Year 12 bio notes

Fertilisation

Fusion of the sperm nucleus (haploid) and the ovum nucleus (haploid) to form a zygote cell (diploid).

External fertilisation

A process where eggs and sperm are released into the water, commonly found in aquatic animals.

Internal fertilisation

Process where fertilisation occurs inside the body of the female, providing protection to the developing embryo.

Parthenogenesis

A form of asexual reproduction where offspring develop from the female gamete without fertilisation by a male gamete.

Spermatogenesis

The process of producing male gametes (sperm) through mitosis and meiosis in males.

Oogenesis

The process of creating female gametes (ova) through the stages of development regulated by hormones in females.

Follicle Stimulating Hormone (FSH)

A hormone that stimulates the maturation of follicles in the ovaries and prepares eggs for ovulation.

Luteinising Hormone (LH)

A hormone that promotes final maturation of ovarian follicles and ovulation.

Binary fission

A form of asexual reproduction in which a prokaryotic cell splits into two genetically identical daughter cells.

Gametogenesis

The production of male and female gametes in gonads through meiosis.

Mitosis

A cell division process that results in two identical daughter cells, crucial for growth and repair.

Meiosis

A specialized cell division that produces haploid gametes, creating genetic diversity through recombination and independent assortment.

Blastocyst

A stage of embryonic development consisting of an inner cell mass that forms the embryo and an outer layer that forms the placenta.

Embryo

An early stage of development after fertilisation, usually when implantation occurs.

Corpus luteum

A hormone-secreting structure formed in the ovary after ovulation which produces hormones to maintain pregnancy.

Zygote

The diploid cell resulting from the fusion of a sperm and an ovum, which divides to form an embryo.

Amniotic sac

A fluid-filled sac that surrounds and protects the developing fetus.

Oxytocin

A hormone that stimulates uterine contractions during childbirth and facilitates milk release during breastfeeding.

Gene technology

Techniques that allow scientists to manipulate genes, including the creation of genetically modified organisms (GMOs).