Reproduction

Daniel's Y8 Science

Asexual Reproduction

One parent. Offspring are exact copies of the parent, with no variation

Sexual Reproduction

Two parents. Their sex cells (sperm and egg) combine to make a new individual with genetic variation

Gametes

Sex cells (sperm/ovum) They carry half the number of chromosomes

Sperm

Male sex cell.

Ovum (Egg)

Female sex cell.

Haploid

A cell with half the usual number of chromosomes (23), a sperm/ovum is a haploid.

Diploid

A cell with the full number of chromosomes (46), a zygote and most body cells are a diploids.

Zygote

The single cell formed when a sperm and egg fuse. It’s the very beginning of a new life

Embryo

The stage after the zygote starts dividing. It’s a tiny ball of cells developing into a baby

Foetus

A later stage of development, where the baby has recognisable human features (usually after 8 weeks)

Cervix

Ring of muscle between the uterus and vagina.

Fallopian Tube

Tube that connects the ovary to the uterus. This is where the egg meets the sperm

Ovary

The female organ that produces eggs (ova) and hormones like oestrogen

Urethra

The tube that carries urine out of the body. In males, it also carries semen in addition to urine.

Uterus (Womb)

Where a fertilised egg implants and grows into a baby

Vagina

Muscular tube that receives male penis during sexual intercourse

Gonad (Testis)

The male organ that makes sperm and the hormone testosterone

Epididymis

A coiled tube where sperm are stored and mature after being made in the gonads/testes

Penis

The male organ that delivers sperm into the female body during sex

Prostate Gland

Makes fluid that mixes with sperm to make semen

Scrotum

A pouch of skin that holds the testes outside the body to keep them cooler for sperm production

Seminal Vesicle

Makes fluid that mixes with sperm to make semen. Gives sperm its energy.

Vas Deferens

The tube that carries sperm from the epididymis to the urethra

Acrosome

The tip of the sperm head. Shaped like a spear head to penetrate an egg

Nucleus

Part of a sex cell that holds its DNA (half the chromosomes)

Mitochondria

Tiny structures that give sperm its energy

Follicle Cells

Cells around the egg that help protect it and give it nutrients

Zona Pellucida

A protective layer surrounding the egg that the sperm has to penetrate during fertilisation

Cytoplasm

The jelly-like inside of the egg. It holds nutrients to help the embryo grow at the start

Parts of a Sperm Cell (five)

Acrosome, Nucleus, Centrioles, Mitochondria, Flagellum (Tail)

Parts of an Ovum Cell (four)

Follicle Cells, Zona Pellucida, Cytoplasm, Nucleus

Oestrogen

A female hormone that helps build up the lining of the uterus and controls female puberty and the menstrual cycle

Ovulation

The release of a mature egg from the ovary, usually around day 14 of the menstrual cycle

FSH (Follicle Stimulating Hormone)

A hormone from the brain that causes an egg to mature in the ovary

LH (Luteinising Hormone)

A hormone that triggers ovulation and helps the ovary form the corpus luteum

Corpus Luteum

The empty follicle left behind after ovulation that makes progesterone

Progesterone

A hormone that keeps the uterus lining thick so a fertilised egg can implant

Endometrium

The inner lining of the uterus that builds up each month to prepare for pregnancy

Menstrual Cycle

The monthly process where hormones control egg release and changes in the uterus lining

Menstruation

The period. When there is no fertilisation, this is shedding of the uterus lining.

Menopause

When a woman’s periods permanently stop, usually around age 45–55, ending her ability to have children

Copulation

Sexual intercourse. 500 million sperm are released into the vagina

Cilia

Tiny hair-like structures that move the egg along the fallopian tube

Fimbriae

Finger-like structures at the end of the fallopian tube that help catch the egg from the ovary

Blastocyst

A ball of cells formed due to cell division of zygote, before it implants in the uterus

Implantation

When the blastocyst burrows into the uterus lining and starts to grow into an embryo

Ectopic Pregnancy

When a fertilised egg implants outside the uterus, for example in the fallopian tube. This is a dangerous condition