Bio341 Unit 1 Essay
BIO 341 Homework #2
Questions:
1. A chromosome about to start mitosis is made of two sister chromatids. In what stage of the cell cycle were those sister chromatids made? When do they become visible and distinguishable by light microscopy?
2. For each of the events in mitotic phase, give the stage of mitotic phase in which it occurs
The nuclear membrane breaks down during _______________________.
Chromosomes have reached the equator of the cell during _______________________.
The connection between the sisters breaks during _______________________.
Chromatin condenses into visible chromosomes during _______________________.
Sister chromatids are pulled away from each other during _______________________.
Chromosomes disperse …show more content…
to chromatin form again during _______________________.
Nuclear membrane reforms during _______________________.
The mitotic spindle assembles during _______________________.
Chromosomes move toward the equator of the cell during _______________________.
Spindle fibers grow and attach to chromosomes during _______________________.
3. What is the purpose of spindle structure in mitosis? Where do they connect to the chromosome?
4. What stage of the cell cycle comes after telophase of mitosis?
5. What stage of meiosis is the most like anaphase of mitosis?
6.
A. The amount of DNA in a gamete is ______ times the amount of DNA in a cell in G1 of the cell cycle. B. The amount of DNA in a gamete is ______ times the amount of DNA in a cell in G2 of the cell cycle.
C. The number of chromosomes in a gamete is _____ times the number of chromosomes in a cell in G2 of the cell cycle
7. The domestic dog has a diploid number of 78 (in other words, 2n = 78).
A. How many chromosomes are there in a dog gamete? ________
B. How many pairs of homologs does a dog have? ________
8.
The following are events that occur in meiosis. For each name the stage in which it occurs.
Remember to specify I or II.
__________________ Chromatin condenses
__________________ Crossing over occurs.
__________________ Chromosomes are at the cells’s equatorial plane, but homologs are not paired.
__________________ The nuclear membrane breaks down.
__________________ The spindle forms and fibers attach to the centromeres of the paired homologs.
__________________ Paired homologs, visible as tetrads are all at the equatorial plane of the cell.
__________________ Homologs are pulled apart from each other.
__________________ Sister chromatids are pulled apart from each other.
__________________ A nuclear membrane forms around each of four haploid nuclei.
__________________ Chromosomes pair with their homologs.
9. What are the two ways in which meiosis brings about genetic recombination and which stage or stages of meiosis is responsible?
10. Why can two paired homologs be described as a tetrad?
11. How many kinds of microtubule make up the mitotic spindle?
12. How do sister chromatids compare to each other?
13. Draw diagrams of chromosomes that are metacentric telocentric
acrocentric …show more content…
submetacentric
BIO 341 Homework #2
Answers:
1.
S – phase, prophase
2.
The nuclear membrane breaks down during __prophase_____________________.
Chromosomes have reached the equator of the cell during _____metaphase____________.
The connection between the sisters breaks during _____anaphase________________.
Chromatin condenses into visible chromosomes during _______prophase____________.
Sister chromatids are pulled away from each other during ______anaphase_________________.
Chromosomes disperse to chromatin form again during ________telophase_______________.
Nuclear membrane reforms during _________telophase______________.
The mitotic spindle assembles during ________prophase_______________.
Chromosomes move toward the equator of the cell during ______prometaphase___________.
Spindle fibers grow and attach to chromosomes during ______proaphase______________.
3. It is responsible for moving chromosomes around in the cell. They connect each chromosome at its centromere.
4. Cytokinesis
5. anaphase II of meiosis
6. A. ½
B. ¼
C. ½
7. A. 39
B. 39
8. See the text
9. 1. One way in which meiosis brings about genetic recombination is from the fact that the segregation of each pair of homologs occurs independently of the others. In other words, which member of a pair of homologs, maternal or paternal goes to a given pole is independent of the others. This separation occurs in anaphase
I.
2. The other way is crossing over. This occurs in Prophase I
10. The word tetrad in general means four of something. When two homologs pair up, there will be a total of four chromatids there because each homolog is in the form of two sister chromatids.
11.
