9700_w16_qp_22
A paper of Biology, 9700
Questions:
6
Year:
2016
Paper:
2
Variant:
2
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2
Phloem sap containing sucrose is transported in phloem sieve tubes from the source to the sink. A student carried out an experiment using Visking tubing to investigate osmosis. The student prepared a sucrose solution to represent phloem sap at the source. This was put into Visking tubing that was tied at one end, so that the tubing was approximately 75% full. The rest of the procedure is summarised in . The tubing was removed after 20 minutes, dried and re-weighed. tubing tied at both ends Visking tubing outside of tubing washed with distilled water, dried and weighed sucrose solution 20 minutes appearance of Visking tubing inside the test-tube after 20 minutes distilled water Complete to show the appearance of the Visking tubing inside the test-tube after 20 minutes. State, with reasons, whether there would be a change in the mass of the Visking tubing containing the sucrose solution after 20 minutes. Explain how osmosis is involved in the mass flow of phloem sap. Amino acids synthesised in the mesophyll cells of leaves are also transported in phloem sap to other locations where they are used to synthesise polypeptides. Amino acids are joined by peptide bonds to form the polypeptides. Two amino acids are shown below. Describe the formation of a peptide bond between these two amino acids. You may use the space below. C C O OH R N H H H C C O OH R N H H H
7. Transport in plants  →  7.2. Transport mechanisms
4. Cell membranes and transport  →  4.2. Movement into and out of cells
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High fructose corn syrup, made from maize, can be used as a replacement for sucrose to sweeten food and drink products. Commercial production of high fructose corn syrup involves the enzyme glucose isomerase, extracted from bacteria. Fructose and sucrose are both sugars. State two structural differences between fructose and sucrose. The glucose isomerase used in the production of high fructose corn syrup is extracted from a strain of a bacterium, Thermus thermophilus, which is found in hot springs. The enzyme has an optimum temperature of 95 °C. Suggest and explain the advantages of using glucose isomerase from T. thermophilus to produce high fructose corn syrup, rather than using glucose isomerase that has an optimum temperature of 37 °C. The commercial production of high fructose corn syrup uses immobilised glucose isomerase. shows the effect of pH on the activity of immobilised glucose isomerase compared to glucose isomerase free in solution. percentage activity pH glucose isomerase free in solution (free enzyme) immobilised glucose isomerase (immobilised enzyme) With reference to , describe the differences shown between the immobilised enzyme and the free enzyme as pH changes. The amino acid sequence of the enzyme glucose isomerase has been determined. The first five amino acids of this sequence are shown in Table 3.1. Table 3.2 (on page 11) shows the genetic code (mRNA codons). A student was asked to use Table 3.2 to work out an mRNA nucleotide sequence that would correspond to the first five amino acids of glucose isomerase. The student’s sequence is shown in Table 3.1. Table 3.1 amino acid sequence met tyr glu pro lys student’s nucleotide sequence AUG UAU GAC CCU UGU correct = 3 incorrect = 7 Complete Table 3.1 using a 3 or a 7 to indicate whether the student has used Table 3.2 correctly to identify the codons for each amino acid in the nucleotide sequence. Discuss, with reasons, how an mRNA nucleotide sequence worked out to correspond to the first five amino acids using Table 3.2 may not be the same as the mRNA nucleotide sequence for those amino acids present in the bacterial cell.
3. Enzymes  →  3.2. Factors that affect enzyme action
12. Energy and respiration  →  12.2. Respiration
2. Biological molecules  →  2.2. Carbohydrates and lipids
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is a cross-section of a human renal artery, a vessel that supplies blood to the kidney. elastic layer X Y tunica media The elastic layer shown in , located between the endothelium and the tunica media, is one feature that suggests that the blood vessel is the renal artery and not the renal vein, which may be of a similar size. Complete the sentence to state one additional structural feature, visible in , that would identify the blood vessel as an artery. This is an artery because it has Explain the relationship between the structure of the tunica media and the function of an artery, such as the renal artery. The actual diameter of the lumen of the renal artery at the point X–Y in is 5.2 mm. Calculate the magnification of the image shown in . Write down the formula you will use to make your calculation and show your working. formula magnification × Blood plasma contains approximately 90% water. Many of the properties of water are due to its ability to form hydrogen bonds. Outline how the properties of water make it ideal as the largest component of plasma.
14. Homeostasis  →  14.1. Homeostasis in mammals
8. Transport in mammals  →  8.1. The circulatory system
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A disease can be described as infectious or non-infectious. Lung cancer is a non-infectious disease. Explain the term non-infectious disease. non-infectious disease In a person with lung cancer one or more healthy cells undergo changes to produce cancerous cells that can form a tumour. Suggest and explain the cellular changes that occur in the development of lung cancer. is a summary of some infectious diseases. infectious disease A in body fluids animal vector contaminated food and water aerosol infection HIV/AIDS measles malaria D cholera TB HIV Plasmodium spp Variola virus Mycobacterium tuberculosis E Vibrio cholerae type of pathogen mode of transmission name of disease causative organism C B virus Use the information in to answer parts to . Name the type of pathogen represented by A and B. A B State the mode of transmission represented by C. Name the disease represented by D. Name the causative organism represented by E. Explain how vaccination can control infectious diseases.
10. Infectious diseases  →  10.1. Infectious diseases
11. Immunity  →  11.2. Antibodies and vaccination
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6
represents one complete cell cycle for a eukaryotic cell. Complete by naming the stages represented by J, K and L. J K L Name the stage in the cell cycle in which semi-conservative replication of DNA occurs. The development of stem cells to become neutrophils occurs in several stages. Some of these stages are capable of cell division. is a summary of neutrophil development. Some details of cellular structure are included. myeloblast no granules visible large spherical or ovoid nucleus promyelocyte capable of cell division primary granules appear smaller spherical or ovoid nucleus myelocyte secondary granules appear nucleus may appear slightly indented or flattened on one side tertiary granules appear U–shaped nucleus all three types of granule present mature neutrophil released into circulation metamyelocyte All three types of granule indicated in are membrane-bound cell structures containing hydrolytic enzymes. Each type of granule contains a different group of enzymes and other chemicals that enable the neutrophil to carry out its role. State the location in the body where development and maturation of the neutrophil occurs. Describe the shape of the nucleus in the mature neutrophil. State the alternative name of the cell structures described in as “granules”. Primary granules contain proteins known as defensins. These bind to cell surface membranes of bacteria and form very small pores in the membrane. Suggest how defensins contribute to the role of the neutrophil in killing bacteria. Secondary granules contain lysozyme. This is an enzyme that breaks bonds in peptidoglycan molecules. Explain how the action of lysozyme will lead to the destruction of the bacterial cell.
1. Cell structure  →  1.2. Cells as the basic units of living organisms
6. Nucleic acids and protein synthesis  →  6.1. Structure of nucleic acids and replication of DNA
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