Biology Genetics
- Created by: miriammorris
- Created on: 28-01-15 11:53
View mindmap
- B1 - Genetics
- Genetic variation
- Fertilisation
- This is when the sperm and the egg join to form the full 46 chromosomes.
- fertilisation is a bit random- you dont know which gametes will join.
- Mutations (changes) can occur.
- This just means that there are new characteristics, increasing variation.
- Gamete formation
- Gametes are sperm/egg cells. In each pair of chromosomes, one is inherited from the mother and one from the father.
- Gametes are formed in the ovaries/testes.
- When these body cells split to form Gametes, chromosomes are split up. Gametes end up with 1/2 the number of chromosomes of a normal body cell - 23.
- In each gamete, some of your dad's chromosomes are grouped with some of your mums.
- This shuffling of chromosomes leads to variation in the new generation.
- Fertilisation
- Genes and the environment
- intelligence
- one theory is that your genes affect your IQ.
- However, ti may depend on school and upbringing.
- one theory is that your genes affect your IQ.
- health
- Some people are more likely to get diseases(eg cancer) than others.
- Due to their genes. However, habits such as smoking etc can affect the risk.
- Some people are more likely to get diseases(eg cancer) than others.
- Sporting ability
- Genes determine your potentiol, but training ensures you suceed.
- intelligence
- Sex inheritance and genetic disorders
- All men have an X and a Y chromosome.
- Women have two X chromosomes.
- This is true for all mammals but not plants.
- Genetic inherited disorders
- For a child to inherit the disorder, both the parents must be either carriers or sufferers.
- There is a 1 in 4 chance of the child having the disorder if both parents are carriers.
- The allele which causes cystic fibrosis is a recessive allele, carried by 1 in 25 people.
- as it is recessive, people only carrying one copy of the allele wont have the disorder.
- Theyre known as carriers.
- as it is recessive, people only carrying one copy of the allele wont have the disorder.
- For a child to inherit the disorder, both the parents must be either carriers or sufferers.
- All men have an X and a Y chromosome.
- Genes and chromosomes
- In most animal cells chromosomes come in pairs
- humans have 23 pairs of chromosomes where as guinea pigs have 32.
- Chromosomes carry genes. Genes control development of different characteristics.
- eg. eye colour
- Most cells in your body has a nucleus.
- The nucleus contains genetic material in the form of chromosomes
- genes are short lengths of a chromosome - which is a long length of DNA.
- DNA is coiled up to form the arms of the chromosome
- In most animal cells chromosomes come in pairs
- Genetic variation
Comments
No comments have yet been made