Microbiology- Unit 3.4

Question 1

What is another word for murein?

Answer 1

Peptidoglycan

Question 2

Describe gram positive bacteria: (2)

Answer 2

-Thick layer of murein
-Stains purple with crystal violet dye

Question 3

Describe gram negative bacteria: (3)

Answer 3

-Thin layer of murein
-Stains red/pink as crystal violet does not retain
-Additional layer of lipopolysaccharide & outer membrane

Question 4

Name the conditions of growth for bacteria: (4)

Answer 4

-NUTRIENTS supplied
-25C - 37C for most
-pH- slightly alkaline (7.4)
- Oxygen supply for obligate areobes & facultative anaerobes

Question 5

What nutrients need to be supplied to bacteria? (4)

Answer 5

Glucose, nitrogen, vitamins & mineral salt

Question 6

What shape is cocci bacteria?

Answer 6

Spherical

Question 7

What shape is bacilli bacteria?

Answer 7

Rods

Question 8

What shape is spirilla bacteria?

Answer 8

Spiral

Question 9

What shape is vibrio bacteria?

Answer 9

Curved rods

Question 10

What is the lag phase?

Answer 10

Adjusting to new conditions

Question 11

What is the exponential phase? (log)

Answer 11

Rapid growth

Question 12

What is the stationary phase?

Answer 12

Equilibrium

Question 13

What is the decline phase?

Answer 13

Death of organism/cells
-Resources depleted
-Toxin build up

Question 14

What are obligate aerobes and where would they be positioned in a test tube?

Answer 14

Bacteria requiring oxygen to grow that will position at the top

Question 15

What are obligate anaerobes and where would they be positioned in a test tube?

Answer 15

Bacteria that cannot grow with oxygen present so will position at the bottom

Question 16

What are facultative anaerobes and where would they be positioned in a test tube?

Answer 16

Bacteria that can survive without oxygen but grow better with it so can position anywhere, but mainly at the top