12.2. Respiration
A subsection of Biology, 9700, through 12. Energy and respiration
Listing 10 of 158 questions
shows the structure of an ATP molecule. N NH2 CH2 O P O O P O O O P O N O N N O– O– O– adenine ribose State two ways in which the structure of ATP differs from the structure of an adenine nucleotide in a DNA molecule. 1. 2. In respiration, energy from various substrates is used to synthesise ATP. Explain why less ATP can be synthesised from the same mass of glucose in anaerobic respiration than in aerobic respiration. Explain why more ATP can be synthesised in aerobic respiration from one gram of lipid than from one gram of glucose.
9700_w14_qp_41
THEORY
2014
Paper 4, Variant 1
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shows the structure of an ATP molecule. N NH2 CH2 O P O O P O O O P O N O N N O– O– O– adenine ribose State two ways in which the structure of ATP differs from the structure of an adenine nucleotide in a DNA molecule. 1. 2. In respiration, energy from various substrates is used to synthesise ATP. Explain why less ATP can be synthesised from the same mass of glucose in anaerobic respiration than in aerobic respiration. Explain why more ATP can be synthesised in aerobic respiration from one gram of lipid than from one gram of glucose.
9700_w14_qp_42
THEORY
2014
Paper 4, Variant 2
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All living organisms require a continuous supply of energy. Outline the need for energy in living organisms. is a diagram of ATP. N NH2 CH2 O P O O P O O O P O N O N A B N O– O– O– Name A and B. A B Describe how the structure of ATP is related to its role as energy currency. Thermus thermophilus is a bacterium found in geothermal environments, such as hot springs. The bacterium respires aerobically, even though at high temperatures the solubility of oxygen in water is low. Explain how aerobic respiration may be affected by a decrease in oxygen availability. One strain of T. thermophilus, HB8, has an enzyme, nitrate reductase, which allows nitrate to be used as the final electron acceptor in the electron transport chain (ETC). Suggest an advantage to the bacterium of this adaptation. A mutant strain of HB8 (HB8 mutant) was made by adding an insertion mutation to the gene that codes for the enzyme nitrate reductase. An investigation was carried out into population growth of HB8 and of HB8 mutant in aerobic and in anaerobic conditions. In each experiment, a flask containing bacterial culture medium was incubated. Table 4.1 shows how the flasks were set up. The number of bacteria of each strain per cm3 was calculated after 20 hours. Table 4.1 flask bacteria conditions HB8 aerobic HB8 mutant aerobic HB8 and HB8 mutant aerobic HB8 anaerobic HB8 mutant anaerobic HB8 and HB8 mutant anaerobic Compare the growth of the two strains of bacteria in aerobic and anaerobic conditions in separate cultures. Compare the growth of the two strains of bacteria in aerobic and anaerobic conditions in mixed cultures. Suggest an explanation for the results shown in flask 6.
9700_w14_qp_43
THEORY
2014
Paper 4, Variant 3
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is an electron micrograph of a mitochondrion. 0.7 +m A State the function of mitochondria. Name structure A. Calculate the magnification of the image in . Show your working. magnification × Explain why the light microscope could not be used to produce the image in . Scientists think that mitochondria were once prokaryotes. The evidence for this is that mitochondria have features in common with prokaryotes. State two features that mitochondria have in common with prokaryotes. 1. 2.
9700_w15_qp_21
THEORY
2015
Paper 2, Variant 1
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Questions Discovered
158