Sexual reproduction, meiosis and gamete formation
Sexual reproduction
Two parents are needed in The formation of a new organism by combining the genetic material of two organisms.. During this process the nuclei of the male and female Sex cell (sperm in males and ova/eggs in females). are fused in order to create a A fertilised egg cell.. This process is known as fertilisation. The gametes contain half the number of chromosomes in each (haploid). When the male and female gametes combine they create the full complement of chromosomes (diploid) in order to create a human embryo.
The gametes in:
- animals are sperm and eggs
- flowering plants are pollen and eggs
The offspring produced in sexual reproduction are To do with the genes that an organism contains. different to each other and the parents. This process results in variation as it involves the mixing of genetic information.
Meiosis
This short video explains the role of meiotic cell division
Sexual reproduction uses the process of Reduction division in a cell in which the chromosome number is halved from diploid to haploid., which creates gametes. The process of meiosis happens in the male and female reproductive organs. As a cell divides to form gametes:
- copies of the genetic information is made
- the cell divides twice to form four gametes, each with a single set of chromosomes (A sex cell (gamete) that contains one set of chromosomes.)
- all gametes are genetically different from each other
Fertilisation
Fertilisation is the fusion of the The nucleus controls what happens inside the cell. Chromosomes are structures found in the nucleus of most cells. The plural of nucleus is nuclei. of a male Sex cell (sperm in males and ova/eggs in females). with the nucleus of a female gamete. In humans, each gamete has half the number of the total 46 chromosomes that the body requires. Twenty three chromosomes within a gamete are referred to as a haploid. When the two gametes combine, they merge the two sets of chromosome to have 46, which are referred to as diploid.
This produces a new cell called a zygote, which will mature into an embryo. The number of cells increase by mitosis, and as the embryo develops, the cells begin to differentiate (or specialise).