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Infectious Disease Final > Lecture 7 > Flashcards

Lecture 7 Flashcards

1
Q

true or false

bacteria are the smallest living cells

A

TRUE

0.1-10 micrometers

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2
Q

are bacteria prokaryotic cells or eukaryotic cells?

A

prokaryotic

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3
Q

nearly ALL bacteria have….

A

a rigid cell wall

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4
Q

what is the size of cell respiration in prokaryotes and in eukaryotes?

A

prokaryotes – the cell membrane

eukaryotes – the mitochondria

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5
Q

bacteria can be classified by which 6 things?

A

-appearance

-requirements for their growth

-their metabolism

-biochemistry

-antigenicity

-genotype

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6
Q

what do you mean that bacteria can be classified by their appearance?

A

their shape and their gram stain

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7
Q

what do you mean that bacteria can be classified based on the requirements for their growth?

A

the specific nutrients they need and can be selective on the media they grow in

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8
Q

what do you mean that bacteria can be classified based on their metabolism?

A

if they’re aerobic, anaerobic, or facultative (does aerobic if oxygen is present, but capable of switching to fermentation in absence of oxygen)

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9
Q

what do you mean that bacteria can be classified based on their biochemistry?

A

their proteases and enzymes

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10
Q

what do you mean that bacteria can be classified by their antigenicity?

A

by their recognition by the immune system

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11
Q

the cytoplasm of prokaryotes is rich in ____ ribosomes

A

70s

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12
Q

name the different shapes of bacteria

A

coccus (circular)

bacillus (rod shaped)

curved (coil/spiral)

OTHER – helical or club

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13
Q

name 4 FUNCTIONS of the bacterial cell wall

A

-maintains shape, strength, and rigidity

-protects against osmotic lysis

-allows for ATTACHMENT to (host) cells and to other surfaces

-provides PROTECTION against the immune system

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14
Q

explain the difference between the gram positive and the gram negative bacterial cell wall

A

gram positive: has THICK layer of peptidoglycan that serves as the cell wall. has plasma membrane inside.

gram negative: has outer and inner membrane. has thinner layer of peptidoglycan in the periplasmic space.

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15
Q

using GRAM STAIN is an easy way to determine what?

A

if the bacteria has a thick or thin cell wall. the stain stays in the THICK cell wall (cell wall)

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16
Q

name the 4 steps of using gram stain

A
  1. Crystal violet
  2. gram iodine
  3. decolorizer (alcohol or acetone)
  4. safranin red
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17
Q

when using the 4 step process of gram stain, what color will gram-positive be? what about gram negative?

A

gram positive — purple

gram negative – red

2 EXCEPTIONS
-some gram-positive bacteria are easily decolorized

-some gram-negative can retain the crystal violet color and appear somewhat gram positive

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18
Q

the CAPSULE of bacteria is also known as the __ layer

A

slime layer

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19
Q

what is the COMPOSITION of the capsule of bacteria?

A

polysaccharide or polypeptide

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20
Q

what is the term for the space between the 2 membranes of certain bacteria? which bacteria have this? what is it composed of?

A

space = periplasm

only in gram negative bacteria

composition = proteins and oligosaccharides in solution

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21
Q

what is the nucleoid? which bacteria have it?

A

nucleoid = DNA with associated RNA and proteins

both gram positive and gram negative bacteria have it

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22
Q

what are plasmids composed of?

A

DNA

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23
Q

Which bacteria have endospore?

A

NOT gram negative

gram positive can have it or not have it

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24
Q

an ENDOSPORE consists of….

A

all cell components + dipicolinate and special envelope components

25
Q

true or false

gram positive bacteria does not have an outer membrane

A

TRUE

26
Q

Which type of bacteria has a high lipid content?
explain

A

gram NEGATIVE

this is so because it has both an outer and inner membrane, and gram positive only has inner membrane

27
Q

which is RESISTANT to cell wall disruption and WHY?
(gram positive or gram negative)

A

gram negative is resistant to cell wall disruption.
-has an outer membrane

28
Q

which is relatively featureless? (has few proteins)

-gram positive or gram negative

A

gram positive – only has 1 membrane for proteins to be inserted into

29
Q

explain the structure of a cell wall

A

composed of peptidoglycan.

has rigid glycan (polysaccharide; carbon based) chains that are crosslinked by flexible peptide bridges

30
Q

which 2 classes of antibiotics inhibit bacterial cell wall synthesis?

