Flashcards

• Explain the structure of human sperm with a neat labelled diagram. View Answer
• Describe a transmissible disease as a disease in which the pathogen can be passed from one host to another... View Answer
• Describe that a double circulation provides a low pressure circulation to the lungs and a high pressure circulation to the body tissues... View Answer
• Describe the functions of the types of human teeth in physical digestion of food View Answer
• How does the staining process with fast green differ from that with safranin View Answer
• What are the most effective dyes for staining xylem vessels in plant stems View Answer
• What types of stains are best for visualizing water pathways in plant stems View Answer
• Investigate, using a suitable stain, the pathway of water in a cut stem 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 how fish stocks can be conserved using education, closed seasons, protected areas, controlled net types and mesh size, quotas and monitoring... View Answer
• Explain how forests can be conserved using education, protected areas, quotas and replanting... View Answer
• Discuss reasons for conservation of species with reference to: (a) maintenance of biodiversity (b) reducing extinction (c) protecting vulnerable envir... View Answer
• Describe the harmful effects of: (a) water pollution by untreated sewage and nitrogen-containing fertilisers leading to eutrophication, limited to: (i... View Answer
• Describe the impacts humans have through: (a) over-harvesting of plant and animal species (b) introducing a non-native species to an ecosystem... View Answer
• Outline the causes and describe the consequences of deforestation, limited to its effects on: biodiversity, extinction, loss of soil, flooding and con... View Answer
• Describe that the growth of the human population is increasing the demand for global resources... View Answer
• Identify and state the factors affecting the rate of population growth for a population of an organism, limited to: food supply, competition, predatio... View Answer
• Outline the role of fungi and bacteria in decomposition View Answer
• Explain why it is more energy efficient for humans to eat crop plants than to eat livestock that have been fed on crop plants... View Answer
• Explain 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 inefficient... View Answer
• Describe food webs as networks of interconnected food chains and construct and interpret them... View Answer
• Describe the terms producer, consumer, herbivore, carnivore and decomposer View Answer
• Construct and interpret simple food chains View Answer
• Describe the flow of energy through food chains and webs including energy from light and energy in living organisms and its eventual transfer to the e... View Answer
• Explain why most forms of life are completely dependent on photosynthesis View Answer
• Describe that the Sun is the principal source of energy input to most biological systems... View Answer
• Discuss potential advantages and risks of genetic modification, limited to modifying crop plants and bacteria... View Answer
• Outline the use of genetic modification in crop plants by inserting genes: (a) to confer resistance to herbicides (b) to confer resistance to insect p... View Answer
• Explain that the gene that controls the production of human insulin has been inserted into bacterial DNA, for commercial production of insulin... View Answer
• Describe genetic modification as changing the genetic material of an organism by removing, changing or inserting individual genes... View Answer
• Describe the use of: (a) enzymes in biological washing powders (b) pectinase for fruit juice production (c) lactase for lactose-free milk... View Answer
• Describe how fermenters can be used for the large-scale production of useful products by bacteria and fungi, including the conditions that need to be ... View Answer
• Discuss why bacteria are useful in biotechnology and genetic modification, limited to: (a) no ethical concerns over their manipulation and growth (b) ... View Answer
• Describe that bacteria are useful in biotechnology and genetic modification due to their rapid reproduction rate and their ability to make complex mol... View Answer
• Explain the role of yeast in the production of bread and ethanol View Answer
• Describe the role of artificial selection in the production of economically important plants and animals... View Answer
• Describe artificial selection (selective breeding) with reference to: (a) selection by humans of animals or plants with desirable features (b) crossin... View Answer
• Describe the development of strains of antibiotic-resistant bacteria, including MRSA, as an example of natural selection... View Answer
• Describe how the inherited features of a population can evolve over time as a result of natural selection... View Answer
• Describe natural selection with reference to: (a) variation within populations (b) production of many offspring (c) struggle for survival, including c... View Answer
• Understand that ionising radiation and some chemicals increase the rate of mutation... View Answer
• State that mutation, meiosis, random mating and random fertilisation are sources of genetic variation in populations... View Answer
• Describe a chromosome mutation as a change in the chromosome number or structure, using Down’s syndrome as an example (47 chromosomes instead of 46)... View Answer
• Describe a gene mutation as a random change in the base sequence of DNA, using sickle cell anaemia as an example... View Answer
• Describe the determination of sex in humans (XX and XY chromosomes) View Answer
