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Microbiology > Chapter 3 lecture notes > Flashcards

Chapter 3 lecture notes Flashcards

1
Q

All prokaryotes don’t have?

A

Cytoskeleton.

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2
Q

A prokaryotes shell is made of?

A

Sugar and protein. The rigid structure works as exoskeleton to keep shape & cell from bursting

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3
Q

The pili on prokaryotes adhere to?

A

Substrates & glue to each other using capsules

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4
Q

Sperical round shape

A

Coccus

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5
Q

Rod shape

A

Bacillus

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6
Q

Short round rod

A

Coccobacillus

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7
Q

Curved rod

A

Vibrio

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8
Q

Spiral shape

A

Spirillus. Fiber in cell wall allows to curve on itself

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9
Q

Helical shape, tight coiling

A

Spirochete

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10
Q

Vary in shape

A

Pleomorphic. Can assume different forms

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11
Q

Diplobacilli=

A

2 bacilli

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12
Q

Streptobacilli=

A

String

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13
Q

Prokaryotic cells may form groupings

A

After cell division. Cells adhere together after cell division for characteristic arrangements. Arrangements depends on plan of division

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14
Q

Division along two or three perpendicular planes form

A

Cubical packets

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15
Q

Division along several random planes form

A

Clusters

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16
Q

General function of capsules and slime layer of glycocalyces

A

Protection and attachment.
Protection: Protects bacteria from host defenses
Attachment: Enables bacteria to adhere

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17
Q

Organized layer of sugar=

Disorganized layer of sugar=

A 
Organized= capsule
Disorganized= slime layer
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18
Q

Distinct gelatinous layer

A

Capsule

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19
Q

Irregular diffuse layer

A

Slime layer

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20
Q

Chemical composition of capsules & slime layers varies depending on bacterial species. Most are made of?

A

Polysaccharides

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21
Q

Glyco=

Calyx=

A 
Glyco= Sugar
Calyx= Shell
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22
Q

Cell wall of bacteria 6 main points

A

1) Rigid structure
2) Surrounds cytoplasmic membrane
3) Determines shape of bacteria
4) Holds cell together
5) Prevents cell from bursting
6) Unique chemical structure (distinguishes Gram + from -)

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23
Q

The rigidity of the bacterial cell wall is due to?

A

Peptidoglycan (PTG)

24
Q

The basic structure of peptidoglycan

A

Peptido=protein
Glycan=sugar
Alternating series of two subunits; N-acetylclucosamine (NAG) and N-aceetylmuramic acid (NAM). Joined subunits form glycan chain and the chains are held together by string of four amino acids (tetrapeptide chain)

25
Q

What are the sugars in peptidoglycan

A

N-acetylglucosamine (NAG)

N-acetylmuramic acid (NAM)

26
Q

Gram-positive cell wall

A

1) Relatively thick layer of peptidoglycan (PTG)
2) As many as 30 layers of PTG chains
3) Teichoic acid component of PTG
4) Gives cells a negative charge

27
Q

Main points about prokaryotes

A

1) Lack nucleus
2) Lack various internal structures bound with phospholipid membranes
3) Small ( ~ 1.0 micrometers in diameter)
4) Simple structure
5) Include bacteria & archaea
6) Do not have cytoskeleton
7) Shell is made out of sugar & protein
8) Capsules are important infector in disease
9) Flagellum responsible for motility, different than eukaryotic cells
10) Pili adheres to substrates & glue to each other using capsules

28
Q

Gram-negative cell wall main points (4)

A

1) More complex than Gram +
2) Only contains thin layer of peptigoglycan (3-10)
3) PTG sandwiched between outer membrane and cytoplasmic membrane
4) Region between outer membrane and cytoplasmic membrane is called periplasm ( most secreted proteins are contained here, proteins of ABC transport system are located here)

29
Q

Cytoplasmic membrane main points

A

1) Selectively permeable
2) Molecules pass through membrane via simple diffusion or transport mechanisms that may require carrier proteins & energy

30
Q

Simple diffusion

A

Molecules move freely across the cytoplasmic membrane like H20, some gases & small hydrophobic molecules pass via simple diffusion

31
Q

Facilitated diffusion main points (3)

A

1) Moves compounds in the direction of the concentration gradient (from greater concentration to lesser)
2) Molecules diffuse until equilibrium is reached (system can only eliminate concentration gradient; it cannot create one)
3) No energy required
* Example movement of glycerol into the cell

32
Q

Some bacteria have protein appendages which are not essential for life. They aid in survival in certain environments. They include?

