5090_w21_qp_21
A paper of Biology, 5090
Questions:
9
Year:
2021
Paper:
2
Variant:
1
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2
A farmer is growing a crop of tomato plants. The tomato plants carry out photosynthesis. Describe the process of photosynthesis. The farmer grows the tomato plants in a glasshouse instead of in an open field. Suggest reasons why this is an advantage to the farmer. Suggest one disadvantage, other than cost, of growing plants in this way. The graph shows how the rate of photosynthesis can vary with light intensity when all other environmental conditions are kept the same. P rate of photosynthesis light intensity Q Explain how this graph shows that light intensity is the limiting factor for photosynthesis at light intensity P but not at light intensity Q. Name one environmental condition that could be limiting photosynthesis at light intensity Q.
6. Plant nutrition  →  6.1. Photosynthesis
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3
A man is cooking in a hot kitchen and sweat is being released by sweat glands in his skin. Explain the term homeostasis with reference to sweating. Explain how receptors and blood vessels in the man’s skin are also involved in homeostasis when he is in the hot kitchen. Sweat contains very small quantities of the waste product urea. State the name of the organ where most urea is made in the body. The table shows the concentrations of some chemicals found in the sweat, urine and blood plasma of a healthy human. chemical concentration of chemical / mmol per dm3 sweat urine blood plasma urea sodium chloride Use the data in the table to compare the chemical composition of urine and blood plasma. A patient has kidney disease and is about to start dialysis treatment. Suggest and explain the concentration of urea in the sweat of the patient compared to that of a person who does not have kidney disease.
13. Excretion  →  13.2. Urinary system
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4
The kapok tree is a flowering plant that grows rapidly to become one of the tallest trees in a tropical rainforest ecosystem. Climbing plants wind up its stem and the tree provides a habitat for insect-eating birds and frogs. Bats feed on the nectar from its flowers and pollinate them so they can produce small, light seeds. Insects feed on its leaves and when the leaves fall to the ground they will come into contact with soil bacteria and fungi. Use the information provided to draw a food chain for this tropical rainforest in the space provided. The chain should contain three organisms. Suggest and explain ways in which being tall may be helpful for the survival of this tree species. Explain why the bacteria and fungi found in the rainforest soil are important in this ecosystem. Every year large areas of tropical rainforest are destroyed by burning. A large percentage of the mass of a kapok tree is made of the element carbon. Name one substance, found in plants but not in animals, that contains carbon. Explain how burning trees contributes to global warming.
19. Relationships of organisms with one another and with the environment  →  19.4. Effects of humans on ecosystems
6. Plant nutrition  →  6.2. Leaf structure
19. Relationships of organisms with one another and with the environment  →  19.1. Energy flow
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5
The graph shows how blood alcohol concentration changes after a person drinks alcohol. 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 time after drinking alcohol / hours blood alcohol concentration / g per dm3 Suggest how the shape of the graph can be explained by what happens in parts of the body after drinking alcohol. The graph shows that the highest blood alcohol concentration for this person after drinking alcohol is 0.75 g per dm3. Suggest two reasons why the highest blood alcohol concentration may be different for two people after drinking the same volume of alcohol. Describe the short-term effects of a high blood alcohol concentration.
12. Disease and immunity  →  12.1. Disease
14. Coordination and control  →  14.6. Blood glucose control
14. Coordination and control  →  14.3. Mammalian hormones
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9
Sperm cells and pollen grains are both involved in sexual reproduction. Compare the functions of a sperm cell and a pollen grain and describe how the structure of each is related to its function. Suggest reasons why sexual reproduction may be better for the survival of a species than asexual reproduction.
16. Development of organisms and continuity of life  →  16.2. Asexual and sexual reproduction
16. Development of organisms and continuity of life  →  16.3. Sexual reproduction in plants
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