micro exam 3 pq

Question 1

Which of the following is an example of amensalism?

Answer 1

streptomyces producing an antibiotic that that inhibits the growth of other microorganisms

Question 2

Which of the following is the correct definition of therapeutic index?

Answer 2

ratio of toxic dose to therapeutic dose

Question 3

Which of the following is FALSE about Clostrium difficile?

Answer 3

TcdC promotes expression of toxins A and B, TcdN is a negative regulator of toxins A and B

Question 4

Describe the sporulation pathway with as few word as possible

Answer 4

Signaling cascade results in differentation of the mother cell into the forespore and the development of the spore structure

Question 5

If region 2 of the RNA pairs with regions 3 of the RNA, then _____ stem loop forms.

Answer 5

nonterminating

Question 6

If region 3 of RNA pairs with region 4 of the RNA, then _______ stem loops forms

Answer 6

Transcription terminates

Question 7

Which are the four major cytokines, and what are their functions?

Answer 7

chemokines
hematopoietins
interleukins
tumor necrosis factor

Question 8

Indicate the term best describes the relationship between pathogenic bacteria and humans?

Answer 8

parasitism

Question 9

Describe what are the cationic antimicrobial peptides (CAMPs)?

Answer 9

Three classes
1.linear, alpha helical peptides. Lack cysteine
2.definsins: open ended, rich in arginine and cysteine and disulfide linked; in neutrophils, intestinal paneth cells, and epithelial cells
3.larger peptides enriched in specific amino acids and repeats

Question 10

What are the primary difference between Toll-like Receptors (TLRs) and NOD-like Receptors (NLRs)?

Answer 10

TLRs recognize extracellular PAMPs, NLRs recognize intracellular PAMPs

Question 11

What is lysozyme and how does it exert its antimicrobial activity?

Answer 11

Lysozyme is an enzyme found i various bodily secretions. Natural antimicrobial agent.
involve its ability to hydrolyze peptidoglycan.

Question 12

Name examples of Toll-like receptors are examples which of the following?

Question 13

Describe the cationic antimicrobial pepetides (CAMPs) with as few words:

Answer 13

positively charged amino acids that inhibit bacterial growth

Question 14

Name and describe antibody functions when encountering bacterial pathogens and or antigens

Question 15

Describe the different mechanisms that drive antibody diversity

Answer 15

Class switching (IgM to IgG) splice site-variability (V1 V2 V3) somatic hypermutation

Question 16

What are the difference between MHC I and MHC II?

Answer 16

MHC I = on all nucleated cells, present endogenous antigens to cytotoxic T cells
MHC II= on cells that process non-self cells, exogenous antigens to helps T cells

Question 17

Describe the function of : antigen presenting cells, T cells, B cells

Answer 17

Antigen presenting cells
-Capture and present antigens to T cells
T Cells
-T helper
-Cytotoxic T lymphocyte
= Regulatory T cell
B Cell

Question 18

Exaplin how MCH-1 , MCH -11 and B receptors work

Question 19

How is cytotoxic T cell different from other T cells?

Answer 19

Role/difference = directly kill infected or aberrant cells. their ability to recognize specific antigens presented on target cells allows them to perform immune surveillance and provide protection against intracellular pathogens

Question 20

How does T activiation occur

Answer 20

highly regulated process, involves antigen recognition, co-stimulation
binding specific antigen –> antigen presentation –> initiates signaling cascade –> second signal for lymphocyte proliferation

Question 21

describe how cytotoxic t cells work

Answer 21

kill through apoptosis using granule enzmes

Question 22

are cytotoxic t cells recognized antigens by MHC I or MHC II

Answer 22

MHC I

Question 23

Define superantigen; how do they work?

Answer 23

trick t cells into activation : bind to MHC class II crosslinking T cell receptors to activation of T cells