Mitosis

Question 1

what is nuclear division called?

Answer 1

karyokinesis

Question 2

what is cell division called?

Answer 2

cytokinesis

Question 3

what happens in prophase?

Answer 3

♣ Chromosomes condense and centriole pairs separate and move towards opposite poles of the cell
• Spindle apparatus forms between them and the nuclear membrane dissolves
This allows spindle fibres to interact with chromosomes

Question 4

what happens in metaphase?

Answer 4

♣ Centriole pairs now at opposite ends of the cell
• Fibres of the spindle apparatus attach to each chromatid at the kinetochore (protein location in the centromere)
o Spindle fibres align the chromosomes at the equator of the cell
♣ This forms the metaphase plate

Question 5

what happens in anaphase?

Answer 5

♣ The centromeres split so that each chromatid has its own centromere
• This allows sister chromatids to separate
♣ Spindle fibres (composed of microtubules) shorten
• This pulls the chromatids towards the poles of the cell

Question 6

what happens in telophase?

Answer 6

♣ Spindle apparatus disappears
♣ Nuclear membrane forms around each new set of chromosomes
♣ Each nucleus is diploid
Chromosomes uncoil, resuming their interphase form

Question 7

what happens during cytokinesis?

Answer 7

♣ Near the end of telophase, cytoplasm (cytosol+organelles) divide into two daughter cells
♣ In animal cells a cleavage furrow forms and the cell membrane invaginates along the equator
In plant cells the cell plate forms which splits the tetraploid cell in half

Question 8

what is interphase?

Answer 8

♣ A period of growth and chromosome replication
♣ A cell normally spends 90% of its life in interphase
• During this phase, cell performs its normal cellular functions
• After replication, the chromosomes consist of two identical sister chromatids
o Held together at a region called the centromere
• During interphase, individual chromosomes are not visible; the DNA is uncoiled and called chromatin
♣ Consists of three parts:
• G1
o Initiates interphase
o Active growth phase and can vary in length (from cell to cell or species to species?)
o Cell increases in size and synthesizes proteins
o The length of the G1 phase determines the length of the entire cell cycle
• S
o DNA synthesis
• G2
o Now the cell prepares to divide
o Cell grows and synthesizes proteins
o The last phase of the cell cycle is the M phase
♣ During this phase, mitosis or meiosis occurs