Microbiology

Question 1

Microbiology

Structure of a bacterial cell

Answer 1

Question 2

Microbiology

What the bacterial cell wall does

Answer 2

Resists environmental stress like osmatic pressure

Acts as a barrier

Provides mechanical strength

Question 3

Microbiology

Gram positive cell wall structure

Answer 3

Question 4

Microbiology

Gram negative cell wall structure

Answer 4

Question 5

Answer 5

Coccus

Question 6

Answer 6

Bacillus

Question 7

Answer 7

Vibrio

Question 8

Answer 8

Spirochete

Question 9

Answer 9

Question 10

Microbiology

Which type of bacteria retain the purple dye in the gram stain test?

Answer 10

Gram positive

Question 11

Microbiology

Polymers that may also be present in the cell walls of gram positive bacteria

Answer 11

Teichic acids

M protein

Mycolic acid

Question 12

Microbiology

Teichoic acid

Answer 12

May appear in cell walls of gram positive bacteria

Provides rigidity to the cell wall

Question 13

Microbiology

M protein

Answer 13

May be found in the cell wall of gram positive bacteria

Helps to prevent phagocytosis by immune cells

Question 14

Microbiology

Mycolic acid

Answer 14

May be found in the cell wall of gram positive bacteria

Waxy lipid

Aids survival in environmental stress

Provides a barrier to antibiotics

Question 15

Microbiology

Virulence factor that provides a barrier to antibiotics

Answer 15

Mycolic acid

Question 16

Microbiology

Catalase test

Answer 16

Tests for enzyme catalase

Question 17

Microbiology

Catalase

Answer 17

Enzyme required by many organisms for the decomposition of hydrogen peroxide to water and oxygen

Question 18

Microbiology

Gram negative bacteria unique outer membrane of the cell wall is called?

Answer 18

Lipopolysaccharide layer (LPS)

Question 19

Microbiology

What’s unique about the LPS layer?

Answer 19

It is made up of lipopolysaccharides instead of the standard phospholipid molecules

Question 20

Microbiology

What are the 2 parts of the LPS layer and their roles?

Answer 20

Lipid A

• Anchors the LPS to the phospolipid bilayer

O polysaccharides

• Carbohydrate chains facing the extracellular fluid

Question 21

Microbiology

Role of the LPS layer

Answer 21

Acts as a major barrier to the outside world

Offers protection against antiseptics and antibiotics

Acts as an endotoxin

Question 22

Microbiology

How is an endotoxin released?

Answer 22

When the cell lyses and dies

Question 23

Microbiology

What is the cause of most symptoms of gram negative bacteria

Answer 23

The LPS which acts as an endotoxin

Question 24

Answer 24

Question 25

Answer 25

Question 26

# Microbiology Four structures of bacteria found outside the cell wall

Answer 26

The capsule Fimriae and pili Axail filaments Flagellum

Question 27

# Microbiology The capsule

Answer 27

Surrounds the cells of some bacteria Made of polysaccharides and peptides secreted from the cell Allows bacteria to stick to surfaces Can help resist phagocytosis

Question 28

# Microbiology How does the capsule help resisit phagocytosis?

Answer 28

The capsule inhibits opsinisation and phagocytosis

Question 29

# Microbiology Opsinisation

Answer 29

Proteins called opsonins are released as part of an immune response Opsonin targets pathogen and binds to it and then binds to a macrophage Increases chances of macrophages binding to pathogen

Question 30

# Microbiology Fimbriae and Pili

Answer 30

Sticky projections involved in sticking to host and other bacterial cells Move by retacting pili

Question 31

# Microbiology What are fimbriae and pili made up of?

Answer 31

A single protein called pilin

Question 32

# Microbiology Axial filaments

Answer 32

Required for motility in spirochetes Wrap around the cell between the plasma membrane and the outer membrane

Question 33

# Microbiology Flagullem

Answer 33

Helps bacteria move to favourable conditions

Question 34

# Microbiology Bacterial movement can be caused by either...

Answer 34

Chemotaxis Phototaxis

Question 35

# Microbiology Chemotaxis

Answer 35

Movement in response to chemicals

Question 36

# Microbiology Phototaxis

Answer 36

Movement in response to light

Question 37

# Microbiology Main way bacteria reproduce and what that actually means

Answer 37

Binary fission * Divide by splitting in two

Question 38

# Microbiology When bacteria reproduce, how similar are the daughter cells to the mother cell?

Answer 38

Identical unless mutation occurs

Question 39

# Microbiology Bacteial cell divsion steps

Answer 39

Question 40

# Microbiology What causes a very long cell to occur?

Answer 40

Depletion of FtsZ FtsZ acts as a contractile ring and cause the two cells to seperate

Question 41

# Microbiology What gene is responsible for maintaining the rod shape in some bacteria?

Answer 41

MreB gene

Question 42

# Microbiology What happens when MreB is depleted?

Answer 42

It leads to cocci shapped cells occuring

Question 43

# Microbiology Endospores

Answer 43

Can survive dormant in harsh conditions such as: * Extreme heat * UV radtion * Antibiotics

Question 44

# Microbiology Cellular differentation that is involved in endospore formation

Answer 44

Bacterial sporulation

Question 45

# Microbiology Stages of endospores converting back to a vegative cell

Answer 45

Activation Germination Outgrowth

Question 46

# Microbiology When a endospore germinates, what happens during outgrowth?

Answer 46

Synthesis of RNA, proteins and DNA Cell begins to divide

Question 47

# Microbiology Exotoxin

Answer 47

Toxin made in the bacteria and released

Question 48

# Microbiology Which sort of toxin does a gram positive bacteria produce?

Answer 48

Exotoxin

Question 49

# Microbiology Which sort of toxin does a gram negative bacteria produce?

Answer 49

Endotoxin

Question 50

# Microbiology Cytotoxin

Answer 50

Exotoxin Kills cells that comes in contact with it

Question 51

# Microbiology Nuerotoxin

Answer 51

Exotoxin Interferes with neurological signal transmission

Question 52

# Microbiology Enterotoxin

Answer 52

Targets the linning of the diggestive system

Question 53

# Microbiology Which type of toxin causes a fever?

Answer 53

Endotoxins

Question 54

# Microbiology Which type of toxin is unstable at 60^oC?

Answer 54

Exotoxins

Question 55

# Microbiology Which type of toxin requires a large amount to be toxic?

Answer 55

Endotoxin

Question 56

# Microbiology Which type of toxin only needs a small amount to be toxic?

Answer 56

Exotoxins

Question 57

# Microbiology Damage to the plamsa membrane can:

Answer 57

Inhibit DNA replication Destroy the ability to produce energy Cause loss of membrane integrity and destroy the cell

Question 58

# Microbiology Ribosomes

Answer 58

Required for protein production

Question 59

# Microbiology Koch's postulates

Answer 59

1. The same pathogen must be present in every case of the disease 2. The pathogen must be isolated from the sick host and purified 3. The pure pathogen must cause the same disease when given to uninfected host 4. The pathogen must be re-isolated from these newly infected hosts

Question 60

# Microbiology Who developed the germ theory of disease?

Answer 60

Robert Koch

Question 61

# Microbiology What is the difference between gram positive and gram negative cell walls?

Answer 61

Gram positive has a thick peptidoglycan layer Gram negative has a thin peptidoglycan layer and outer membrane lipolysaccharide