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Microbiology Unit 1 > Prokaryotes: Structure & Function (BE #2) > Flashcards

Prokaryotes: Structure & Function (BE #2) Flashcards

1
Q

Prokaryotic cells

A
  • lack a membrane bound nucleus and membrane-bound organelles
  • have one circular chromosome
  • have a cell wall made of peptidoglycan
  • much smaller than eukaryotic cell
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2
Q

Eukaryotic cell

A
  • has a membrane-bound nucleus & organelles
  • may or may not have a cell wall
  • includes:
    • fungi
    • plants
    • protistans
    • animals
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3
Q

Viruses

A
  • considered acellular
  • not prokaryotic or eukaryotic
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4
Q

Which of the following groups or organisms have cells with cell walls?

What are the primary compounds found in their cells’ walls?

  1. animals
  2. plants
  3. protistans
  4. bacteria
  5. viruses
A

animals - no cell wall

plants - yes, cell wall - cellulose

protistans - plant-like ones (algae) - yes; other cells don’t have a cell wall

bacteria - yes, cell wall - made of peptidoglycan

viruses - acellular, so no cell wall

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5
Q

What are the advantages to having a small cell size?

A

Allows cells to grow faster & multiply more rapidly than eukaryotic cells.

It’s easier to meet their modest nutritional needs.

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6
Q

Why is it important to know the differences between prokaryotes and eukaryotes?

A

it allows us to control disease causing bacteria without harming our own cellls.

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7
Q

lysing

A

too much water in the cell will cause it to lyse

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8
Q

crenate

A

the loss of too much water will cause the cell to shrink or crenate

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9
Q

Which group of bacteria lack a cell wall?

A

mycoplasmas

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10
Q

How do mycoplasmas keep from lysing?

A
  1. they actively pump sodium ions out of the cell
  2. they have cholesterol within their plasma membrane to help keep it rigid.
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11
Q

The plasma membrane is composed primarily of ____________ molecules.

A

phospholipid

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12
Q

The plasma membrane is “semipermeable.” Explain.

A

Only some molecules are allowed into the cell.

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13
Q

Name one structure that allows the membrane to behave more like a fluid.

A
  • kinked fatty acid tails
  • shorter tails keep tails from packing
  • cholesterol and proteins also create space
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14
Q

What is the major function of integral proteins in the plasma membrane?

A

transport proteins

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15
Q

Name 2 major types of transport proteins

A
  • carrier protein
  • channel protein
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16
Q

What is a major function of peripheral proteins in the plasma membrane?

A

Act as enzymes (catalyze chemical reactions)

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17
Q

Name 3 types of passive transport

A
  1. diffusion
  2. facilitated diffusion
  3. osmosis
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18
Q

How do molecules move from a high to a low concentration?

A

Their own kinetic energy causes them to move & they bump into one another (diffusion).

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19
Q

How do molecules move from a low concentration to high concentration?

A

active transport

20
Q

Indicate whether the transport protein used for each of the following is a channel or carrier protein:

  1. simple diffusion thru the phospolipid
  2. osmosis
  3. active transport
  4. facilitated diffusion
A
  1. uses no protein
  2. channel protein
  3. carrier protein
  4. carrier or channel protein
21
Q

How are the following molecules transported across the plasma membranein prokaryotes?

1 oxygen

  1. water
  2. carbon dioxide
  3. glucose
A
  1. simple diffusion thru phospholipids
  2. osmosis
  3. simple diffusion thru phospholipids
  4. active transport (using group translocation)
22
Q

Why can’t water be easily transported directly across the phospholipid bilayer?

A

It’s polar (charged), so is repelled by nonpolar fatty acid tails of phospholipid molecules.

23
Q

Describe phagocytosis and give an example.

A

The plasma membrane envelopes the substance to be imported & pinches off to form a vesicle that moves into the cytoplasm. Endocytic vesicles then fuse with enzyme-containing vesicles called “lysosomes” to digest their contents. Ex. white blood cell engulfing a bacteria.

24
Q

Most bacteria transport nutrients by _____________.

A

active transport (w/ group translocaiton)

25
Q

A typical bacterial cell that is hypertonic to its environment is in danger of _______________ .

A

The cell is not in danger.

The cell wall resists turgor pressure and the cell does not lyse.

26
Q

A mycoplasm cell that is hypertonic to its environment is in danger of ______________.

A

lysing

bursting

These bacterial cells have no cell wall.

27
Q

Why can’t glucose be transported using a channle protein?

A

The molecule is too large to fit through the channel.

28
Q

What are two functions of the cell wall?

A
  1. Maintian shape
  2. Withstand/resist turgor pressure
29
Q

Identify the shape of the following & give an example of a bacterial species for each:

  1. cocci
  2. bacilli
  3. spirilli
  4. vibrio
A
  1. spherical - Staphylococcus aureus
  2. rod - Bacillus anthracis
  3. spiral shaped - * Treponema pallidum*
  4. comma shaped - Vibrio cholerae
30
Q

A bacterium is ordinarily (hypertonic or hypotonic) to its environment.

A

hypertonic

31
Q

How does the antibiotic penicillin kill bacterial cells?

A

Interferes with cell wall synthesis

32
Q

The outer membrane is found primarily in (G+ or G-) cells. It is composed of bilayer of phospholipids and _________. Special proteins called _________ regulate the transport of substances across the membrane. When bacteria die they release LPS’s that act as ___________, causing fever, shock and possibly death.

A
  1. G-
  2. lipopolysaccarides (LPS)
  3. porins
  4. endotoxins
33
Q

Why are G(-) bacteria more resistant to some antibiotics than G(+) bacteria?

A

Some antibiotics are too large to fit through the channels in porin proteins in the outer membrane. G(+) bacteria don’t have an outer membrane, so there is no issue with porins.

34
Q

What are some other names for the glycocalyx?

A
  1. capsule
  2. slime layer
35
Q

Name 3 functions of the glycocalyx.

A
  1. protection from drying out
  2. helps a cell adhere to a surface where conditions are favorable for growth.
  3. provides protection against phagocytosis - a slippery glycocalyx makes it difficult for the phagocyte to grab hold of the bacterium.
36
Q

Describe the bacterial chromosome. How many? Shape?

A
  1. One
  2. circular
37
Q

Endospores

A

Extrememly hardy, resting (non-growing) structures that some bacteria produce when nutrients are exhausted or conditions are harsh.

38
Q

Name 5 endospore-producing bacteria that are pathogenic to humans.

A
  1. Clostridium tetani - tetanus
  2. Clostridium botulinum - botulism
  3. Clostridium perfringens - gas gangrene
  4. Bacillus anthracis - anthrax
  5. Bacillus cereus - food poisoning
39
Q

Pili

A
  • short, hollow appendages
  • help cells adhere to other cells and allow for genetic exchange between cells
40
Q

flagella

A
  • long, hairlike stuctures
  • used for motility
41
Q

nucleoid

A
  • nuclear region
  • not surrounded by a membrane
42
Q

axial filaments (periplasmic flagella)

A
  • bundles of flagella which wrap about the cell body between the cell wall & outer membrane
  • cause organism to move like a corkscrew
43
Q

ribosomes

A
  • not membrane-bound
  • site of protein synthesis
44
Q

fimbriae

A
  • short, hairlike structures
  • help in adhesion to other cells and surfaces
45
Q

inclusion body

A

store nutrients such as fat or glycogen deposited in dense crystals or particles

in prokaryotic cells

46
Q
A

Microbiology Unit 1 (9 decks)

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