Post-Lab Questions- please answer all In this experiment, how many chromosomes w
ID: 100440 • Letter: P
Question
Post-Lab Questions- please answer all
In this experiment, how many chromosomes were present when meiosis I started?
I started with a total of 46 chromosomes in meiosis 1.
In this experiment, how many nuclei are present at the end of meiosis II? How many chromosomes are in each?
At the end of meiosis II each nuclei end up with half of the 46 chromosomes in which will make 23.
What is the ploidy of the DNA at the end of meiosis I? What about at the end of meiosis II?
Meiosis I chromosome number is no haploid from diploid. In Meiosis II haploid cells did not change in the number of chromosomes.
How are meiosis I and meiosis II different? List two reasons.
In meiosis I the main cell in which is the parent cell goes through the cell division prosses creating 2 daughter cells and the sister chromatids remain intact. In meiosis II is where the 2 daughter cells go through cell division and split in to 4 haploid daughter cells. This time the sister chromatids that remained intact from the first anaphase in meiosis I will now separate making the 4 daughter cells.
Why do you use non-sister chromatids to demonstrate crossing over?
Non sister chromatids are used to show the genetic material amongst the parent chromosomes.
What combinations of alleles could result from a crossover between BD and bd chromosomes?
Identify two ways that meiosis contributes to genetic recombination.
Why is it necessary to reduce the number of chromosomes in gametes, but not in other cells?
Blue whales have 44 chromosomes in every cell. Determine how many chromosomes you would expect to find in the following:
Sperm Cell:
Egg Cell:
Daughter Cell from Mitosis:
Daughter Cell from Meiosis II:
Research and find a disease that is caused by chromosomal mutations. When does the mutation occur? What chromosomes are affected? What are the consequences?
Diagram what would happen if sexual reproduction took place for four generations using diploid (2n) cells.
Explanation / Answer
A single cell in the end of meiosis produces four cells.So at the end of meiosis II four nuclei wiil be there and all with haploid set of chromosomes as that of the parent i.e., 23.
In the end of meiosis I,cells with half the number of chromosomes and chromatids are present.So haploid.In meiosis only chromatid number is halved not chromosome number.So it is also haploid.
Meiosis I results in halving of both chromosome and chromatid number i.e.,from 46 chromosome 92 chromatids to 23 chromosome 46 chromatids. And in meiosis two there is 23 chromosomes and 23 chromatids.Crossing is only seen in meiosis I not in meiosis II.In meiosis I homologous chromosomes are separated but in meiosis II sister chromatids of chrosomes are separated.
Non sister chromatids are homologous to each other and present at two distinct chromosomes.They possess different alleles at the same loci of the two chromosomes.So crossing over occurs between them to exchange the alleles for the same trait.