AQA GCSE Chromosome structure (Biology)
Chromosome Structure
Chromosomes are made up of DNA.
1 DNA molecule = 1 Chromosome
In a Eukaryotic cell (animal or plant cell) the chromosomes are found within the nucleus of the cell.
The chromosome carries genes. So a gene is a short length of DNA that codes for a protein.
A typical human body cell will contain 23 pairs of chromosomes, or 46 individual chromosomes. The chromosomes are in pairs because one of each pair came from the father and the other chromosome came from the mother.
Chromosomes and cell division.
In order for a cell to divide the genetic material must be replicated.
Below is a diagram showing how the DNA in the chromsome is replicated.
Practice Question
1.Where, within a eukaryotic cell is the DNA found?
2.Define the term gene
3. How many pairs of chromosomes does a human cheek cell have?
4. Why are human chromosomes in pairs?