B1: CELL DIVISION

Question 1

What is the name of the process whereby cells divide in multicellular organisms?

Answer 1

Mitosis

Question 2

What are the stages of cell division called?

Answer 2

-interphase
-mitosis
-cytokinesis

Question 3

What happens during interphase?

Answer 3

-cell grows
-DNA replicates
-organelles duplicate

Question 4

What happens during mitosis?

Answer 4

-chromosomes line up in the centre on the cell and cell fibres pull them apart
-2 arms of each chromosome go to opposite ends of the cell
-membranes form around each of the set of chromosomes (the nucleus has divided to form 2 identical nuclei)

Question 5

What happens during cytokinesis?

Answer 5

-cytoplasm and cell membrane divides to form 2 identical cells

Question 6

What is the name of the process whereby prokaryotic cells divide?

Answer 6

binary fission

Question 7

Describe the process of binary fission?

Answer 7

-circular DNA and plasmids replicate
-cell gets bigger and circular DNA strands move to opposite poles of cell
-cytoplasm begins to divide and new cell walls begin to form
-cytoplasm divides and 2 cells are produced. Both have one copy of the circular strand of DNA but each can have a variable number of plasmids

Question 8

How can you use mean division time to work out the number of bacteria in a population?

Answer 8

-make sure both times are in the same unit
-divide the total time that the bacteria are producing cells by the mean division time (this gives you number of divisions)
-1x2^n to find number of cells