iGCSE Biology 3 - reproduction - humans

Male reproductive system - XY or XX?

XY

Female reproductive system - XY or XX?

XX

The MRS produces — — in order to fertilise the — —.

• sperm cells

• egg cell

The FRS produces — — (ova) to develop into a/an —

• egg cells

• embryo

Gland

Produces fluids that mix with sperm to make semen

Penis

Allows urine and semen to pass out of man’s body

Scrotum

Bag of skin that holds testes and provides an optimal environment

Testis

Produces sperm and releases male sex hormone (testosterone)

Urethra

A tube carrying urine and semen

Sperm duct

Carries sperm cells from testes to urethra

Uterus

Where embryo and foetus develop during pregnancy

Ovary

Contains many undeveloped egg cells

Every month, one egg cell matures and is released

Vagina m

Muscular tube that leads from cervix to outside world

Cervix

Ring of muscle at lower end of uterus that dilates during labour

Oviduct

Carries egg cells from ovaries to uterus

Male vs Female gametes - made by…

Meiosis in testes vs meiosis in ovaries

Male vs Female gametes - movement?

Yes, with flagellum vs no, wafted along by cilia in oviduct

Male vs Female gametes - chromosomes

23 haploid vs 23 haploid

Male vs Female gametes - energy source?

Many mitochondria in sperm’s mid piece vs nutrient-rich cytoplasm

Male vs Female gametes - key adaptations

Chromosomes with enzymes + flagella vs jelly coat hardens after fertilisation

Male vs Female gametes - size

Small, 5 um vs 120 um

Male vs Female gametes - number produced

Hundreds of millions in one ejaculation vs one p/month, mature egg released at ovulation