• State that two identical homozygous individuals that breed together will be pure-breeding... View Answer
• Explain why observed ratios often differ from expected ratios, especially when there are small numbers of offspring... View Answer
• Use genetic diagrams, including Punnett squares, to predict the results of monohybrid crosses and calculate phenotypic ratios, limited to 1:1 and 3:1 ... View Answer
• Understand and use the terms: dominant, recessive, phenotype, genotype, homozygous and heterozygous... View Answer
• Define an allele as an alternative form of a gene View Answer
• Describe inheritance as the transmission of genetic information from generation to generation... View Answer
• Describe that different sequences of amino acids give different shapes to protein molecules... View Answer
• Describe that the sequence of bases in a gene determines the sequence of amino acids needed to make a specific protein (knowledge of the details of nu... View Answer
• Explain that DNA controls cell function by controlling the production of proteins, including enzymes... View Answer
• Define a gene as a length of DNA that codes for a protein View Answer
• Investigate and describe examples of continuous and discontinuous variation View Answer
• Describe that discontinuous variation is usually caused by genes only and continuous variation is caused by genes and the environment... View Answer
• Describe that discontinuous variation results in a limited number of phenotypes with no intermediates, including ABO blood groups, seed shape and seed... View Answer
• Describe variation as differences between individuals of the same species View Answer
• State that some viruses can pass across the placenta and affect the fetus View Answer
• Identify, on diagrams, the placenta and umbilical cord and describe their functions in relation to the exchange of dissolved nutrients, gases and excr... View Answer
• State the functions of the amniotic sac and the amniotic fluid View Answer
• Describe the early development of the zygote, limited to the formation of a ball of cells (embryo) that becomes implanted in the lining of the uterus... View Answer
• Explain the roles of follicle-stimulating hormone (FSH), luteinising hormone (LH), oestrogen and progesterone in controlling the menstrual cycle... View Answer
• Describe the roles of testosterone and oestrogen in the development and regulation of secondary sexual characteristics during puberty... View Answer
• Compare male and female gametes in terms of size, structure, numbers and motility... View Answer
• Describe the process of germination, including the role of enzymes View Answer
• Investigate and state the environmental conditions that affect germination of seeds, limited to: suitable temperature, water and oxygen... View Answer
• Relate the features of wind-dispersed fruits and animal-dispersed fruits to their functions... View Answer
• Explain that seed and fruit dispersal by wind and by animals is a means of colonising new areas and of reducing competition... View Answer
• Investigate and describe the structure of a seed, limited to embryo (radicle, plumule and cotyledons) and testa... View Answer
• Understand that after fertilisation the ovules develop into seeds and the ovary develops into a fruit... View Answer
• Describe the growth of the pollen tube and its entry into the ovule followed by fertilisation (production of endosperm and details of development are ... View Answer
• Discuss the potential effects of self-pollination and cross-pollination on a population, in terms of variation, capacity to respond to changes in the ... View Answer
• Compare the flower structure and the pollen from insect-pollinated and wind-pollinated flow... View Answer
• Identify and draw the anthers and stigmas of a wind-pollinated flower View Answer
• Identify and draw the sepals, petals, stamens (anthers and filaments) and carpels (stigmas, styles, ovaries and ovules) of an insect-pollinated flower... View Answer
• Discuss the advantages and disadvantages of asexual reproduction and sexual reproduction... View Answer
• Identify examples of asexual reproduction View Answer
• Explain that cancers form as a result of uncontrolled cell division 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 meiosis is involved in the production of gametes View Answer
• Describe stem cells as unspecialised cells that divide by mitosis to produce daughter cells that can become specialised for specific functions... View Answer
• Outline the role of mitosis in growth, repair of damaged tissues, replacement of dying cells and asexual reproduction... 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 chromosomesDescribe a diploid nucleus as a nucleus containing two sets of chromosomes... View Answer
• Describe a haploid nucleus as a nucleus containing a single set of chromosomes View Answer
• Understand that chromosomes contain DNA, which carries genetic information in the form of genes... View Answer
• Investigate gravitropism and phototropism in shoots and roots View Answer
• Explain the role of auxin in controlling shoot growth, limited to: (a) auxin is made in the shoot tip (b) auxin spreads through the plant from the sho... View Answer
• Describe phototropism as a response in which parts of a plant grow towards or away from light... View Answer
• Describe gravitropism as a response in which parts of a plant grow towards or away from gravity... View Answer
• Describe the signs of Type 1 diabetes (limited to increased blood glucose concentration and glucose in urine) and its treatment (administration of ins... View Answer
• Describe the control of blood glucose concentration by the liver and pancreas and the roles of insulin and glucagon... View Answer
