Cells - Cell Cycle And Mitosis

Question 1

What is the role of mitosis?

Answer 1

To produce identical daughter cells for growth and asexual reproduction.

All the cells produced by mitosis are genetically identical therefore mitosis does not give rise to genetic variation.

Question 2

What are the three stages of the cell cycle?

Answer 2

Mitosis
Interphase
Cytokinesis.

Question 3

What is mitosis?

Answer 3

Mitosis is a form of cell division that produces identical cells. There are four stages of mitosis: prophase metaphase anaphase and telophase.

Question 4

What is interphase?

Answer 4

During this stage, the cell grows and then prepares itself to divide – chromosomes and some organelles are replicated, chromosomes also begin to condense.

Question 5

For what reasons is mitosis important?

Answer 5

Growth: all cells produced are identical so organisms can grow using mitosis.
Repair: all cells produced are identical so organisms can replace dead tissue using mitosis.
Reproduction: some single celled organisms like yeast reproduced by dividing into two identical daughter cells by mitosis.

Question 6

Explain what happens in prophase

Answer 6

Spindle fibres appear
Chromosomes condensed

Question 7

What happens during metaphase?

Answer 7

Spindle fibres attached to chromosomes and the chromosomes align.

Question 8

What happens during anaphase?

Answer 8

Centromeres divide and sister chromatids move to opposite poles.

Question 9

What happens during telophase?

Answer 9

Nuclear membrane reform and chromosomes decondense And spindle fibres disappear.

Question 10

What is binary fission?

Answer 10

The process by which prokaryotic cells divide.

Question 11

What is the process of binary fission?

Answer 11

1. The circular DNA in the cells replicate and both copies attached to the cell membrane. The plasmids also replicate.
2. The cell membrane begins to grow between the two DNA molecules and pinches inwards dividing the cytoplasm into.
3. A new cell wall forms between the DNA molecules dividing the original cell the identical daughter cells each have a single copy of the circular DNA and a variable number of copies of the plasmids.

Question 12

Viruses are nonliving therefore they do not undergo cell division. How do they replicate?

Answer 12

They inject their nucleic acid into a host cell the infected host cell replicates the virus particles.