17.2

Question 1

Describe the 4 stages of Binary Fission. (4)

Answer 1

(1) chromosome replication begins & 1 copy of the origin of replication moves rapidly towards the other end of the cell
(2) replication continues & one copy of the origin is now at each end of the cell
(3) replication finishes & the plasma membrane grows inwards & the new cell wall is deposited
(4) 2 daughter cells are produced

Question 2

Bacterial cells also contain plasmids. They each have their own independent ___(1)___ of ______(2)______. This means that Bacterial cells can have many copies of a single plasmid.

Answer 2

(1) origin
(2) replication

Question 3

Describe what conjugation is in context of bacterial cells. (1)

Answer 3

it’s the DNA transfer from 1 bacterial cell to another

Question 4

Describe the process of conjugation. (5)

Answer 4

(1) one cell produces a thin projection that meets another cell & forms a thin conjugation tube
(2) the donor cell replicates one of its plasmids
(3) the plasmid is broken to make it linear before it passes along the tube into the recipient cell
(4) contact between the cells is brief, so only a portion of the donor’s DNA is transferred
(5) so, the recipient cell acquires new characteristics from the donor cell

Question 5

What is horizontal gene transmission? (2)

Answer 5

(1) it is when the DNA can be passed from one species to another species
(2) during conjugation

Question 6

What is vertical gene transmission? (1)

Answer 6

it is when genes are passed down from 1 generation of a species to the next generation of the same species

Question 7

“Discuss the significance of the fact that many antibiotic resistance genes are found on plasmids” (2)

Answer 7

(1) resistance can spread horizontally through a population of bacteria
(2) and may pass from 1 species of bacterium to another

Question 8

“Vancomycin is an antibiotic that acts on the cell wall of the bacterium. Explain why vancomycin doesn’t affect human cells.” (1)

Answer 8

(human cells) don’t have a cell wall

Question 9

Tetracycline is an antibiotic that acts on the ribosomes of the bacterium. Explain how tetracycline prevents bacterial growth.” (1)

Answer 9

(affects) protein synthesis

Question 10

“Vancomycin is an antibiotic that acts on the cell wall of the bacterium.
Frequent treatment with vancomycin can result in resistant strains of bacteria. Explain how.” (2)

Answer 10

any 2 of:
(1) mutation present / occurs
(2) resistance gene / allele
(3) resistant bacteria (survive and) reproduce