Bacteria

Question 1

What type of cell are bacteria?

Answer 1

Prokaryotes

Question 2

In what form is the genetic material present in bacteria?

Answer 2

Double stranded DNA without a nuclear membrane.

Plasmids

Question 3

What organelles are present in bacteria?

Answer 3

Only ribosomes for protein synthesis

Question 4

What do antimicrobials target?

Answer 4

The 70S ribosomes present in bacteria

Question 5

How are bacteria classified?

Answer 5

According to their cell well as either gram positive or gram negative

Question 6

What is a bacterial cell wall made up of?

Answer 6

Peptidoglycan and teichoic acids

Question 7

Describe the structure of gram positive bacteria.

Answer 7

Has a thick peptidoglycan cell wall external to the outer cell membrane.

Question 8

Describe the structure of gram negative bacteria.

Answer 8

Has a thin peptidoglycan cell wall overlaid by an outer membrane made up of lipopolysaccharides and lipoprotein.

Question 9

How do gram positive bacteria damage the host?

Answer 9

Production of exotoxins

Question 10

How do gram positive bacteria share genetic information?

Answer 10

Transformation

Question 11

What is transformation in terms of genetics?

Answer 11

Transformation is the uptake of genetic material from the environment e.g the DNA from another dead bacterium.

Question 12

What colour do gram positive bacteria stain?

Answer 12

Blue

Question 13

What colour do gram negative bacteria stain?

Answer 13

Red

Question 14

How do gram negative bacteria share their genetic material?

Answer 14

Through transduction and conjugation.

Question 15

What is transduction in terms of genetics?

Answer 15

The sharing of genetic information by phages. Enables bacteria to pass on antibiotic resistance to one another.

Question 16

What is a bacteriophage?

Answer 16

A virus that infects bacteria

Question 17

What is conjugation in terms of genetics?

Answer 17

The cell membranes of two bacteria merge enabling them to transmit genetic material to one another.

Question 18

Which type of bacteria share genetic information through conjugation?

Answer 18

Gram negative bacteria

Question 19

Outline the process of gram staining.

Answer 19

1. Add crystal violet
2. Add iodine
3. Wash with alcohol/acetone
4. Add safranin

Question 20

What does iodine do?

Answer 20

Fix the stain in place

Question 21

Staphylococci and streptococci are what types of bacteria?
Anaerobic or aerobic?
Gram positive or negative?

Answer 21

Gram positive aerobic cocci

Question 22

What is s.aureus?

Answer 22

S.aureus is a coagulase positive staphylococci.

Gram positive and aerobic

Question 23

What infection can s.aureus cause?

Answer 23

Cellulitis
Bone and joint infections e.g septic arthritis
Endocarditis
Bacteraemia

Question 24

What are the three types of strepcocci?

Answer 24

Alpha haemolytic strep
Beta haemolytic strep
Non-haemolytic strep

Question 25

What does alpha haemolytic strep do?

Answer 25

Partially haemolyses red blood cells in blood.

Question 26

What does beta haemolytic strep do?

Answer 26

Completely haemolyses red blood cells in blood.

Question 27

What does non-haemolytic strep do?

Answer 27

Does not haemolyses red blood cells in blood at all.

Question 28

What are the two main types of alpha haemolytic streptococci?

Answer 28

Viridans streptococci

Streptococci pneumoniae

Question 29

What is Viridans streptococci?

Answer 29

Normal flora of the skin and mouth

Question 30

What can Viridans streptococci cause?

Answer 30

Endocarditis, particularly following dental work.

Question 31

What does s.pneumoniae cause?

Answer 31

pneumonia and meningitis

Question 32

What are the three types of beta haemolytic strep?

Answer 32

Groups A B C

Question 33

What does group A beta haemolytic strep cause?

Answer 33

Cellulitis, pharyngitis, necrotising fascitis.

Question 34

What does group B beta haemolytic strep cause?

Why?

Answer 34

Neonatal sepsis as Group B beta haemolytic strep is normally found in the vagina and can be passed on to a baby during birth.

Question 35

What is non-haemolytic strep also known as?

Answer 35

Non-haemolytic step

Question 36

Give an example of non-haemolytic strep and what it can cause.

Answer 36

Enterococci - UTI’s, endocarditis, intra-abdominal infection.

Question 37

Neisseria meningitides and Neisseria gonnorrhoea are what types of bacteria?

Answer 37

Gram negative aerobic bacteria

Question 38

N. meningitides is found where and what can it cause?

Answer 38

Commensal of the throat and may cause sepsis and meningitis.

Question 39

Pseudomonas aeruginosa - can cause infections where?

Answer 39

Pseudomonas aeruginosa bacterium can cause a range of infection such as pneumonia, urinary tract infections and skin infections amongst others.

Question 40

How does vibrio cholera present and how is it treated?

Answer 40

Vibrio cholerae which can cause severe rice-water diarrhea in places where water has been contaminated with the organism. Dehydration and electrolyte imbalance is a common cause of death, and therefore proper hydration is vital to prevent death.

Question 41

Staphylococcus epidermis can cause infections where?

Answer 41

Staphylococcus epidermidis which is part of the normal skin flora but can also be responsible for infection of catheters and other devices such as mechanical heart valves.