Microbiology

Question 1

What is gyrase topoisomerase?

Answer 1

Enzymes that uncoils bacterial DNA–good target for antibiotic

Question 2

What is a plasmid?

Answer 2

circular “extra” piece of bacterial DNA that often carry genes for resistance

Question 3

What 4 things are located in the membrane of bacteria?

Answer 3

motility machinery
electron transport chain
ion transport machinery
metabolite uptake and release machinery

Question 4

What type of rRNA do bacteria have?

Answer 4

have 5s and 16s

Question 5

Mycoplasmatales

Answer 5

Bacteria with no cell wall

Question 6

Penicillin, Cephalosporin, Vancomycin, Bacitracin

Answer 6

Inhibit cell wall

Question 7

What is peptidoglycan made of?

Answer 7

Repeating units of muramic acid and glucosamine

Question 8

Transglycosidation

Answer 8

assembly of peptidoglycan subunits

Question 9

Transpeptidation

Answer 9

cross-linking of Mur and Glu chains to make peptidogylcan

Question 10

Gram + bacteria

Answer 10

2 layers–Thick peptidoglycan (teichoi acid) and inner membrane

Question 11

Gram - bacteria

Answer 11

3 layers–outer membrane with LPS, thin layer of peptidoglycan, and inner membrane

Question 12

Lipopolysaccharide

Answer 12

ENDOTOXIN that binds TLR4

Question 13

Which part of LPS is toxic?

Answer 13

Lipid A

Question 14

Which part of LPS is variable depending on bacteria?

Answer 14

O antigen

Question 15

Gram + bacteria stain

Answer 15

Purple (purple dye and iodine)

Question 16

Gram - bacteria stain

Answer 16

Pink (sulfranin)

Question 17

Capsules

Answer 17

Protective layer for bacteria that creates a physical barrier, inhibit phagocytosis by interfering with complement, immune evasion through molecules mimicry

Question 18

What do spores contain?

Answer 18

contain DNA and just a few proteins–protected by peptidoglycan

Question 19

Why do spores form?

Answer 19

Form due to limited nutrients and harsh environments

Question 20

Which type of bacteria undergo sporulation?

Answer 20

ONLY GRAM +

Question 21

What is a biofilm

Answer 21

Community of bacterial cells enclosed in a self-produced polymeric matrix, adherent to an inert or living surface, and resistant to host defenses and antibiotics–dental plaque

Question 22

Flagella

Answer 22

Provide motility so that bacteria can swim–get energy from inner membrane

Question 23

Pili or Fimbriae

Answer 23

Hairlike structures on surface that are responsible for the attachment of bacteria and communication

Question 24

Obligate aerobes

Answer 24

must be in oxygen–oxidative pathways

Question 25

Obligate anaerobes

Answer 25

NO OXYGEN--it is toxic!--fermentation

Question 26

facultative anaerobes

Answer 26

Grow in presence or absence of oxygen

Question 27

Microaerophilic aerobes

Answer 27

Needs oxygen, but too much will kill (use aerobic respiration)

Question 28

Aerotolerant bacteria

Answer 28

Tolerate small amounts of oxygen

Question 29

How do bacteria break down oxygen radicals?

Answer 29

Same enzymes as humans Superoxide dismutase Catalase or Peroxidase

Question 30

Why do bacteria need nitrogen?

Answer 30

Protein and nucleic acid synthesis--obtained from decamp

Question 31

Where do bacteria get carbon from?

Answer 31

organic carbon sources, carbohydrates, proteins, fats

Question 32

Things required for bacterial growth

Answer 32

Sulfur, phosphorus, trace elements, iron

Question 33

Siderophore

Answer 33

iron scavengers--have high affinity for ferric iron

Question 34

Glycolysis

Answer 34

aerobic and anaerobic process that creates 2ATP and 2 NADH

Question 35

Fermentation

Answer 35

Breaks down pyruvate to FAs, alcohol, and CO2

Question 36

Citric Acid Cycle

Answer 36

Breaks down pyruvate aerobically to create materials for ETC

Question 37

Anaerobic respiration

Answer 37

Better than fermentation but less efficient than aerobic

Question 38

What do you need to culture bacteria in virgo?

Answer 38

Special atmospheres Incubators Supplemental CO2 Synthetic media

Question 39

How can you identify bacteria?

Answer 39

Look at their byproducts

Question 40

Why is there a lag phase on a growth curve?

Answer 40

During this time, bacteria are synthesizing everything they need to replicate

Question 41

How do we count bacteria by dilution?

Answer 41

Serial 10 fold dilution are plated and then colonies counted and multiplied by the dilution factor

Question 42

What is a spectrophotometer used for?

Answer 42

Measure the turbidity of broth culture to determine how many bacteria are present

Question 43

What 4 things can cause bacterial death?

Answer 43

Membrane disruption Denaturation of proteins DNA replication disruption Oxidation

Question 44

Sterilization

Answer 44

Use of physical or chemical means to destroy all microbial forms (vegetative and spores)

Question 45

Autoclave

Answer 45

Sterilization technique where increased pressure raises boiling point and temp

Question 46

Ethylene oxide gas

Answer 46

Sterilization technique

Question 47

Ionizing radiation

Answer 47

Sterilization technique used for syringes and catheters

Question 48

Disinfection

Answer 48

Use of physical or chemical means to destroy most bacterial cells and spores on surface and objects

Question 49

Antisepsis

Answer 49

use of chemical agents on skin or other tissues to remove or inhibit bacterial agents

Question 50

Pasteurization

Answer 50

Heat treatment at specific temp for duration of time

Question 51

Boiling

Answer 51

purifying technique that kills bacteria but not all spores (can release endotoxin)