Double award science - biology

B1: Humans as organisms

Cell activity
You should be able to:
B1.01 recall that a nucleus, cytoplasm and a cell membrane are present in most animal cells
B1.02 understand that substances move into and out of cells through the cell membrane by diffusion; define osmosis in terms of the movement of water molecules from a higher concentration of water to a lower concentration of water through a selectively permeable membrane; interpret data from experiments on osmosis
B1.03 understand that active transport across the cell membrane requires energy to move molecules from a low concentration to a high concentration
B1.04 recognise that the co-ordinated activity of organisms results from the action of cells adapted to different functions; relate the structure of a motor neurone (nerve cell) to its function

Nutrition
You should be able to:
B1.05 describe the functions of the mouth, oesophagus (gullet), stomach, small and large intestines, pancreas, liver and gall bladder
B1.06 understand the role of the muscular wall of the gut in peristalsis
B1.07 explain how the structure of villi (large surface area, single layer of cells and capillary network) allows efficient absorption of the soluble products of digestion
B1.08 understand the role of bile and of digestive enzymes: bile neutralises stomach acid and emulsifies fats; amylase digests starch to simple sugars; proteases (eg pepsin) digest proteins to amino acids; lipase digests fats to fatty acids and glycerol
B1.09 understand that enzymes are sensitive to temperature and pH; interpret data from experiments relating to digestion

Circulation
You should be able to:
B1.10 describe the composition of blood: plasma, red blood cells, white blood cells and platelets
B1.11 understand the roles of these components in: the transport of oxygen, nutrients, carbon dioxide, urea, hormones and thermal energy (heat); combating infection, including the ingestion of micro-organisms and the production of antibodies which destroy micro-organisms; blood clotting (to prevent blood loss and entry of micro-organisms)
B1.12 relate the structure of the heart to its function as a pump, including the roles of atria and ventricles, the valves in the heart and the coronary vessels
B1.13 relate the structure of arteries, veins and capillaries to their functions
B1.14 understand that substances, including oxygen, carbon dioxide, glucose and urea, are exchanged by diffusion between capillaries and tissues
B1.15 recall the plan of the double circulatory system, including aorta, vena cava and blood vessels, to and from lungs, kidneys and liver

Breathing and respiration
You should be able to:
B1.16 describe the structure of the thorax including ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes
B1.17 explain the role of the intercostal muscles and diaphragm in ventilating the lungs
B1.18 understand the similarities and differences between aerobic and anaerobic respiration; recall the word equation for anaerobic respiration in animal cells: glucose, lactic acid and energy released
B1.19 explain how vigorous exercise can result in an oxygen debt

Nervous coordination
You should be able to:
B1.20 recall that the central nervous system (brain and spinal cord) is linked to sense organs by nerves
B1.21 understand that stimulation of receptors in the sense organs sends electrical impulses along nerves into and then out of the central nervous system, resulting in rapid responses; describe the differences between voluntary and reflex responses
B1.22 describe the pathway taken by electrical impulses along a sensory neurone, a relay neurone and a motor neurone to an effector (muscle or gland); understand the role of transmitter chemicals at synapses; explain the removal of a finger from a hot object
B1.23 describe the role of the iris and pupil, retina and optic nerve in the iris reflex
B1.24 explain the role of cornea, ciliary body, suspensory ligaments and lens in forming sharp images of near and distant objects on the retina

Hormonal coordination
You should be able to:
B1.25 define hormones as chemicals released directly into the blood from glands: insulin from the pancreas, testosterone from the testes, oestrogen from the ovaries, progesterone from the ovaries and placenta, follicle stimulating hormone (FSH) and lutenising hormone (LH) from the pituitary gland
B1.26 explain the role of insulin in regulating the level of blood sugar and its use in treating diabetes
B1.27 describe the roles of oestrogen and testosterone in promoting secondary sexual characteristics and the production of gametes
B1.28 explain:
-the role in the menstrual cycle of FSH, oestrogen, LH and progesterone
-the use of sex hormones in the control and promotion of fertility
B1.29 describe the roles of adrenaline, released from the adrenal glands, in preparing the body for increased activity

