozygous and heterozygous... View Answer
• Explain that the random fusion of gametes at fertilisation produces genetically different individuals... View Answer
• Explain that crossing over and random orientation (independent assortment) of pairs of homologous chromosomes and sister chromatids during meiosis pro... View Answer
• Interpret photomicrographs and diagrams of cells in different stages of meiosis and identify the main stages of meiosis... View Answer
• Describe the behaviour of chromosomes in plant and animal cells during meiosis and the associated behaviour of the nuclear envelope, the cell surface ... View Answer
• Explain the need for a reduction division during meiosis in the production of gametes... View Answer
• Explain what is meant by homologous pairs of chromosomes View Answer
• Explain the meanings of the terms haploid (n) and diploid (2n) View Answer
• Describe the role of gibberellin in the germination of barley View Answer
• Explain the role of auxin in elongation growth by stimulating proton pumping to acidify cell walls... View Answer
• Describe the rapid response of the Venus fly trap to stimulation of hairs on the lobes of modified leaves and explain how the closure of the trap is a... View Answer
• Explain the sliding filament model of muscular contraction including the roles of troponin, tropomyosin, calcium ions and ATP... View Answer
• Describe the ultrastructure of striated muscle with reference to sarcomere structure using electron micrographs and diagrams... View Answer
• Describe the roles of neuromuscular junctions, the T-tubule system and sarcoplasmic reticulum in stimulating contraction in striated muscle... View Answer
• Describe the structure of a cholinergic synapse and explain how it functions, including the role of calcium ions... View Answer
• Explain the importance of the refractory period in determining the frequency of impulses... View Answer
• Describe and explain the rapid transmission of an impulse in a myelinated neurone with reference to saltatory conduction... View Answer
• Describe and explain changes to the membrane potential of neurones, including: • how the resting potential is maintained • the events that occur durin... View Answer
• What is the Difference between nervous system and the endocrine system? View Answer
• Explain the principles of operation of test strips and biosensors for measuring the concentration of glucose in blood and urine, with reference to glu... View Answer
• Explain how negative feedback control mechanisms regulate blood glucose concentration, with reference to the effects of insulin on muscle cells and li... View Answer
• Describe the principles of cell signalling using the example of the control of blood glucose concentration by glucagon, limited to: • binding of hormo... View Answer
• Relate the detailed structure of the Bowman’s capsule and proximal convoluted tubule to their functions in the formation of urine... View Answer
• Describe the roles of the hypothalamus, posterior pituitary gland, antidiuretic hormone (ADH), aquaporins and collecting ducts in osmoregulation... View Answer
• State that urea is produced in the liver from the deamination of excess amino acids... View Answer
• Describe and carry out investigations using whole plants, including aquatic plants, to determine the effects of light intensity, carbon dioxide concen... View Answer
• Describe and carry out investigations using redox indicators, including DCPIP and methylene blue, and a suspension of chloroplasts to determine the ef... View Answer
• Explain the effects of changes in light intensity, carbon dioxide concentration and temperature on the rate of photosynthesis... View Answer
• Explain that during photophosphorylation: • energetic electrons release energy as they pass through the electron transport chain (details of carriers ... View Answer
• Explain that in non-cyclic photophosphorylation: • photosystem I (PSI) and photosystem II (PSII) are both involved • photoactivation of chlorophyll oc... View Answer
• Explain that in cyclic photophosphorylation: • only photosystem I (PSI) is involved • photoactivation of chlorophyll occurs • ATP is synthesised... View Answer
• State that cyclic photophosphorylation and non-cyclic photophosphorylation occur during the light-dependent stage of photosynthesis... View Answer
• Describe and use chromatography to separate and identify chloroplast pigments (reference should be made to Rf values in identification of chloroplast ... View Answer
• Interpret absorption spectra of chloroplast pigments and action spectra for photosynthesis... View Answer
• Describe the role of chloroplast pigments (chlorophyll a, chlorophyll b, carotene and xanthophyll) in light absorption in thylakoids... View Answer
• State that within a chloroplast, the thylakoids (thylakoid membranes and thylakoid spaces), which occur in stacks called grana, are the site of the li... View Answer
