Download Meiosis homework Questions ANSWER KEY

Meiosis homework Questions
ANSWER KEY
1. What is the difference between metaphase I and metaphase II?
 Tetrads line up at the equator in metaphase I
 Chromosomes line up at the equator in metaphase II
2. What is the difference between anaphase I and anaphase II?
 Chromosomes move to opposite poles in anaphase I
 Chromatids move to opposite poles in anaphase II
3. Which stage of meiosis (I or II) is most like mitosis? Explain.
Meiosis II is most like mitosis since chromosomes are lined up at the equator, and
chromatids move to opposite poles.
4. How are haploid cells different from diploid cells in humans?
Haploid cells are cells that contain half the amount of genetic information, while
diploid cells have two copies of their genetic information in cells.
5. What is a tetrad?
A tetrad is where two homologous
chromosomes synapse with each
other (line up together) during
metaphase.
6. What are homologous chromosomes?
Homologous chromosomes are
chromosomes that carry the same
genes. They have several
characteristics in common such as
their length, centromere location,
and banding pattern.
7. Do homologous chromosomes have
the same number of genes? YES
8. Do homologous chromosomes have identical genes? Explain.
YES. They are identical but they carry different forms (alleles) of the same genes.
9. What are the two key features of meiosis that contribute to genetic variations?
1. Pairing of homologous chromosomes allows for crossing over, resulting in
exchange of chromosome sections between chromosomes.
2. Independent assortment of homologous maternal and paternal chromosomes
during metaphase I results in gametes that have different combinations of
parental chromosomes. **the way they line up at metaphase I**
10. Explain why synapsis may lead to the exchange of genetic information.
Synapsis is when homologous chromosomes pair up, chromosomes are close enough
for “crossing over” to occur, resulting in the exchange of genetic information.
11. How is crossing over different from independent assortment?
Crossing over involves homologous chromosomes exchanging pieces of chromosomes,
so individual chromosomes may contain maternal and paternal genes.
Independent assortment involves combinations of maternal and paternal
chromosomes that can occur in a gamete.
12. Compare the key similarities and differences between spermatogenesis and Oogenesis.
Similarities:
 Process of creating sex cells by meiosis
Differences:
 Oogenesis occurs in females, uneven division produces one gamete and three
polar bodies (later destroyed).
 Spermatogensis occurs in males, even division produces four gametes
13. A muscle cell of a mouse contains 22 chromosomes. Based on this information, how many
chromosomes are there in the following types of mouse cells?
a. Daughter muscle cell formed from mitosis
22 chromosomes
b. Egg cell
22 chromatids
c. Fertilized egg cell
22 chromosomes
14. When meiosis occur in females, the cytoplasm is not divided equally among the resulting
four cells. Explain why.
The egg cell (ovum) that results from meiosis is larger than the other 3 polar bodies
because it contains most of the nutrients and organelles within the cytoplasm. This
becomes important “fuel” for future cell divisions in the event that the egg cell
becomes fertilized.
15. Draw a diagram of meiosis to show how a female child is produced from the union of a
sperm and an egg.
Parent 1 (XY, male)
Parent 2 (XX, female)
↓
↓
Meiosis
Meiosis
↓
↓
Sperm cells (n – haploid)
Egg cell (n - haploid)
↘
↙
Fertilization (sexual reproduction: X from father, X from mother) (2n-diploid)
↓
Gamete produced (XX, female baby) (2n)
↓
Embryo
↓
Child (XX, female)
16. Fill in the blanks:
A diploid cell undergoes ONE nuclear division(s) in mitosis. Mitosis produces TWO diploid
cells.
A diploid cell undergoes TWO nuclear division(s) in meiosis. Meiosis produces FOUR haploid
daughter cells.
The Difference Between Mitosis & Meiosis
Cell type of parent
(2n or n)
Cell type of daughter
cell(s)
(2n or n)
Number of daughter
cells produced
Genetic relationship
of daughter cells to
parent cells and to
each other
(identical or unique)
Number of cell
division
Mitotic Cell
Division
Meiotic Cell
Division
2n
2n
2n
N
2
4
Identical
Unique
1
2