Higher Biology. Unit 2: Homework Booklet Metabolism and Survival

Transcription

1 Higher Biology Unit 2: Homework Booklet Metabolism and Survival 0

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3 Sub Topic 2.1: Regulation of Metabolism 1. Membranes can form small compartments within cells. Small compartments have: A high surface to volume ratios and allow low concentrations of substrates inside B high surface to volume ratios and allow high concentrations of substrates inside C low surface to volume ratios and allow low concentrations of substrates inside D low surface to volume ratios and allow high concentrations of substrates inside 2. An inhibitor of an enzyme-catalysed reaction can be described as competitive if: A its effect is decreased by raising substrate concentrations B it is the final product in a metabolic pathway C it switches off the gene encoding the enzyme D it permanently changes the shape of the active site 3. The graph below shows the effect of substrate concentration on the rate of an enzyme-controlled reaction. 20 rate of reaction (units) substrate concentration (units) At which substrate concentration is the reaction rate equal to 75% of the maximum rate? A 5 units B 8 units C 12 units D 15 units 2

4 4. The reaction below is part of a metabolic pathway in cells: amino acids protein Which line in the table below correctly identifies the type of reaction and whether it takes up or releases energy? Type of reaction Energy taken up or released A catabolic released B anabolic released C catabolic taken up D anabolic taken up 5. The following diagram shows a small section of the plasma membrane from a mammalian liver cell: A (a) What type of molecule does A belong to? (b) Name an example of this type of molecule that may be found in the plasma membrane. 6. The diagram below shows a metabolic pathway that is controlled by end product inhibition. enzyme 1 enzyme 2 enzyme 3 substrate intermediate1 Intermediate2 product (a) For substance 4 to bring about end product inhibition, which substance in the metabolic pathway will it interact with? (b) What is the advantage of end product inhibition to the cell? 3

5 7. The diagram below represents the molecules involved in an enzyme controlled reaction. active site Which line in the table correctly identifies X, Y and Z? A B C D competitive inhibitor competitive inhibitor non competitive inhibitor non competitive inhibitor X Y Z enzyme substrate enzyme substrate non competitive inhibitor non competitive inhibitor competitive inhibitor competitive inhibitor 4

6 8. An experiment was carried out to investigate the effect of enzyme concentration on the rate of a reaction. The reaction investigated was the breakdown of starch to maltose by the enzyme α-amylase. The rate of the reaction was determined by measuring the time taken for a change in iodine staining (from brown to blue/black). TIME IN MINUTES TUBE: Key: = BLUE /BLACK = FAINT BLUE/BLACK = BROWN (NO STARCH PRESENT) The results are displayed in the table below. Tube Volume of starch added (ml) Concentration of α amylase added (%) Time taken for change in iodine staining to occur (mins) no change no change (a) Draw a line graph that shows the effect of the concentration of the α-amylase vs the time taken for the change in iodine staining. a. label each axis b. select a suitable scale c. plot each point accurately (3) 5

7 (b) Describe the effect of the concentration of α-amylase on the time taken for the change in iodine staining. (c) Explain the purpose of tubes 6 and 7? (d) Describe one other variable, not mentioned in the question that would need to be controlled during the experiment. Total = 15 marks 6

8 Sub-Topic 2: Cellular Respiration 1. Which of the following are required for glycolysis? A Oxygen and ATP B Water and ATP C Enzymes and oxygen D ATP and enzymes 2. During fermentation in muscle fibers, what is the fate of pyruvate? A It is converted to lactate. B It is broken down by the mitochondria. C It is broken down to carbon dioxide and water. D It is converted to citrate. 3. The graphs below show the results of an experiment into the effect of aerobic and fermentation conditions on the uptake of calcium and magnesium ions by pond algae. Uptake of calcium ions by pond algae Uptake of magnesium ions by pond algae Which of the following is a valid conclusion that can be drawn from the results? A B C D At 120 minutes in aerobic conditions the uptake of calcium ions is greater than that of magnesium ions. At 60 minutes in fermentation conditions there was a greater uptake of calcium ions compared with magnesium ions. Over the 120 minutes in aerobic conditions the average rate of uptake of calcium ions is greater than that of magnesium ions. At 60 minutes in fermentation conditions there was a greater uptake of magnesium ions compared with calcium ions. 7

9 4. (a) What name is given to Stage R? (b) What happens to Acetyl Coenzyme A when it enters the Citric Acid cycle? (2) (c) What change in conditions would cause Stage R to occur instead of Stage Q? During the process of respiration, hydrogen and high energy electrons are released and carried to the electron transport chain. (d) (i) Name the molecule which carries most of the hydrogen and high energy electrons to the electron transport chain? (ii) Name the final electron acceptor in the electron transport chain? (e) The energy from cellular respiration is required for many processes in cells. Give one example of an energy requiring process in yeast cells. 8

10 5. Which line in the table describes correctly both aerobic respiration and fermentation in human muscle tissue? 6. The diagram shows energy transfer within a cell. Which line in the table below identifies compounds X and Y? 7. The diagram shows the role of ATP in cell metabolism. Complete the diagram by entering the names of the missing substances in the boxes and naming the processes X and Y. (3) 9

