Brainscape's Knowledge GenomeTM

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


See full index

Microbiology HIS > Basics of bacteriology > Flashcards

Basics of bacteriology Flashcards

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

Capsule (found in some species)?

A

Assist with adhesion
Prevents phagocytosis
Reservoir for polysaccharides
Helps the cell not to dry out

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

Cell-wall?

A

Provides structural support

Protects against physical and chemical effects

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

Cell-membrane (plasma-membrane)?

A

Separates inside from outside (selective barrier)

Regulates transport in and out of the cell

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

DNA?

A

Present in a region called nucleoid

Usually a single circular chromosome

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

Plasmids?

A

Extrachromosomal DNA (usually contains 5-100 genes)
Often encodes advantageous properties (antibiotic-resistance)
Are moved by pili via conjugation

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

Pili (f-pili and p-pili)?

A

Some pili (fertility-pili) are used to transfer plasmids
Others are used by the bacterium to attach (p-pili)
Shorter than fimbriae

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

Fimbriae?

A

Attachment

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

Flagella?

A

Movement

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

Cell-wall?

A

Provides structural support

Protects against physical and chemical effects

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

Gram-staining?

A

Primary system of classification
The bacteria are exposed to different dyes
Gram-positive: blue-purple
Gram-negative: pink-red

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

Gram positive?

A

Thick cell-wall
• 35-40 layers of peptidoglycan

Quite large quantities of teichoic acid (TA)
• Unique sort of polysaccahride
• Maintains structure of the cell-wall
o Attract cations such as Mg2+ och Na+
Lipoteichoic acid (LTA)
• Teichoic acid with a ”lipid-tail” that is
anchored within the cell-membrane

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

Gram negative?

A 
Thin cell-wall
• 1-2 layers of peptidoglycan
Has two membranes
• Inner cytoplasmic membrane
• Bacterial outer-membrane
Structures ”unique” for Gram-negatives
• Porins
• Lipopolysaccharides (LPS)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Porins?

A 
Crosses the bacterial outer-membrane
Acts as a pore
• Molecules can diffuse through
• Concentration-gradient is required
Other protein-systems then transport the molecules further

The genes encoding the porin-proteins can mutate
• The permeability changes

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

LPS?

A

Present in most Gram-negative bacteria
Has a very complex lipid-structure
• Uncommon sugar and fetty-acids

Function
• Increases the negative charge of the cell-membrane
• Stabilizing the membrane-structure
Lipid A (endotoxin)
• Has fatty-acids associated that ”anchor” LPS to the cell-membrane
• Strongly immunogenic

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

Structure cell-wall?

A

Mainly consists of peptidoglycan

• Polysaccharide that consists of two sugar-derivatives
o N-acetylmuramic acid (NAM)
o N-acetylglucosamine (NAG)

NAMs are ”linked” by short polypeptides

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

Lysozyme?

A

An enzyme found in e.g. tears, saliva och intestines
• Prevents bacterial infections
• Break glycosidic bonds between
NAG and NAM (hydrolysis)

Gram-negatives often less sensitive than -positives
• Protected by the bacterial outer-membrane

17
Q

Coccus?

A

(Lat. cocci ≈ ”berry”)

• E.g. Staphylococcus spp. and Streptococcus spp.

18
Q

Bacillus?

A

(Lat. bacilli ≈ small rod)

• E.g. Bacillus spp.

19
Q

Vibrion?

A

(spiral, slightly bent)

• E.g. Vibrio cholerae

20
Q

Spirillum?

A

(spiral, twisted - one or several turns)

• E.g. Campylobacter jejuni

21
Q

Spirochaete?

A

(spiral, very thin, long and twisted)
• E.g. Borrelia spp.

And pleomorphic (change shape)

22
Q

Diplococcus?

A

(two and two)

• E.g. Streptococcus pneumoniae

23
Q

Tetrad?

A

(four and four)

• E.g. Micrococcus luteus

24
Q

Sarcinae?

A

(eight and eight)

• E.g. Sarcina spp

25
Q

Streptococcus?

A

(chains)

• E.g. Streptococcus pyogenes

26
Q

Staphylococcus?

A

(bunches)

• E.g. Staphylococcus aureus

27
Q

Single bacillus?

A

(one and one)

• E.g. Bacillus cereus

28
Q

Diplobacilli?

A

(two and two)

• E.g. Moraxella bovis

29
Q

Streptobacilli?

A

(chains)

• E.g. Streptobacillus moniliformis

30
Q

Palisades?

A

(picked-fence)

• E.g. Corynebacterium diphtheriae

31
Q

Capsule?

A

The capsule is glycoproteins firmly attached to cell-wall
• Assist with adhesion to surfaces
• Prevents phagocytosis from different immune-cells
Examples of encapsulated bacteria
• Streptococcus pneumoniae
• Haemophilus influenzae typ B

32
Q

Slime-layer?

A

Slime is glycoproteins loosely attached to cell-wall
• Assist with adhesion to surfaces
• The slime-layer prevents the bacteria from drying out

Examples of slime-producing bacteria
• Streptococcus spp.
o The slime-layer of S. mutans helps the bacteria to adhere the tooth-enamel
• Staphylococcus spp.
o The slime-layer of S. epidermidis helps the bacteria to survive on the
salty hypertonic skin

33
Q

Biofilm?

A

A natural way for different bacteria to grow

Consists of
• Bacterial-cells
• Polysaccharides
• Proteins and nucleic acid

Formation
• Bacteria adhere to a surface (colonization)
• Growth
• Production of exopolymers such as EPS
• Formation of a biofilm
• Other organisms attend
• Spread
34
Q

Surfaces?

A 
Important microbiological habitats
• Physical forces
• Nutrient-access
• Protection
• Toxic molecules
35
Q

Endospores?

A

Some Gram-positive bacilli can form endospores

Very robust structure
• Radiation
• Dehydration
• Temperature
• Starvation
• Chemical disinfectants
36
Q

Spore-formation?

A
  1. The chromosome is replicated
    • Aligns alongside the cell
  2. The cytoplasmic membrane invaginates
    • A ”pre-spore” is formed
  3. The cytoplasmic membrane grows and engulfs the ”pre-spore”
    • The DNA of the vegetative cell is dissolved
  4. A cortex of calcium and dipicolinic acid is formed between the membranes
    • Most of the water is removed from the cell
  5. A spore-coat is formed around the endospore
    • Consists for instance of keratin that makes the endospore extremely rough
  6. Finally an outer spore-coat is formed
    • Increases its resistance to heat and different chemicals
  7. The endospore is released
    • The vegetative cells goes through lysis

Microbiology HIS (18 decks)

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