Organisation Of The DNA

Question 1

What are the types of DNA molecules?

Answer 1

Linear

Circular

Question 2

What does the type of DNA molecule depend on?

Answer 2

1. The type of cell

2. The location of the DNA within the cell

Question 3

What are the 2 types of cells?

Answer 3

Prokaryotic

Eukaryotic

Question 4

Describe prokaryotic cells

Answer 4

1. They have no distinct nucleus

2. The DNA is organised in circular chromosomes and plasmids

Question 5

Describe eukaryotic cells

Answer 5

1. Eukaryotic cells are cells which have a distinct nucleus.
2. In the nuclei of eukaryotic cells the DNA is found tightly coiled into linear chromosomes.
3. However not all of a eukaryotic organism’s DNA is located in the the nuclear chromosomes.
4. Small circles of DNA are present in chloroplasts and mitochondria.

Question 6

Describe DNA in linear chromosomes

Answer 6

A strand of DNA is several thousand times longer than the length of the cell it is stored in. This means the DNA has to be tightly coiled to fit into the nucleus. As well as being tightly coiled, the DNA is usually packaged around associated proteins. This prevents the DNA from becoming tangled.