11 8. The diagram below summarises a metabolic pathway within a cell. (a) Name the process which results in the formation of pyruvate. (b) Name substance Q. (c) What is the role of NAD in this process? (d) Why does the electron transport chain stop when oxygen is absent? (e) Substance R is the main product of the electron transport chain. Name substance R? Total = 20marks 10

12 Sub-Topic: 2.3 Metabolic Rate Sub Topic: 2.4 Metabolism in Conformers and Regulators 1. In an investigation into the metabolic rate of a snail at rest, its oxygen uptake was measured using the apparatus shown in the diagram below. The apparatus was kept at 10 C with the tap open for 15 minutes. To start the experiment, the tap was closed and the reading on the scale recorded. Every 2 minutes for 10 minutes, the oxygen uptake was recorded by taking readings from the scale. The results are shown in the table below. a)(i) Explain why the apparatus was left for 15 minutes with the tap open before readings were taken. (ii) To ensure validity, identical apparatus was set up without the snail. Explain why this ensures valid results. b)(i) Identify the dependent variable in this investigation. (ii) Identify one variable, not already mentioned, which would have to be kept the same each time to ensure that the procedure was valid. (iii) What name is given to a set up such as this? 11

13 c) Draw a line graph to show the oxygen uptake against time. (2) d) The mass of the snail was 5 0g. Use the results in the table to calculate the average rate of oxygen uptake per gram of snail per minute over the 10 minute period. Space for calculation cm 3 per gram per minute e) Predict the effect of an increase in temperature to 15 C on the oxygen uptake by the snail and justify your answer. Prediction: Justification: f) Explain how the respiration of the snail and the presence of the solution in the test tube results in the movement of liquid on the scale. (2) 2. The diagram below represents a section through the skin of a mammal. 12

14 a) Select one structure labelled in the diagram and explain how it responds to a decrease in temperature to bring about a correction in body temperature. Structure: Explanation: (2) b)(i) Explain the importance of thermoregulation to mammals. (2) (ii) Reptiles have behavioural adaptations to help them to thermoregulate. Give one example of this. c) Name one external abiotic factor, other than temperature, which can affect the ability of an organism to maintain its metabolic rate. 13

15 3. The following diagrams represent the structures of fish, mammal and amphibian hearts. a) Complete the table below by inserting the correct letters, animal group and type of circulation. Heart S Animal group (complete double) Mammal Type of circulation (single, incomplete double or complete double) Single (3) b) Add arrows in the vessels X, Y and Z on the diagrams to indicate the direction of flow of blood within them. c) Explain how heart R is better adapted than heart S to allow a high metabolic rate in the cells which it supplies with blood. (2) Total:23 14

16 Sub -Topic: 2.5 Maintaining Metabolism 1. Rufous hummingbirds migrate thousands of kilometres each year between their summer breeding areas in Canada and their wintering areas in Mexico. They feed on nectar throughout the year and save energy at night by entering a temporary state of torpor in which the body temperature and respiration rate are greatly reduced. The chart below shows the average body mass of the hummingbirds and the average number of hours per night spent in torpor throughout the year. (a) (i) Use the values from the chart to describe the changes in average body mass of the hummingbirds from the beginning of August until the end of November. (2) (ii) Calculate the percentage increase in body mass of the hummingbirds during the summer in Canada. (iii) Suggest one reason for the increase in body mass of the hummingbirds during the summer in Canada. (b) (i) Suggest why the increased time spent in torpor during migration is an advantage to the hummingbirds. 15

17 (ii) Calculate the average period of torpor per month of the hummingbirds throughout the winter in Mexico. (c) The table below shows that average oxygen consumption of the hummingbirds at rest is affected by their body temperature. Body Temperature Average oxygen consumption at rest (cm 3 per gram of body mass per hour) Normal 15.0 Lowered during torpor 2.0 Using the information from the chart and the table, calculate the average volume of oxygen consumed per hour by a hummingbird at the end of September at normal body temperature. (d) Describe a technique which could be used to track species such as the Rufous hummingbird which undertake long distance migration. 2. Some species of lungfish live in African lakes. If there is a drought, lakes may dry out but the lungfish can survive by burying themselves in the remaining mud and becoming dormant. Which line in the table correctly identifies the description and the type of dormancy displayed by the lungfish in these circumstances? 16

18 3. The giant bullfrog of South Africa lives in a habitat in which hot and dry conditions can occur at any time of year. To survive these conditions, the frogs respond by becoming dormant. Which of the following descriptions applies to this type of dormancy? A predictive aestivation B predictive hibernation C consequential aestivation D consequential hibernation Total = 10 Marks 17

19 Sub -Topic 2.6: Environmental Control of Metabolism 1. Bacterial cells were heated to 121 C for increasing lengths of time to determine the number of live cells left after treatment. The graph below shows the number of bacterial cells which survived. How many cells survive after 6 mins? A 1300 B 4000 C 5000 D The diagram below shows an image of a bacterial cell that has been magnified 1500 times. Given that 1mm = 1000micrometres. What is the actual length of the cell in micrometres (μm)? A B C 6750 D

