MIP: Intro to Bacteriology Flashcards Preview

1 Foundations of Disease and Therapy > MIP: Intro to Bacteriology > Flashcards

Flashcards in MIP: Intro to Bacteriology Deck (42):
1

Why doesn't prokaryotic mRNA need processing?

It doesn't contain introns and can be translated immediately as it is synthesized

2

Where do many eukaryotic organelle functions take place in prokaryotic cells?

Within the cell membrane

3

What allows antibiotics to target bacterial protein synthesis without affect human protein synthesis?

Prokaryotes have 70S ribosomes, and eukaryotes have 80S ribosomes

4

What is the general process of performing a Gram Stain?

1) Smear on Glass Slide
2)Heat fixing
3)Crystal Violet stain
4) Gram's iodine
5) Decolorizer
6) Safranin red

5

Following the process of Gram staining, how will a Gram + bacteria appear compared to a Gram - bacteria?

Gram + bacteria will be purple and Gram - will be red

6

What does an acid fast positive stain look like? An acid- fast negative?

Acid fast positive will stain cytoplasm red, negative will stain cytoplasm blue

7

What are some factors that could complicate a Gram stain?

Prior antibiotic exposure, age of bacterial cells, starvation of bacterial cells, ineptness at staining

8

What is a bacterial capsule?

A high molecular weight polysaccharide or peptide that surrounds the bacterial cell wall

9

Which branch(es) of the immune system is/are important to defeating encapsulated bacteria and how?

Both innate (complement opsonization) and acquired (antibody opsonization)

10

A deficiency in what part of the immune system will make a patient more susceptible to encapsulated bacteria?

Complement deficiency

11

What are the structural components of Gram + and - bacterial cell walls?

Gram + cell walls contain a thick layer of peptidoglycan, with teichoic and lipoteichoic acids intertwined within the cell wall. Gram - have an outer membrane comprised of lipopolysaccharide

12

What is peptidoglycan?

N-acetylmuramic acid and N-acetylglucosamine crosslinked with peptide chains and pentaglycine interbridges

13

What bacteria have a periplasmic space? What is it? What's in it?

Gram negative between the outer and inner cell walls- contains a thin layer of peptidoglycan and multiple enzymes like beta-lactamases

14

What are the two cellular appendages that extend off of bacteria?

Pili and Flagella

15

What are the two types of pili and what are they used for?

Common (type Iv) pili that extend, grab onto something, and retract, moving the cell; Sex pili- for sexual reproduction

16

What are flagella?

Long helical filaments extending from cell membrane to exterior of the cell

17

What are bacterial inclusion bodies?

Storage Reserve granules

18

What are spores?

A survival structure- nucleic acid, encapsulated in endospores

19

What are the three major pathways nutrients are fed into?

Glycolytic or anaerobic pathways, TCA cycle, Pentose phosphate pathway

20

True or False: Bacteria do not use oxidative phosphorylation.

False- some anaerobes may

21

What aerobic bacterial enzymes are esp. useful in detoxifying molecular oxygen?

Catalase and superoxide dismutase

22

What is a facultative aerobe?

They can use O2 if present, but can survive on aerobic metabolism.

23

Which antibiotics are only useful for treating infections caused by aerobic bacteria?

Aminoglycosides

24

Which antibiotic is widely used for treating infections caused by strict anaerobes?

Metronidazole

25

What was the first antibiotic? To what category of antibiotics does it belong?

Prontosil; Sulfonamides

26

How do sulfonamides work?

Sulfa drugs block the synthesis of folic acid

27

What is the mechanism of trimethoprim's action?

Inhibition of bacterial dihydrofolate reductase

28

How does rifampicin work as an antibiotic?

Inhibiting RNA polymerase

29

What is the structure of bacterial chromosomes?

Circular and supercoiled

30

What enzymes involved in unwinding unwind the bacterial chromosome and allow replication of the chromosome? What antibiotic interferes with this process?

Topoisomerase and DNA gyrase; Fluoroquinolones

31

How are bacterial chromosomes contained within the cell?

Packaged with polyamines into structure called the nucleoid

32

What are plasmids? What are the three major types?

Genetic elements that replicate independently from chromosomes; F (fertility) plasmids, R (resistance) plasmids, and Virulence plasmids

33

What is a bacteriophage?

A virus that infects bacteria

34

True or False: Some pathogenic bacteria actually need to be infected with a phage in order to be virulent.

True

35

What is transduction?

The use of phage to transfer bacterial DNA from one organism to another

36

What is transformation?

When bacteria die, their DNA is released into the environment and can be taken up by other bacteria

37

What are the phases of the bacterial growth cycle? In which phase are many antibiotics most effective?

Lag phase, log phase, stationary phase, and death phase; Log phase

38

What are the factors that keep bacterial growth in check in reality?

Limitation of nutrients; competition for food and space, immune systems

39

What is metabolic parsimony?

Organisms expend energy only if they have to

40

What is sterilization and what are the methods to achieve it?

Sterilization is the killing of all microbial forms, including spores- can be done by autoclaving, dry heat, irradiation, or gas vapors.

41

What is disinfection? What agents are commonly used for this?

Most microbial forms are destroyed, but spores and other resistant forms endure; Chloride (bleach) and phenolic (lysol) compounds are commonly used.

42

What is antisepsis? What are commonly used agents to achieve this?

Microbes are inhibited or eliminated in or on living tissue. Ethyl or isoproyl alcohol, betadine, etc.