9700_m16_qp_42
A paper of Biology, 9700
Questions:
10
Year:
2016
Paper:
4
Variant:
2
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1
The rate of photosynthesis is affected by a number of environmental factors. shows the effect of light intensity on the rate of photosynthesis. rate of photosynthesis light intensity C A B State the limiting factor in region A of the graph. Explain what is meant by the term limiting factor. Explain why there is no further increase in the rate of photosynthesis beyond point C. For many plants living in temperate regions, the optimum temperature for photosynthesis is approximately 25 °C. Suggest reasons why the rate of photosynthesis decreases at temperatures above 25 °C.
13. Photosynthesis  →  13.2. Investigation of limiting factors
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The IUCN Red List provides information about the conservation status of species throughout the world, including the American badger, Taxidea taxus, and the black-footed ferret, Mustela nigripes. shows an American badger and shows a black-footed ferret. shows the IUCN conservation status of the American badger and the black-footed ferret in 1987 and in 2013. American badger, T. taxus conservation status American badger, T. taxus black-footed ferret, M. nigripes black-footed ferret, M. nigripes critically endangered extinct in the wild endangered vulnerable near threatened least concern American badgers and black-footed ferrets are both predators. • American badgers feed on prairie dogs and a range of other animals. • Black-footed ferrets feed almost entirely on prairie dogs. • American badgers do not have any animal predators. • Black-footed ferrets are preyed upon by American badgers and several other predators. Suggest reasons why black-footed ferrets are an endangered species but American badgers are not. In 1987, the world population of black-footed ferrets consisted of only 18 animals living in captivity. A number of different agencies worked together to prevent the extinction of this species. Their goal was to produce young black-footed ferrets to be released into the wild. The survival and breeding of the animals in the wild would then be monitored and supported. The collaborating agencies included: • local government • universities • zoos • native tribes that owned undeveloped reservation land. Outline how these different agencies could contribute to successful conservation of the black-footed ferret. Black-footed ferrets were released at three different locations in the wild at different times. Each population was established from captive-bred animals. shows the population sizes of black-footed ferrets at the three release locations. year population size / number of individuals South Dakota Wyoming Arizona Describe the patterns of population growth at the three locations where black-footed ferrets were released. Table 2.1 shows information about the gene pool of the populations of black-footed ferrets and the leg sizes of the black-footed ferrets at each release location in 2004. All three populations were started by animals from the same captive population. In this original captive population, 100% of the genes surveyed showed polymorphism, that is, they had more than one allele. The mean number of alleles per gene locus was two. The population at the South Dakota location in 2004 maintained the same level of genetic variation and leg size data as the original captive population, but the populations in Wyoming and Arizona showed changes. Table 2.1 population location gene pool data leg size data percentage of genes that are polymorphic mean number of alleles per gene locus mean length of lower back leg bone / mm mean length of lower front leg bone / mm South Dakota 2.00 69.4 59.0 Wyoming 1.43 68.0 56.7 Arizona 2.14 69.4 59.0 Use Table 2.1 to describe how the gene pools and leg sizes of the Wyoming and Arizona black-footed ferret populations have changed, compared to the original captive population. With reference to , suggest reasons for the changes you have described in . In 2008 some black-footed ferrets were born in captivity as a result of IVF using frozen sperm that had been stored for several years. Explain the benefits of using frozen sperm in captive breeding programmes.
18. Classification, biodiversity and conservation  →  18.3. Conservation
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Myofibrils in striated muscle consist of contractile units called sarcomeres. When an impulse stimulates striated muscles to contract, calcium ions are released from the sarcoplasmic reticulum. Describe how the release of calcium ions leads to the contraction of a sarcomere. The many-banded krait, Bungarus multicinctus, is a venomous snake. shows a many-banded krait. The venom from the many-banded krait contains bungarotoxin. In mammals that are bitten by this snake, the venom acts at the neuromuscular junction, causing muscle paralysis (loss of muscle function). Suggest how bungarotoxin may cause muscle paralysis.
15. Control and coordination  →  15.1. Control and coordination in mammals
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The process of gametogenesis in male and female vertebrates, including humans, involves meiosis. Describe how gametogenesis differs between human males and females. shows a Komodo dragon, Varanus komodoensis. This species of lizard is only found on five Indonesian islands. Using Table 4.1, identify the gene locus that shows the most genetic variability and name the process that gives rise to the different lengths of the alleles. locus process Using Table 4.1, state and explain which animals are heterozygous at one or more of the gene loci. Clones are organisms or cells that are genetically identical. Students made suggestions about the Komodo dragon offspring (1– 4) produced by a female that had never mated with a male. • Offspring 1 and 2 are clones of each other, and offspring 3 and 4 are clones of each other. • Offspring 1– 4 were produced by asexual reproduction using mitosis only. Explain, with reference to specific loci, whether the data in Table 4.1 support or do not support these suggestions. Offspring 1 and 2 are clones of each other, and offspring 3 and 4 are clones of each other. Offspring 1– 4 were produced by asexual reproduction using mitosis only. Reproduction without a male has evolved in a number of species that live on islands. Suggest advantages and disadvantages of this type of reproduction in an island habitat.
