Topic 9: How can DNA from two parents combine to form one offspring?

Question 1

How many chromosomes do human somatic cells have?

Answer 1

23

Question 2

What do chromosomes carry?

Answer 2

Genes which programme cells to produce specific proteins

Question 3

How are traits inserted from parents?

Answer 3

By the passing of genes

Question 4

What are somatic cells?

Answer 4

All cells of the body expect gametes and their precursor (sperm and eggs)

Question 5

In prophase 1 homologous chromosomes become linked through…

Answer 5

Meiotic recombination

Question 6

What happens in meiosis 1 and meiosis 2?

Answer 6

Meiosis 1 - homologous separate
Meiosis 2 - sister chromatids separate

Question 7

Stages of meiotic recombination

Answer 7

• Homologous chromosomes find each other
• DNA breaks are introduced (synaptomental complex assembly begins)
• Crossing over occurs (synaptomental complex assembly complete)
• Chiasma visible (synaptomental complex disassembles)
• Chromosomes condense nucleus envelope breaks down and we are ready for Metaphase 1