18. Biotechnology and genetic modification
A section of Biology, 5090
Listing 10 of 128 questions
Yoghurt is a milk product. Outline the role of microorganisms in the process of yoghurt production. The diagram shows a food label from a pot of yoghurt. contents nutritional values in 100 g of yoghurt energy 344 kJ fat 4.5 g total carbohydrates 5.5 g sugar 5.5 g fibre 0.0 g protein 4.2 g salt 0.1 g calcium 0.125 g water 81% Yoghurt can contribute to a balanced diet but adult humans cannot survive by eating only yoghurt. Explain this statement using the information on the label.
5090_s21_qp_21
THEORY
2021
Paper 2, Variant 1
View
A student carried out two investigations into the action of yeast. In the first investigation, the student dissolved 20.0 g of glucose in 100 cm3 of water in a beaker. The student then added 3.5 g of yeast and used a balance to measure the loss in mass from the beaker over the next 24 hours. The results of this investigation are shown in the graph. 0.0 time / hours 2.0 4.0 6.0 mass lost / g 8.0 9.0 1.0 3.0 5.0 7.0 Calculate the rate at which mass was lost during the first 6 hours. Space for working. g per hour Explain why mass was lost during the investigation. The student then repeated this first investigation changing only the mass of yeast. Draw a line on the graph on page 6 to show the pattern of results you would expect the student to obtain when using 7.0 g of yeast. In a second investigation, the student prepared three samples of bread dough. Each sample of dough had a volume of 50 cm3 and contained: • 1 g of yeast • 25 cm3 of water • 40 g of flour. Starch molecules in the flour are used to provide the yeast with a source of glucose. Describe how the action of a named chemical, produced by yeast cells, makes glucose available from starch. Each sample of dough was placed at the bottom of a 200 cm3 measuring cylinder. The three measuring cylinders were then placed in water-baths at different temperatures for 60 minutes. The temperatures chosen were 20 °C, 40 °C and 80 °C. After this time, the student measured the volume of dough in each measuring cylinder. The diagram shows the volume of dough in the measuring cylinder from the water-bath at a temperature of 20 °C at the end of the investigation. cm3 dough Estimate the volumes of the dough at the end of the investigation in the other two measuring cylinders, from water-baths at temperatures of: 40 °C cm3 80 °C cm3 Explain the results of this investigation.
5090_s22_qp_22
THEORY
2022
Paper 2, Variant 2
View
Bacillus subtilis is a species of bacterium that is widely used in biotechnology. It can be used to manufacture the protein lipase for industrial use. is a diagram of B. subtilis. plasmid flagella D C B A Two of the parts labelled A, B, C and D in are involved in the manufacture of proteins such as lipase. Identify the two parts, name them and explain their role in protein manufacture. letter name role letter name role Suggest why B. subtilis has flagella. Explain why plasmids are useful in biotechnology. B. subtilis can be grown industrially in large containers. When B. subtilis is in ideal conditions it can reproduce rapidly, increasing the population size and the biomass of bacteria in the container. Graphs E and F in show how the biomass of B. subtilis increases after small populations of bacteria are added to two containers with different environmental conditions. 0.0 0.1 0.2 0.3 0.4 0.5 0.6 biomass of B. subtilis / g per dm3 time / hours F E Give the name of the large industrial containers used to grow bacteria. In graph E the biomass increases as shown in . Indicate using the letter M the part of graph E where bacteria are reproducing most rapidly. Calculate the percentage increase in biomass for graph E in the first 6 hours. Space for working. percentage increase in biomass = % Describe two differences between graph E and graph F. Suggest one environmental condition which could have caused the differences between graph E and graph F. Lipase is also produced by the human body. Explain why it is produced and how its function is different from the function of bile.
5090_s24_qp_21
THEORY
2024
Paper 2, Variant 1
View
Questions Discovered
128