| Date | May 2022 | Marks available | 1 | Reference code | 22M.1.SL.TZ1.29 |
| Level | Standard level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 29 | Adapted from | N/A |
Question
Leptin helps to regulate body mass in humans and mice. The image shows an obese mouse (O) and a normal mouse (N).
[Source: [Obesity in mice]. [image online] Available at: https://commons.wikimedia.org/wiki/File:Fatmouse.jpg Oak Ridge National Laboratory, U.S. Department of Energy.]
What hypothesis could account for the differences between the mice?
A. The hypothalamus of mouse O stopped producing leptin.
B. Adipose cells of mouse O are continuously producing leptin.
C. Mouse N has a defective leptin receptor.
D. Leptin binds to receptors in the hypothalamus of mouse N.
Markscheme
D
Examiners report
Here was yet another question that proved too difficult for many candidates, with the percentage answering correctly at no better than if based on guess-work. Most candidates thought that obesity in mice is caused by the hypothalamus stopping producing leptin. This reveals two misunderstandings — that the brain rather than adipose cells produces leptin and that obesity is due to a lack of the hormone rather than receptors failing to respond to it.
Syllabus sections
-
22M.2.HL.TZ1.1i:
Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.
- 22M.2.SL.TZ1.1a.i: State the relationship between sloth body temperature and ambient temperature.
- 22M.2.SL.TZ1.1b.i: Describe the trend in body posture as ambient temperature rises from 22 to 34 °C.
- 19N.1.SL.TZ0.30: On the graph, which curve represents the change in FSH levels during the menstrual cycle?
- 18M.1.SL.TZ2.30: Which hormone is matched with its site of production and its role?
- 17M.3.SL.TZ2.3c.ii: State the target that leptin normally acts on.
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20N.2.SL.TZ0.1d.i:
Compare the data for plasma insulin levels before and after the study diet.
- 21M.1.SL.TZ2.30: What is a similarity between the testes of males and the ovaries of females in humans? A....
- 17M.3.SL.TZ2.3c.i: State the tissue that produces leptin in humans.
- 17N.1.SL.TZ0.29: Which hormone inhibits appetite? A. Epinephrine B. Leptin C. Thyroxin D. Glucagon
- 16N.1.SL.TZ0.29: Which hormone controls circadian rhythms? A. ThyroxinB. MelatoninC. LeptinD. Glucagon
- 22M.1.SL.TZ2.30: Which labelled structure of the male reproductive system contributes to formation of semen?
- 17M.1.HL.TZ1.25: The graph shows the changes in blood glucose concentration of an untreated patient with type...
- 17M.2.SL.TZ2.2a: Glands are organs that secrete and release particular chemical substances. Melatonin is an...
- 17M.1.SL.TZ1.27: Which hormone promotes the thickening of the endometrium and also inhibits the hormone that...
- 17N.1.HL.TZ0.25: The graph shows changes in an individual’s blood glucose concentration over time. What...
- 20N.1.SL.TZ0.30: A female is overweight, feels cold and tired, and often fails to ovulate during the menstrual...
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20N.2.SL.TZ0.1d.ii:
State which cells secrete insulin.
- 21N.1.HL.TZ1.25: Leptin is a hormone which initiates the process to reduce food intake. What is the location...
- 18N.1.SL.TZ0.29: Which hormone controls metabolic rate? A. Glucagon B. Insulin C. Thyroxin D. Melatonin
-
21M.1.SL.TZ1.28:
The graph shows the blood levels of hormones associated with the menstrual cycle.
[Source: By OpenStax College - Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013., CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/), https://commons.wikimedia.org/w/index.php?curid=30148641.]
Which line on the graph represents progesterone?
A. Line A
B. Line B
C. Line C
D. Line D
- 18N.1.SL.TZ0.27: What helps to regulate the levels of glucose in blood? A. Insulin and glucagon B. Kidneys...
- 16N.1.SL.TZ0.30: Which is a negative feedback mechanism in the menstrual cycle? A. Follicle stimulating...
- 17M.1.SL.TZ1.30: Pancreatic gland cells produce and secrete large amounts of digestive enzymes. Which...
- 22M.1.SL.TZ2.29: What is an example of negative feedback in the menstrual cycle? A. High levels of estrogen...
- 17M.3.SL.TZ2.3a: Distinguish between the effect of leptin injection on 24 hour food intake in the mice fed the...
- 17M.1.SL.TZ2.27: The bacterium Neisseria gonorrhoeae causes infections related to the human reproductive...
- 18M.1.HL.TZ1.25: What releases leptin? A. Thyroid gland B. Hypothalamus C. Pineal gland D. Adipose tissue
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19M.1.HL.TZ2.31:
The diagram shows the human male reproductive system.
[Source: logika600/Shutterstock]
Which numbers indicate a gland providing fluid for sperm and a tube that transports sperm only?
