What statistical test could the scientists have used to determine whether there was a significant relationship between the amount of CD20 on the surface of B cells and the percentage of B cells destroyed by Rituximab? What is a homologous pair of chromosomes? ... June 2018: A Level – Paper 1: A Level – Paper 1 MS: A Level – Paper 2: A Level – Paper 2 MS: A Level – Paper 3: A Level – Paper 3 MS: When preparing the cells for observation the scientist placed them in a solution that had a slightly higher (less negative) water potential than the cytoplasm. Cell membranes made from phospholipid; Explain how ultracentrifugation separates CENP-W from other molecules. Use the information provided to explain why the number of people showing LP would rapidly increase once selection for this condition had been established. Name the blood vessels that carry blood to the heart muscle. 1. Please write clearly in block capitals. Used to compare effect of other treatments / as. Both contain ester bonds (between glycerol and. (Less/no) carbon dioxide (reacts) with RuBP; The scientists concluded that heat stress reduces the activity of rubisco in plant leaves by affecting rubisco activase. (Transcriptional factor/antibody) has a, Suggest how single-stranded cDNA could prevent transcription of the P34 gene. The scientists began by lysing (breaking open) cells and organelles using a detergent that dissolves lipids in water. 1. 1. mRNA does not have hydrogen bonds / base. Start studying A-Level Biology Past Papers (2018). English Literature. Law. (Many mitochondria) release energy / ATP for. All the volunteers were given the same food for 3 days. 1. These gland cells have adaptations that include many mitochondria and many Golgi vesicles. This section includes recent A-Level Biology past papers (AS and A2) from AQA, CIE, Edexcel, OCR, CCEA and WJEC. Give two ways in which the arrangement of prokaryotic DNA is different from the arrangement of the human DNA in Figure 1. Monday 11 June 2018 Afternoon Time allowed: 2 hours ... • The maximum mark for this paper is 91. Anaerobic respiration produces carbon dioxide; Explain why a log scale is used to record the number of cells. Add 1 part (bacteria) culture to 9 parts (sterile), The student looked at cells in the 1 in 10 dilution during his preliminary work. Maths. (The water content of the leaves was) not. This mutation does not occur in the gene coding for lactase. 1. B cells specific to the venom reproduce by. Describe how you would determine the mean percentage cover for beach grass on a sand dune. (Both) negatively charged to positively charged. 1. 1. (Change in pH) changes / breaks ionic /. Count unlikely to be accurate / repeatable /. 1. 2 *02* IB/M/Jun18/7402/2 Do not write outside the Answer all questions in the spaces provided. During vaccination, each animal is initially injected with a small volume of venom. The scientists also concluded that this heat treatment did not affect the xylem. This cell was typical of other cells in anaphase in these root tips. Geography. The syllabus includes the main theoretical concepts which are fundamental to the subject, a section on some current applications of biology, and a … 1. 1. Practicing past papers is one of the best ways to prepare for an exam. Suggest a reason for the difference in the results shown in Figure 5 with and without lyxose. Examine large number of fields of view / many. 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Use all of the information to suggest how the mutation of NOTCH1 led to the difference in the percentage of B cells destroyed by Rituximab. Stops anaphase / cell division / mitosis; Treatment D box is a control. Describe how you would test a liquid sample for the presence of lipid box and how you would recognise a positive result. 1. (Antivenom/Passive immunity) antibodies. 1. Revision resources for Edexcel A Level Biology exams | Save My Exams. Suggest one way the structure of the chromosome could differ along its length to result in the stain binding more in some areas. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This did not cause the cells to burst but moved the chromosomes further apart in order to reduce the overlapping of the chromosomes when observed with an optical microscope. Weak / easily broken hydrogen bonds between, Name the process by which prokaryotic cells divide. 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. 1. mRNA associates with a ribosome / ribosome. History. The importance of the control of movement in cells and organisms. Describe how alterations to tumour suppressor genes can lead to the development of tumours. Cambridge International AS and A Level Biology builds on the skills acquired at Cambridge IGCSE (or equivalent) level. A. chlorogaster and A. piperi are more. No selection against resistant bacteria / resistance, Compare and contrast the DNA in eukaryotic cells with the DNA in prokaryotic cells. 1. Past papers and mark schemes for the CIE A Level Biology course. 1. Use your knowledge of directional selection to explain the results shown in Table 3. This treatment is an example of passive immunity. People with red-green colour blindness are unable to distinguish between red and green, and also between other colours. Suggest and explain two ways in which the scientists could have improved the method used for data collection in this investigation. 1. Using evidence from Figure 6, what can you conclude about the net primary productivity (NPP) in the sand dunes that are older than 1000 years? Red-green colour blindness affects more men than women. 1. (So the) oxygen is used/absorbed/respired; During her investigation, the coloured liquid moved to the right. 1. Give two structural differences between a molecule of messenger RNA (mRNA) and a molecule of transfer RNA (tRNA). Endocellulase create more ends / increases. Biology A (Salters Nuffield) June 2018 – Edexcel Past Papers (8BN0 & 9BN0) AS-Level Biology A: Paper 1 – Lifestyle, Transport, Genes and Health (8BN0/01) Download Paper - Download Marking Scheme. (DNA) helicase causes breaking of hydrogen/H, Describe the gross structure of the human gas exchange system and how we breathe. Differences in the primary structure of haemoglobin molecules can provide evidence of phylogenetic (evolutionary) relationships between species. Dopamine stimulates the production of nerve impulses in postsynaptic neurones. 1. Morphine is a drug that has a similar structure to endorphins and can provide pain relief. (Lactulose) lowers the water potential of. Formation of an enzyme-substrate complex increases the rate of reaction. (Some people) have a mutation / allele / gene; Heat stress decreases the light-dependent reaction of photosynthesis. 1. The same change at amino acid 279 significantly reduced the rate of reaction catalysed by the enzyme. 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. 1. A mixture of venoms from several snakes of the same species is used. The mass flow hypothesis is used to explain the movement of substances through phloem. Click on the links below to go to the relevant subject's past papers, they are free to download. Describe how a peptide bond is formed between two amino acids to form a dipeptide. 1. The scientists selected/used for breeding plants. Rubisco activity increases with temperature. Biology. More than one codon codes for a single amino. Give two similarities in the movement of substances by diffusion and by osmosis. Human breast milk is produced and secreted by gland cells. (Movement) down a gradient / from high. Figure 3 is a drawing showing the chromosomes in a single cell observed in the squash of one of these root tips in anaphase.