A

penicillins and cephalosporins

31
Q

which type of bacteria (gram positive or gram negative) has a feature that makes it resistant to antibiotics that breakdown the cell wall?
explain

A

gram negative

they have an outer membrane to protect the cell wall

32
Q

LPS is part of which bacteria?
explain its structure

A

gram NEGATIVE

has CORE of polysaccharide
O side chain
Lipid A

33
Q

what gives bacteria motility?

A

flagella

34
Q

only _________ bacteria form spores

A

GRAM POSITIVE

35
Q

What is the function of spores

A

to protect the bacteria. they are vegetative.
they have many layers

36
Q

name 4 methods of bacterial metabolism

A

aerobic respiration
anaerobic respiration
glycolysis (fermentation)
pentose phosphate pathway (generates NADPH)

37
Q

can aerobe bacteria ferment?

A

NO

38
Q

What happens if anaerobes are exposed to O2?

A

they’re killed

39
Q

what do anaerobes do in the absence of O2?

A

They ferment

40
Q

explain what facultative bacteria can do in the presence and absence of oxygen

A

presence of oxygen – they respire

absence of oxygen – they ferment

41
Q

what are “microaerophilic” bacteria?

A

they grow BEST at LOW O2

AND can grow without O2

42
Q

give an example of a microaerophilic bacteria?

A

campylobacter jejuni

43
Q

the metabolic end products of bacterial metabolism can be used to do what?

A

identify certain bacteria

44
Q

what is facilitated diffusion?
does it require energy?

A

moving from high to low concentration with the help of a transmembrane protein

does NOT require energy

45
Q

name 2 transport mechanisms of bacteria

A

facilitated diffusion and active transport

46
Q

explain active transport

A

uses a gated pore.

once a particle binds to the protein gating the pore, it transports it in, using ATP and breaking it down into ADP and Pi

47
Q

what is the function of secretion systems?

A

through use of secretion systems, bacteria can deliver their proteins and toxins to the interstitial fluid and into cells

48
Q

which type of bacteria have secretion systems?

A

both gram positive and gram negative

49
Q

as mentioned, both gram positive and gram negative bacteria have secretion systems.

is there any difference? if so, explain

A

YES

the secretion system is simpler in gram positive bacteria – only have ONE transmembrane protein (remember: gram positive only has 1 membrane while gram negative has 2)

50
Q

how many and what are the names of the secretion systems in gram positive and in gram negative bacteria?

A

gram positive – 2 types
gram negative – 5 types

gram positive = Tat and Sec

gram negative = types 1-5

type I = direct transport
type II = 2-step process
type III = nanosyringe
type IV = nanosyringe
type V = 2 step process

51
Q

in gram negative bacteria, which type(s) of secretion systems involve a chaperone protein?

A

types III and V

52
Q

bacterial DNA is found in what configuration? what does this mean about bacterial replication?

A

bacterial DNA is a circular, double helix

therefore, to replicate the DNA must be unwound for the polymerase to come in and replicate the bacterial genome

53
Q

where does bacterial DNA replication start and end?

A

starts at “origin of replication”, ends at “ter” region

54
Q

once 2 forks are generated in bacterial DNA replication, they need to be unlinked by which enzyme? what happens if they’re not unlinked?

A

topoisomerase

if not unlinked, the bacterial cell will die

55
Q

what can you say about the clinical aspects of topoisomerase

A

it is the target of many antibiotics (such as cipro).

targeting topoisomerase prevents bacterial DNA replication and thus causes it to die

56
Q

true or false

in bacterial translation (mRNA–> protein) there is 1 ribosome for each mRNA transcript

A

FALSE

there are MANY ribosomes for a single mRNA transcript

57
Q

How many steps are there in bacterial protein translation?

name them

A

initiation
elongation
peptidyl transferase
translocation

58
Q
A

Infectious Disease Final (13 decks)

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