Cell Biology- Cell Division

Question 1

Mitosis allows cells to divide for ______, ______ and ____________ of an embryo.

Answer 1

Mitosis allows cells to divide for growth, repair and development of an embryo.

Question 2

What happens during stage 1 of the cell cycle?

Answer 2

Stage 1 – DNA is copied & number of subcellular structures, mitochondria & ribosomes are increased

Question 3

What happens during stage 2 of the cell cycle?

Answer 3

Stage 2 – chromosomes are pulled to either end of the cell and nucleus divides

Question 4

What happens during stage 3 of the cell cycle?

Answer 4

Stage 3 – cytoplasm and cell membranes divide to form 2 genetically identical
cells.

Question 5

how do bacteria multiply

Answer 5

simple cell division - binary fission

Question 6

how often can bacteria carry of binary fission

Answer 6

once every 20 minutes as long as there is enough nutrients and the temperature is suitable

Question 7

how do you calculate the number of bacteria

Answer 7

number
of x 2 ^n
bacteria
n is number of rounds of division

Question 8

how do you write the number of bacteria or binary fissions

Answer 8

in standard form
512 = 5.12 x 10^2

Question 9

why is mitosis important

Answer 9

• essential for the growth and development of multicellular organisms e.g plants of animals
• mitosis occurs when an organism repairs its self e.g a broken bone healing
• asexual reproduction

Question 10

required practical - culturing microorganisms

Answer 10

1. sterilize all Petri dishes, bacterial nutrient broth and agar which will kill any unwanted microorganisms and prevents contamination
2. use an inoculating loop to transfer the bacteria - sterilize loop before use by using bunsen burner
3. once bacteria has been transferred, attach the lid to the dish using adhesive tape
4. place agar plate upside down and into an incubator (stops moisture disrupting the colonies)
5. incubate bacteria at 25 degrees celsius

Question 11

required practical - effect of antibiotics on bacterial growth

Answer 11

everything the same as last practical however after you spread the bacteria place sterile filter paper discs contains the antibiotic

Question 12

what should you see after that practical

Answer 12

zone of inhibition

Question 13

how can you measure the effect of the antibiotic

Answer 13

measure the zone of inhibition using the formula for the area of a circle