Brainscape's Knowledge GenomeTM

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


See full index

Pathogenic microbiology > Lecture 3 > Flashcards

Lecture 3 Flashcards

1
Q

once in the body what kind of cell do bacteria usually adhere to?

A

Epithelial cells

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

after establishment, through where do bacteria spread?

A

through tissues or via the lymphatic system

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

what are the 4 steps to the infection process?

A
  1. adhere to host cell
  2. spread
  3. survive defenses
  4. transfer to new host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are some negatives for bacteria when it comes to attachment?

A

attachment could stimulate immune cell infiltration, activation, and phagocytosis

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

what are the components of adhesion for bacteria?

A

consists of lectin carbohydrate associations or Beta 1 integrins via ECM components for indirect association

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

direct interaction between what can allow bacterial entry into a host cell?

A

direct interaction between host integrin or cadherin receptors with bacteria surface ligand

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

what are the 4 big classes of the ECM?

A

collagen, fibronectin, laminin, and proteoglycan

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

what makes up collagen fibers and what about this set up is special?

A

it is 3 left hand helises wound to make fibrils which come to form the collagen fibers and all this winding gives it tensile strength

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

what is the make up of proteoglycans?

A

starts with a central molecule of hyaluronic acid, connected to this are then core proteins and connected to core proteins are sugars either chondroitin sulfate or keratan sulfate

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

what are some traits of fibronectin?

A

heterodimer but very close to being a homodimer, 2 proteins connected by disulfide bonds

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

what are some traits for laminin?

A

creates basal lamina which is foundation for cells to sit on, involved in general interaction and signaling, and can interact with collagen network

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

what are the 4 steps for pathogen induced upregulation of adhesion?

A
  1. bind
  2. receptor up regulation
  3. make more receptors
  4. increased adhesion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

true or false: granuloma formation is always a good thing

A

false, granuloma formation can be both good and bad

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

what are some factors in bacteria-host surface interactions?

A
  1. net surface charge (on host and bacteria)
  2. surface hydrophobicity (if one cell is phobic and other is philic then bad bonding)
  3. binding molecules on bacteria and host cell receptors ( ligands and adhesins)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how small does a distance have to be for specific adhesion?

A

less than 1 nm, anything larger would be nonspecific adhesion (could be van der waals, electrostatic repulsion, and hydrophobic interactions)

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

What are some traits of nonspecific adhesion?

A

weak adhering, can allow colonization to surfaces that isnt subject to strong washing force (skin) but not to places with strong washing forces (urinary tract)

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

what are the aspects of specific adhesion?

A

on the bacterial surface you have the surface protein (lectins) and on the host cell you have the carbohydrate part of the glycolipid or glycoprotein

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

where would you find bacterial adhesins on gram negative and positive bacteria? what advantage do they provide?

A

on gram negative bacteria you would find the proteins on the outer membrane and on gram positive would find it on cell wall. Allow for binding from safe distance

19
Q

what are the three types of adhesins?

A
  1. pili/fimbriae
  2. non-pilus surface proteins
  3. polysaccharides
20
Q

what are some traits of bacterial fimbriae?

A

multimeric, adhesive appendages protruding many microns out allowing for farther safer connection than surface proteins

21
Q

what are the consequences of adhesion?

A
  1. organism colonizes surface
  2. pathogen colonizes surface and secretes toxin
  3. colonize and form a biofilm
22
Q

what is a biofilm?

A

a community of microorganisms, associated with a surface, and encased in an extracellular polymeric matrix

23
Q

what are the types of biofilms?

A

simple: single species
complex: multiple species, co-aggregation, and polysaccharides trap others

24
Q

what are the 4 steps for biofilm formation?

A
  1. interaction of cells with a surface or with each other
  2. films aggregate
  3. cells form an extracellular matrix
  4. structures differ based on organisms in film and environmental conditions
25
Q

what does the Extracellular matrix of the biofilm do?

A

allows the emerging biofilm to grow and develop into a complex 3D structure

26
Q

What are the key components of the Extracellular polymeric matrix?

A

polysaccharides and proteins

27
Q

when it comes to polysaccharides what substance do many bacteria such as E. coli and Salmonella produce?

A

cellulose, many other bacteria have cellulose synthesis genes

28
Q

how do humans use biofilms to our benefit?

A

they can be used to help treat and diagnose bacteria

29
Q

What is special about Quorum sensing bacterial cells?

A

they communicate with each other to control signaling and gene expression, this occurs at higher cell density

30
Q

what do autoinducers do and where would you find them?

A

they are mediators of quorum sensing found in the extracellular medium

31
Q

what happens to quorum sensing cells when they exceed a particular threshold?

A

they are internalized and activate genes that could be responsible for virulence, competence, stationary phase etc

32
Q

What are some processes that are controlled by quorum sensing?

A
  1. biolumenescence
  2. biofilm formation
  3. virulence gene expression
  4. sporulation
  5. competence
33
Q

what are the 3 types of quorum sensing molecules?

A
  1. acyl homoserine lactones (AHLs)
  2. autoinducer peptides (AIPs)
  3. Autoinducer-2 (AI-2)
34
Q

What exactly does do AHL’s do?

A

mediate quorum sensing in gram negative bacteria

and mediate exclusively intracellular communication

35
Q

what synthesizes and what recognizes AHL?

A

synthesized by Lux I and recognized by Lux R

36
Q

what do autoinducer peptides do?

A

they regulate competence and sporulating gene expression in gram positive bacteria

37
Q

what is the receptor for autoinducer peptides?

A

membrane bound histidine kinase

38
Q

what does AI-2 do?

A

induces expression of stationary phase genes and inhibition of initiation of DNA replication present in gram positive and negative bacteria

39
Q

what are the steps to get to AI-2

A

start with SRH then with LuxS we get to DPD and with cyclization we get to AI-2

40
Q

what are the three modes of interaction of invading pathogens with epithelial cells?

A
  1. bridging mechanism
  2. entry via specialized cells (M cells)
  3. entry after receptor distribution following trauma or polymorphonuclear cells transmigration
41
Q

what are the main lipids in lipid rafts?

A

cholesterol, glycosphingolipids and sphingomyelin

42
Q

What are the proteins that specifically partition into the rafts of lipid rafts, what kind are on the outer and inner leaf let?

A

lipid anchored proteins are the proteins, GPI-AP are on the outer leaflet and G proteins on the inner leaflet

43
Q

what is signal transduction?

A

any process by which a cell converts one kind of signal or stimulus into another

Pathogenic microbiology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions