Section. Section Due at the start of your discussion 3/23 or 3/24 1. Consider a hypothetical (2N diploid organism with a chromosome number of 8. A. How many pairs of homologous chromosomes are there? B. What is the haploid number of chromosomes? C. During metaphase of mitosis how many chromatids are present in the cell? D. During anaphase of meiosis I how many telomeres are present in the cell? 2. Go to the Genetics Home Reference website using the following link: http lahr.nlm nih.gov/chromosomes A. How many genes are estimated to be present on human chromosome 13? B. Draw human chromosome 13. Indicate the correct chromosome structure and the position of the RB1 gene causative for a cancer of the eye known as retinoblastoma. C. What is the genetic term used to describe the structure of chromosome 13? D. Select \'How do geneticists the position of a gene?\' (Located below the illustration of the chromosome 13) Use the descriptions of \"cytogenetic location\' and molecular location to explain advantage of knowing a gene\'s molecular location. Late submissions: -25% per day late if not turned in at beginning of discussion 3/23 or 3/24.
1. a. As the organism has 8 number of chromosomes, 4 pairs of homologous chromosomes are present. 8 is the diploid number of chromosomes in the organism. In the karyotype, the homologous chromosomes are present side by side. So, the number of homologous chromosomes is 4 pairs.
b. The number of haploid chromosomes in the organism is 4. Since 2n=8, n=8/2, n=4.
c.During metaphase of mitosis 16 chromatids are present. It is because the genetic material is duplicated in mitosis which gets condensed to form chromatids during the prophase of mitosis. These chromatids get aligned on the metaphase plate during metaphase stage of mitosis.
d. Since meiosis 1 is a reductional division, 4 number of chromosomes are present in each cell and hence 4 telomeres will be present.
Homework Sourse
