Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Medical Microbiology > Section 1- Prokaryotic Cell Structure/Function > Flashcards

Section 1- Prokaryotic Cell Structure/Function Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards USMLE® Step 1 flashcards
1
Q

3 domains of life

A 
Bacteria
Archaea
Eukarya
All contain single-celled microbes
Archaea and Eukarya more closely related
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Prokaryotes

A

Lack nuclear membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Archaea

A

Prokaryote

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Bacteria

A

Prokaryote
Range from 0.2 to 2 microns in diameter
Seen mostly by electron microscopy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Eukarya

A

Eukaryote
Have nuclear membranes
Ex: paramecium, fungi, plants, animal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Virus

A

Non living

Smaller than bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Coccus, Cocci

A

Spherical cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Bacillus, bacilli

A

Rod-shaped cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Spiral-shaped bacteria

A

Usually motile
Comma-like
Coiled
Ex: spirochete

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

4 main types of Prokaryotic cells

A

Coccus
Coccobacillus
Bacillus
Vibrio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Pleomorphic bacteria

A

Can have many different appearances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Diplococci

A

Cocci pair

One plane of division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Streptococci

A

Cocci chain

One plane of division, repeated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Staphylococci

A

Cocci bunch

3 planes of division, repeated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Binary fission- multiplication

A

How bacteria divide
Cell replicates DNA, membrane elongates to separate DNA molecules, cross-wall forms and membrane invaginates, cross-wall forms completely, daughter cells separate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Endospores

A

Produced by gram (+) Bacillus and Clostridium species
Each vegetative cell transforms into one endospore
Each endospore germinates to form one vegetative cell
*Dormant state for bacteria
Constitute a defense strategy against hostile or unfavorable conditions
Very resistant to drying, heat, radiation, and disinfectants
Can remain viable for 10-1000 years
Serious concern to food industry and hospitals (1000 cases/day)
Potential biological weapons of mass destruction (b/c create toxins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Endospore Formation steps

A

DNA replicates, membrane invaginates to form forespore, membrane engulfs forespore in 2nd membrane, and vegetative cell’s DNA disintegrates
Next, cortex of calcium and dipicolinic acid deposits between 2 membranes, spore coat forms around endospore, endospore “matures” (coat thicker), endospore released

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Differential stains

A

Ex: Gram Stain

Acid-Fast Stain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Gram Stain

A

Gram (+) vs Gram (-)
Differentiates MOST bacteria
Steps: Crystal Violet, Gram’s Iodine (Fixes stain), Decolorizer (Alcohol or Acetone), Safranin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Gram (+)

A

Stain purple

Ex: Staphylococcus aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Gram (-)

A

Stain red/pink

Ex: Escherichia coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Gram stain NOT used for

A

Atypical cell walls

  • Mycoplasmas
  • Archaea
  • Mycobacterial/Nocardia
23
Q

Mycoplasmas

A

Only bacteria without cell wall

Sterols in plasma membrane

24
Q

Archaea

A

Not bacteria

Wall-less or have walls of pseudomurein

25
Q

Mycobacteria/ Nocardia

A

Acid fast bacteria (AFB)
Very waxy outer layer–> resistant
Ex: Mycobacterium tuberculosis, Mycobacterium leprae, Nocardia asteroides

26
Q

Acid-Fast stain

A

AFB resist decolorization with acid-alcohol and stain raid, the color of the initial stain, CARBOL FUCHSIN
Other bacteria will be decolorized and stain blue with counterstain, METHYLENE BLUE

27
Q

Central endospores

A

Bacillus
Endospore stain (green within red)
Stain everything but spore

28
Q

Terminal endospores

A

Clostridium botulinum and Clostridium tetani

29
Q

Clostridium botulinum

A

Causes botulism
Most potent toxin known
Disease is an intoxication by neurotoxin
Forms spores
Clinical sign=flaccid paralysis (no muscles contract)
Most affects infants less than 6 months b/c they are more susceptible to spores; HONEY often infected
150 cases/year

30
Q

Clostridium tetani

A

Causes tetanus
Neurotoxin; causes spastic paralysis (all muscles contract)
Lockjaw first sign

