a level biology past papers 2018

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1. Method to ensure all cut surfaces of the eight, (A measure of) the number of (different) species in, In each case, suggest one consideration the scientists had taken into account to make sure their method. (Transcriptional factor/antibody) has a, Suggest how single-stranded cDNA could prevent transcription of the P34 gene. Spin (liquid / supernatant) at (very) high speed /. 1. Water moves into the cells/cytoplasm by. Dopamine stimulates the production of nerve impulses in postsynaptic neurones. Please write clearly in block capitals. 1. Binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind. 1. Tetracycline used more often / in higher doses; In recent years, these farm animals have not been given tetracycline in their food. Antivenom contains antibodies against the snake toxin. (Binding) alters the tertiary structure. 1. This mutation does not occur in the gene coding for lactase. The scientists also concluded that this heat treatment did not affect the xylem. The genetic code is described as degenerate. (Increased) methylation (of tumour suppressor. (a monomer is a smaller / repeating) unit /. Morphine is a drug that has a similar structure to endorphins and can provide pain relief. During vaccination, each animal is initially injected with a small volume of venom. 1. Drama and Theatre Studies. A decrease in the activity of the enzyme rubisco would limit the rate of photosynthesis. During the procedure shown in Figure 8 the animals are under ongoing observation by a vet. 1. 1. Describe how you would test a liquid sample for the presence of lipid box and how you would recognise a positive result. The scientists selected/used for breeding plants. This cell was typical of other cells in anaphase in these root tips. 1. Past papers and mark schemes for the Edexcel A Level Biology course. Add 1 part (bacteria) culture to 9 parts (sterile), The student looked at cells in the 1 in 10 dilution during his preliminary work. When counting, cells that touch top or left lines are counted but cells that touch right or bottom lines are not counted. (Mix / shake sample) with ethanol, then water; 1. (Movement) down a gradient / from high. Rubisco activity increases with temperature. Give two ways in which the arrangement of prokaryotic DNA is different from the arrangement of the human DNA in Figure 1. Binding of first oxygen changes tertiary /. 1. 2 *02* IB/M/Jun18/7402/2 Do not write outside the Answer all questions in the spaces provided. Suggest one way the structure of the chromosome could differ along its length to result in the stain binding more in some areas. GABA causes negatively charged chloride ions to enter postsynaptic neurones. 1. Binding of insulin leads to an increase in the rate of respiration in cells such as osteoblasts. (Inside of postsynaptic) neurone becomes more. Cambridge International AS and A Level Biology builds on the skills acquired at Cambridge IGCSE (or equivalent) level. Explain why the antibody binds to the transcription factor. He decided not to use this dilution to determine the number of cells in the undiluted liquid, 1. Start studying A-Level Biology Past Papers (2018). Mutations change base / nucleotide (sequence); The secretion of osteocalcin (in an inactive form) by osteoblasts is controlled by positive feedback. The syllabus includes the main theoretical concepts which are fundamental to the subject, a section on some current applications of biology, and a … Use your knowledge of water potential to suggest why lactulose can be used to help people suffering from constipation. Examine large number of fields of view / many. 1. Where dividing cells are found / mitosis occurs; Describe and explain what the student should have done when counting cells to make sure that the mitotic index he obtained for this root tip was accurate. Human breast milk is produced and secreted by gland cells. All the volunteers were given the same food for 3 days. Anaerobic respiration produces carbon dioxide; Explain why a log scale is used to record the number of cells. (Antivenom/Passive immunity) antibodies. Past papers and mark schemes for the CIE A Level Biology course. Both contain ester bonds (between glycerol and. 1. Use these to practice your exam question answers and highlight revision topics you need to work on. Red-green colour blindness affects more men than women. (So the) oxygen is used/absorbed/respired; During her investigation, the coloured liquid moved to the right. (It shows) smaller groups within larger groups /, (The proteome is the full) range of / number of. The mass flow hypothesis is used to explain the movement of substances through phloem. (The alveolar epithelium) is one cell thick; The Crohn's disease symptom of swelling of the lining of the intestines could be triggered by pathogenic bacteria in the intestines. If you are not sure which exam board you are studying ask your teacher. The same change at amino acid 279 significantly reduced the rate of reaction catalysed by the enzyme. Used to compare effect of other treatments / as. Explain how the measurement obtained from this control is, 1. 1. Revision resources for CIE A Level Biology exams | Save My Exams ... CIE A Level Biology: Past Papers. Endocellulase create more ends / increases. 1. We provide detailed revision materials for A-Level Biology students and teachers. Differences in the primary structure of haemoglobin molecules can provide evidence of phylogenetic (evolutionary) relationships between species. Formation of an enzyme-substrate complex increases the rate of reaction. No selection against resistant bacteria / resistance, Compare and contrast the DNA in eukaryotic cells with the DNA in prokaryotic cells. The scientists concluded that the results shown in Figure 5 were due to succession taking place. 1. In the space, write the equation for calculating the percentage loss in mass. Condensation (reaction) / loss of water; The secondary structure of a polypeptide is produced by bonds between amino acids. Describe how a peptide bond is formed between two amino acids to form a dipeptide. The milk, 1. Weak / easily broken hydrogen bonds between, Name the process by which prokaryotic cells divide. The scientists concluded that this heat treatment damaged the phloem. (Insulin stimulates release of osteocalcin - no mark). 1. Biology. 1. Mass/number of amino acids/polypeptides; Describe how farming cattle as a source of milk could have led to an increase in LP. The scientist used the same concentration of endocellulase and exocellulase in the mixtures. 1. Click on the links below to go to the relevant subject's past papers, they are free to download. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Affects water potential (of blood/body); Furosemide is sometimes used to treat high blood pressure. 1. Describe the relationship between size and surface area to volume ratio of organisms, As size increases, ratio (of surface area to, Suggest one practical advantage of measuring the masses of frog eggs, tadpoles and, Explain why oxygen uptake is a measure of metabolic rate in organisms, (Oxygen used in) respiration, which provides.

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