• Explain that energy transferred as ATP and reduced NADP from the light-dependent stage is used during the lightindependent stage (Calvin cycle) of pho... View Answer
• Describe and carry out investigations using simple respirometers to determine the effect of temperature on the rate of respiration... View Answer
• Describe and carry out investigations using redox indicators, including DCPIP and methylene blue, to determine the effects of temperature and substrat... View Answer
• Explain how rice is adapted to grow with its roots submerged in water, limited to the development of aerenchyma in roots, ethanol fermentation in root... View Answer
• Explain why the energy yield from respiration in aerobic conditions is much greater than the energy yield from respiration in anaerobic conditions (a ... View Answer
• Explain that, when oxygen is available, pyruvate enters mitochondria to take part in the link reaction... View Answer
• Describe the link reaction, including the role of coenzyme A in the transfer of acetyl (2C) groups... View Answer
• Outline respiration in anaerobic conditions in mammals (lactate fermentation) and in yeast cells (ethanol fermentation)... View Answer
• Describe the relationship between the structure and function of mitochondria using diagrams and electron micrographs... View Answer
• Describe the role of NAD and FAD in transferring hydrogen to carriers in the inner mitochondrial membrane... View Answer
• Explain that reactions in the Krebs cycle involve decarboxylation and dehydrogenation and the reduction of the coenzymes NAD and FAD... View Answer
• Describe and carry out investigations, using simple respirometers, to determine the RQ of germinating seeds or small invertebrates (e.g. blowfly larva... View Answer
• Calculate RQ values of different respiratory substrates from equations for respiration... View Answer
• State that the respiratory quotient (RQ) is the ratio of the number of molecules of carbon dioxide produced to the number of molecules of oxygen taken... View Answer
• Explain the relative energy values of carbohydrates, lipids and proteins as respiratory substrates... View Answer
• Describe the features of ATP that make it suitable as the universal energy currency... View Answer
• Outline the need for energy in living organisms, as illustrated by active transport, movement and anabolic reactions, such as those occurring in DNA r... View Answer
• Outline how penicillin acts on bacteria and why antibiotics do not affect viruses... View Answer
• Outline the hybridoma method for the production of monoclonal antibodies View Answer
• Explain that vaccines contain antigens that stimulate immune responses to provide long-term immunity... View Answer
• Explain how vaccination programmes can help to control the spread of infectious diseases... View Answer
• Explain the role of memory cells in the secondary immune response and in long-term immunity... View Answer
• Describe the sequence of events that occurs during a primary immune response with reference to the roles of: • macrophages • B-lymphocytes, including ... View Answer
• Explain what is meant by an antigen and state the difference between self antigens and non-self antigens... View Answer
• Discuss the biological, social and economic factors that need to be considered in the prevention and control of cholera, malaria, TB and HIV (details ... View Answer
• Explain how cholera, malaria, TB and HIV are transmitted View Answer
• State that infectious diseases are caused by pathogens and are transmissible View Answer
• Describe gas exchange between air in the alveoli and blood in the capillaries View Answer
• Describe the functions in the gas exchange system of cartilage, smooth muscle, elastic fibres and squamous epithelium... View Answer
• Describe the functions of ciliated epithelial cells, goblet cells and mucous glands in maintaining the health of the gas exchange system... View Answer
• Recognise trachea, bronchi, bronchioles and alveoli in microscope slides, photomicrographs and electron micrographs and make plan diagrams of transver... View Answer
• Recognise cartilage, ciliated epithelium, goblet cells, squamous epithelium of alveoli, smooth muscle and capillaries in microscope slides, photomicro... View Answer
• Describe the distribution in the gas exchange system of cartilage, ciliated epithelium, goblet cells, squamous epithelium of alveoli, smooth muscle an... View Answer
• Explain the roles of the sinoatrial node, the atrioventricular node and the Purkyne tissue in the cardiac cycle (knowledge of nervous and hormonal con... View Answer
• Explain the differences in the thickness of the walls of the: • atria and ventricles • left ventricle and right ventricle... View Answer
• Describe the Bohr shift and explain the importance of the Bohr shift View Answer