• Explain the need to control blood glucose concentration View Answer
• Explain how each of the following processes contributes to the maintenance of constant internal body temperature in mammals: (a) sweating (b) shiverin... View Answer
• Describe the roles of the hypothalamus and of temperature receptors in the skin in maintaining a constant internal body temperature in mammals... View Answer
• Describe the role of insulation in maintaining a constant internal body temperature in mammals... View Answer
• Describe homeostasis as the maintenance of a constant internal environment View Answer
• Compare nervous and hormonal control, limited to speed of action and duration of effect... View Answer
• Explain accommodation to view near and distant objects in terms of the contraction and relaxation of the ciliary muscles, tension in the suspensory li... View Answer
• Explain the pupil reflex in terms of light intensity and antagonistic action of circular and radial muscles in the iris... View Answer
• Identify, on a diagram, the structures of the eye, limited to: cornea, iris, pupil, lens, ciliary muscles, suspensory ligaments, retina, fovea, optic ... View Answer
• Describe that synapses ensure that impulses travel in one direction only View Answer
• Describe the events at a synapse: (a) an impulse stimulates the release of neurotransmitter molecules from vesicles into the synaptic gap (b) the neur... View Answer
• Describe simple reflex arcs in terms of receptor, sensory neurone, relay neurone, motor neurone and effector (muscles and glands)... View Answer
• State that electrical impulses travel along neurones View Answer
• Identify, on diagrams, sensory, relay and motor neurones View Answer
• Describe that the nervous system (brain, spinal cord and nerves) coordinates and regulates body functions... View Answer
• Describe deamination in the liver as the removal of the nitrogen-containing part of amino acids, resulting in the formation of urea... View Answer
• Describe the role of the liver in the assimilation of amino acids by converting them to proteins... View Answer
• Outline the function of a nephron and its associated blood vessels, limited to: (a) the role of the glomerulus in the filtration from the blood of wat... View Answer
• Explain the need for excretion, limited to toxicity of urea View Answer
• Identify, on diagrams, the kidneys, ureters, bladder and urethra and state the function of each (the function of the kidney should be described simply... View Answer
• State that urea is a toxic waste product produced in the liver from the breakdown of excess amino acids... View Answer
• State that carbon dioxide is a waste product of respiration, which is excreted through the lungs... View Answer
• Describe excretion as the removal of toxic materials and the waste products of metabolism from organisms... View Answer
• Outline how HIV affects the immune system, limited to: decreased lymphocyte numbers and reduced ability to produce antibodies, which weakens the immun... View Answer
• Describe that memory cells are not produced in passive immunity View Answer
• Explain the importance of breast-feeding for the development of passive immunity in infants... View Answer
• Explain the role of vaccination in controlling the spread of transmissible diseases... View Answer
• Outline the process of vaccination: (a) weakened pathogens or their antigens are given (b) the antigens stimulate an immune response by lymphocytes wh... View Answer
• Explain that active immunity is gained after an infection by a pathogen, or by vaccination... View Answer
• Describe that specific antibodies have complementary shapes which fit specific antigens... View Answer
• State that each pathogen has its own antigens, which have specific shapes View Answer
• Explain how development of antibiotic-resistant bacteria, including MRSA, can be minimised by using antibiotics only when essential... View Answer
• State that antibiotics kill bacteria but do not affect viruses View Answer
• Describe a drug as any substance taken into the body that modifies or affects chemical reactions in the body... View Answer
• Describe the effects of tobacco smoke and its major toxic components (nicotine, tar and carbon monoxide): strong association with bronchitis, emphysem... View Answer
• Describe the effects of excessive consumption of alcohol: reduced self-control, depressant, effect on reaction times, damage to liver and social impli... 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
• Explain the importance of a clean water supply, hygienic food preparation, good personal hygiene, waste disposal and sewage treatment in controlling t... View Answer
• Describe the role of the mosquito as a vector of disease View Answer
• Describe that a pathogen may be transmitted: (a) through direct contact, including through blood or other body fluids (b) indirectly, including from c... View Answer
• Describe a pathogen as a disease-causing organism View Answer
• List the components of blood as red blood cells, white blood cells, platelets and plasma... View Answer
• Describe the transfer of substances between blood in capillaries, tissue fluid and body cells... View Answer
• State the functions of the components of blood: (a) red blood cells – oxygen transport (b) white blood cells – antibody production by lymphocytes and ... View Answer
• Explain how the structure of arteries, veins and capillaries is related to the pressure of the blood that they transport... View Answer
• Describe, and identify on diagrams and photomicrographs, the structure of arteries, veins and capillaries, limited to: (a) relative thickness of wall ... View Answer
