Chromosomes And Mitosis

Question 1

What do chromosomes contain ?

Answer 1

Chromosomes contain genetic information

Question 2

What are chromosomes coiled up into ?

Answer 2

Chromosomes are coiled up lengths of DNA molecules

Question 3

What do each chromosome carry ?

Answer 3

Each chromosome carries a large number of genes

Different genes control the development of different characteristics, e.g. hair colour

Question 4

How many copies of chromosomes does the body cells have ?

Answer 4

Body cells normally have two copies of each chromosome

One from the organism’s “mother” and the other one from its “father”.

Question 5

Why do body cells in multicellular organisms divide ?

Answer 5

Body cells in multicellular organisms divide to produce new cells as part of a series of stages called the cell cycle.

Question 6

What is the stage of the cell cycle called when it divides ?

Answer 6

The stage of the cell cycle when the cell divides is called mitosis

Question 7

What do multicellular organisms use mitosis for ?

Answer 7

Multicellular organisms use mitosis to grow all or to replace cells that have been damaged

Question 8

How many stages are there of the cell cycle ?

Answer 8

There are 2 stages

Question 9

What is the first stage of the cell cycle ?

Answer 9

The first stage is growth and DNA replication:

In a cell that’s not dividing, the DNA is all spread out in long strings

Before it divides the cells have to grow and increase the amount of sub cellular structures such as mitochondria and ribosomes

It then duplicates it’s DNA so there’s only one copy for each new cell the DNA is copied and forms x-shaped chromosomes. Each arm of the chromosome is an exact duplicate of the other.

Question 10

What is the second stage of the cell cycle?

Answer 10

The second stage of the cell cycle is mitosis

The chromosomes line up at the centre of the cell and cell fibres pull them apart. The two arms of each chromosome go to opposite ends of the cell

Membranes form around each of the sets of chromosomes. These become the nuclei of the two new cells- the nucleus had divided

The cytoplasm and cell membrane has divided

The cell has two new daughter cells. The daughter cells contain exactly the same DNA - they’re identical. Their DNA is also identical to the parent cell