• Explain the importance of the oxygen dissociation curve at partial pressures of oxygen in the lungs and in respiring tissues... View Answer
• Describe and explain the oxygen dissociation curve of adult haemoglobin View Answer
• Describe the role of plasma in the transport of carbon dioxide View Answer
• Describe the chloride shift and explain the importance of the chloride shift View Answer
• Describe the role of red blood cells in transporting oxygen and carbon dioxide with reference to the roles of: • haemoglobin • carbonic anhydrase • th... View Answer
• State the functions of tissue fluid and describe the formation of tissue fluid in a capillary network... View Answer
• State that water is the main component of blood and tissue fluid and relate the properties of water to its role in transport in mammals, limited to so... View Answer
• Recognise and draw red blood cells, monocytes, neutrophils and lymphocytes from microscope slides, photomicrographs and electron micrographs... View Answer
• Explain how the structure of muscular arteries, elastic arteries, veins and capillaries are each related to their functions... View Answer
• Recognise arteries, veins and capillaries from microscope slides, photomicrographs and electron micrographs and make plan diagrams showing the structu... View Answer
• Describe the functions of the main blood vessels of the pulmonary and systemic circulations, limited to pulmonary artery, pulmonary vein, aorta and ve... View Answer
• State that assimilates dissolved in water, such as sucrose and amino acids, move from sources to sinks in phloem sieve tubes... View Answer
• Explain how companion cells transfer assimilates to phloem sieve tubes, with reference to proton pumps and cotransporter proteins... View Answer
• Make annotated drawings of transverse sections of leaves from xerophytic plants to explain how they are adapted to reduce water loss by transpiration... View Answer
• Explain how hydrogen bonding of water molecules is involved with movement of water in the xylem by cohesion-tension in transpiration pull and by adhes... View Answer
• Explain that transpiration involves the evaporation of water from the internal surfaces of leaves followed by diffusion of water vapour to the atmosph... View Answer
• State that some mineral ions and organic compounds can be transported within plants dissolved in water... View Answer
• Explain mass flow in phloem sieve tubes down a hydrostatic pressure gradient from source to sink... View Answer
• Describe the distribution of xylem and phloem in transverse sections of stems, roots and leaves of herbaceous dicotyledonous plants... View Answer
• Relate the structure of xylem vessel elements, phloem sieve tube elements and companion cells to their functions... View Answer
• State that a polypeptide is coded for by a gene and that a gene is a sequence of nucleotides that forms part of a DNA molecule... View Answer
• Explain that a gene mutation is a result of substitution or deletion or insertion of nucleotides in DNA and outline how each of these types of mutatio... View Answer
• State that a gene mutation is a change in the sequence of base pairs in a DNA molecule that may result in an altered polypeptide... View Answer
• State that the strand of a DNA molecule that is used in transcription is called the transcribed or template strand and that the other strand is called... View Answer
• Explain that, in eukaryotes, the RNA molecule formed following transcription (primary transcript) is modified by the removal of non-coding sequences (... View Answer
• Describe how the information in DNA is used during transcription and translation to construct polypeptides, including the roles of: • RNA polymerase •... View Answer
• Describe the principle of the universal genetic code in which different triplets of DNA bases either code for specific amino acids or correspond to st... View Answer
• Describe the differences between leading strand and lagging strand replication as a consequence of DNA polymerase adding nucleotides only in a 5′ to 3... View Answer
• Describe the linking of nucleotides by phosphodiester bonds View Answer
• Differences in hydrogen bonding between C–G and A–T base pairs View Answer
• Describe the importance of complementary base pairing between the 5′ to 3′ strand and the 3′ to 5′ strand (antiparallel strands)... View Answer
• State that the bases adenine and guanine are purines with a double ring structure, and that the bases cytosine, thymine and uracil are pyrimidines wit... View Answer
• Interpret photomicrographs, diagrams and microscope slides of cells in different stages of the mitotic cell cycle and identify the main stages of mito... View Answer
• Outline the role of stem cells in cell replacement and tissue repair by mitosis View Answer
• Explain how uncontrolled cell division can result in the formation of a tumour View Answer
• Outline the role of telomeres in preventing the loss of genes from the ends of chromosomes during DNA replication... View Answer
• Explain the importance of mitosis in the production of genetically identical daughter cells during: growth of multicellular organisms replacement of d... View Answer
• Explain the movement of water between cells and solutions in terms of water potential and explain the different effects of the movement of water on pl... View Answer
• Investigate the effects of immersing plant tissues in solutions of different water potentials, using the results to estimate the water potential of th... View Answer
• Investigate the effect of changing surface area to volume ratio on diffusion using agar blocks of different sizes... View Answer
• Illustrate the principle that surface area to volume ratios decrease with increasing size by calculating surface areas and volumes of simple 3-D shape... View Answer
• Investigate simple diffusion and osmosis using plant tissue and non-living materials, including dialysis (Visking) tubing and agar... View Answer
• Describe the roles of phospholipids, cholesterol, glycolipids, proteins and glycoproteins in cell surface membranes, with reference to stability, flui... View Answer
• Investigate the progress of enzyme-catalysed reactions by measuring rates of formation of products using catalase and rates of disappearance of substr... View Answer
• Investigate the difference in activity between an enzyme immobilised in alginate and the same enzyme free in solution, and state the advantages of usi... View Answer
• State that enzymes are globular proteins that catalyse reactions inside cells (intracellular enzymes) or are secreted to catalyse reactions outside ce... View Answer
• Relate the structure of haemoglobin to its function, including the importance of iron in the haem group... View Answer
• What is Water high specific heat capacity and latent heat of vaporisation? View Answer
• Describe the molecular structure of phospholipids with reference to their hydrophilic (polar) phosphate heads and hydrophobic (non-polar) fatty acid t... View Answer
• Relate the molecular structure of triglycerides to their functions in living organisms... View Answer
• State that triglycerides are non-polar hydrophobic molecules and describe the molecular structure of triglycerides with reference to fatty acids (satu... View Answer
• Describe the molecular structure of the polysaccharide cellulose and outline how the arrangement of cellulose molecules contributes to the function of... View Answer
• Describe the molecular structure of the polysaccharides starch (amylose and amylopectin) and glycogen and relate their structures to their functions i... View Answer
• Describe the breakage of a glycosidic bond in polysaccharides and disaccharides by hydrolysis, with reference to the non-reducing sugar test... View Answer
• Describe the formation of a glycosidic bond by condensation, with reference to disaccharides, including sucrose, and polysaccharides... View Answer
• State that glucose, fructose and maltose are reducing sugars and that sucrose is a non-reducing sugar... View Answer
• State the role of covalent bonds in joining smaller molecules together to form polymers... View Answer
• Define the terms monomer, polymer, macromolecule, monosaccharide, disaccharide and polysaccharide... View Answer
• Describe and carry out a semi-quantitative Benedict’s test on a reducing sugar solution by standardising the test and using the results (time to first... View Answer
• describe and carry out a test to identify the presence of non-reducing sugars, using acid hydrolysis and Benedict’s solution... View Answer
• State that cells use ATP from respiration for energy-requiring processes View Answer
• state that all viruses are non-cellular structures with a nucleic acid core (either DNA or RNA) and a capsid made of protein, and that some viruses ha... View Answer
• compare the structure of a prokaryotic cell as found in a typical bacterium with the structures of typical eukaryotic cells in plants and animals... View Answer
• outline key structural features of a prokaryotic cell as found in a typical bacterium, including: • unicellular • generally 1–5 µm diameter • peptidog... View Answer
• How to draw cells from microscope slides and photomicrographs View Answer
• define resolution and magnification and explain the differences between these terms, with reference to light microscopy and electron microscopy... View Answer
• use an eyepiece graticule and stage micrometer scale to make measurements and use the appropriate units, millimetre (mm), micrometre (µm) and nanometr... View Answer
• calculate magnifications of images and actual sizes of specimens from drawings, photomicrographs and electron micrographs (scanning and transmission)... View Answer