1. Complete these sentence.
- a) Every cell has tiny rod shaped bodies called chromosomes
- b) Genes determine the inherited characteristics of an animal.
- c) Each cell of a dog has 39 pairs of chromosomes. This is a total of 78 single chromosomes.
- d) Every organism has a specific number of chromosomes.
- e) The chemical compound that makes up the chromosomes is DNA
- f) A dog sperm or egg has 39 single chromosomes.
- g) Body cells have the chromosomes in pairs. These cells are known as diploid cells.
- h) Egg and sperm cells are known as gametes
- i) Egg and sperm cells have a single set of chromosomes. They are known as haploid cells.
2. Add the type of cell division: Mitosis, Meiosis or Both.
- a) The cell division that produces the sperm and egg is called Meiosis
- b) The cell division taking place in all tissues for growth and repair is called Mitosis
- c) The cell division that occurs immediately after the ovum is fertilised by the sperm is called Mitosis
- d) The cell division that produces haploid cells is called Meiosis
- e) The cell division that produces diploid cells is called Mitosis
3. Circle to correct choice. Meiosis only occurs in the: c) ovary and testis
4. Circle to correct choice. During meiosis: c) the number of chromosomes are halved
5. A gamete has: half the number of chromosomes that a body cells has.
6. If the gamete of a mosquito has 3 chromosomes, how many chromosomes are there in the body cells? 6
7. If the body cells of chickens have 18 chromosomes, how many chromosomes are there in the sperm cells? 9
8. If the sperm and eggs cells of the housefly have 6 chromosomes, how many chromosomes are there in the maggot? 12
9. If human gametes have 23 chromosomes, how many pairs of chromosomes are there in human body cells? 23
10. The tissues where mitosis occurs most rapidly are the:
- skin / intestinal wall / bone marrow
11. Complete the following table:
|Purpose of division||Growth and repair||Production of gametes/
|Where process occurs in body||In all body cells||Only in gonads-ovary & testis|
|Number of chromosomes
in daughter cells
|Same as in parent call||Half the number
in the parent cell
|Daughter cells are:||Identical to parent
cell & each other
|Different to parent
cell & to each other