The human reproductive systems and gametes
Answers are for parents and teachers.
1
There are 60 primary spermatocytes in a tubule. How many sperm can they make? How many chromosomes has each sperm if body cells have 46?
60 × 4 = 240 sperm. Each has 46 ÷ 2 = 23 chromosomes.
2
Name the four phases of spermatogenesis in order, and say what the cell is called at the end of the growth phase.
Multiplication, growth, maturation and metamorphosis. At the end of the growth phase the cell is a primary spermatocyte (2N).
3
Each of 15 secondary spermatocytes divides by meiosis II. How many spermatids form, and how many chromosomes has each if body cells have 46?
15 × 2 = 30 spermatids, each with 23 chromosomes.
4
In oogenesis, when does meiosis II of the secondary oocyte take place, and what does it produce?
It happens at the moment a sperm enters, and it gives an ovum and a second polar body.
5
A student has a question about her own cycle and another has a question about male fertility. Who should each ask, and why not a book or the internet alone?
A doctor or a trusted adult. A book gives general biology; only a doctor can examine a person and give advice about that person.