The Cell cycle

Question 1

Briefly describe G2 of Interphase

Answer 1

• Nuclear envelope surrounds cell
• Nucleus has one or more nuclei
• Centrosomes formed by duplication
• Chromosomes duplicated during S phase can’t be seen (haven’t condensed)

Question 2

Prophase

Answer 2

• Chromosomes become discrete chromosomes
• Chromosomes visible as two chromatids connected to a centromere by cohesins
• Mitotic spindle fibres form (centrosomes and microtubules)
• Centrosomes move away from each other (microtubules form bet them)

Question 3

Prometaphase

Answer 3

• Nuclear envelope begins to fragment
• Kinetochores are found at the centromere
• Microtubules connect to kinetochore found at the centromere of each chromosome
• non-kinetochore microtubules connect to the non-kinetochore microtubules from opposite poles

Question 4

Metaphase

Answer 4

• Chromosome align themselves along the metaphase plate

* Kinetochore of chromatids form opposite poles

Question 5

Anaphase

Answer 5

• Cohesin proetins cleaved, allowing for separation of sister chromatids
• Chromatids are now visible as distinct chromosomes
• Shortening of kinetochore tubules allows the movement of chromosomes to their opposite poles

Question 6

Telophase

Answer 6

• Chromosomes at the poles form nuclei
• Parent cell’s nuclear envelope fragments help form the nuclear envelope of the daughter cells
• Nucleoli reappear
• Chomosomes less discrete
• Remaining spindle fibres depolymerise
• Mitosis complete

Question 7

What is CDK? Where is it found? What is its function?

Answer 7

• Chemical that speeds up actions within cell