21. Biotechnology and genetic modification
A section of Biology, 0610
Listing 10 of 260 questions
Pectinase is an enzyme used in the production of fruit juice. Describe in detail how enzymes function, using pectinase as an example. An experiment to test the effect of the size of apple pieces on the activity of pectinase was performed by a group of students. Some of their apparatus is shown in . filter paper funnel measuring cylinder Describe how the students should use the measuring cylinder to obtain accurate measurements of volume. The students added 1.5 cm3 of pectinase solution to pieces of apple in a beaker. They then poured the mixture into the funnel. They found that it took 10 minutes to collect 19 cm3 of juice. Calculate the rate of the enzyme reaction. Show your working. Write your answer to the nearest whole number. cm3 per min The students performed four experiments using different ways to prepare the apples. The same total mass and type of apple was used each time. A 0.5 cm3 apple cubes B 1.0 cm3 apple cubes C whole peeled small apples D whole unpeeled small apples Predict and explain which experiment (A, B, C or D) would result in the fastest rate of reaction.
0610_w16_qp_43
THEORY
2016
Paper 4, Variant 3
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Pectinase is an enzyme that is used in the production of apple juice. A student investigated how pH affected the volume of apple juice produced when using pectinase. The student chopped an apple into small pieces. The pieces of apple were put into solutions with different pH values. Pectinase was added to each solution. After two hours the mixture was filtered and the volume of apple juice obtained was recorded. Table 6.1 shows the results. Table 6.1 pH volume of apple juice obtained / cm3 1.0 23.2 2.0 24.2 3.0 23.5 4.0 25.7 5.0 27.6 6.0 27.4 7.0 24.0 8.0 22.0 State the pH at which pectinase is most active. Give a reason for your answer. pH reason State one factor, other than pH, that would affect the activity of pectinase. Pectinase is an enzyme. The box on the left shows the beginning of a sentence. The boxes on the right show some endings of sentences. Draw three lines from the word ‘Enzymes’ to make three correct sentences. are living organisms. are proteins. can only be used once. have a complementary shape to their substrate. increase the rate of chemical reactions. in the stomach are most active at pH 8. Enzymes State one use of enzymes in biotechnology other than fruit juice production. Many types of enzymes are involved in digestion. State the names of two digestive enzymes in the human alimentary canal.
0610_w20_qp_31
THEORY
2020
Paper 3, Variant 1
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A student investigated the effect of different concentrations of pectinase on the volume of apple juice produced. 1 cm3 of pectinase solution was added to 5 g of mashed apples and the volume of apple juice produced was recorded. Six different concentrations of pectinase solution were tested. The results are shown in Table 7.1. Table 7.1 percentage concentration of pectinase solution volume of apple juice produced / cm3 4.4 5.0 5.4 5.8 7.4 Predict the volume of apple juice produced using pectinase solution with a concentration of 20%. cm3 Calculate the percentage increase in the volume of apple juice produced when the concentration of pectinase solution increased from 0% to 10%. Space for working. % Crops such as apples can be selectively bred. The box on the left contains a sentence beginning. The boxes on the right contain some sentence endings. Draw two lines to make two correct sentences about selective breeding. is carried out over many generations. is caused by mutation. is caused by the environment. requires human involvement. involves one parent only. Selective breeding Some of the statements shown correctly describe events that happen during the process of natural selection. Two of the statements are incorrect. There is no variation within populations. Many offspring are produced so there is more competition for resources. Individuals that are not suited to the environment die. Individuals that are better suited to the environment survive and breed. Offspring pass their alleles to their parents. State the numbers of the two incorrect statements. and State the term that is defined as an inherited feature that helps an organism to survive and reproduce in its environment.
0610_w21_qp_32
THEORY
2021
Paper 3, Variant 2
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Penicillin can be produced in fermenters. State the name of the type of organism that produces penicillin. shows the change in biomass of the organism that produces penicillin, when grown in a fermenter under controlled conditions. time the organisms are in the fermenter / hours biomass / g per dm3 X Y Z State the name of the growth stages of the organism, shown by the letters X, Y and Z in . X Y Z is a diagram of a fermenter containing the organisms that produce penicillin. air in air out product out tap water in temperature recorder paddle water jacket motor water out air filter Explain why air is supplied to the fermenter shown in . Explain why the temperature in the fermenter must be controlled. State the role of the paddles in the fermenter. Other than penicillin, state the names of two commercial products that can be made using fermenters.
0610_w24_qp_41
THEORY
2024
Paper 4, Variant 1
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Dairy cattle are kept for milk production. Approximately half of all the calves born are male. Sex is determined in cattle in exactly the same way as it is in humans. Explain why 50% of all cattle are born male. You may draw a genetic diagram to help your explanation. Dairy farmers only need a very small number of male calves. They limit the number by using sex selection. Sperm cells are identified and sorted before they are used in artificial insemination (A. Explain how artificial insemination is carried out. Table 2.1 shows the composition of 100 g of cow’s milk compared with the same quantities of commercial formula milk and human milk. Table 2.1 nutrient cow’s milk formula milk human milk carbohydrate / g 6.5 7.3 7.5 protein / g 3.3 1.3 1.3 – 1.6 fat / g 3.9 3.6 4.1 calcium / mg iron / mg 0.02 0.64 0.07 vitamin D / µg 0.05 1.20 0.06 vitamin A / µg Some women do not breast-feed their babies but bottle-feed them using formula milk. Health authorities advise against the use of cow’s milk until babies are about 9 months old. Use the information in Table 2.1 to explain the advantages of using formula milk rather than cow’s milk. One of the components of human milk is the enzyme lysozyme that is present in many body fluids and is responsible for breaking down the cell walls of bacteria. Define the term enzyme. The effect of human lysozyme on two common species of bacteria, A and B, was investigated at two different values of pH. The investigation was set up as shown in . The test-tubes were kept at 37 °C for 24 hours. A tube number pH of medium boiled lysozyme species of bacteria fresh lysozyme A A B 4.0 4.0 9.0 4.0 After 24 hours, samples were taken from each test-tube. Each sample was placed onto nutrient agar in Petri dishes. The dishes were incubated at 28 °C for a further 24 hours to allow any bacteria to grow. The results are shown in . sample from test- tube result after incubation for 24 hours Key: no growth of bacteria growth of bacteria Explain the results shown in by comparing the following pairs: 1 and 3 1 and 4 1 and 2 Human milk also contains antibodies. Explain the benefits of antibodies to a newborn child.
0610_s14_qp_31
THEORY
2014
Paper 3, Variant 1
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Questions Discovered
260