Immunity

Question 1

What is the difference between a gram + and a gram - bacteria?

Answer 1

Gram - has an extra cell wall which prevents the dye (ethyl violet) from changing the color of the peptidaglycan layer

Question 2

What is the difference between a cocci and a bacillus bacteria?

Answer 2

cocci- sphere shaped

bacillus- rod shaped

Question 3

What type of climate would be ideal for an aerobic bacteria?

Answer 3

• Requires O2, would die without it
• found on skin and in respiratory tract

Question 4

What type of climate does a microaerobic bacteria need?

Answer 4

• Needs a little O2, but cannot tolerate lots
• found in stomach

Question 5

What type of climate does a Facultative anaerobic bacteria need?

Answer 5

• Can use O2 if they have it, but can survive without it
• not great at either

Question 6

What type of toxin do gram - and gram + bacteria release?

Answer 6

• Gram - : endotoxin
  
  • release by bacterial cell death
• Gram + : Exotoxin
  
  • secreted from live bacteria (ex. botulinum toxin)

Question 7

What is a spore?

Answer 7

• Hard shell around a bacteria makes it extremely difficult to kill.
• It will emerge from spore when environment is improved.

Question 8

Staphylococcus

gram stain

O2 req

shape

characteristic

Answer 8

Gram +

Aerobic

cocci

clusters

1st and 2nd most common bact. b/c of MRSA

Question 9

Streptococcus

gram stain

O2 req

shape

characteristics

Answer 9

gram +

aerobic

cocci

chains, pairs

Question 10

Clostridium

gram stain

O2 req

shape

characteristic

Answer 10

Gram +

anaerobic

bacilli

spore forming

Question 11

What are the 4 clostridiums that cause disease in humans?

Answer 11

perfingens

difficil

botulinum

tetanus

Question 12

Bacillus

gram stain

O2 req

shape

characteristics

Answer 12

Gram +

aerobic

bacilli

spore forming

Question 13

Bacteroides

gram stain

O2 req

shape

characteristic

Answer 13

Gram -

anaerobic

bacilli

Most common cell in body

Question 14

What is a plasmid?

Answer 14

DNA found in bacteria that is separate from it’s chromosomal DNA. Contains genes that give the bacteria a genetic advantage (superpower).

Can be easily shared to other bacteria via a Pilus

Question 15

How does a virus infect a host cell?

Answer 15

1. becomes attached to a specific plasma protein
2. releases enzymes that weaken the membrane and allow it to enter the cell
3. uncoats itself
4. enters the nucleus and the host cell replicates it
5. matures and escapes cell to infect other host cells

Question 16

What are the three most medically relevant Fungi and what do that do?

Answer 16

• Candida albacans
  
  • normal gut flora
  • causes opportunistic infections
• Aspergillus spp.
  
  • highly aerobic
  • causes respiratory infections
• Tinea (skin plant):
  
  • Capitus- head
  • cruris-jock
  • pedis- foot

Question 17

What happens after a Mast cell has been activated?

Answer 17

• Degranulation- release of the active substances the cell holds
  
  • histamine- causes vascular effects
  • chemotactic factors- attracts neutrophils and eosinophils
• Synthesis- lipid based molecules are made out of the phospholipids of the plasma membrane
  
  • platelet activator
  • prostaglandins
  • leukotrienes

Question 18

What are the stages of inflammation?

Answer 18

• Initiate response- vessel leakage
• Recruitment of cells- chemotaxis, leukocyte growth and proliferation
• Remove debris- activate leukocytes, lymphocyte growth, and antibody synthesis
• Promote repair and regeneration- induce fibroblast growth and collagen production

Question 19

epitope

Answer 19

the part of the antigen (a large polysaccharide or protein) that is recognized by the antibody.

Question 20

IgA

IgE

IgG

IgM

Answer 20

• IgA- Gets secreted into orifices
  
  • GI, bronchi, mouth, vagina
• IgE- tissue
• IgG- blood
• IgM- all of them start as IgM

Question 21

Describe the structure of an Antibody

Answer 21

An antibody is made up of a light chain and a heavy chain. The light chain is made specifically to bind with an antigen. The heavy chain is constant and easy for the macrophages to recognize.

Question 22

How is a parasite destroyed (with IgE)?

Answer 22

• Antigens released by the parasite cause B-cells to produce IgE antibody
• IgE binds to the mast cell surface
• Antigens from the parasite then link to the IgE on the mast cell
  
  • causes the mast cell to degranulate, causing inflammation and releasing chemotactic factor
• Eosinophils are attracted by the chemotactic factor and come
• Eosinophil attaches to the parasite and releases lysosomal enzymes that damage it

Question 23

What is the difference between primary and secondary immune response?

Answer 23

• Primary immune response
  
  • IgM dominates
  • process takes longer
  • IgG response is much smaller
• Secondary immune response
  
  • Response happens much quicker
  • larger amounts of IgG are produced

Question 24

What is a Peyer’s patch and how does it function?

Answer 24

• Peyer’s patch- an aggregation of lymphoid tissue found in the ileum.
• antigens in the lumen of the digestive tract are captured by M-cells
• antigen is recognized by B-cells and they are displayed by APCs to Thelper cells
• B-cells are stimulated by T_H cells to become IgA-secreting plasma cells which are then transported into the intestinal lumen.

Question 25

What is the difference between Class I and Class II MHC cells?

Answer 25

* Class I * found on all nucleated cells and platelets * presents "endogenous" antigens * Class II * found on B cells, APCs, and some epithelial cells * presents "exogenous" antigens

Question 26

What areas are immune privileged?

Answer 26

placenta/fetus testes and ovaries eyes brain thymus

Question 27

What type of climate is ideal for an **obligate anaerobe**?

Answer 27

* Cannot tolerate oxygen * Found in colon or deep penetrating wounds