| Date | May 2022 | Marks available | 4 | Reference code | 22M.2.HL.TZ2.6 |
| Level | Higher level | Paper | Paper 2 | Time zone | Time zone 2 |
| Command term | Describe | Question number | 6 | Adapted from | N/A |
Question
Describe how plants transport organic compounds from where they are made to where they are stored.
The processes of photosynthesis and respiration have some factors in common and others differ. Compare and contrast both processes for specific factors.
Humans rely on carbohydrates for much of their energy. Outline the process of digestion and absorption of starch in the human digestive system.
Markscheme
- (overall) process is translocation / bidirectional / movement from source to sink;
- sugars/sucrose/organic compounds produced in leaves;
- (loaded by) active transport / passage by apoplast route;
- loaded into companion cells / transported in phloem / sieve tubes;
- high concentrations of solutes at the source cause uptake of water (by osmosis);
- water provides hydrostatic pressure for transport (from source to sink);
- unloaded / stored / used at sink;
- lowers pressure at sink / creates pressure differential / water re-entry to xylem;
- salivary amylase breaks down starch in the mouth
OR
pancreatic amylase breaks down starch in small intestine; - product is disaccharides / maltose;
- maltase digest disaccharides into monosaccharides / glucose / simple sugars;
- monosaccharides/glucose absorbed in the small intestine;
- villi increase the surface area of the intestinal epithelium for greater absorption;
- (monosaccharides are) absorbed by co-transport/active transport (into intestinal cell) / absorbed byfacilitated diffusion into blood (from intestinal cell);
Do not accept glucose or sugars for mpb.
Examiners report
Question 6 was the least popular in section B.
Most candidates provided correct and complete details of the process of translocation.
The comparison of the processes of cellular respiration and photosynthesis was done effectively. Some very good and well-organized answers were noted. It was common for students to use a table to organize their answers. Some correct answers contained full descriptions of the Calvin and the Krebs cycle, which was unnecessary.
Most candidates presented full and correct answers regarding the enzymes and molecules involved in starch digestion. The main recommendation here was to watch the accuracy of statements.
Syllabus sections
- 19M.3.SL.TZ1.2a.iii: Other than humidity, suggest a variable that would need to be controlled in this experiment.
- 22M.2.HL.TZ2.6b: The processes of photosynthesis and respiration have some factors in common and others...
- 17M.2.SL.TZ2.1c.i: State the time when the point of fatigue occurred in the Epi–exercise group.
- 17M.3.SL.TZ2.1a: Suggest how the oxygen consumption rate is determined using this apparatus.
- 17M.2.SL.TZ2.1c.ii: Compare and contrast the results for the water–no exercise group and the Epi–no exercise group.
- 16N.1.SL.TZ0.12: Which pair of molecules are products of aerobic and anaerobic cell respiration in some...
- 22M.1.SL.TZ1.11: The graph shows the changes in lactate measured in an athlete’s blood during...
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21M.1.SL.TZ2.11:
The graph shows the results of an experimental investigation that compared the rates at which lactose, glucose and galactose are broken down in the process of anaerobic cellular respiration by the yeast Torulopsis cremoris.
[Source: Rogosa, M., 1948 Mechanism of the Fermentation of Lactose by Yeasts. Journal of Biological Chemistry, 175, p.418. (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/.]
What can be concluded from these results?
A. Cellular respiration of lactose involves the production of glucose and galactose.
B. The breakdown of glucose and galactose occurs more slowly in the presence of lactose.
C. The rate of cellular respiration is greater for glucose than for lactose and galactose.
D. The percentage of sugar remaining after 42 hours is greater for galactose than glucose.
- 17M.2.SL.TZ2.1b: Describe how increased capillary density could affect the aerobic capacity of muscle.
- 18N.1.HL.TZ0.10: What are final products of photosynthesis and of aerobic respiration?
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19N.1.SL.TZ0.13:
The diagram shows a respirometer used to measure respiration rate in germinating seeds.
[Source: used with the kind permission of the Nuffield Foundation and the Royal Society of Biology]
What is the expected direction of movement of the fluid at X and the function of the fluid at Y?
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21N.2.SL.TZ0.4b.ii:
Outline the use of ATP.
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21N.2.SL.TZ0.4b.i:
State one process that produces ATP.
- 16N.3.SL.TZ0.1a: Suggest the purpose of the wire mesh.
