What causes variation?
Variation happens for two reasons:
- Inherited features (you get them from your parents)
- environmental features (caused by the environment)
Examples of inherited features:
- Natural eye colour
- Blood groups
- Tongue rolling
- Natural hair colour
Examples of environmental features
- Tatoos
- Tans
- Piercings
- Diffrent type of accents
Continuous variation:
Data that can have any value e.g. Height, weight ( 4.7 kg or 193cm)
Bars can be joined in a bar chart
Discontinuos variation:
Data that has to be put in categories e.g. Skin colour, eye couloir
Bars have to be apart not joined in a bar chart
Who discovered DNA:
Rosalind Franklin, James Watson, Francis Livick
Inside a cell there is a
Nucleus
Inside a nucleus
There are 46 chromosomes , 23 from each parent
Chromosomes are in
Pairs
Each chromosomes
Contain thousands of genes
Definition genes:
A section of a chromosome that codes for a specific protein, which determine our characteristics.
One section of a gene is a
DNA
Our characteristics are determined by
- environmental features
- Inherited features
- and a combination of both
What is DNA
The DNA is a cell which contains all our characteristics, it is used to differentiate people because if not everyone would be the same.
In a sex cell there are…
Only 23 chromosomes
DNA has a…
Sugar phosphate back bone
A double helix structure
A 4 pair base
A+T
G+C
Boys have….
X and y cells
Girls only have X and X cells
A normal cell is called a….
Zygote
