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Microbiology > Lecture 5 > Flashcards

Lecture 5 Flashcards

1
Q

What are the 3 domains coming from the universal ancestor?

A
  • eukaryota
  • archaea
  • bacteria
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2
Q

What does biocide mean?

A

It is a general term describing a chemical agent that inactivates microorganisms. (examples: antiseptics, disinfectants, or preservatives)

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3
Q

What does bacteriostatic mean?

A

A term referring to the property by which a biocide is able to inhibit bacterial multiplication. Multiplication resumes upon removal of the agent (reversible).

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4
Q

What does bactericidal mean?

A

A term referring to the property by which a biocide is able to kill bacteria. It is irreversible.

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5
Q

What does sterilization mean?

A

A physical or chemical process that completely destroys or removes all microbial life, including spores.

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6
Q

What are disinfectants?

A

Products or biocides used to kill microorganisms on inanimate objects or surfaces

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7
Q

What is an antiseptic?

A

A biocide or product that destroys or inhibits the growth of microorganisms in or on living tissue.

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8
Q

What is aseptic?

A

Characterized by the absence of pathogenic microbes.

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9
Q

What is preservation?

A

The presentation of multiplication of microorganisms in formulated products, including pharmaceuticals and foods.

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10
Q

What are antibiotics?

A

Naturally occurring or synthetic organic compounds which inhibit or destroy selective bacteria, generally at low concentrations.

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11
Q

What does septic mean?

A

Characterized by the presence of pathogenic microbes in living tissue

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12
Q

Where are bacterial capsules found?

A

Found outside the cell envelope

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13
Q

Most capsules are what?

A

Polysaccharides (hydrophilic and gel-like)

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14
Q

What do bacterial capsules protect against?

A

They protect against phagocytosis by the white cells (macrophages and PMNs)–this is important in virulence.

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15
Q

What is the chemical basis of several vaccines?

A

Bacterial capsules because they are important antigenic determinants.

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16
Q

What is the glycocalyx?

A

It is adhesive polysaccharides, polypeptides or both (biofilm). It is a planktonic form to colony with biofilm or a viscous gelatinous polymer that is external to the cell wall.

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17
Q

Where are flagella found?

A

In motile bacteria that can alter the direction of rotation as well as speed.

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18
Q

How long are flagella?

A

3 to 12 microns long (125 to 250 angstroms thick)

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19
Q

What types of flagella are there and what are they used for?

A
  • can be at one or both ends (polar) or all around (peritichous)
  • used for locomotion
20
Q

What do flagellin protein make up?

A

H-antigens–they are highly changeable (phase variation) to evade immune attack

21
Q

What are the 3 types of bacterial chemotaxis?

A
  • directional movement (counterclockwise)
  • tumbling motility (clockwise)
  • aggressive, speedy movement (pathogenic role in mucus penetration and invasion)–counterclockwise
22
Q

What are the 5 purposes of bacterial chemotaxis?

A
  1. Swim toward an attractant (mucosal epithelial cellular target)
  2. Avoid being swept away by mucus
  3. Flee from an attacker (WBC)
  4. Swim towards nutrients
  5. Invasion and Intracellular movement
23
Q

What propels the flagellum?

A

PMF: proton motive force from membrane bound oxidative phosphorylation. It propels a motor that allows the flagellum to rotate.

24
Q

What is oxidative phosphorylation?

A

Protons flow down concentration gradient turning ADP into ATP. The flow of protons across the bacterial cell membrane is due to the concentration gradient.

25
Q

What does Proton Motive Force (PMF) come from?

A

It is provided by proton turbines and is driven by electrical potential generated by respiration linked proton pumping NOT by ATP

26
Q

What does chemiosmotic mean?

A

The movement of ions across a selectively permeable membrane down their electrochemical gradient.

27
Q

What is the other name for pili?

A

fimbriae

28
Q

What are pili?

A

Proteinaceous appendages that are thinner and shorter than flagella.

29
Q

What are pili involved in?

A

adhesion

30
Q

The larger F-pilus is involved in what?

A

Bacterial conjugation (gene transfer)

31
Q

What characteristic does pili have that is similar to flagella?

A

It is antigenic, but also highly changeable (like flagella) to evade immune attack.

32
Q

What are R-pili involved in?

A

Antibiotic resistance gene cassette transfer between bacteria

33
Q

What is the cytoplasmic membrane?

A

A typical lipid bilayer composed of phospholipids and proteins (similar to eukaryotes), but it contains NO cholesterol and NO sterols

*one exception is Mycoplasma spp.

34
Q

What is the typical function of the cytoplasmic membrane?

A

The uptake of substrates from the medium. Bacteria usually take up mainly small molecular weight compounds. They very rarely go after macromolecules and phosphate esters.

35
Q

Macromolecules are usually hydrolyzed by what?

A

By enzymes in the periplasm

36
Q

What breakdown products are found in the cytoplasmic membrane?

A
  • peptides
  • oligosaccharides
  • nucleosides
  • phosphate

All can be transported across the cytoplasmic membrane.

37
Q

What is facilitated diffusion? Describe the gradient. What is it driven by?

A

A small molecule is carried across the membrane down a concentration gradient.

  • high to low conc.
  • driven by intracellular use
38
Q

What is group translocation? What is it driven by?

A

Sugars are phosphorylated as they are transported across the membrane. It is driven by phosphorylase.

39
Q

What is active transport (ABC)?

A

A process whereby the cell uses metabolic energy to transport substances across the membrane against their concentration gradient.

40
Q

ABC transporter involves what kind of protein? Where is it located?

A

It involves substrate specific binding proteins located in gram negative bacteria periplasmic space.

41
Q

What do periplasmic binding proteins do in ABC?

A

They pick up the substance to be transported and carry it to a membrane spanning transport protein.

42
Q

In ABC transport, what does ATPase do?

A

It catalyses the reaction below.

ATP = ADP + Pi + energy

It is this energy that powers the transport of the substrate (amino acids, antibiotics, etc.) by way of the membrane binding transporter across the membrane and into the cytoplasm.

43
Q

The ATP system occurs in what type of bacterial cells?

A

Gram negative

44
Q

In the Na/K pump, what is pumped in? What is pumped out?

A
  • In: 2 K+

* Out: 3 Na+

45
Q

Name some functions of motile bacteria.

A
  • tumbling movement
  • chemotaxis and tumbling movement
  • moving toward mucosal epithelial cell target
  • swimming toward organic nutrients
46
Q

What is true about antimicrobial agents?

A
  • they are able to inactivate organisms
  • sepsis results when pathogenic microorganisms are present in living tissue
  • biocides are defined as chemical agents that inactivate microorganisms
  • biocides are typically broad spectrum

Microbiology (10 decks)

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