16. Inheritance  →  16.1. Passage of information from parents to offspring
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outlines how two hormones, A and B, are involved in the regulation of blood glucose concentration. normal blood glucose concentration endocrine tissue hormone A produced target tissue: liver release of glucose hormone B produced target tissue: liver absorption of glucose fall in blood glucose concentration fall in blood glucose concentration rise in blood glucose concentration rise in blood glucose concentration With reference to , name: the control mechanism that regulates blood glucose concentration hormone A. The enzymes glycogen synthetase and glycogen phosphorylase are both involved in the formation and breakdown of glycogen in the liver. shows the activity of the two enzymes in the liver after consumption of a glucose meal. time after glucose meal / s activity of enzyme / arbitrary units glycogen phosphorylase glycogen synthetase Describe and suggest an explanation for the changes in the activity of the enzymes glycogen synthetase and glycogen phosphorylase.
14. Homeostasis  →  14.1. Homeostasis in mammals
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Paramecium is a ciliated, unicellular protoctist. The cilia are similar in structure to those found in the trachea of a human. The cilia beat to move Paramecium through the water in which it lives. shows Paramecium. Paramecium has anterior and posterior ends. Generally the cilia beat so that the organism is moved forwards. Sometimes reverse movement is needed, for example when the Paramecium meets an obstacle. • The direction of beating of the cilia is linked to the difference in concentration of calcium ions inside and outside the cell. • There is usually a higher concentration of calcium ions outside than inside the cell. • When Paramecium touches an object, its cell surface membrane becomes deformed. • The membrane potential becomes more positive inside the cell. • The organism moves backwards for a short time. Suggest the sequence of events that occurs to cause the Paramecium to move backwards when it touches an object. Suggest how Paramecium ensures that there is usually a higher concentration of calcium ions in the surrounding water than inside the cell. Paramecium has a contractile vacuole that fills up with water. When it is full, the contractile vacuole contracts to expel the water. The rate of contraction of the vacuole depends on the water potential of the surrounding water. Name the process by which water enters Paramecium. Suggest the relationship between the rate of contraction of the contractile vacuole and the water potential of the surrounding water. Describe how the DNA of Paramecium differs from that of a prokaryotic cell.
4. Cell membranes and transport  →  4.2. Movement into and out of cells
1. Cell structure  →  1.2. Cells as the basic units of living organisms
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is a diagram of a section through a mitochondrion. circular DNA P Q R S Using , state the letter which indicates the site of: • the Krebs cycle • oxidative phosphorylation • decarboxylation. Suggest one function for the circular DNA in . During respiration, exchange of substances takes place between the cytoplasm and the mitochondria. Complete the table below to list three substances that enter the mitochondria and three substances that leave the mitochondria. substance that enters the mitochondria substance that leaves the mitochondria The poison cyanide binds with cytochrome oxidase, one of the carriers in the electron transport system. Suggest how ingestion of cyanide by humans leads to death by muscle failure. Tripalmitin is a triglyceride. The chemical equation for the aerobic respiration of tripalmitin is: 2C51H98O6 + 145O2 102CO2 + 98H2O Calculate the RQ value for tripalmitin. Give your answer to 2 decimal places. Show your working. answer Explain why the usual RQ value for respiration in humans is between 0.7 and 1.0.
12. Energy and respiration  →  12.2. Respiration
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In a species of snail, shell colour is controlled by a gene with three alleles: • allele CB codes for a brown shell • allele CP codes for a pink shell • allele CY codes for a yellow shell. Allele CB is dominant to both CP and CY. Allele CP is dominant to CY. The shells of this snail may be banded (have dark stripes) or non-banded. The allele for non-banded, N, is dominant to the allele for banded, n. State what is meant by the terms dominant and allele. dominant allele A cross between a brown, non-banded snail and a pink, non-banded snail produces some offspring that are both yellow and banded. State the genotypes of both parents. brown, non-banded pink, non-banded List the parental gametes. brown, non-banded pink, non-banded State the genotype of the offspring that are both yellow and banded. Suggest the proportion of offspring expected to be both yellow and banded.
16. Inheritance  →  16.2. The roles of genes in determining the phenotype
17. Selection and evolution  →  17.2. Natural and artificial selection
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