• Name the main blood vessels that carry blood to and from the heart, lungs, liver and kidneys, limited to: aorta, vena cava, pulmonary artery, pulmonar... View Answer
• Discuss the role 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, sedentary lifestyle,... View Answer
• Investigate and explain the effect of physical activity on heart rate View Answer
• State that blood is pumped away from the heart in arteries and returns to the heart in veins... 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 in a heartbeat... View Answer
• Explain the relative thickness: (a) of the muscle walls of the left and right ventricles (b) of the muscle walls of the atria compared to those of the... View Answer
• Outline how the oxygen debt is removed after exercise, limited to: (a) continuation of fast heart rate to transport lactic acid in blood from muscles ... View Answer
• Explain why lactic acid builds up in muscles and blood during vigorous exercise causing Excess Post-exercise Oxygen Consumption (EPOC) or an ‘oxygen d... View Answer
• State the word equation for anaerobic respiration in yeast View Answer
• State the word equation for anaerobic respiration in humans View Answer
• Describe anaerobic respiration as the release of a relatively small amount of energy by the breakdown of glucose without using oxygen... View Answer
• State the word equation and balanced chemical equation for aerobic respiration View Answer
• Describe aerobic respiration as the release of a relatively large amount of energy by the breakdown of glucose in the presence of oxygen... View Answer
• Investigate and describe the effect of temperature on respiration in yeast View Answer
• State the uses of energy in living organisms including muscle contraction, protein synthesis, cell division, active transport, growth, the passage of ... View Answer
• Describe respiration as the chemical reactions in all living cells that release energy from glucose... View Answer
• Explain the role of goblet cells, ciliated cells and mucus in protecting the gas exchange system from pathogens and particles... View Answer
• Investigate and explain the effect of physical activity on rate and depth of breathing... 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, ... View Answer
• Identify, on diagrams and images, the ribs, internal and external intercostal muscles and the diaphragm... View Answer
• Describe the characteristics of, and describe the role of, the exchange surface of the alveoli in gas exchange... View Answer
• Identify, on diagrams and images, the larynx, trachea, lungs, bronchi, bronchioles, alveoli and associated capillaries... View Answer
• Investigate and explain the differences between inspired and expired air View Answer
• State the percentages of the gases in atmospheric air View Answer
• Describe the features of gas exchange surfaces in humans, limited to: large surface area, thin surface, good blood and air supply... View Answer
• State the function of the hepatic portal vein as the route taken to the liver by most of the molecules and ions absorbed from the ileum... View Answer
• Understand that water is absorbed from the lumen of the small intestine and the colon, but that most absorption of water happens in the small intestin... View Answer
• Explain the significance of villi and microvilli in increasing the internal surface area of the ileum... View Answer
• Describe the structure of a villus and the roles of capillaries and lacteals View Answer
• Understand that assimilation is the uptake and use by cells of nutrients from the blood... View Answer
• Understand that absorption (by diffusion, osmosis and active transport) is the movement of nutrients from the intestines into cells lining the digesti... View Answer
• State that the small intestine is the region where nutrients are absorbed View Answer
• Describe peristalsis as waves of contractions of longitudinal and circular muscles which move food through the digestive system... View Answer
• Outline the role of bile in emulsifying fats to increase the surface area for the chemical digestion of fat to fatty acids and glycerol by lipase... View Answer
• Understand that the different proteases present in the stomach and the duodenum work best at different pH levels... View Answer
• Describe the function of hydrochloric acid in the stomach as killing ingested bacteria... View Answer
• Describe the functions of amylase, maltase, protease and lipase, listing the substrates and endproducts, limited to: (a) amylase breaks down starch to... View Answer
• State that physical digestion increases the surface area of food for the action of enzymes in chemical digestion... View Answer
• Explain why most foods must be digested before they can be absorbed View Answer
• Understand the concept of a balanced diet View Answer
• Name the diseases and describe the symptoms resulting from deficiencies of vitamin C (scurvy), vitamin D (rickets), calcium (rickets) and iron (anaemi... View Answer
• List the principal sources of, and describe the dietary importance of, carbohydrates, lipids, proteins, vitamins (C and D only), mineral salts (calciu... View Answer
• Relate the structure of xylem vessels to their function, limited to: (a) thick walls with lignin (details of lignification are not required) (b) no ce... View Answer
• State the functions of xylem as transport of water and mineral ions, and support View Answer
• Identify the positions of tissues as seen in transverse sections of non-woody dicotyledonous roots and stems, limited to: xylem, phloem and cortex... View Answer
• Describe translocation as the movement of sucrose and amino acids in the phloem from parts of plants that produce or release them (sources) to parts o... View Answer
