Unit 4.1 - DNA, Genes and the continuity of Life

recognise the role of homologous chromosomes

Homologous chromosomes, found in pairs within a cell, play a crucial role in inheritance and genetic variation.

describe the process of crossing over

The exchange of genetic material during Prophase I between non-sister chromatids of homologous chromosomes when the chromosomes break at corresponding points, and the broken ends can then exchange genetic material.

describe the process of recombination

Occurring in Metaphase I: Independent assortment of chromosomes

demonstrate how recombination and crossing over contribute to genetic variation

Recombination and crossing over shuffle and rearrange the genetic material, creating new combinations of alleles in each generation, ensuring the continuity of a species.

Why is random fertilisation important?

The gametes that form the zygote are not deliberately chosen by the organisms. Therefore, any combinations of gametes are possible this exponentially increases potential for genetic diversity within a species.

Define spermatozoa

A motile sperm cell, or moving form of the haploid cell that is the male gamete.

Define spermatocyte

A male gametocyte, from which a spermatozoon develops.

Define spermatid

A haploid cell produced by meiosis of a spermatocyte that develops into a spermatozoon.

Define spermatogonium

Any of the undifferentiated cells in the male gonads become spermatocytes

Primary location of spermatogenesis

occurring entirely in the testes

Size of gametes

sperm are smaller than the spermatocytes.

When does spermatogenesis begin and what type of process is it?

Uninterrupted continuous process that starts during puberty