Cells - Replication

Question 1

What are the processes of mitosis?

Answer 1

(IPMAT)
Interphase
Prophase
Metaphase
Anaphase
Telophase

Question 2

Describe prophase

Answer 2

• Chromosomes condense and first become visible.
• Animal cells contain centrioles which separate and move to the opposite poles.
• From the centrioles, spindle fibres develop which span pole to pole to form the spindle apparatus.
• Nucleolus disappears and nuclear envelope breaks down, freeing the chromosomes.

Question 3

Describe metaphase

Answer 3

• Chromosomes align along the equator of the cell.

- Spindle fibres released from the poles now attach to the centromere and chromatids on the chromosomes.

Question 4

Describe anaphase

Answer 4

Spindle fibres contract so the centromere and chromatids are pulled towards the poles.

This requires ATP via respiration in the mitochondria.

Question 5

Describe telophase

Answer 5

• Chromosomes reach poles and become indistinct.
• Nuclear envelope reforms.
• Nucleolus reforms.
• Spindle disintegrates.

Cytokinesis then occurs.
Cytoplasm splits in two to create two new genetically identical cells.

Question 6

Describe binary fission

Answer 6

• Circular DNA molecule replicates and both copies attach to the cell membrane.
• Cell membrane begins to form between the two DNA molecules, diving the cytoplasm into two.
• New cell wall begins to form between the two molecules of DNA, dividing the original cell into two identical daughter cells.

Question 7

What are the products of meiosis?

Answer 7

• Produces four daughter cells

- Each with half the number of chromosomes of the parent cell.

Question 8

What does diploid mean?

Answer 8

Two copies of every chormosome

Question 9

What type of cells does mitosis form?

Answer 9

Diploid cells

Question 10

What is the formula for mitotic index?

Answer 10

number of cells in mitosis/total number of cells X100

Question 11

How do viruses replicate?

Answer 11

• Virus attaches to the cell using its attachment proteins
• Inject nucleic acid into their host
• Host cell replicates virus particles

Question 12

What are the stages of the cell cycle?

Answer 12

Interphase - G1, S, G2
Longest stage.
G1 - Growth, cell increases in size and organelle doubles.
S - DNA replication occurs
G2 - Further growth, error check where if there are any errors such as mutations the cell will be destroyed

Nuclear Division - M
Mitosis or Meiosis

Cytokinesis - Cytoplasm divides to create two new cells