• Explain the mechanism by which water moves upwards in the xylem in terms of a transpiration pull that draws up a column of water molecules, held toget... View Answer
• Investigate the effects of wind speed, light intensity and temperature variation on transpiration rate... View Answer
• Explain: (a) the effects of wind speed, and the variation of temperature, humidity and light intensity on transpiration rate (b) how wilting occurs... View Answer
• Understand that water evaporates from the surfaces of the mesophyll cells into air spaces and then diffuses out of the leaves through the stomata as w... View Answer
• Explain the importance of magnesium ions for making chlorophyll View Answer
• Explain the importance of nitrate ions for making amino acids, required for the production of proteins... View Answer
• Identify and label the cuticle, cellular and tissue structures of a dicotyledonous leaf, as seen in diagrams or photomicrographs, and explain how thes... View Answer
• State that most leaves have a large surface area and are thin, and explain how these features are adaptations for photosynthesis... View Answer
• Identify and explain the limiting factors of photosynthesis in different environmental conditions... View Answer
• Investigate the effect of varying light intensity, carbon dioxide concentration and temperature on the rate of photosynthesis using submerged aquatic ... View Answer
• Describe and explain the effect of varying light intensity, carbon dioxide concentration and temperature on the rate of photosynthesis... View Answer
• Investigate the need for chlorophyll, light and carbon dioxide for photosynthesis, using appropriate controls... View Answer
• State the word equation and balanced chemical equation for photosynthesis View Answer
• Outline the subsequent use and storage of the carbohydrates made in photosynthesis, limited to: (a) starch as an energy store (b) cellulose to build c... View Answer
• State that chlorophyll transfers light energy into chemical energy for the formation of glucose and other carbohydrates... View Answer
• State that chlorophyll is a green pigment that is found in chloroplasts View Answer
• Explain the effect of changes in temperature and pH on enzyme activity in terms of kinetic energy, shape and fit, denaturation and the frequency of ef... View Answer
• Investigate and describe the effects of temperature and pH on enzyme activity View Answer
• Describe that the progress of enzyme-catalysed reactions can be followed by measuring the concentrations of reactants and products... View Answer
• Explain the specificity of enzymes in terms of the complementary shape and fit of the active site with the substrate (‘lock and key’ hypothesis)... View Answer
• Explain enzyme action with reference to the substrate, active site, enzyme-substrate complex, and product... View Answer
• Describe enzymes as proteins that function as biological catalysts and are involved in all metabolic reactions... View Answer
• Describe a catalyst as a substance that increases the rate of a chemical reaction and is not changed by the reaction... View Answer
• Describe and be able to do chemical tests for: (a) starch (iodine solution) (b) glucose and maltose (Benedict’s solution) (c) protein (biuret test) (d... View Answer
• State that large molecules are made from smaller molecules, limited to: starch, cellulose and glycogen from glucose; proteins from amino acids; lipids... View Answer
• Explain the importance of active transport in ion uptake by root hair cells View Answer
• Describe active transport as the movement of molecules or ions into or out of a cell through the cell membrane, from a region of their lower concentra... View Answer
• Investigate osmosis using materials such as dialysis tubing View Answer
• Investigate and explain the effects on plant tissues of immersing them in solutions of different concentrations, using the terms turgid, turgor pressu... View Answer
• Describe the effects of osmosis on plant and animal tissues and explain the importance of water potential gradient and osmosis in the uptake and loss ... View Answer
• Understand that plants are supported by the pressure of water inside the cells pressing outwards on the cell wall... View Answer
• Investigate the factors that influence diffusion, limited to: surface area, temperature, concentration gradient and distance... View Answer
• Understand diffusion as the net movement of molecules or ions from a region of their higher concentration to a region of their lower concentration (i.... View Answer
• Understand that the energy for diffusion and osmosis comes from the kinetic energy of random movement of molecules and ions... View Answer
• Describe the role of water as a solvent in organisms with reference to digestion, excretion and transport... View Answer
• Describe that viruses can only replicate in living cells View Answer
• State the main features used to place organisms into groups within the plant kingdom, limited to ferns and flowering plants (dicotyledons and monocoty... 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 all organisms into one of the five kingdoms: Animal, Plant, Fungus, Prokaryote, Protoctist... 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
• Describe that organisms can be classified into groups by the features they share View Answer
• Understand the terms cell, tissue, organ, organ system and organism as illustrated by examples covered in the syllabus... View Answer
• Understand that cells can become specialised and that their structures are related to their specific functions, as illustrated by examples covered in ... View Answer
• What is the formula of Magnification? View Answer