Name________________________________________
REPRODUCTION AND GENETICS LAB
Part 1. Gametogenesis in Humans
1. View slides of ovary and testis at 400x magnification. Sketch on a separate sheet of paper and label at least
three structures on each.
2. What is oogenesis?
3. How many secondary follicles can you find on your slide of the ovary?
4. Normally, how many chromosomes are in a human gamete?
5. Referring to your text or other sources, identify six structures on this figure.
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6. Differentiate between ova and polar bodies.
7. What takes place in the secondary oocyte after fertilization?
8. What is spermatogenesis?
9. How many sperm cells do you estimate are in the testis cross-section?
10. Name the hormonal products of the testes.
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11. Referring to your text or other sources, identify structures A-F on this figure.
Marieb. Art Labeling Quiz.http://wps.aw.com/bc_marieb_hap_9_oa/221/56741/14525815.cw/index.html. Web 3 Nov 2014
12. What is semen composed of? What glands produce it?
13. Following fertilization in humans, how many chromosomes does the zygote, the first cell of the new individual,
have?
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Part 3. DNA Structure and Function
1. How does DNA replication relate to cell division?
2. In a cell, what causes the hydrogen bonds between base pairs to break in the first step of replication?
3. Base pairing occurs when “free-floating nucleotides” are hydrogen-bonded to complementary nucleotides.
Where in the cell is this supply of “free-floating nucleotides”?
4. What does the precise nature of the replication process ensure (for the most part)?
Transcription
1. List five differences between DNA and RNA.
2. Which mRNA base pairs with each of the four bases of DNA in transcription? In other words C pairs with G, G
pairs with C ….
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3. What information does mRNA carry from the gene on DNA to the ribosomes?
4. Where is mRNA formed and through what structure must it pass to move to the ribosomes?
5. If DNA is described as a double helix, how should RNA be described?
6. What is the job of tRNA?
7. How does the structure of tRNA differ from that of mRNA?
8. What is the end result of translation?
Part 4. Cell Division
1. In what type of cell does the mitotic cell cycle take place?
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2. Give an example of a specific cell or tissue type that would participate in the mitotic cell cycle.
3. During what stage of the cell cycle does chromosome duplication occur, and why is this critical to mitosis?
4. Please describe the resulting daughter cells as compared to the original parent cell.
5. Can mutations in a cell that undergoes mitosis be passed to future generations? Explain why or why not.
6. State one significant event of each stage.
I
G1
S
G2
M
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7. What is synapsis, and why is it critical to meiosis?
8. What events could account for a male that has an XXY karyotype?
9. Draw a duplicated (replicated) chromosome and label the sister chromatids and the centromere.
10. What is the benefit to the cell for using non-sister chromatids and not sister chromatids in the crossing over
process?
11. Name two ways that meiosis contributes to genetic variation.
a.
b.
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12. How many cells usually will be present when meiosis II is complete?
13. How many chromosomes (human) are in the daughter cells?
14. In meiosis, the parent cell has the diploid (2n) number of chromosomes, and the daughter cells have the
_____________ number of chromosomes.
15. Meiosis is cell division in which the chromosome number is reduced to _____________.
16. A zygote contains the same number of chromosomes as the parent, but are these exactly the same
chromosomes?
Part 5. Genetics. Please show Punnett Square where appropriate.
1. How many pairs of autosomal chromosomes are there in a human?
2. Are most human traits autosomal? Explain.
3. Use letters for the genotype of an individual that is heterozygous. Does this person have cystic fibrosis?
4. Use letters for the genotype of a person who has cystic fibrosis. Use words for this genotype.
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5. Are dominant phenotypes always the most common in a population? Explain.
6. Both Nancy and Jim are homozygous dominant for freckles, a dominant trait. What is their genotype?
7. What are the chances that Nancy and Jim will have children with freckles?
8. If a genetic disorder is recessive and the parents are heterozygous, what are the chances that an offspring will
have the disorder?
9. If a genetic disorder is dominant and the parents are heterozygous, what are the chances that an offspring will
have the disorder?
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10. Huntington disease is a dominant disorder. Mary is 25 years old and as yet has no signs of Huntington disease.
However, her mother is heterozygous for Huntington disease, but her father is free of the disorder. What are
the chances that Mary will develop Huntington disease?
11. Tay-Sachs is an autosomal recessive disorder. Is it possible for two individuals who do not have Tay-Sachs to
have a child with the disorder? Explain.
12. What is the genotype for a color-blind female? How many recessive alleles does a female inherit to be colorblind?
13. What is the genotype for a color-blind male? How many recessive alleles does a male inherit to be colorblind?
19. Does a color-blind male give his son a recessive-bearing X or a Y that holds no recessive allele?
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