Question

9. After the DNA replicates doutes the stor chromats are attached by and the whole r ed to as ONE chromosome until the stars separate after which 10 Dyploid have pairs of chromosomes that carry ones to the same traits, such as color, though one of the pairs may have a gene for brown eyes from the father and the other blue eyes from the mother, Humans have to chromosomes in pairs, half from the father and half from the 11 Do humans or goldfish have more chromosomes? 12. Briefly describe where the chromosomes are and their appearance at each stage or phase of mitosis PROPHASE PROMETAPHASE METAPHASE ANAPHASE TELOPHASE 13. what are the kinetochores and what do they do?

Answer 1

Answer in After the DNA replicates (doubles ) a the 2 sister chromatids are attached by a Centromere and the whole unit is still reffered to as ONE Chromosome, untill the sister separate after Metaphase of - mitosis or during Anaphase of mitosis. Explanation in - The centromere is the specialized DNA sequence of a chromosome that links a pair of sister chromatids. - p arms - 9 arms - centromere - Chromatid Fig:- homologous chromosome. And we separate all know during sister chromatids are anaphase or after the metaphase.

Diploid cells have pairs of chromosomes that carry genes for the same traits. Such as eye colour, though one of the Pairs may have a gene for brown eyes from the father and the other blue eyes from the mother Humans have 46 Chromosomes in 23 pairs, half from the father and half from the - mother . Explanation in We know In human an=46 n = 23 So, 23 pairs of Chromosomes. half comes from father and half from mother in the process of crossing i. e. when male and female gamete form the zygote. 11. - the In between human and gold tish have more gold fish - Chromosome. Explanation : - In goldfish 2n = 94, n = 47 In human 2n= 46, n=23 ..

12. • Prophase in During prophase, the complex of DNA and proteins contained in the nucleus, known as Chromatin, condenses. The Chromatin coils and becomes compact, resulting in the formation of visible Chromosomes. x x Nuclear envelope Fig! Prophase I. Prometaphase in It is the second phases of mitosis.- Here kineto chore fibers interact with the Spindle fibers. Here Chromosome begin to migrate toward the cell center. Here nuclear envelope also breaks down. nuclear envelops breaks down - chromosome fully Condensed Fig: Prometaphase.

Metaphase in Metaphase is the third phase of mitosis. Here Chromosomes condense and become distinguishable as they align in the of the dividing cell... metaphase Plate centrioles spindle fiber chromosome metaphase • Anaphase :- . It is the fourth step of mitosis . ? During anaphase each pair of Chromosomes is separated into two identical, independent Chromosomes. The chromosomes are separated by a structure called the mitotic spindle. Sister Chromosomes moves to opposite - da Poles. figår Anaphase.

• Telophase : It is the last step of mitosis. Here the chromosomes arrive at the cell poles, the mitotic Spindle disassembles, and two daughter cells are formed with two sets of Chromosome. Telophase 13. kinetochores in tanti ti It is a complex of proteins - associated with the centro mere of a Chromosome during cell division, to which the microtubules of the spindle attach. function:- a i. Attach the chromatid with Spindle fiber.& ii. Puit the chromatids ? apart. kinetochore.