Mitosis and Meiosis | 9-1 GCSE Science Biology | OCR, AQA, Edexcel
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They key points covered in this video include:
1. Mitosis and Meiosis
2. Sexual Reproduction and Asexual Reproduction
Meiosis and Mitosis
Mitosis is the process where body cells divide to produce two genetically identical diploid cells. Normal body cells are made by mitosis. They are diploid - they have two sets of each chromosome. Meiosis is another type of cell division which happens in the testes in males and the ovaries in females. Meiosis is the process where a cell divides to produce four non-identical haploid cells. Haploid means the cells only have one of each chromosome.
Sexual Reproduction
Sexual reproduction occurs when genetic information from two parents (the mother and father) is combined to produce offspring which are genetically different from either parent. Most organisms reproduce by sexual reproduction. As sexual reproduction results in non-identical offspring - it creates genetic variation. Sexual reproduction involves gametes (sperm and egg cells). These gametes fuse together during fertilisation to produce a cell called a diploid zygote. Meiosis is used to make gametes - these are haploid. It is important that the gametes are haploid - this means when they fuse the cell produced will be diploid. This cell (the zygote) will have the correct number of chromosomes. The zygote then divides many times through mitosis to produce an embryo. As the embryo develops, the cells differentiate.
The zygote contains genetic information from the father, passed on through the sperm. It also has genetic information from the mother, passed on through the egg. This means the zygote has a mixture of the parent's genetic information - it has a unique genome. This also creates variation in the offspring. Plants can also sexually reproduce - the female gametes are egg cells and their male gametes are pollen. Fertilisation happens in the ovule of the plant. In summary: Sexual reproduction involves the fusion of male and female gametes where the offspring has a mixture of their parent's genes. The offspring are genetically different to their parents.
Asexual Reproduction
Asexual reproduction involves one parent - the offspring is a clone of the parent. Asexual reproduction happens by mitosis. There is no fusion of gametes, no mixing of genetic material and no genetic variation between the parents and the offspring. Plants, such as potatoes, can reproduce asexually. Each tuber produced can grow into a new plant. Bacteria and some animals (such as star fish) can also reproduce asexually.
Summary
1. Sexual reproduction involves meiosis
2. Sexual reproduction involves the fusion of male and female gametes where the offspring has a mixture of their parent's genes
3. In sexual reproduction the offspring are genetically different to their parents
4. Asexual reproduction involves mitosis
5. There is no fusion of gametes, no mixing of genetic material and no genetic variation between the parents and the offspring
They key points covered in this video include:
1. Mitosis and Meiosis
2. Sexual Reproduction and Asexual Reproduction
Meiosis and Mitosis
Mitosis is the process where body cells divide to produce two genetically identical diploid cells. Normal body cells are made by mitosis. They are diploid - they have two sets of each chromosome. Meiosis is another type of cell division which happens in the testes in males and the ovaries in females. Meiosis is the process where a cell divides to produce four non-identical haploid cells. Haploid means the cells only have one of each chromosome.
Sexual Reproduction
Sexual reproduction occurs when genetic information from two parents (the mother and father) is combined to produce offspring which are genetically different from either parent. Most organisms reproduce by sexual reproduction. As sexual reproduction results in non-identical offspring - it creates genetic variation. Sexual reproduction involves gametes (sperm and egg cells). These gametes fuse together during fertilisation to produce a cell called a diploid zygote. Meiosis is used to make gametes - these are haploid. It is important that the gametes are haploid - this means when they fuse the cell produced will be diploid. This cell (the zygote) will have the correct number of chromosomes. The zygote then divides many times through mitosis to produce an embryo. As the embryo develops, the cells differentiate.
The zygote contains genetic information from the father, passed on through the sperm. It also has genetic information from the mother, passed on through the egg. This means the zygote has a mixture of the parent's genetic information - it has a unique genome. This also creates variation in the offspring. Plants can also sexually reproduce - the female gametes are egg cells and their male gametes are pollen. Fertilisation happens in the ovule of the plant. In summary: Sexual reproduction involves the fusion of male and female gametes where the offspring has a mixture of their parent's genes. The offspring are genetically different to their parents.
Asexual Reproduction
Asexual reproduction involves one parent - the offspring is a clone of the parent. Asexual reproduction happens by mitosis. There is no fusion of gametes, no mixing of genetic material and no genetic variation between the parents and the offspring. Plants, such as potatoes, can reproduce asexually. Each tuber produced can grow into a new plant. Bacteria and some animals (such as star fish) can also reproduce asexually.
Summary
1. Sexual reproduction involves meiosis
2. Sexual reproduction involves the fusion of male and female gametes where the offspring has a mixture of their parent's genes
3. In sexual reproduction the offspring are genetically different to their parents
4. Asexual reproduction involves mitosis
5. There is no fusion of gametes, no mixing of genetic material and no genetic variation between the parents and the offspring
6 سال پیش
در تاریخ 1397/06/09 منتشر شده
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