- 21N.1.SL.TZ0.29: Which hormone regulates the hours of sleep and wakefulness? A. Thyroxine B. Insulin C....
- 18M.1.SL.TZ1.30: What hormone controls the metabolic rate of body cells? A. Insulin B. Leptin C....
-
19M.1.SL.TZ1.30:
The diagram shows the human female reproductive system.
[Source: © International Baccalaureate Organization 2019]
What is produced by structure X?
A. FSH
B. X chromosomes
C. Fertilized eggs
D. Estrogen and progesterone
-
20N.2.SL.TZ0.2c:
Outline one aspect of how P. caudatum carries out homeostasis.
- 17M.1.SL.TZ1.28: The diagram shows the male reproductive organs in front view. Which structures are...
- 17M.1.SL.TZ1.21: Cladograms can be created by comparing DNA or protein sequences. The cladogram on the left is...
- 21M.1.SL.TZ2.29: What is the function of the hormone leptin? A. Increase the uptake of glucose from the...
- 17M.3.SL.TZ2.3b: Discuss the implications of these results for recommending leptin injections as an appetite...
- 22M.1.SL.TZ1.30: What is most likely to increase in the presence of insulin? A. The rate of anaerobic...
- 19N.1.SL.TZ0.29: What is the role of the hormone leptin? A. To regulate the metabolic rate B. To inhibit...
-
22M.2.HL.TZ1.1g:
Describe what is happening to the bone during hibernation.
-
22M.2.HL.TZ1.1j:
A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.
- 19M.1.HL.TZ2.32: The hormones insulin, glucagon, thyroxin and leptin can all affect energy storage in the...
- 22M.2.SL.TZ1.1a.ii: Explain how this relationship differs from that in humans.
-
21M.1.HL.TZ1.25:
The graph showing blood levels of hormones associated with the menstrual cycle.
[Source: By OpenStax College - Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013, CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/), https://commons.wikimedia.org/w/index.php?curid=30148641.]
What event occurs approximately at the time of the dotted line (time X)?
A. Menstruation
B. Ovulation
C. Development of the primary follicle
D. Implantation
- 19M.1.SL.TZ2.29: Which hormone is part of a negative feedback control system and acts on cells in the...
-
17M.2.HL.TZ2.7c:
Explain the roles of specific hormones in the menstrual cycle, including positive and negative feedback mechanisms.
-
22M.2.HL.TZ1.1k:
Discuss how helpful these studies of bears can be in developing an understanding of osteoporosis in humans.
-
21M.2.HL.TZ1.6a:
Describe the genetic and hormonal control of male sexual characteristics in a human.
- 18M.2.HL.TZ1.8a: Describe the process of spermatogenesis leading to the production of four sperm cells in a...
- 17N.1.SL.TZ0.30: What is the name and source of the hormone that regulates basal metabolic rate?
-
22M.2.HL.TZ2.5b.i:
Explain what happens in a person when they develop type I diabetes.
- 17M.2.HL.TZ1.1f.ii: Suggest a reason for the greater expression of the gene for the urea transporter after an...
-
21M.2.HL.TZ1.6c:
Compare and contrast hormonal and nervous communication.
- 20N.2.SL.TZ0.1d.iii: Outline the reason for plasma insulin levels changing in the first 30 minutes of the test.
- 21M.2.SL.TZ1.1g: Outline the role of leptin in appetite control.
-
21N.1.SL.TZ0.30:
What is a function of luteinizing hormone (LH) in the female menstrual cycle?
A. To promote secondary sexual characteristics
B. To inhibit progesterone secretion
C. To stimulate the follicle to release estrogen
D. To trigger ovulation
- 17M.2.SL.TZ1.1c: Estimate how much smaller drilled oysters raised in seawater at a high CO2 concentration were...
- 18N.1.SL.TZ0.30: Which pituitary hormones regulate the human menstrual cycle? A. FSH and LH B. ...
-
19M.1.SL.TZ2.30:
The diagram shows the human female reproductive system
[Source: © International Baccalaureate Organization 2019]
Which labels indicate where fertilization occurs and where luteinizing hormone (LH) acts?
- 22M.2.SL.TZ1.1b.ii: Suggest reasons for this trend.
- 22M.2.HL.TZ2.5b.ii: State how type I diabetes should be treated to avoid harmful health consequences of the...
- 19M.2.HL.TZ2.3c: Hormones are distributed throughout the body by the blood. Outline the roles of two...
- 17M.2.SL.TZ1.6c: Outline how leptin controls appetite.
-
17N.2.SL.TZ0.06b:
Explain how hormones are used to control the human menstrual cycle.
-
19M.2.SL.TZ2.6c:
Discuss the control of blood glucose levels and the consequences if they are not maintained.
- 21M.2.SL.TZ1.1f: Based on the data, evaluate the evidence for leptin promoting regeneration of liver tissue.
- 18M.1.SL.TZ1.27: After 8 hours of sleep and before eating, which hormone will be secreted and what cells...
