1.1b Organisation of DNA

Question 1

What is the genome?

Answer 1

An organism’s entire hereditary information encoded in DNA.

Question 2

How can DNA be organised?

Answer 2

It can be linear or circular (depending on which type of cell it is in and where it is located in the cell)

Question 3

What are prokaryotic cells (prokaryotes)?

Answer 3

Prokaryotes are organisms that lack a true membrane-bound nucleus.

eg. bacteria

Question 4

What are eukaryotic cells (eukaryotes)?

Answer 4

Eukaryotes are organisms that have a true nucleus (bound by a double membrane containing pores) which contains its genetic material.

eg. animals, plants, fungi

Question 5

How is DNA organised in a prokaryotic cell?

Answer 5

• Large, circular chromosome associated with few / no proteins
• Plasmids (small rings of DNA)
  in the cytoplasm

Question 6

How is DNA organised in a eukaryotic cell?

Answer 6

• Linear chromosomes that are tightly coiled and packaged with associated proteins (histones) , found in the nucleus.
• Small circular chromosomes, found in eukaryote chloroplasts and mitochondria

Plasmids are also sometimes present in some yeast cells.

Question 7

What substance is DNA packaged with, in the nucleus of eukaryotic cells?

Answer 7

Associated proteins (histones)

Question 8

What are two sources of circular DNA in eurkaryotes?

Answer 8

Mitochondria & chloroplasts

plasmids are also present in some yeast cells