Maintaining the internal environment
You should be able to:
B1.30 define homeostasis as the maintenance of a constant internal environment and understand why this is important
B1.31 explain how sweating and shivering help to maintain constant body temperature
B1.32 explain the role of vasodilation and vasoconstriction in temperature regulation
B1.33 recall that carbon dioxide is removed by the lungs in exhaled air
B1.34 recall that urea is removed by the kidneys in urine
B1.35 describe the structure of a nephron to include Bowman’s (renal) capsule and glomerulus, coiled tubules, collecting duct, arterioles and capillaries
B1.36 describe:
-ultrafiltration in Bowman’s capsule
-the composition of glomerular filtrate
-reabsorption in the coiled tubules
B1.37 explain the role of ADH in regulating the water content of the blood
B1.38 understand the roles of skin, stomach acid and blood in defending the body against infection
B1.39understand the role of the mucous membranes of the respiratory tract in defending the body against infection
B1.40 describe the harmful effects of:
-solvents on the lungs and neurones
-alcohol on reaction times, behaviour, liver and brain
-smoking tobacco on the occurrence of bronchitis, emphysema, lung cancer and addiction to nicotine ()
B1.41 evaluate the use and misuse of drugs, including antibiotics (eg penicillin), pain killers (eg aspirin and heroin), stimulants (eg caffeine and amphetamines), sedatives (eg barbiturates) and the dangers of contracting HIV and hepatitis by the use of intravenous drugs ()

B2: Green plants as organisms

Cell activity
You should be able to:
B2.01 recall that a plant cell has a nucleus, cytoplasm and a cell membrane; it also has a cellulose cell wall, a large vacuole and (in green parts of plants) chloroplasts
B2.02 recognise that the co-ordinated activity of organisms results from the adaptation of cells to different functions; relate the structure of a palisade leaf cell to its function

Nutrition
You should be able to:
B2.03 understand that carbon dioxide and water are converted to glucose and oxygen by photosynthesis using sunlight energy absorbed by chlorophyll, the green pigment contained in chloroplasts
B2.04 understand that carbon dioxide from the atmosphere diffuses in through stomata and oxygen diffuses out as a result of photosynthesis
B2.05 explain the pattern of gas exchange between a plant and the atmosphere resulting from photosynthesis and respiration over a 24 hour period
B2.06 describe how the rate of photosynthesis varies with carbon dioxide concentration, light intensity and temperature; interpret data from experiments relating to photosynthesis
B2.07 understand that plants use the glucose produced by photosynthesis for respiration to release energy, for conversion to starch for storage and to cellulose for cell walls, and as a component in protein synthesis
B2.08understand the need for mineral ions for healthy plant growth, including nitrates for protein synthesis and magnesium for chlorophyll; interpret data from water culture experiments

Water relations and transport
You should be able to:
B2.09explain how water is taken in by osmosis
B2.10understand the role of water in maintaining cell turgidity to support plant tissues
B2.11explain the uptake of mineral ions by active transport
B2.12 recall that the substances required for growth and reproduction are transported within plants in xylem (water and mineral ions) and in phloem (sugars and amino acids)
B2.13 understand how leaf structure (shape, cuticle, palisade layer, spongy layer, veins, guard cells and stomata) is adapted for photosynthesis and transpiration
B2.14 explain how leaves lose water by transpiration, including the evaporation of water within the leaf and diffusion of water vapour through stomata; interpret data from experiments relating to transpiration
B2.15describe how atmospheric conditions affect the rate of transpiration

Control of growth
You should be able to:
B2.16 recall that auxins influence cell division and the elongation of cells at the tips of roots and shoots
B2.17describe commercial applications of plant hormones: stimulating the growth of roots in cuttings; regulating the development of fruits; killing weeds by disrupting their normal growth pattern

B3: Variation, inheritance and evolution

Variation
You should be able to:
B3.01 recall that the nucleus of a cell contains chromosomes on which genes (units of inherited information) are located
B3.02 understand that each gene is a section of a molecule of DNA
B3.03 describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases (adenine with thymine and cytosine with guanine)
B3.04 understand that:
-variation between individuals arises from genetic and environmental causes and from a combination of both
-environmental conditions during growth and development cause variation between genetically identical individuals
B3.05 understand:
-that genes exist in alternative forms (alleles) which cause variation in inherited characteristics
-the terms dominant and recessive
-that some alleles cause diseases which can be inherited
B3.06 recall that:
-chromosomes are present as pairs in body cells and singly in gametes
-46 and 23 are the diploid and haploid numbers of chromosomes in human cells
B3.07 understand that division of a cell by mitosis produces two cells which contain identical sets of chromosomes for growth and replacement; interpret diagrams showing the overall behaviour of chromosomes during mitosis
B3.08 understand that division of a cell by meiosis produces four cells, each with half the number of chromosomes for the formation of genetically different haploid gametes during sexual reproduction; interpret simple diagrams and photographs showing stages in meiosis (technical terms not required)
B3.09define fertilisation as the fusion of haploid male and female gametes, restoring the diploid number of chromosomes in the zygote; explain the resulting genetic variation in the new generation of individuals
B3.10explain that asexual reproduction involves only one parent and gives rise to genetically identical offspring (clones)
B3.11 recall that a mutation is a change in a gene, DNA or the number of chromosomes in a cell, which leads to genetic variation
B3.12 understand that many mutations are harmful, some are neutral and a few are beneficial and can increase in the population by natural selection
B3.13 understand that exposure to ionising radiation (including gamma rays, ultraviolet rays and X-rays) and some chemical mutagens (including chemicals in tobacco) increase the incidence of mutations

Inheritance
You should be able to:
B3.14 recall that the sex of a person is controlled by one pair of chromosomes, XX in a female or XY in a male, and describe the determination of the sex of offspring at fertilisation, using a genetic diagram
B3.15describe the mechanism of monohybrid inheritance using a crossing diagram
B3.16 understand how individuals can be homozygous or heterozygous for particular alleles; distinguish between genotype and phenotype
B3.17 predict probabilities of inheritance from parents using genetic diagrams
B3.18explain family trees showing the inheritance of polydactyly (dominant allele) and cystic fibrosis (recessive allele)
B3.19 describe some of the implications of the outcome of the Human Genome Project
B3.20 describe how selective breeding is used to develop crop plants and agricultural animals with desirable characteristics such as resistance to disease and high yields
B3.21 understand that cloning is used to produce large numbers of identical individuals with desirable characteristics (eg plant cuttings)
B3.22 describe the ethical implications of selective breeding and cloning
B3.23 describe how the transfer of a required gene from a donor to a recipient, including the use of restriction enzymes and ligase, can produce genetically modified organisms
B3.24 evaluate the ethical implications of genetic modification

Evolution
You should be able to:
B3.25 understand that fossils provide evidence of evolution
B3.26 describe how inherited variation can lead to evolution or extinction by the process of natural selection

B4: Living organism in their environment

Humans and the environment
You should be able to:
B4.01 understand the principles of interdependence, adaptation, competition and predation; explain how these factors influence the distribution and population sizes of organisms in a given terrestrial or aquatic environment
B4.02 describe the impact of human activity on the environment, including the pollution of air and of water; recall the effects of air pollutants (eg sulfur dioxide, carbon monoxide) and of water pollutants (eg sewage, nitrates and phosphates)
B4.03relate the level of impact on the environment to population size, economic factors and industrial requirements
B4.04describe the effects of deforestation and overfishing; understand the importance of protecting natural populations

Ecosystems
You should be able to:
B4.05 describe food chains quantitatively using pyramids of biomass
B4.06 understand that energy is transferred through food chains and that energy and biomass are lost between trophic levels
B4.07 understand that energy transfer can be maximised in food production, for example in fish farms
B4.08 explain the techniques used to maximise food production in terms of optimum feeding conditions, disease and predator control
B4.09 describe the stages in the carbon cycle, including the roles of micro-organisms; interpret carbon cycle diagrams
B4.10 describe the stages in the nitrogen cycle, including the roles of nitrogen-fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria (specific names of bacteria are not required); interpret nitrogen cycle diagrams