Question

es and that they 7) Suppose that one human rypote has the normal number of DNA proofreading and repair enzymes and that the function correctly, while another, for some reason, has no such functioning enzymes. As growth and developmen. proceeded, what differences in DNA structure in the cells and overall organism functioning would you expect to f... between the two? 8) In what normal human cells does telomerase function? In what disease does telomerase function in the cells (much to our dismay)? 9) During which part of the cell cycle is the DNA copied? 10) For the following statements, indicate 'MI' (for mitosis), ME (for meiosis), or 'B' (for both) to denote for which process the statement is true. In mammals, occurs only in the ovaries and testes Results in clonal (or near clonal) offspring (or daughter) cells Is a way for I cell to become multiple cells (more than 1) Occurs in a zygote to begin the process of tissue generation Occurs not only in animals but also in plants Involves 2 rounds of cytokinesis Has mechanisms to ensure diversity in the offspring (or daughter) cells Must occur to produce a fully functioning. physiologically normal adult human Homologous chromosomes line up next to each other in metaphase Requires the successful duplication of chromosomes prior to beginning 11) There are 2 processes that occur during meiosis that have the effect of ensuring diversity in the offspring cells. Name each of them and describe how each works. 12) What is cytokinesis?

Answer 1

7. In normal zygote, the All DNA s will be of normal structure and function. They will code for the correct genes and the   functioning will be correct,. The organism will be a normal type.

But in the abnormal zygote, which does not have a proof reading and repair activity, the forming DNA will be abnormal, or will have defect in structure or defect in base pairing and the forming organism will have some genetic problems.

8. a) Telomerase is the enzyme responsible for the maintenance of Telomeres by adding guanine rich sequences. They are mainly present in gametes, stem cells and tumor cells.

   b) In cancer,the telomerase activity is high in the cells.

9. The DNA copied (replicated) during the S phase of cell cycle.

10. a) ME

     b) MI

     c) B

     d) MI

     e) B

     f) ME

     g) ME

     h) B

     i) B

    j) MI

11. The process occur during meiosis is crossing over,a form of homologous recombination. Crossing over is the process by which the genetic information is transferred from one chromosome to another. This takes place during the meiosis I. During this chormosome replicates and crossing over occurs. The next stage of meiosis,ie,Meiosis Involves the seggragation of the recombinated chromosome into four daughter cells (haploid cells).

12. Cytokinesis is the process by which the cell divides into daughter cells after mitosis or meiosis. It involves the division of cytoplasm also.