31
Q

External structure of prokaryotes

A 
Flagellum (flagella)
Fimbria (fimbriae)
Pilus (pili)
Capsule
Glycocalyx
32
Q

Flagellum

A 
Not on every bacterium
Molecular motor-responsible for movement
Propels bacterium forward
3-12 microns long
Whiplike structures that extend beyond surface of cell
Made up of flagellin protein
Rotate 360 degrees
33
Q

Motile cells

A

Rotate flagella to run or tumble
Ex: Helicobacter pylori
Flagella proteins are H antigens

34
Q

Fimbriae and Pili

A 
Same function
Nonmotile extensions
Sticky, hairlike projections
Used to adhere/attach
May be 100s per cell
Shorter than flagella
Serve important function in biofilms
Virulence determinants
PILI ONLY- can join 2 bacterial cells and mediate transfer of DNA via conjugation- called conjugation pili or sex pili
35
Q

Glycocalyx

A 
"Slime"
Loosely attached to cell surface
Sugary, extracellular polysaccharide
Protects cells from drying out 
Promotes adherence
36
Q

Capsule

A 
Firmly attached to cell surface
Polysaccharide
Protects cells from drying out
Promotes adherence (adherence factor)
Antiphagocytic (WBCs don't recognize)
Virulence factor
Antigens- stimulate immune response
Vaccine component (if you inject purified capsule, body will may antibodies against it)
37
Q

Planktonic bacteria

A

Free living bacteria

38
Q

Biofilm

A

Community of bacteria surrounded by slime

39
Q

Prokaryotic cell wall

A

Provides structure and shape and protects cell from osmotic forces
Assists some cells in attaching to other cells or in eluding antimicrobial drugs
Absent in animal cells
Target of important antibiotics
“-cillins” target cell wall

40
Q

Bacterial cell wall

A

2 basic types: Gram+ and Gram-

Most have peptidoglycan

41
Q

Peptidoglycan

A

Polysaccharide polymer of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)
Has cross-linked tetrapeptides also that make it stronger
In most bacterial cell walls
NOT in Mycoplasma species
Mesh-like coat around cell
Function: shape, protection, diffusion (mesh)
Target of antibiotics- ex: penicillin stops cross links

42
Q

Gram (+) cell wall

A 
Simple
Thick peptidoglycan
Stains purple
Has teichoic acids (anchor peptidoglycan to cell membrane)
One membrane (no outer membrane)
No LPS
43
Q

LPS

A 
Lipopolysaccharide
Endotoxin (toxin within cell)
Made up of Lipid A (toxic), a core oligosaccharide, and the O polysaccharide antigen
Lipid A is released from dead cells when the cell wall disintegrates; causes fever, vasodilation, inflammation, shock, and blood clotting; released when antimicrobial drugs kill bacteria
44
Q

Gram (-) cell wall

A 
Complex 
Thin peptidoglycan
Stains red/pink
No teichoic acids
2 membranes (Has outer membrane)
LPS present
Has periplasmic space between outer and cytoplasmic membranes
45
Q

Protoplast

A

Gram (+) bacterium minus a cell wall
Ex: formed when lysozyme destroys the cell wall
Cell wall can be regrown

46
Q

Spheroplast

A

Gram (-) bacterium minus cell wall

47
Q

Outer membrane

A 
Gram (-) only
Protects from phagocytes and antibiotics
Has LPS
Porins form channels through membrane
Has outer membrane proteins (OMPs)
48
Q

Periplasmic space

A

Between outer membrane and cell membrane in gram (-) bacteria
Contains peptidoglycan and periplasm with water, nutrients, digestive enzymes, and transport proteins

49
Q

Internal structures of prokaryotes

A

Cytoplasmic membrane
Cytoplasm
Endospores
Inclusions (not covered)

50
Q

Prokaryotic cytoplasmic membrane

A 
Phospholipid bilayer
Function similar to eukaryotic membrane
Electron transport chain
Energy production (ATP)
Transport proteins
51
Q

Prokaryotic cytoplasm

A

Contains ribosomes (protein synthesis sites)
Inclusions (reserve energy molecules)
Cytoskeleton (cell shape)
Plasmids
Antibiotic targets (Nucleoid- 1 or 2 circular ds DNA, mRNA, 30S/50S ribosomal subunits)- all gene to protein targets

52
Q

Plasmids

A

Usually circular
Extrachromosomal DNA
Confer antibiotic resistance

53
Q

Ribosomes

A

Site of protein synthesis
30S+50S subunits
70S ribosomes

Medical Microbiology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions