Flashcards

• Explain the undesirable effects of deforestation as an example of habitat destruction, to include: reducing biodiversity, extinction, loss of soil, fl... View Answer
• State that through altering food webs and food chains, humans can have a negative impact on habitats... View Answer
• Describe the reasons for habitat destruction, including: (a) increased area for housing, crop plant production and livestock production (b) extraction... View Answer
• Describe biodiversity as the number of different species that live in an area View Answer
• Discuss the advantages and disadvantages of genetically modifying crops, including soya, maize and rice... View Answer
• Outline the process of genetic modification using bacterial production of a human protein as an example, limited to: (a) isolation of the DNA making u... View Answer
• Outline examples of genetic modification: (a) the insertion of human genes into bacteria to produce human proteins (b) the insertion of genes into cro... View Answer
• Describe genetic modification as changing the genetic material of an organism by removing, changing or inserting individual genes... View Answer
• Describe and explain the conditions that need to be controlled in a fermenter, including: temperature, pH, oxygen, nutrient supply and waste products... View Answer
• Describe how fermenters can be used for the large-scale production of useful products by bacteria and fungi, including insulin, penicillin and mycopro... View Answer
• Explain the use of lactase to produce lactosefree milk View Answer
• Investigate and describe the use of biological washing powders that contain enzymes... View Answer
• Describe the use of pectinase in fruit juice production View Answer
• Describe the role of anaerobic respiration in yeast during bread-making View Answer
• Describe the role of anaerobic respiration in yeast during the production of ethanol for biofuels... View Answer
• Discuss why bacteria are useful in biotechnology and genetic modification, limited to: (a) few ethical concerns over their manipulation and growth (b)... View Answer
• State that bacteria are useful in biotechnology and genetic modification due to their rapid reproduction rate and their ability to make complex molecu... View Answer
• Explain the risks to a species if its population size decreases, reducing genetic variation (knowledge of genetic drift is not required)... View Answer
• Describe the use of artificial insemination (AI) and in vitro fertilisation (IVF) in captive breeding programmes... View Answer
• Describe the reasons for conservation programmes, limited to: (a) maintaining or increasing biodiversity (b) reducing extinction (c) protecting vulner... View Answer
• Describe how endangered species can be conserved, limited to: (a) monitoring and protecting species and habitats (b) education (c) captive breeding pr... View Answer
• Explain why organisms become endangered or extinct, including: climate change, habitat destruction, hunting, overharvesting, pollution and introduced ... View Answer
• State that some resources can be conserved and managed sustainably, limited to forests and fish stocks... View Answer
• Describe a sustainable resource as one which is produced as rapidly as it is removed from the environment so that it does not run out... View Answer
• Explain the process of eutrophication of water, limited to: • increased availability of nitrate and other ions • increased growth of producers • incre... View Answer
• Describe the sources and effects of pollution of the air by methane and carbon dioxide, limited to: the enhanced greenhouse effect and climate change... View Answer
• Describe the effects of non-biodegradable plastics, in both aquatic and terrestrial ecosystems... View Answer
• Describe the effects of untreated sewage and excess fertiliser on aquatic ecosystems... View Answer
• Describe the advantages and disadvantages of intensive livestock production View Answer
• Describe the advantages and disadvantages of large-scale monocultures of crop plants... View Answer
• Describe how humans have increased food production, limited to: (a) agricultural machinery to use larger areas of land and improve efficiency (b) chem... View Answer
• Explain the factors that lead to each phase in the sigmoid curve of population growth, making reference, where appropriate, to the role of limiting fa... View Answer
• Interpret graphs and diagrams of population growth View Answer
• Identify the lag, exponential (log), stationary and death phases in the sigmoid curve of population growth for a population growing in an environment ... View Answer
• Describe an ecosystem as a unit containing the community of organisms and their environment, interacting together... View Answer
• Describe a community as all of the populations of different species in an ecosystem... View Answer
• Describe a population as a group of organisms of one species, living in the same area, at the same time... View Answer
• State the roles of microorganisms in the nitrogen cycle, limited to: decomposition, nitrification, nitrogen fixation and denitrification (generic name... View Answer
• Describe the nitrogen cycle with reference to: • decomposition of plant and animal protein to ammonium ions • nitrification • nitrogen fixation by lig... View Answer
• Describe the carbon cycle, limited to: photosynthesis, respiration, feeding, decomposition, formation of fossil fuels and combustion... View Answer
• Explain, in terms of energy loss, why food chains usually have fewer than five trophic levels... View Answer
• Explain why the transfer of energy from one trophic level to another is often not efficient... View Answer
• Discuss the advantages of using a pyramid of energy rather than pyramids of numbers or biomass to represent a food chain... View Answer
• Draw, describe and interpret pyramids of energy View Answer
• Identify the following as the trophic levels in food webs, food chains and ecological pyramids: producers, primary consumers, secondary consumers, ter... View Answer
• Describe a trophic level as the position of an organism in a food chain, food web or ecological pyramid... View Answer
• Discuss the advantages of using a pyramid of biomass rather than a pyramid of numbers to represent a food chain... View Answer
• Draw, describe and interpret pyramids of numbers and pyramids of biomass View Answer
• Use food chains and food webs to describe the impact humans have through overharvesting of food species and through introducing foreign species to a h... View Answer
• Describe a decomposer as an organism that gets its energy from dead or waste organic material... View Answer
• Describe a carnivore as an animal that gets its energy by eating other animals View Answer
• Describe a herbivore as an animal that gets its energy by eating plants View Answer
• State that consumers may be classed as primary, secondary, tertiary and quaternary according to their position in a food chain... View Answer
• Describe a consumer as an organism that gets its energy by feeding on other organisms... View Answer
• Describe a producer as an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis... View Answer
• Describe a food web as a network of interconnected food chains and interpret food webs... View Answer
• Describe a food chain as showing the transfer of energy from one organism to the next, beginning with a producer... View Answer
• Describe the flow of energy through living organisms, including light energy from the Sun and chemical energy in organisms, and its eventual transfer ... View Answer
• State that the Sun is the principal source of energy input to biological systems View Answer
• Outline the differences between natural and artificial selection View Answer
• Describe the development of strains of antibiotic resistant bacteria as an example of natural selection... View Answer
• Describe adaptation as the process, resulting from natural selection, by which populations become more suited to their environment over many generatio... View Answer
• Outline how selective breeding by artificial selection is carried out over many generations to improve crop plants and domesticated animals and apply ... View Answer
• Describe selective breeding with reference to: (a) selection by humans of individuals with desirable features (b) crossing these individuals to produc... View Answer
• Describe natural selection with reference to: (a) genetic variation within populations (b) production of many offspring (c) struggle for survival, inc... View Answer
• Explain the adaptive features of hydrophytes and xerophytes to their environments... View Answer
• Interpret images or other information about a species to describe its adaptive features... View Answer
• Describe an adaptive feature as an inherited feature that helps an organism to survive and reproduce in its environment... View Answer
• Describe gene mutation as a random change in the base sequence of DNA View Answer
• State that ionising radiation and some chemicals increase the rate of mutation View Answer
• State that mutation is the way in which new alleles are formed View Answer
• Describe mutation as genetic change View Answer
• State that discontinuous variation is usually caused by genes only and continuous variation is caused by both genes and the environment... View Answer
• State that discontinuous variation results in a limited number of phenotypes with no intermediates; examples include ABO blood groups, seed shape in p... View Answer
• State that continuous variation results in a range of phenotypes between two extremes; examples include body length and body mass... View Answer
• Use genetic diagrams to predict the results of monohybrid crosses involving codominance or sex linkage and calculate phenotypic ratios... View Answer
• Describe red-green colour blindness as an example of sex linkage View Answer
• Describe a sex-linked characteristic as a feature in which the gene responsible is located on a sex chromosome and that this makes the characteristic ... View Answer
• Explain the inheritance of ABO blood groups: phenotypes are A, B, AB and O blood groups and alleles are IA, IB and Io... View Answer
• Describe codominance as a situation in which both alleles in heterozygous organisms contribute to the phenotype... View Answer
• Explain how to use a test cross to identify an unknown genotype View Answer
• Use Punnett squares in crosses which result in more than one genotype to work out and show the possible different genotypes... View Answer
• Use genetic diagrams to predict the results of monohybrid crosses and calculate phenotypic ratios, limited to 1:1 and 3:1 ratios... View Answer
• Interpret pedigree diagrams for the inheritance of a given characteristic View Answer
• Describe a recessive allele as an allele that is only expressed when there is no dominant allele of the gene present in the genotype... View Answer
• Describe a dominant allele as an allele that is expressed if it is present in the genotype... View Answer
• State that a heterozygous individual will not be pure-breeding View Answer
• Describe heterozygous as having two different alleles of a particular gene View Answer
• Describe homozygous as having two identical alleles of a particular gene View Answer
• Describe phenotype as the observable features of an organism View Answer
• Describe genotype as the genetic make-up of an organism and in terms of the alleles present... View Answer
• Describe meiosis as a reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells (de... View Answer
• State that during mitosis, the copies of chromosomes separate, maintaining the chromosome number in each daughter cell... View Answer
• State that the exact replication of chromosomes occurs before mitosis View Answer
• State the role of mitosis in growth, repair of damaged tissues, replacement of cells and asexual reproduction... View Answer
• Describe mitosis as nuclear division giving rise to genetically identical cells (details of the stages of mitosis are not required)... View Answer
• State that in a diploid cell, there is a pair of each type of chromosome and in a human diploid cell there are 23 pairs... View Answer
• Describe a diploid nucleus as a nucleus containing two sets of chromosomes View Answer
• Explain that most body cells in an organism contain the same genes, but many genes in a particular cell are not expressed because the cell only makes ... View Answer
• Explain how a protein is made, limited to: • the gene coding for the protein remains in the nucleus • messenger RNA (mRNA) is a copy of a gene • mRNA ... View Answer
• Explain that DNA controls cell function by controlling the production of proteins, including enzymes, membrane carriers and receptors for neurotransmi... View Answer
• Explain that different sequences of amino acids give different shapes to protein molecules... View Answer
• State that the sequence of bases in a gene determines the sequence of amino acids used to make a specific protein (knowledge of the details of nucleot... View Answer
• Describe the inheritance of sex in humans with reference to X and Y chromosomes View Answer
• State that chromosomes are made of DNA, which contains genetic information in the form of genes... View Answer
• Explain the importance of excretion, limited to toxicity of urea View Answer
• Describe deamination as the removal of the nitrogen-containing part of amino acids to form urea... View Answer
• State that urea is formed in the liver from excess amino acids View Answer
• Outline the structure and function of a nephron and its associated blood vessels, limited to: (a) the role of the glomerulus in the filtration from th... View Answer
• Identify in diagrams and images the structure of the kidney, limited to the cortex and medulla... View Answer
• Identify in diagrams and images the kidneys, ureters, bladder and urethra View Answer
• State that the kidneys excrete urea and excess water and ions View Answer
• State that carbon dioxide is excreted through the lungs View Answer
• Explain how the spread of STIs is controlled View Answer
• Describe the methods of transmission of HIV View Answer
• State that HIV infection may lead to AIDS View Answer
• State that human immunodeficiency virus (HIV) is a pathogen that causes an STI View Answer
• Describe a sexually transmitted infection (STI) as an infection that is transmitted through sexual contact... View Answer
• Explain the role of hormones in controlling the menstrual cycle and pregnancy, limited to FSH, LH, progesterone and oestrogen... View Answer
• Describe the sites of production of oestrogen and progesterone in the menstrual cycle and in pregnancy... View Answer
• Describe the menstrual cycle in terms of changes in the ovaries and in the lining of the uterus... View Answer
• State that some pathogens and toxins can pass across the placenta and affect the fetus... View Answer
• Describe the function of the placenta and umbilical cord in relation to the exchange of dissolved nutrients, gases and excretory products between the ... View Answer
• Identify on diagrams and state the functions of the following in the development of the fetus: umbilical cord, placenta, amniotic sac and amniotic flu... View Answer
• State that in early development, the zygote forms an embryo which is a ball of cells that implants into the lining of the uterus... View Answer
• Compare male and female gametes in terms of: size, structure, motility and numbers... View Answer
• Explain the adaptive features of egg cells, limited to: energy stores and the jelly coat that changes at fertilisation... View Answer
• Explain the adaptive features of sperm, limited to: flagellum, mitochondria and enzymes in the acrosome... View Answer
• Describe fertilisation as the fusion of the nuclei from a male gamete (sperm) and a female gamete (egg cell)... View Answer
• Identify on diagrams and state the functions of the following parts of the female reproductive system: ovaries, oviducts, uterus, cervix and vagina... View Answer
• Identify on diagrams and state the functions of the following parts of the male reproductive system: testes, scrotum, sperm ducts, prostate gland, ure... View Answer
• Describe the growth of the pollen tube and its entry into the ovule followed by fertilisation (details of production of endosperm and development are ... View Answer
• Describe cross-pollination as the transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same spe... View Answer
• Describe self-pollination as the transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the s... View Answer
• Investigate and describe the environmental conditions that affect germination of seeds, limited to the requirement for: water, oxygen and a suitable t... View Answer
• Describe the structural adaptations of insect-pollinated and wind-pollinated flowers... View Answer
• State that fertilisation occurs when a pollen nucleus fuses with a nucleus in an ovule... View Answer
• Describe pollination as the transfer of pollen grains from an anther to a stigma View Answer
• Distinguish between the pollen grains of insect-pollinated and wind-pollinated flowers... View Answer
• Identify in diagrams and images and describe the anthers and stigmas of a wind-pollinated flower... View Answer
• State the functions of the structures – sepals, petals, stamens, filaments, anthers, carpels, style, stigma, ovary and ovules... View Answer
• Identify in diagrams and images and draw the following parts of an insect-pollinated flower: sepals, petals, stamens, filaments, anthers, carpels, sty... View Answer
• Discuss the advantages and disadvantages of sexual reproduction: (a) to a population of a species in the wild (b) to crop production... View Answer
• State that nuclei of gametes are haploid and that the nucleus of a zygote is diploid... View Answer
• Describe fertilisation as the fusion of the nuclei of gametes View Answer
• Describe sexual reproduction as a process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are ... View Answer
• Discuss the advantages and disadvantages of asexual reproduction: (a) to a population of a species in the wild (b) to crop production... View Answer
• Identify examples of asexual reproduction in diagrams, images and information provided... View Answer
• Describe asexual reproduction as a process resulting in the production of genetically identical offspring from one parent... View Answer
• Explain how using antibiotics only when essential can limit the development of resistant bacteria such as MRSA... View Answer
• State that some bacteria are resistant to antibiotics which reduces the effectiveness of antibiotics... View Answer
• Describe the use of antibiotics for the treatment of bacterial infections View Answer
• Explain the role of auxin in controlling shoot growth, limited to: (a) auxin is made in the shoot tip (b) auxin diffuses through the plant from the sh... View Answer
• Explain phototropism and gravitropism of a shoot as examples of the chemical control of plant growth... View Answer
• Investigate and describe gravitropism and phototropism in shoots and roots View Answer
• Describe phototropism as a response in which parts of a plant grow towards or away from the direction of the light source... View Answer
• Describe the maintenance of a constant internal body temperature in mammals in terms of: insulation, sweating, shivering and the role of the brain 8 D... View Answer
• Outline the treatment of Type 1 diabetes 6 Identify in diagrams and images of the skin: hairs, hair erector muscles, sweat glands, receptors, sensory ... View Answer
• Describe the control of blood glucose concentration by the liver and the roles of insulin and glucagon... View Answer
• Explain the concept of homeostatic control by negative feedback with reference to a set point... View Answer
• State that insulin decreases blood glucose concentration View Answer
• Describe the role of adrenaline in the control of metabolic activity, limited to: (a) increasing the blood glucose concentration (b) increasing heart ... View Answer
• State that glucagon is secreted by the pancreas View Answer
• Describe adrenaline as the hormone secreted in ‘fight or flight’ situations and its effects, limited to: (a) increased breathing rate (b) increased he... View Answer
• Identify in diagrams and images specific endocrine glands and state the hormones they secrete, limited to: (a) adrenal glands and adrenaline (b) pancr... View Answer
• Describe a hormone as a chemical substance, produced by a gland and carried by the blood, which alters the activity of one or more specific target org... View Answer
• Identify in diagrams and images the position of the fovea and state its function View Answer
• Outline the function of rods and cones, limited to: (a) greater sensitivity of rods for night vision (b) three different kinds of cones, absorbing lig... View Answer
• Describe the distribution of rods and cones in the retina of a human View Answer
• Explain the pupil reflex in terms of the antagonistic action of circular and radial muscles in the iris... View Answer
• Explain the pupil reflex, limited to changes in light intensity and pupil diameter... View Answer
• Describe the function of each part of the eye, limited to: (a) cornea – refracts light (b) iris – controls how much light enters the pupil (c) lens – ... View Answer
• Identify in diagrams and images the structures of the eye, limited to: cornea, iris, pupil, lens, retina, optic nerve and blind spot... View Answer
• Describe sense organs as groups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicals... View Answer
• State that synapses ensure that impulses travel in one direction only View Answer
• Describe the events at a synapse as: (a) an impulse stimulates the release of neurotransmitter molecules from vesicles into the synaptic gap (b) the n... View Answer
• Describe the structure of a synapse, including the presence of vesicles containing neurotransmitter molecules, the synaptic gap and receptor proteins... View Answer
• Describe a synapse as a junction between two neurones View Answer
• Describe a reflex action as a means of automatically and rapidly integrating and coordinating stimuli with the responses of effectors (muscles and gla... View Answer
• Describe a simple reflex arc in terms of: receptor, sensory neurone, relay neurone, motor neurone and effector... View Answer
• Identify in diagrams and images sensory, relay and motor neurones View Answer
• Describe the role of the nervous system as coordination and regulation of body functions... View Answer
• Describe the mammalian nervous system in terms of: (a) the central nervous system (CNS) consisting of the brain and the spinal cord (b) the peripheral... View Answer
• Outline how the oxygen debt is removed after exercise, limited to: (a) continuation of fast heart rate to transport lactic acid in the blood from the ... View Answer
• State that lactic acid builds up in muscles and blood during vigorous exercise causing an oxygen debt... View Answer
• State the balanced chemical equation for anaerobic respiration in yeast as: C6H12O6 → 2C2H5OH + 2CO2... View Answer
• State the word equation for anaerobic respiration in muscles during vigorous exercise as: glucose → lactic acid... View Answer
• State the word equation for anaerobic respiration in yeast as: glucose → alcohol + carbon dioxide... View Answer
• State that anaerobic respiration releases much less energy per glucose molecule than aerobic respiration... View Answer
• Describe anaerobic respiration as the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen... View Answer
• State the balanced chemical equation for aerobic respiration as: C6H12O6 + 6O2 → 6CO2 + 6H2O... View Answer
• State the word equation for aerobic respiration as: glucose + oxygen → carbon dioxide + water... View Answer
• Describe aerobic respiration as the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy... View Answer
• State the uses of energy in living organisms, including: muscle contraction, protein synthesis, cell division, active transport, growth, the passage o... View Answer
• Explain the role of goblet cells, mucus and ciliated cells in protecting the breathing system from pathogens and particles... View Answer
• Explain the link between physical activity and the rate and depth of breathing in terms of: an increased carbon dioxide concentration in the blood, wh... View Answer
• Explain the differences in composition between inspired and expired air View Answer
• Explain the role of the ribs, the internal and external intercostal muscles and the diaphragm in producing volume and pressure changes in the thorax l... View Answer
• State the function of cartilage in the trachea View Answer
• Identify in diagrams and images the internal and external intercostal muscles View Answer
• Investigate and describe the effects of physical activity on the rate and depth of breathing... View Answer
• Describe the differences in composition between inspired and expired air, limited to: oxygen, carbon dioxide and water vapour... View Answer
• Investigate the differences in composition between inspired and expired air using limewater as a test for carbon dioxide... View Answer
• Identify in diagrams and images the following parts of the breathing system: lungs, diaphragm, ribs, intercostal muscles, larynx, trachea, bronchi, br... View Answer
• Describe the features of gas exchange surfaces in humans, limited to: large surface area, thin surface, good blood supply and good ventilation with ai... View Answer
• Explain that the cholera bacterium produces a toxin that causes secretion of chloride ions into the small intestine, causing osmotic movement of water... View Answer
• Describe cholera as a disease caused by a bacterium which is transmitted in contaminated water... View Answer
• State that memory cells are not produced in passive immunity View Answer
• Explain that passive immunity is a short-term defence against a pathogen by antibodies acquired from another individual, including across the placenta... View Answer
• Explain the role of vaccination in controlling the spread of diseases View Answer
• Outline the process of vaccination: (a) weakened pathogens or their antigens are put into the body (b) the antigens stimulate an immune response by ly... View Answer
• State that specific antibodies have complementary shapes which fit specific antigens... View Answer
• Describe antibodies as proteins that bind to antigens leading to direct destruction of pathogens or marking of pathogens for destruction by phagocytes... View Answer
• Describe active immunity as defence against a pathogen by antibody production in the body... View Answer
• Explain the importance of the following in controlling the spread of disease: (a) a clean water supply (b) hygienic food preparation (c) good personal... View Answer
• Describe the body defences, limited to: skin, hairs in the nose, mucus, stomach acid and white blood cells... View Answer
• State that a pathogen is transmitted: (a) by direct contact, including through blood and other body fluids (b) indirectly, including from contaminated... View Answer
• Describe the process of clotting as the conversion of fibrinogen to fibrin to form a mesh... View Answer
• State the functions of: (a) lymphocytes – antibody production (b) phagocytes – engulfing pathogens by phagocytosis... View Answer
• Identify lymphocytes and phagocytes in photomicrographs and diagrams View Answer
• State the roles of blood clotting as preventing blood loss and the entry of pathogens... View Answer
• State the functions of the following components of blood: (a) red blood cells in transporting oxygen, including the role of haemoglobin (b) white bloo... View Answer
• Identify red and white blood cells in photomicrographs and diagrams View Answer
• List the components of blood as: red blood cells, white blood cells, platelets and plasma... View Answer
• Identify, in diagrams and images, the main blood vessels to and from the liver as: hepatic artery, hepatic veins and hepatic portal vein... View Answer
• Explain how the structure of capillaries is related to their functions View Answer
• Explain how the structure of arteries and veins is related to the pressure of the blood that they transport... View Answer
• Identify in diagrams and images the main blood vessels to and from the: (a) heart, limited to: vena cava, aorta, pulmonary artery and pulmonary vein (... View Answer
• State the functions of capillaries View Answer
• Describe the structure of arteries, veins and capillaries, limited to: relative thickness of wall, diameter of the lumen and the presence of valves in... View Answer
• Explain the effect of physical activity on the heart rate View Answer
• Describe the functioning of the heart in terms of the contraction of muscles of the atria and ventricles and the action of the valves... View Answer
• Explain the importance of the septum in separating oxygenated and deoxygenated blood... View Answer
• Explain the relative thickness of: (a) the muscle walls of the left and right ventricles (b) the muscle walls of the atria compared to those of the ve... View Answer
• Identify in diagrams and images the atrioventricular and semilunar valves in the mammalian heart... View Answer
• Discuss the roles of diet and exercise in reducing the risk of coronary heart disease... View Answer
• Describe coronary heart disease in terms of the blockage of coronary arteries and state the possible risk factors including: diet, lack of exercise, s... View Answer
• Investigate and describe the effect of physical activity on the heart rate View Answer
• State that the activity of the heart may be monitored by: ECG, pulse rate and listening to sounds of valves closing... View Answer
• Describe the single circulation of a fish View Answer
• Describe the circulatory system as a system of blood vessels with a pump and valves to ensure one-way flow of blood... View Answer
• Explain why some parts of a plant may act as a source and a sink at different times... View Answer
• Describe: (a) sources as the parts of plants that release sucrose or amino acids (b) sinks as the parts of plants that use or store sucrose or amino a... View Answer
• Explain how and why wilting occurs View Answer
• Explain the effects on the rate of transpiration of varying the following factors: temperature, wind speed and humidity... View Answer
• Explain how water vapour loss is related to: the large internal surface area provided by the interconnecting air spaces between mesophyll cells and th... View Answer
• Investigate and describe the effects of variation of temperature and wind speed on transpiration rate... View Answer
• State that water evaporates from the surfaces of the mesophyll cells into the air spaces and then diffuses out of the leaves through the stomata as wa... View Answer
• Describe transpiration as the loss of water vapour from leaves View Answer
• Investigate, using a suitable stain, the pathway of water through the above-ground parts of a plant... View Answer
• Outline the pathway taken by water through the root, stem and leaf as: root hair cells, root cortex cells, xylem, mesophyll cells... View Answer
• Identify in diagrams and images the position of xylem and phloem as seen in sections of roots, stems and leaves of non-woody dicotyledonous plants... View Answer
• State the functions of xylem and phloem: (a) xylem – transport of water and mineral ions, and support (b) phloem – transport of sucrose and amino acid... View Answer
• Describe the roles of capillaries and lacteals in villi View Answer
• Describe the structure of a villus View Answer
• Explain the significance of villi and microvilli in increasing the internal surface area of the small intestine... View Answer
• State that most water is absorbed from the small intestine but that some is also absorbed from the colon... View Answer
• Explain that bile is an alkaline mixture that neutralises the acidic mixture of food and gastric juices entering the duodenum from the stomach, to pro... View Answer
• Describe the digestion of protein by proteases in the digestive system: (a) pepsin breaks down protein in the acidic conditions of the stomach (b) try... View Answer
• Describe the digestion of starch in the digestive system: (a) amylase breaks down starch to maltose (b) maltase breaks down maltose to glucose on the ... View Answer
• Describe the functions of hydrochloric acid in gastric juice, limited to killing harmful microorganisms in food and providing an acidic pH for optimum... View Answer
• State where, in the digestive system, amylase, protease and lipase are secreted and where they act... View Answer
• Describe the functions of enzymes as follows: (a) amylase breaks down starch to simple reducing sugars (b) proteases break down protein to amino acids... View Answer
• State the role of chemical digestion in producing small soluble molecules that can be absorbed... View Answer
• Describe chemical digestion as the breakdown of large insoluble molecules into small soluble molecules... View Answer
• Outline the role of bile in emulsifying fats and oils to increase the surface area for chemical digestion... View Answer
• Describe the function of the stomach in physical digestion View Answer
• Identify in diagrams and images the types of human teeth: incisors, canines, premolars and molars... View Answer
• Describe physical digestion as the breakdown of food into smaller pieces without chemical change to the food molecules... View Answer
• Describe the functions of the organs of the digestive system in relation to: (a) ingestion – the taking of substances, e.g. food and drink, into the ... View Answer
• Identify in diagrams and images the main organs of the digestive system, limited to: (a) alimentary canal: mouth, oesophagus, stomach, small intestine... View Answer
• State the causes of scurvy and rickets View Answer
• State the principal dietary sources and describe the importance of: (a) carbohydrates (b) fats and oils (c) proteins (d) vitamins, limited to C and D ... View Answer
• Describe what is meant by a balanced diet View Answer
• Identify in diagrams and images the following structures in the leaf of a dicotyledonous plant: chloroplasts, cuticle, guard cells and stomata, upper ... View Answer
• Investigate and describe the effect of light and dark conditions on gas exchange in an aquatic plant using hydrogencarbonate indicator solution... View Answer
• Investigate and describe the effects of varying light intensity, carbon dioxide concentration and temperature on the rate of photosynthesis... View Answer
• Explain the importance of: (a) nitrate ions for making amino acids (b) magnesium ions for making chlorophyll... View Answer
• State that chlorophyll transfers energy from light into energy in chemicals, for the synthesis of carbohydrates... View Answer
• State the word equation for photosynthesis as: carbon dioxide + water → glucose + oxygen in the presence of light and chlorophyll... View Answer
• Describe photosynthesis as the process by which plants synthesise carbohydrates from raw materials using energy from light... View Answer
• Explain the effect of changes in pH on enzyme activity in terms of shape and fit and denaturation... View Answer
• Explain the effect of changes in temperature on enzyme activity in terms of kinetic energy, shape and fit, frequency of effective collisions and denat... View Answer
• Explain the specificity of enzymes in terms of the complementary shape and fit of the active site with the substrate... View Answer
• Explain enzyme action with reference to: active site, enzyme-substrate complex, substrate and product... View Answer
• Investigate and describe the effect of changes in temperature and pH on enzyme activity with reference to optimum temperature and denaturation... View Answer
• Describe enzyme action with reference to the shape of the active site of an enzyme being complementary to its substrate and the formation of products... View Answer
• Describe why enzymes are important in all living organisms in terms of a reaction rate necessary to sustain life... View Answer
• Describe enzymes as proteins that are involved in all metabolic reactions, where they function as biological catalysts... View Answer
• Describe the structure of a DNA molecule: (a) two strands coiled together to form a double helix (b) each strand contains chemicals called bases (c) b... View Answer
• Describe the use of: (a) iodine solution test for starch (b) Benedict’s solution test for reducing sugars (c) biuret test for proteins (d) ethanol emu... View Answer
• State that large molecules are made from smaller molecules, limited to: (a) starch, glycogen and cellulose from glucose (b) proteins from amino acids ... View Answer
• List the chemical elements that make up: carbohydrates, fats and proteins View Answer
• State that protein carriers move molecules or ions across a membrane during active transport... View Answer
• Explain the importance of active transport as a process for movement of molecules or ions across membranes, including ion uptake by root hairs... View Answer
• Describe active transport as the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentratio... View Answer
• Explain the importance of water potential and osmosis in the uptake and loss of water by organisms... View Answer
• Explain the effects on plant cells of immersing them in solutions of different concentrations by using the terms: turgid, turgor pressure, plasmolysis... View Answer
• Describe osmosis as the net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential... View Answer
• State that plants are supported by the pressure of water inside the cells pressing outwards on the cell wall... View Answer
• Investigate and describe the effects on plant tissues of immersing them in solutions of different concentrations... View Answer
• State that water moves into and out of cells by osmosis through the cell membrane... View Answer
• State that water diffuses through partially permeable membranes by osmosis View Answer
• Describe the importance of diffusion of gases and solutes in living organisms View Answer
• State that some substances move into and out of cells by diffusion through the cell membrane... View Answer
• State that the energy for diffusion comes from the kinetic energy of random movement of molecules and ions... View Answer
• Describe diffusion as the net movement of particles from a region of their higher concentration to a region of their lower concentration (i.e. down a ... View Answer
• Calculate magnification and size of biological specimens using millimetres as units... View Answer
• State and use the formula: magnification = image size ÷ actual size View Answer
• Describe the meaning of the terms: cell, tissue, organ, organ system and organism as illustrated by examples given in the syllabus... View Answer
• State that specialised cells have specific functions, limited to: (a) ciliated cells – movement of mucus in the trachea and bronchi (b) root hair cell... View Answer
• State that new cells are produced by division of existing cells View Answer
• Describe the structure of a bacterial cell, limited to: cell wall, cell membrane, cytoplasm, ribosomes, circular DNA, plasmids... View Answer
• Describe and compare the structure of a plant cell with an animal cell, limited to: cell wall, cell membrane, nucleus, cytoplasm, chloroplasts, riboso... View Answer
• State the main features used to place organisms into groups within the animal kingdom, limited to: (a) the main groups of vertebrates: mammals, birds,... View Answer
• State the main features used to place animals and plants into the appropriate kingdoms... View Answer
• Explain that classification systems aim to reflect evolutionary relationships View Answer
• Construct and use dichotomous keys based on identifiable features View Answer
• Describe the binomial system of naming species as an internationally agreed system in which the scientific name of an organism is made up of two parts... View Answer
• Describe a species as a group of organisms that can reproduce to produce fertile offspring... View Answer
• State that organisms can be classified into groups by the features that they share... View Answer
• Describe the characteristics of living organisms by describing: (a) movement as an action by an organism or part of an organism causing a change of po... View Answer