Aster microtubules, kinetochore microtubules, and interpolar microbutules
[pic]
12. Identical
13. see text
Questions:
1. A chromosome about to start mitosis is made of two sister chromatids. In what stage of the cell cycle were those sister chromatids made? When do they become visible and distinguishable by light microscopy?
2. For each of the events in mitotic phase, give the stage of mitotic phase in which it occurs
The nuclear membrane breaks down during _______________________.
Chromosomes have reached the equator of the cell during _______________________.
The connection between the sisters breaks during _______________________.
Chromatin condenses into visible chromosomes during _______________________.
Sister chromatids are pulled away from each other during _______________________.
Chromosomes disperse …show more content…
to chromatin form again during _______________________.
Nuclear membrane reforms during _______________________.
The mitotic spindle assembles during _______________________.
Chromosomes move toward the equator of the cell during _______________________.
Spindle fibers grow and attach to chromosomes during _______________________.
3. What is the purpose of spindle structure in mitosis? Where do they connect to the chromosome?
4. What stage of the cell cycle comes after telophase of mitosis?
5. What stage of meiosis is the most like anaphase of mitosis?
6.
A. The amount of DNA in a gamete is ______ times the amount of DNA in a cell in G1 of the cell cycle. B. The amount of DNA in a gamete is ______ times the amount of DNA in a cell in G2 of the cell cycle.
C. The number of chromosomes in a gamete is _____ times the number of chromosomes in a cell in G2 of the cell cycle
7. The domestic dog has a diploid number of 78 (in other words, 2n = 78).
A. How many chromosomes are there in a dog gamete? ________
B. How many pairs of homologs does a dog have? ________
8.
The following are events that occur in meiosis. For each name the stage in which it occurs.
Remember to specify I or II.
__________________ Chromatin condenses
__________________ Crossing over occurs.
__________________ Chromosomes are at the cells’s equatorial plane, but homologs are not paired.
__________________ The nuclear membrane breaks down.
__________________ The spindle forms and fibers attach to the centromeres of the paired homologs.
__________________ Paired homologs, visible as tetrads are all at the equatorial plane of the cell.
__________________ Homologs are pulled apart from each other.
__________________ Sister chromatids are pulled apart from each other.
__________________ A nuclear membrane forms around each of four haploid nuclei.
__________________ Chromosomes pair with their homologs.
9. What are the two ways in which meiosis brings about genetic recombination and which stage or stages of meiosis is responsible?
10. Why can two paired homologs be described as a tetrad?
11. How many kinds of microtubule make up the mitotic spindle?
12. How do sister chromatids compare to each other?
13. Draw diagrams of chromosomes that are metacentric telocentric
acrocentric …show more content…
submetacentric
BIO 341 Homework #2
Answers:
1.
S – phase, prophase
2.
The nuclear membrane breaks down during __prophase_____________________.
Chromosomes have reached the equator of the cell during _____metaphase____________.
The connection between the sisters breaks during _____anaphase________________.
Chromatin condenses into visible chromosomes during _______prophase____________.
Sister chromatids are pulled away from each other during ______anaphase_________________.
Chromosomes disperse to chromatin form again during ________telophase_______________.
Nuclear membrane reforms during _________telophase______________.
The mitotic spindle assembles during ________prophase_______________.
Chromosomes move toward the equator of the cell during ______prometaphase___________.
Spindle fibers grow and attach to chromosomes during ______proaphase______________.
3. It is responsible for moving chromosomes around in the cell. They connect each chromosome at its centromere.
4. Cytokinesis
5. anaphase II of meiosis
6. A. ½
B. ¼
C. ½
7. A. 39
B. 39
8. See the text
9. 1. One way in which meiosis brings about genetic recombination is from the fact that the segregation of each pair of homologs occurs independently of the others. In other words, which member of a pair of homologs, maternal or paternal goes to a given pole is independent of the others. This separation occurs in anaphase
I.
2. The other way is crossing over. This occurs in Prophase I
10. The word tetrad in general means four of something. When two homologs pair up, there will be a total of four chromatids there because each homolog is in the form of two sister chromatids.
11.
Aster microtubules, kinetochore microtubules, and interpolar microbutules
[pic]
12. Identical
13. see text