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From Flashcardlet > Micro Chapter 3 Test 2 > Flashcards

Micro Chapter 3 Test 2 Flashcards

1
Q

What is a type III secretion?

A

A needle like projection (filament) injects effector proteins into a host cell

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2
Q

What does the type III secretion do when interacting with another cell (2)?

A

The secretion either pumps toxin into the host or the bacteria uses it to penetrate the host

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3
Q

What structure are type III secretions homologous with?

A

Bacterial flagella

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4
Q

What kind of cells are type III secretions common in?

A

Gram negative pathogens

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5
Q

What are two examples of the effects of effector proteins on the host?

A

It could be a protein that inhibits eukaryotic ribosomes or a protein that rearranges eukaryotic cytoskeletal proteins

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6
Q

What term describes what movement is directed towards?

A

Taxis

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7
Q

Why do cells need to move?

A

The move with a purpose, as in towards nutrients and away from harm

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8
Q

What is chemotaxis?

A

Movement away/towards chemicals

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9
Q

What is phototaxis?

A

Movement away/towards light

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10
Q

What is aeotaxis?

A

Movement away/towards oxygen

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11
Q

What is osmotaxis?

A

Movement based on solute concentration

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12
Q

What is the cost of movement to the cell? (Why does the cell move only with a purpose?)

A

It spends energy

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13
Q

What shape is the flagellar filament?

A

Helical

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14
Q

What is a run?

A

When the motor rotates counterclockwise, the bacteria swims and the flagella bundle

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15
Q

What is a tumble?

A

The motor rotates clockwise, the bacteria stops suddenly and randomly changes direction, the bundle flies apart

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16
Q

Where is the flagellar motor located and what part of the flagella is it associated with?

A

The motor is located at the base associated with the basal body

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17
Q

What is a random walk?

A

In the absence of an attractant or repellent, the length of each run is about the same

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18
Q

What is a biased walk?

A

In the presence of an attract or repellent, the runs are longer towards the attractant/repellent than they are in other directions

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19
Q

During a biased walk, why does the cell stop instead of running straight towards an attractant/away from a repellent?

A

The tumble and stop is a chance for the bacteria to reevaluate its environment

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20
Q

What kind of bacteria are spirochaetes?

A

Gram negative

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21
Q

What is the cell shape of a spriochaetes? What causes this shape?

A

Corkscrew, the axial filament (endoflagella)

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22
Q

What diseases do spirochaetes cause?

A

Good spirochaetes inhabit the GI tract of termites and help them digest wood
Bad spirochaetes cause lyme’s disease

23
Q

Do the spirochaetes move slow or fast? What does this allow them to do?

A

They move very fast, allowing them to burrow through tissues and even out run white blood cells

24
Q

What structure causes flagella to move?

A

The axial filament or endoflagella

25
Q

Where is the axial filament/endoflagella located?

A

Wrapped around the periplasmic cylinder running through the center of the cell

26
Q

How does the spirochaetes propelled?

A

Because the endoflagella is wrapped around its periplasm, when the flagella is powered to move, it rotates in a spiral movement

27
Q

What structures are involved with twitching motility?

A

Type IV pili and slime

28
Q

Where does twitching motility occur?

A

On a solid surface, usually moist

29
Q

What does twitching movement look like?

A

It involves short, intermittent, jerky motions

30
Q

When do cells exhibit twitching motility?

A

When they are in contact with each other

31
Q

What is a type IV pili structurally composed of?

A

A chain of pilin proteins

32
Q

What happens to the structure of a type IV pili when it retracts?

A

The pili depolymerizes and loses subunits of pilin, shortening and therefore pulling the cell closer to its destination

33
Q

What is the distinguishing characteristic of an endospore?

A

It is dormant and resilient

34
Q

What types of cells make endospores?

A

Gram positive

35
Q

What conditions are endospores resilient to?

A

Heat, radiation, chemicals, desiccation

36
Q

Where are endospores commonly found?

A

Soil

37
Q

What is the function of an endospore?

A

It is a survival mechanism that allows bacteria to produce a dormant cell that can survive until nutrients are available again

38
Q

What are the layers of an endospore, from its inner structures to outer structures?

A
  1. Inner core
  2. Cortex
  3. Spore coat
  4. Exosporium
39
Q

What is in the inner core?

A

Cytoplasm and DNA, it is dehydrated an gel-like

40
Q

What is in the cortex?

A

Peptidoglycan and cell membrane

41
Q

What is in the spore coat?

A

Protein rich

42
Q

What is in the exosporium?

A

Thin coat

43
Q

What genera produce endospore?

A

Bacillus and Clostridium

44
Q

What are four locations in the cell where an endospore can form?

A

Central, subterminal, terminal, and swollen sporangium

45
Q

How is the endospore so resilient (4)?

A
  1. Calcium (complexed with dipicolinic acid)
  2. Small, acid-soluble DNA binding proteins (SASPs)
  3. Dehydrated core
  4. Spore coat and exosporium protection
46
Q

What diseases do endospores cause?

A

Bacillus - Anthrax

Clostridium - Tetanus, Botulism, Pseudomembraneous colitis, gangrene

47
Q

Is an endospore metabolically active or inactive? What is an endospore’s rate of growth?

A

Metabolically inactive and incapable of growth

48
Q

What is sporulation?

A

A vegetative cell turning into an endospore

49
Q

What is germination?

A

An endospore turning into a vegetative cell

50
Q

What are the steps of sporulation (7)?

A
  1. Axial filament of nuclear material formed
  2. Inward folding of membrane to enclose DNA and produce forespore septum
  3. Membrane grows and engulfs endospore
  4. Cortex laid down, calcium (DIp acid) accumulates
  5. Protein coat forms around cortex
  6. Maturation of endospore
  7. Lytic enzymes destroy sporagium (mother) releasing spore
51
Q

What are the steps of germination?

A
  1. Activation (preparation)
  2. Germination
  3. Outgrowth
52
Q

What happens during germination?

A 
Spore swelling
Rupture/absorption of spore coat
Loss of resistance
Loss of spore components
Increase in metabolic activity
53
Q

What happens during outgrowth of germination?

A

Creation of new components
Emergence from remains of the spore coat
Development into active bacteria

54
Q

Is germination a form of reproduction?

A

NO! An endospore and a vegetative cell are different forms of the same individual

From Flashcardlet (133 decks)

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