20 3. A growth curve in a culture of bacteria is shown in the diagram below. (a) In culturing bacteria it is important to control the ph of the culture medium. Describe how the ph of a culture medium can be controlled. (b) (i) Name each of the phases of growth indicated by the letters on the graph. W, X, Y and Z (ii) Give the letter which indicates a region of the graph in which most enzymes are being induced to metabolise the available substrate. (iii) Give one reason for the decrease in number of cells at phase Z. (2) 4. Buffers are added to culture media to A provide vitamins B maintain the ph C provide fatty acids D maintain the temperature. 19

21 5. Citrate is used in the food industry as a flavouring agent. Large quantities of citrate are produced in fermenters by the fungus Aspergillus niger. The fungus was added to a growth medium and grown in a fermenter for 14 days. The graph below shows the changes in biomass of the fungus and in the concentration of citrate over the growth period. (a) Identify the time period during which the log (exponential) phase of the growth of Aspergillus niger occurs. A Day 0-1 B Day 1-4 C Day 4-12 D Day (b) Suggest one reason why citrate was not produced until day 2. Total= 10 Marks 20

22 Sub-Topic: 2.7: Genetic Control of Metabolism Sub-Topic 2.8: Ethical considerations in the use of Micro-organisms. 1. Diagram 1 below shows a plasmid that contains two genes for antibiotic resistance. Diagram 2 shows the same plasmid after modification by the insertion of a gene from another organism. Diagram 1 Diagram 2 Plasmid before modification Plasmid after modification (a) Two different enzymes are required to produce the modified plasmid. Copy and complete the table below by; (i) (ii) (iii) Naming the enzyme which cuts plasmids at specific sites; Naming the second enzyme required to modify plasmids; Describing the function of the second enzyme. Enzyme required to produce modified plasmids Function of enzyme in the modification process Cuts plasmids at specific restriction sites 21

23 (b) Bacteria took up the modified plasmids. Explain why these bacteria will not have resistance to antibiotic Y. 2. Using recombinant DNA technology, the bacterium E. coli can be modified so that it can produce human insulin. The following steps are involved. 1 Culture large quantities of E. coli in nutrient medium. 2 Insert human insulin gene into E. coli plasmid DNA. 3 Cut insulin gene from human chromosome using enzymes. 4 Extract insulin from culture medium. The correct order of these steps is A 3, 2, 1, 4 B 3, 1, 2, 4 C 1, 4, 3, 2 D 1, 2, 3, The diagram below shows interaction between two strains of fungi X and Y with different genotypes in an area Z. Which statement describes the process occurring in area Z? A mutagenesis B selective breeding C transfer of plasmids D sexual reproduction 22

24 4. Escherichia coli is a species of bacteria found in the lower intestines of humans. Sections of the DNA of two strains of E. coli are shown below. Gene B codes for a protein known as Shiga toxin which can cause serious food poisoning in humans. (a) The gene for Shiga toxin has been acquired by E. coli 0157H7. Give two methods by which the bacterial strain could have acquired this gene. (2) (b) (i) E. coli K12 is routinely used in recombinant DNA technology. Explain why E. coli K12 is used whereas E. coli 0157H7 is not. (ii) Bacteria are used in recombinant DNA technology. Explain why proteins produced from animal DNA that have been transferred to bacteria using recombinant DNA technology may produce proteins which are not functional. 6. The gene encoding a protein was removed from the human genome and transferred into two different recipient cells by different methods as shown in the table below. Recipient Cells bacteria yeast Method of transfer bacterial plasmid artificial chromosome The protein was functional only when produced in yeast cells. The most likely reason for this was because the A B C D bacterial plasmids did not contain marker genes protein produced in bacteria had an incorrect amino acid sequence bacterial plasmids did not contain self-replication genes protein produced in bacteria was not folded correctly. Total= 11 Marks 23

25 Extended Answer Questions 1. Give an account of enzyme action and enzyme inhibition. (8) 2. Give an account of enzyme action under the following headings: i) the induced-fit model of enzyme action. (4) ii) competitive and non-competitive enzyme inhibitors. (6) 3. Give an account of enzyme activity under the following headings: (i) induced fit (2) (ii) enzyme activation (4) (iii) end-product inhibition (4) 4. Give an account of glycolysis and the citric acid cycle in cells. (8) 5. Give an account of the principle of negative feedback with reference to the maintenance of human body temperature. (8) 6. Give an account of the adaptations of organisms to surviving and avoiding adverse environmental conditions. (8) 7. Give an account of: i) the principle of negative feedback ii) maintenance of human body temperature (10) 8. Describe the growing conditions of microorganisms and how these conditions are met in industrial fermentation (8) 9. Describe aseptic technique and the trends in microbial growth with reference to a microbial growth curve. (8) 10. Describe 3 methods to improve a wild type microorganism (8) 11. Give an account of the transfer of extra chromosomal genes to micro-organisms using plasmids or artificial chromosomes and give an example of an ethical consideration of carrying out this procedure. (8) 24

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