Question

Check Your Understanding 3.1 1 What are chromosomes made of? number 2 How many chromosomes are in a human somatic cell? 46 chromosomes 3 The term used to refer to this full complement of chromosomes is the 4 How many chromosomes are in human gametes? 5 This is referred to as the number 6 Wa chicken's skin cell has 78 chromosomes, how many chromosomes would the chicken's sperm cell have? 7 How can we distinguish the 23 types of chromosomes from one another? 8 What is a gene? 9 What makes homologous chromosomes homologous? 10 How many chromosomes does a human zygote have, and where did these chromosomes come from originally? 11 Somatic cells are produced by what type of cell division? 12 Gametes are produced by what type of cell division? 13 What process occurs in the cell nucleus during interphase just prior to both types of cell division? Why is this process necessary? 14 What is the type of cell division resulting in two identical daughter cells?

Answer 1

Ans.1. Chromosomes are the threads like structure made up of the DNA and histones proteins to form deoxyribonucleoprotein. The DNA and protein are arranged in the nucleosomes. First they form chromatin, that loose structure.

Ans.2. In human somatic cells there are 46 chromosomes present. Out of them 44 are autosomes and 2 are sex chromosome.

Ans.3. The term used to refer this full complement of chromosomes is the diploid number. It is represented as 2n.

Ans.4. There will be 23 chromosomes in the human gametes. It is because they are produced by meiosis.

Ans.5. This is referred to as haploid number.

Ans.6. The chicken sperm cell will have 39 chromosomes In them because they are produced by meiosis.