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17N.1.HL.TZ0.09:
A cricket was placed in a respirometer at constant temperature for ten minutes. The soap bubble moved along the pipette.
[Source: © International Baccalaureate Organization 2017]
What was measured by the movement of the soap bubble?
A. Production of carbon dioxide
B. Volume of excretory products
C. Oxygen consumption
D. Release of heat
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19M.1.SL.TZ1.11:
Yeast cells, Saccharomyces cerevisiae, were incubated with and without glucose at three different temperatures for a period of four minutes, during which the rate of CO2 production was measured with a CO2 sensor.
[Source: © International Baccalaureate Organization 2019]
What conclusion can be drawn from the results of this experiment?
A. Yeast uses lipids rather than glucose in respiration at low temperatures.
B. Addition of glucose has a greater impact on rates of cell respiration at lower temperatures.
C. Rates of cell respiration increase with temperature.
D. More glucose is produced at higher temperatures.
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16N.3.SL.TZ0.1c:
Discuss whether the apparatus would be suitable for measuring the oxygen consumption of a small green plant during respiration.
- 19M.3.SL.TZ1.2a.ii: Suggest one conclusion that can be drawn from the results shown in the graph.
- 17M.3.SL.TZ2.1c: Predict the effects of global warming on aerobic respiration in fish.
- 17M.2.SL.TZ2.1f: Mitochondria are essential for aerobic respiration. Suggest one possible role of the proteins...
- 17N.1.SL.TZ0.19: An experiment was set up so that each test tube contained water at a pH of 6.3 and a pH...
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16N.2.SL.TZ0.3b:
Identify the following processes as either anabolism or catabolism by placing a tick (√) in the correct box.
- 17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive...
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16N.2.SL.TZ0.3c:
Describe cell respiration in terms of metabolism.
- 19N.1.SL.TZ0.12: Which compound is a waste product of anaerobic respiration in humans? A. Carbon dioxide B....
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19N.2.SL.TZ0.3d:
Using the following table, compare and contrast anaerobic cell respiration in yeasts and in humans. The first row has been completed as an example.
- 17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
- 17N.1.SL.TZ0.12: Which process causes ADP to change to ATP? A. Hydrolysis B. Protein synthesis C. DNA...
- 16N.3.SL.TZ0.1b: Describe how the apparatus measures the oxygen consumption of the mouse
- 17M.2.SL.TZ2.1e: Analyse the effect of exercise on the presence of the mitochondrial proteins in the leg muscle.
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20N.1.SL.TZ0.11:
The diagram shows a respirometer.
[Source: Courtesy The Royal Society of Biology.]
What solution should be in the bottom of each tube and in which direction will the manometer fluid move?
- 17M.2.SL.TZ2.1d: Discuss the effect of exercise on the results of the experiment.
- 21M.1.SL.TZ1.11: What is a difference between aerobic respiration and anaerobic respiration in yeast? A....
- 17M.1.SL.TZ2.10: The graph shows the changes in lactate and pyruvate measured in an athlete’s blood during and...
- 17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
- 18M.1.HL.TZ2.9: What is a requirement for accurate measurements of the rate of respiration using a...
- 17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
- 17M.3.SL.TZ2.1b: State the relationship between body mass and the oxygen consumption of fish.
- 17M.2.SL.TZ2.1g: The scientists concluded that Epi significantly increased aerobic capacity in leg...
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22M.2.SL.TZ2.3a:
Describe anaerobic respiration in humans and in yeast.
- 19M.3.SL.TZ1.2a.i: Outline how O2 consumption is measured using a respirometer.
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18N.2.HL.TZ0.6b:
Describe the role of oxygen in aerobic cell respiration.
- 21M.2.SL.TZ1.2c: The process X uses oxygen and produces ATP. Identify the process X.
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21N.1.SL.TZ0.12:
A respirometer is used to measure the oxygen consumption of germinating seeds. The distance that the oil drop moves is measured at 15-minute intervals.
[Source: © The Royal Society of Biology.]
What is the function of chemical X?
A. Absorbs carbon dioxide so the oxygen released by the seeds can be measured
B. Absorbs carbon dioxide so the oxygen absorbed by the seeds can be measured
C. Absorbs oxygen so the carbon dioxide released by the seeds can be measured
D. Absorbs oxygen so the carbon dioxide absorbed by the seeds can be measured
