| Date | November 2017 | Marks available | 3 | Reference code | 17N.3.HL.TZ0.02 |
| Level | Higher level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
| Command term | Evaluate | Question number | 02 | Adapted from | N/A |
Question
The light micrograph shows a cross section of seminiferous tubules.
[Source: Micrograph of a seminiferous tubule with sperm by Nephron (https://commons.wikimedia.org/wiki/File:Seminiferous_tubule_and_sperm_low_mag.jpg)]
Concerns have been raised about the effect of rising pollution levels on sperm production in men. To investigate the possible effects of pollution on spermatogenesis, sperm samples from men of similar ages were collected in Kolkata in the 1980s and 2000s. The box plot represents the mean and range of sperm counts in the 1980s and 2000s.
[Source: Republished with permission of Elsevier Science and Technology Journals, from ‘Semen quality and age-specific changes: A study between two decades on 3729 male partners of couples with normal sperm count and attending an andrology laboratory for infertility-related problems in an Indian city’, Dyutiman Mukhopadhyay, Alex C. Varghese, Manisha Pal, Sudip K. Banerjee, Asok K. Bhattacharyya, Rakesh K. Sharma, and Ashok Agarwal, Fertility and Sterility, 93 (7), 2009; permission conveyed through Copyright Clearance Center, Inc]
A hypothesis has been suggested that pollution may have a negative effect on spermatogenesis. Evaluate whether the data support this hypothesis.
Calculate the actual size of the seminiferous tubule in the area indicated by the line across it, giving the units.
Identify the type of cell labelled Z.
Markscheme
a. hypothesis not supported as there is a «slight» increase/not much difference in sperm count between the 1980s and the 2000s
OR
hypothesis not supported as similar means/values for both groups
b. no information on sample size
c. no information/data provided on pollution levels/types of pollution
d. other factors affecting sperm count not considered
OR
other elements than sperm count could be affected
e. data limited to Kolkata/one country/one city
OR
pollution may affect spermatogenesis elsewhere
[Max 3 Marks]
62 mm Υ400 = 0.155 mm/155 μm/micrometers/10-6 m
OR
61 mm Υ400 = 0.153 mm/153 μm/micrometers/10–6 m
Calculation and units required. Accept correct answers expressed in cm
spermatogonium
OR
primary spermatocyte
Examiners report
Syllabus sections
-
17N.1.HL.TZ0.40:
The diagram shows the female reproductive system.
[Source: © International Baccalaureate Organization 2017]
Which structures do K and L identify?
- 22M.1.HL.TZ1.40: What is the role of HCG in early pregnancy? A. It prevents the degeneration of the corpus...
- 22M.1.HL.TZ1.37: Which mechanism prevents polyspermy? A. Polar body formation B. The acrosome reaction C....
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20N.1.HL.TZ0.39:
The diagram shows a section through a seminiferous tubule.
[Source: © International Baccalaureate Organization 2020.]
Which labelled cells are diploid and haploid, respectively?
- 18N.1.HL.TZ0.39: The image shows a flow chart. Which sequence would correspond to the stages shown in the...
- 17M.1.HL.TZ1.38: Which hormone is inhibited during pregnancy in order to prevent contractions of the...
- 16N.1.HL.TZ0.40: Where does the acrosome reaction occur?
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19M.1.HL.TZ1.36:
The diagram shows the chromosomes derived from a single homologous pair following meiosis in a diploid cell.
Which diagram represents the homologous pair from which these chromosomes were derived?
[Source: © International Baccalaureate Organization 2019]
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19M.1.HL.TZ1.40:
The image shows a light micrograph of tissue stained with a dye that binds to the nucleic acids in a cell.
[Source: by Jose Luis Calvo/Shutterstock]
What is the major purpose of the tissue depicted in the image?
A. Absorption of digested food
B. Production of insulin
C. Spermatogenesis
D. Fertilization
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17N.2.HL.TZ0.06b:
Cell biologists play an important role in research into disease, fertility, evolution and many
other areas of science.Compare and contrast the processes of spermatogenesis and oogenesis.
- 17M.1.SL.TZ1.1: Which structure found in eukaryotes has a single membrane? A. Nucleus B. Lysosome C....
- 22M.1.HL.TZ2.40: Hormones maintain the thickness of the endometrium during pregnancy. However, insufficient...
- 17M.1.HL.TZ2.39: What does the blastocyst secrete? A. HCG B. Estrogen C. ADH D. Progesterone
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21N.1.HL.TZ1.40:
The micrograph shows part of a human sperm cell. Which region of the cell is responsible for the greatest production of ATP?
[Source: Oliveira, J.B.A., Petersen, C.G., Massaro, F.C. et al. Motile sperm organelle morphology examination (MSOME):
intervariation study of normal sperm and sperm with large nuclear vacuoles. Reprod Biol Endocrinol 8, 56 (2010).
https://doi.org/10.1186/1477-7827-8-56. https://embryology.med.unsw.edu.au/embryology/index.php/File:Single_
human_spermatozoa.jpg Creative Commons Attribution License (CC BY 2.0) (http://creativecommons.org/licenses/
by/2.0).] -
21N.2.HL.TZ0.2d:
Explain the mechanism that prevents polyspermy during fertilization.
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19N.1.HL.TZ0.40:
The diagram shows a section through the seminiferous tubules. What is the cell labelled X?
[Source: © International Baccalaureate Organization 2019]
A. Spermatid that will differentiate into sperm
B. Primary spermatocyte that will undergo meiosis to form secondary spermatocytes
C. Sertoli cell that provides nutrients
D. Stem cell that will divide by mitosis to form spermatogonia
- 17M.1.HL.TZ2.40: What helps to prevent polyspermy? A. The unequal division of oocytes B. The placental...
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21M.1.HL.TZ1.39:
The pregnancy test for humans is based on detection of the hormone HCG. What is the reason for detection of this hormone indicating pregnancy?
A. HCG is involved in milk production.
B. HCG production is blocked by negative feedback during menstruation.
C. HCG is produced by an embryo.
D. HCG is released during the acrosome reaction.
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20N.1.HL.TZ0.40:
The graph shows three hormones circulating during pregnancy in the rat, with birth occurring at 22 days.
[Source: Dr Paul Kenyon University of Plymouth (retired).]
What are hormones X and Z?
- 17M.2.HL.TZ2.7b: Describe the different cell types in the seminiferous tubules that are involved in the...
- 18M.1.HL.TZ2.40: Which interaction occurs between hormones in the reproductive systems of women? A. Estrogen...
- 18N.1.HL.TZ0.40: If the ovaries of a pregnant woman have to be removed during the first five months of...
-
21M.1.HL.TZ2.40:
What function is maintained as a result of the release of HCG?
A. Production of milk by the mammary glands
B. Release of oxytocin by the posterior pituitary gland
C. Production of FSH by the anterior pituitary gland
D. Production of progesterone by the ovary
-
18M.2.HL.TZ1.8b:
Outline the roles of estrogen and progesterone in females during human reproduction.
- 17M.1.HL.TZ1.40: The diagram shows the exchange processes that take place in the placenta between the maternal...