A

1) Flagella

2) Pili

33
Q

Flagella are

A

Long protein structure that is responsible for motility.

  • Use propeller-like movements to push bacteria
  • Can rotate more than 100,000 revolutions/minute (Equivalent to a 6 ft man running 82 mile/hour)
  • Some important in bacterial pathogenesis (H. pylori penetration through mucous coat)
34
Q

3 basic parts of flagella

A

1) Filament- Extends to exterior. Made of proteins called flagellin
2) Hook- connects filament to cell
3) Basal body- anchors flagellum into cell wall

35
Q

Bacteria use flagella for

A

Motility. Motile through sensing chemicals (chemotaxis) if the chemical compound is a nutrient it acts as attractant. If the compound is toxic it acts as repellent

36
Q

Bacteria can have flagella and pili, the pili are?

A

Considerably shorter and thinner than flagella. They have a similar structure (protein subunits). They function to attach, which are called fimbriae, movement, and conjugation, mechanisms of DNA transfer.

37
Q

Differences in cell wall account for differences in staining characteristics

A

Gram-positive bacterium retain crystal violet- iodine complex of Gram stain-purple
Gram-negative bacterium lose crystal violet-iodine complex-pink

38
Q

Some bacteria lack cell wall

A

Called Mycoplasma.

  • Causes mild pneumonia
  • Sterols in membrane account for strength of membrane
39
Q

If a bacteria doesn’t have a cell wall then what can happen?

A

Antimicrobial drugs directed against cell wall are ineffective

40
Q

Bacteriain Domain Archaea

A

Have a wide variety of cell wall types

– None contain peptidoglycan but rather pseudopeptidoglycan in some

41
Q

Cytoplasmic membrane proteins

A

Membrane is embedded with numerous proteins
– More than 200 different proteins
– Proteins function as receptors and transport gates
– Provides mechanism to sense surroundings
– Harvest light energy in photosynthetic bacteria
– Proteins are not stationary. Constantly changing position. Called fluid mosaic model

42
Q

Osmosis is

A

Simple diffusion of H2O
– H2O flows freely across the cytoplasmic membrane
– H2O flows to equalize solute concentrations inside and outside the cell
– Inflow of H2O exerts osmotic pressure on membrane (Membrane rupture prevented by cell wall)

43
Q

Two primary forms of energy

A

ATP & Proton motive force

44
Q

3 mechanisms for active transport

A

– Uniport
– Antiport
– Coupled Transport (Uniport & Symport)

45
Q

Alters the molecule

A

Group translocation

46
Q

Movement of many molecules directed by

A

Transport systems:
– Transport systems employ highly selective proteins
– Transport proteins include permeases, channels, or ports
– These proteins span membrane
* Single carrier transports a specific molecule
* Most transport proteins are produced in response to need
Transport systems include:
Facilitated diffusion
Active transport
Group translocation

47
Q

Storage granules / Inclusions is

A

Accumulation of polymers
- Synthesized from excess nutrients
Example is glycogen-excess glucose in cell is stored in glycogen granules

48
Q

Gas vesicles main points

A

1) Small protein compartments
2) Provides buoyancy to cell
3) Allows organism to reach ideal position in environment

49
Q

Endospores main points

A

1) Dormant cell types
- Produced through sporulation
- Theoretically remain dormant for 100 yrs
2) Resistant to damaging conditions
- Heat, desiccation, chemicals and UV light
3) Vegetative cell produced through germination
- Germination occurs after exposure to heat or chemicals
- Germination not a source of reproduction
4) Not affected by crenation

50
Q

Essential for translation (proteins)

A

Ribosome

51
Q

Site of protein synthesis, composed of large and small subunits, units make of riboprotein and ribosomal RNA

A

Ribosome

52
Q

Prokaryotic ribosomal subunits
Large=
Small=
Total=

A

Large=50S
Small=30S
Total=70S

53
Q

Eukaryotic ribosomal subunits
Large=
Small=
Total=

A

Large=60S
Small=40S
Total=80S

54
Q

The difference in ribosomal subunits of prokaryotic and eukaryotic cells is often used as?

A

A target for antimicrobials

55
Q

In a prokaryotic cell division along two or three perpendicular planes form?

A

Cubical packets, example Sarcina genus

56
Q

In a prokaryotic cell, division along a single plane may result in?

A

Pairs or chains of cells

  • Pairs= diplococci, example Neisseria gonorrhoeae
  • Chains= streptococci, example species of Streptococcus

Microbiology (35 decks)

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