Thomases Honors Biology
Name _______________________ Per _____
Reproduction
1. Differentiate asexual and sexual reproduction and give an example of each. Asexual 1 parent (fragmentation)
sexual two parents – (humans)
2. Differentiate somatic cells and gametes and give an example of each. Somatic cells are body cells, e.g. skin
cells. Gametes are sex cells e.g. sperm, egg
3. Compare the chromosomes of the parent and offspring in asexual reproduction. The offspring will have 50%
of each parents’ chromosomes. Human parents have 46 chromosomes and so do their offspring but half of
the offspring’s chromosomes come from each parent.
4. Differentiate internal reproduction and external reproduction. Internal reproduction requires penetration of
gametes into the female. External reproduction requires no penetration, e.g. frogs, salmon, corals spray their
sperm and egg into the water.
5. How do prokaryotes and single celled eukaryotes reproduce? Binary fission. DNA is replicated. Cell splits.
There is no nucleus to divide.
Meiosis
6. What type of cell undergoes meiosis? ___sex cells_______________
7. Drawing:
Draw a single chromosome:
as it appears before S
Draw a chromosome as it appears
after S. Be sure to label the chromatids & centromere
8. If half of your chromosomes come from your biological father and half come from your biological mother, why
don’t you have 92 chromosomes?
There are two division in meiosis. 92 to 46, then 46 to 23
9. What are homologous chromosomes?
Chromosomes that carry the same type of traits even though the expression of those traits may differ. Example:
the trait for blue eye color from Mom would be a homolog to the trait for brown eye color from Dad. Every living
thing has two chromosomes for each trait – one came from Mom, one from Dad.
10. What is a tetrad? To homologous chromosomes and their copies.
11. What is the difference between haploid and diploid? Haploid cells contain just one type of chromosome, either
the one from Mom or the one from Dad. Diploid contain both sets of chromosomes.
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12. If the diploid number of a mushroom cell is 52, how many chromosomes are there in and egg of this
organism? __26____
13. When a haploid sperm and haploid egg fuse what is the name of the resulting fertilized egg?zygote
14. Is a fertilized egg diploid or haploid?
State if the cell is haploid or diploid.
15.
Sperm cell = Haploid
18.
Stomach cell = diploid
16.
Liver cell = Diploid
19.
Broccoli cell =diploid
17.
Ovum = haploid
20. After the end of meiosis, the chromosome number:
a. is double the number in the parent cell
b. is half the number of the parent cell
c. remains the same as the parent cell
d. becomes diploid
21. Which of the following best describe the term “crossing over”?
a. An exchange of information between two homologous chromosomes
b. A molecular interaction between two sister chromatids
c. A molecular interaction between two non-sister chromatids
d. A separation of two sister chromatids
e. Genetic recombination
f. Both a and e
22. Meiosis produces haploid reproductive cells called _gametes (sperm, ova)___
23. Name the 2 human gametes & their chromosome number. __ovum 23 sperm 23_________________
____________________
24. Why do sex cells divide twice during meiosis? So each gamete can contribute half of the chromosomes needed
to make a new individual
25. Give the name of the stage between meiosis 1 and meiosis 2 and explain what happens during that time.
Interkinesis – growth but no replication of DNA
26. What type of material is exchanged during crossing-over? Genes (DNA)
27. Crossing-over can be found in what the stage of meiosis? Prophase 1
28. How does meiosis differ from mitosis? Meiosis has two divisions, mitosis has one.
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29. Is DNA copied before Meiosis II? Why or why not? There is no synthesis of DNA between meiosis I and
meiosis II so the resulting gamete can be haploid.
30. Describe the cells formed at the end of oogenesis. One ovum, 3 small polar bodies.
31. Compare oogenesis to spermatogenesis Spermatogenesis produces 4 mature sperm. Oogenesis produces
one egg and 3 polar bodies.
32. Is a zygote diploid or haploid?
Questions 33 – 39. A hypothetical organism has 10 chromosomes in each of its somatic cells.
33. Skin cells are continuously being rubbed off and replaced. How many chromosomes will be contained in each
new skin cell that is replaced? ___10______
34. The replacement of skin cells occurs through the process of __mitosis__
35. The diploid number (2N) for this organism is _10_
36. Each gamete of this organism would have how many chromosomes? _5__
37. This organism would have how many homologous pairs of chromosomes? _5____
38. The female of this organism has an ovary. The number of chromosomes in each of the mature reproductive
cells that are made in ovary would be. _5___
39. How many ovum would this organism make each time it undergoes meiosis? _1_____
Phases of Meiosis
Name of Phase
Description
40. Prophase 1
Homologous chromosomes pair up and form tetrad
41. Anaphase 1
Spindle fibers move homologous chromosomes to opposite sides
42. Telophase 2
Nuclear membrane reforms, cytoplasm divides, 4 daughter cells formed
43. Metaphase 2
Chromosomes line up along equator, not in homologous pairs
44. Prophase 1
Crossing-over occurs
45. Metaphase to anaphase
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Chromatids separate
46. Metaphase I
Homologous pairs line up along the equator
47. Telophase 1
Cytoplasm divides, 2 daughter cells are formed
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