Reproduction and Inheritance.
- Created by: Libby Moore
- Created on: 06-05-13 11:37
View mindmap
- Reproduction and Inheritance in humans.
- Human body cells are diploid - they have two copies of each chromosome, arranged in pairs.
- Genes are chemical instructions.
- proteins control inherited characteristics.
- genes also control our inherited characteristics.
- There can be different versions of the same gene, which give different versions of a characteristic.
- These different versions are called alleles.
- There can be different versions of the same gene, which give different versions of a characteristic.
- genes also control our inherited characteristics.
- proteins control inherited characteristics.
- A DNA molecule has two strands coiled together in the shape of a double helix.
- There are four different bases: adenine, cytosine, guanine and thymine.
- The bases are always paired up in the same way, A-T C-G, this is called complementary base-pairing.
- There are four different bases: adenine, cytosine, guanine and thymine.
- Asexual reproduction involves only one parent. The offsring have identical genes to the parent.
- Mitosis: DNA is spread out into long strings. DNA duplicates so theres one copy for each new cell. DNA forms X shaped chromosones
- Chromosomes then line up at centre of cell and cell fibres pull them apart. The two arms of each chromosome go to opposite ends of the cell.
- Membranes form around each of the new sets of chromosomes. Nuceli of tow new cells.
- cytoplasm divides.
- Membranes form around each of the new sets of chromosomes. Nuceli of tow new cells.
- Chromosomes then line up at centre of cell and cell fibres pull them apart. The two arms of each chromosome go to opposite ends of the cell.
- Mitosis: DNA is spread out into long strings. DNA duplicates so theres one copy for each new cell. DNA forms X shaped chromosones
- Sexual reproduction involves the fusion of male and female gametes. Because their are two parents, the offspring contain a mixture of their parents gene.
- Meiosis: cell duplicates it DNA (so theres enough for each new cell). In first division chromosomes line up in pairs in the centre of the new cell.
- The pairs are then pulled apart so each new cell only has one copy of each chromosome. each cell will have mixture of Mothers and Farthers creating variation.
- In 2nd diivision chromosomes line up at centre of cell and arms are puller apart.
- You get four haploid gametes, eahc cell only have single set of chromosomes, the gametes are genetically different.
- In 2nd diivision chromosomes line up at centre of cell and arms are puller apart.
- The pairs are then pulled apart so each new cell only has one copy of each chromosome. each cell will have mixture of Mothers and Farthers creating variation.
- Meiosis: cell duplicates it DNA (so theres enough for each new cell). In first division chromosomes line up in pairs in the centre of the new cell.
Comments
No comments have yet been made