Are Gametes Made By Mitosis
How do organisms grow and develop?
Multicellular organisms grow by increasing the number of cells they have. This relies on the processes of jail cell segmentation and differentiation.
Sexual reproduction, meiosis and gamete germination
Meiosis
Sexual reproduction uses a type of cell division chosen meiosis , which creates gametes , such as sperm and egg cells. The process of meiosis happens in the male and female person reproductive organs. Only similar in mitosis , a cell starts meiosis in interphase. In interphase, the DNA is copied, the cell grows and the organelles are copied also. Subsequently interphase:
- two meiotic divisions occur which means the prison cell divides twice to form four gametes
- each gamete has half the number of chromosomes found in trunk cells (one chromosome from each pair), and so is known as haploid
All gametes are genetically unlike from each other.
Comparing meiosis and mitosis
| Mitosis | Meiosis |
|---|---|
| Diploid cells made | Haploid cells made |
| Used for growth and repair | Used for sexual reproduction |
| Cells made are genetically identical to starting jail cell and each other | Cells made are genetically unlike to starting jail cell and each other |
| Ii cells are produced | Four cells are produced |
| Ane division occurs | Ii divisions occur |
| Interphase happens before cell division | Interphase happens before jail cell division |
Sexual reproduction
Two parents are needed in sexual reproduction . During this procedure the nuclei of the male and female gametes are fused in social club to create a zygote . This process is known equally fertilisation .
The gametes in:
- animals are eggs (female) and sperm (male)
- flowering plants are eggs/ovules (female) and institute inside pollen (male)
The offspring produced in sexual reproduction are genetically dissimilar to each other and the parents. This process results in variation as it involves the mixing of genetic information.
Fertilisation in humans
Fertilisation is the fusion of the nucleus of a male gamete with the nucleus of a female gamete. In humans, each gamete has half the number of the full 46 chromosomes that the body requires. The 23 chromosomes within a gamete are referred to as a haploid.
When egg and sperm cells combine in fecundation, they merge the ii sets of chromosomes, ending upwardly with 46 chromosomes in full. The maternal chromosomes from the egg cell and the paternal chromosomes from the sperm cell pair up.
The resultant jail cell is called a zygote. Information technology is diploid as it has two copies of every chromosome - one came from the sperm jail cell and ane came from the egg cell.
The zygote volition mature into an embryo . It has DNA from both the female parent and the father so volition have a mixture of characteristics from both parents. In this way, sexual reproduction introduces variation into a species .
The zygote grows past mitosis to course an embryo. As the embryo develops, the cells begin to differentiate .
Are Gametes Made By Mitosis,
Source: https://www.bbc.co.uk/bitesize/guides/zghqfcw/revision/3
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