B1: Variation, Genes, Chromosomes and DNA Flashcards
1
Q
What is variation?
A
When organisms of the same species have different characteristics.
2
Q
What are the two types of variation?
A
- Genetic variation
2. Environmental variation
3
Q
What is genetic variation?
A
- Organisms’ characteristics are determined by the genes inherited from their parents
- The genes are passed on in gametes, which the offspring develop from
- Offspring get genes from both their mother and father
- This combination of genes from the two parents causes genetic variation
- Therefore, an offspring’s characteristics are determined by the genes inherited from their parents
4
Q
What is environmental variation?
A
- The environment that organisms live and grow in causes differences between members of the same species.
- Any difference that has been caused by the conditions something lives in.
5
Q
What are most characteristics caused by?
A
A combination by a mixture of genetic and environmental factors.
6
Q
What does the nucleus contain?
A
The genetic material in the form of chromosomes.
7
Q
How many chromosomes does a nucleus contain?
A
23 pairs.
8
Q
What do chromosomes carry?
A
Genes.
9
Q
What do different genes do?
A
Control the development of different characteristics.
10
Q
What is a gene?
A
A short length of the chromosome.
11
Q
What is an allele?
A
Different versions of the same gene, which gives different versions of a characteristic.
12
Q
What shape is DNA formed in?
A
A double helix.
