Cariation And Inheritance Flashcards
What is a genetic characteristic?
It’s a feature controlled by your genes and can be passed on to offspring
What is a chromosome?
A human cell contains 23 pairs in their nucleus and they are made up of genes
What are genes?
A useful length of DNA that codes for a characteristic. They are found on chromosomes
What is DNA?
The molecule that genes are made of
What is an allele?
Different versions of the same gene
What is meant by dominant?
The allele that will always be expressed, represented by a capital letter
What is meant by recessive?
The allele that is only expressed if there are two copies of it, represented by a lower case letter
What is meant by phenotype?
What the characteristic looks like
What is meant by genotype?
The alleles for the characteristic
What is meant by homozygous?
Two alleles which are the same
What is meant by heterozygous?
Two alleles that are different
What is the chance of having a boy or a girl?
There’s a 50% chance of either male or female
What is an environment characteristic?
A characteristic that is caused by your surroundings and cannot be passed on to next generation
What are the three sources of genetic variation?
- Gamete Formation- Making sperm cells and egg cells
- Fertilisation- the gametes join together
- Mutations- change to the genetic code
What is gamete formation?
Gametes are sperm cells and egg cells. Gametes are formed in the ovaries or testes. The body cells they’re made from have 23 pairs of chromosomes. In each pair there’s one chromosome that was originally inherited from the mother and one that was inherited from the father. When these body cells split to form gametes, the chromosomes are also split up. This means that gametes end up with half the number of chromosomes of a normal body cell- just 23. In each gamete, some of the male’s chromosomes are grouped with some of the female’s. This leads to variation in the new generation
