Human Reproduction and cell division

Question 1

Why are hormones important in human reproduction

Answer 1

Reproductive hormones control development of secondary sexual characteristics turning ovaries and testes into reproductive organs

Oestrogen in girls age 8-14 growth spurt and puberty and eggs form

Testosterone in boys 9-15 causes growth spurt, puberty and sperm production

Question 2

What are the types of reproduction

Answer 2

Asexual

Sexual

Question 3

How does asexual reproduction work

Answer 3

One parent
Cells divide by mitosis
No joining of gametes so no mixing of genetic information
Genetically identical off spring
Common in very small animals, fungi and bacteria and some larger plants
Human cells reproduce asexually all the time

Question 4

How does sexual reproduction work

Answer 4

Male and female sex cells (gametes) fuse together to form zygote
Cell division of zygotes called meiosis
Chromosome number of original cells halved so as gametes join new cell has right number of chromosomes
Offspring inherit genetic information from both parents so produces variation
Plants - gametes are egg cells and pollen
Animals - egg cells and sperm

Question 5

What are Advantages and disadvantages of sexual reproduction

Answer 5

Risky - depends on successful fusing of two gametes
Risk of producing unviable offspring
Benefit is variation
This makes species more likely to survive longer