Microbiology

Question 1

What colour do Gram negative bacteria stain?

Answer 1

Pink

Question 2

What colour do Gram positive bacteria stain?

Answer 2

Purple

Question 3

What shape are cocci?

Answer 3

Spheres

Question 4

What shape are bacilli?

Answer 4

Rods

Question 5

What are the main shapes of bacteria?

Answer 5

Cocci, bacilli, spirals

Question 6

What are cocci in chains called?

Answer 6

Strep

Question 7

What are cocci in clumps called?

Answer 7

Staph

Question 8

Why do Gram positive stain purple?

Answer 8

Due to the presence of a thick layer of peptidoglycan in their cell walls

Question 9

What type of toxin do Gram negative bacteria produce and where are they located?

Answer 9

Endotoxin, part of cell wall

Question 10

What type of toxin do Gram positive bacteria produce and where are they located?

Answer 10

Exotoxin, produced inside of cell and are exported from it

Question 11

How do bacteria reproduce?

Answer 11

Binary fission - asexual reproduction

Question 12

Definition of pathogen?

Answer 12

Harmful organism producing a pathology

Question 13

Definition of commensal?

Answer 13

Part of normal flora

Question 14

Definition of opportunistic pathogen?

Answer 14

Usually causes problems in immunocompromised patients

Question 15

Definition of a contaminant?

Answer 15

Grows in culture by accident

Question 16

Definition of pathogenicity

Answer 16

Ability of an organism to cause disease/infect host

Question 17

Definition of virulence

Answer 17

Degree of pathogenicity/severity of disease in host

Question 18

What is coagulase test used for?

Answer 18

Differentiate between coagulase positive and coagulase negative

Question 19

What organism appears golden on blood agar plate?

Answer 19

Staph Aureus

Question 20

What is alpha haemolysis?

Answer 20

Partial haemolysis

Question 21

What is partial haemolysis caused by?

Answer 21

By enzymes denaturing haemoglobin in RBCs

Question 22

What is beta haemolysis?

Answer 22

Complete haemolysis

Question 23

What is complete haemolysis caused by?

Answer 23

By enzymes that lyse RBCs

Question 24

What is gamma haemolysis?

Answer 24

No haemolysis

Question 25

What is the commonest cause of meningitis?

Answer 25

Neisseria meningitidis

Question 26

What causes gonorrhoea?

Answer 26

Neisseria gonorrhoeae

Question 27

What is the first antibiotic used to treat infections caused by coliforms?

Answer 27

Gentamicin

Question 28

Viral replication

Question 29

Definition of bactericidal

Answer 29

Kills bacteria

Question 30

Definition of bacteriostatic

Answer 30

Inhibits bacterial growth

Question 31

What do antibiotics act on and affect?

Answer 31

Act on cell wall Affect bacterial ribosome Act on bacterial DNA

Question 32

What effect do antibiotics that act on the cell wall have?

Answer 32

Interfere with peptidoglycan synthesis

Question 33

What effect do antibiotics have that affect bacterial ribosomes?

Answer 33

Interfere with protein synthesis

Question 34

What effect do antibiotics that act on bacterial DNA have?

Answer 34

Interfere with nucleic acid synthesis

Question 35

What types of antibiotics act on cell wall?

Answer 35

Penicillins, Clephalosporins and Glycopeptides

Question 36

How does Penicillin affect cell wall?

Answer 36

Stops cross linking and causes autolysins to degrade cell wall

Question 37

What is Flucloxacillin used for?

Answer 37

Is used in skin and soft tissue infection, wound infection and cellulitis

Question 38

Which class of antibiotic is safe in pregnancy?

Answer 38

Penicillin

Question 39

Are Penicillins Bacteriostatic or Bactericidal?

Answer 39

Bactericidal

Question 40

Example of a Cephalosporin

Answer 40

Ceftriaxone

Question 41

Are Cephalosporins Bacteriostatic or bactericidal?

Answer 41

Bactericidal

Question 42

How do penicillins leave the body?

Answer 42

Excreted rapidly via kidneys

Question 43

Example of a Glycopeptide

Answer 43

Vancomycin

Question 44

Are Glycopeptides Bacteriostatic or Bactericidal?

Answer 44

Bactericidal

Question 45

How do Glycopeptides effect the cell wall?

Answer 45

Bind to end of growing chain during synthesis to also prevent cross linking and weaken wall

Question 46

What types of antibiotics affect protein synthesis (as attach to bacterial ribosomes)?

Answer 46

Macrolides, Tetracyclines, Aminoglycosides

Question 47

Example of a Macrolide

Answer 47

Erythromycin

Question 48

Are Macrolides bacteriostatic or bactericidal?

Answer 48

Bacteriostatic

Question 49

How do Macrolides attach to bacteria ribosomes affecting protein synthesis?

Answer 49

Lipophilic Pass through cell membranes easily

Question 50

Example of a Tetracycline

Answer 50

Doxycycline

Question 51

Are Tetracyclines bacteriostatic or bactericidal?

Answer 51

Bacteriostatic

Question 52

Example of an Aminoglycoside

Answer 52

Gentamicin

Question 53

Are Aminoglycosides bacteriostatic or bactericidal?

Answer 53

Bacteriostatic

Question 54

Are Aminoglycosides mainly active against Gram positive or Gram negative bacteria

Answer 54

Mainly active against gram negative bacteria

Question 55

Types of antibiotics that act on DNA

Answer 55

Metronidazole, Trimethoprim, Fluroquinolones

Question 56

What does Metronidazole cause?

Answer 56

Causes strand breakage of bacterial DNA

Question 57

What does Trimethoprim do?

Answer 57

Inhibits bacterial folic acid synthesis

Question 58

What does Fluroquinolones do?

Answer 58

Stops supercoiling of bacterial DNA so it cannot replicate

Question 59

What 4Cs increase risk of C. difficile

Answer 59

Cephalosporins Co-amoxiclav Ciprofloxacin Clindamycin

Question 60

What causes bacterial resistance?

Answer 60

Genetic mutation Transfer of DNA that codes for resistance

Question 61

What is the harm in unnecessary prescription of antibiotics?

Answer 61

Unnecessary antibiotics encourages the development of resistant strains

Question 62

Methods of DNA transfer that cause bacterial resistance

Answer 62

Transformation, Conjugation, Transduction

Question 63

What is transformation in bacterial resistance?

Answer 63

When bacteria die and cells break apart, free floating DNA released into environment and can be scavenged

Question 64

What is conjugation in bacterial resistance?

Answer 64

Plasmid duplicate is transferred from one bacteria to another

Question 65

What is transduction in bacterial resistance?

Answer 65

Viruses infecting bacteria can transfer bits of DNA from one bacterium to another

Question 66

Is meningitis gram negative or gram positive?

Answer 66

Gram negative

Question 67

Is gonorrhoea gram negative or gram positive?

Answer 67

Gram negative