cell cycle + mitosis

Question 1

What are the three stages of the cell cycle?

Answer 1

1. Interphase
2. Nuclear division (mitosis or meiosis)
3. Cytokenisis

Question 2

What is interphase?

Answer 2

The longest stage of the cell cycle.
Consists of G1, S and G2

Question 3

What happens during G1?

Answer 3

• Protein synthesis occurs to make proteins involved in synthesising organelles
• The organelles replicate
• Cell is checked that it is the correct size, has the correct nutrients, growth factors and that there is no damages DNA. if a cell doesn’t grow pass those checks replication will not continue

Question 4

What happens during S phase?

Answer 4

DNA is replicated

Question 5

What happens during G2?

Answer 5

• Cell continues to grow
• energy stores increase
• the newly replicated DNA is checked for copying errors

Question 6

What is mitosis?

Answer 6

It creates 2 indentical diploid cells and is used for growth and tissue repair and asexual reproduction in plants, animals and fungi.

Question 6

What occurs during prophase?

Answer 6

• The chromosones condense and become visible.
• Nuclear envelope breaks down
• In animal cells the centrioles seperate and move to opposite poles of the cells
• The tubulin threads form a spindle between these centrioles
• In plant cells the tubulin threads are formed from the cytoplasm

Question 7

What occurs during metaphase?

Answer 7

• The pairs of chromatids attach to the spindle threads at the equator region
• They attach by their centromeres

Question 8

What occurs during anaphase?

Answer 8

• The centromere of each chromatid splits
• Motor proteins, walking along the tubulin threads, pull each sister chromatid of a pair, in opposite directions, towards opposite poles
• Because their centromere goes first, the chromatids, now called chromosomes, assume a v shape

Question 9

What occurs during telophase?

Answer 9

• The seperated chromosomes reach the poles
• A new nuclear envelope forms around each set of chromosomes
• The cell now contains two nuclei each genetically identical to each other and to the parent cell from which they arose

Question 10

What occurs during cytokensis?

Answer 10

• The cytoplasm splits in 2 genetically identical cells
• In animals, a cleavage furrow forms in the middle of the cell and the cytoskeleton causes the cell membrane to draw inwards until the cell splits in two
• In plant cells, the cell membrane splits into two new cells due to the fusing of vesicles from the golgi body, The cell wall forms new sections around the membrane to complete the division into 2 cells