Week 4

Question 1

antibacterial mechanisms of neutrophils (3)

Answer 1

Question 2

Fc receptors (FcR) on the surface of neutrophils, macrophages and other immune cells recognize which of the following?

• Macrophages that have encountered an antigen
• Complement molecules on a pathogen
• Pathogen-associated molecular patterns
• Antibodies that have coated antigens
• Antigens on pathogens

Answer 2

Antibodies that have coated antigens om the surface of pathogens

Question 3

Describe a dendritic cell

Answer 3

A phagocytic antigen-presenting cell. Expresses MHC class II and Fc receptors. Inhibited by interleukin-10.

Question 4

The cell that links the innate and adaptive immunity is the __________cell

Answer 4

dendritic

Question 5

B cells mediate within humoral/cellular immunity wherease T cells mediate within humoral/cellular immunity

Answer 5

1. B cells –> humoral (mn: B for Blood and antiBodies)
2. T cells –> Cellular (mn: T for touchy touch

Question 6

diff between antibody versus immunoglobulin

Answer 6

Immunoglobulins are attached to the B cell membrane via transmembrane domain while antibodies float in the circulation.

*alternate sources say the words can be used interchangeably

Question 7

MHC I vs MHC II

Answer 7

MHC I molecules are expressed on all nucleated cells and are essential for presentation of normal “self” antigens. Cells that become infected by intracellular pathogens can present foreign antigens on MHC I as well, marking the infected cell for destruction.

MHC II molecules are expressed only on the surface of antigen-presenting cells (macrophages, dendritic cells, and B cells). Antigen presentation with MHC II is essential for the activation of T cells.

Question 8

B cell antigen receptor (BCR) are also called

Answer 8

immunoglobulins

Question 9

TCRs are heterodimers/homodimers? predominately made of

Answer 9

alpha and beta (95%) dimers,

5% are γ and delta 𝛿 (mostly present in mucosal surface as intraepithelial lymphocytes, providing protection of mucosal surface; they recognize antigens without MHC presentation)

Question 10

NK cells are predominately involved in lysing what type of cells

Answer 10

tumor cells, virus infected cells.

Question 11

Immature B cells undergo negative selection, also called clonal deletion, which does what?

Answer 11

removes B cells that bind with self-antigen

Question 12

Two key signals are involved in B cell and T cell interaction and activate B cells, what are they?

Answer 12

• MHC recognition by the T cell, and is necessary for the second signal.
• The B cell displays the antigen-MHC II complex, and that it is recognized by the T-cell receptor (TCR) and CD4 proteins of the Helper T cell.
• The second signal involves co-stimulation by B and T cell proteins:
• Binding of B7-2 with CD-28 triggers cytokine activation.
• Binding of CD40 with CD40L (L is for ligand) triggers class switching and affinity maturation.
  
  • Cytokines released by the Helper T cell influence class switching from IgM/IgD to the other isotypes (IgA, IgG, and IgE).

Question 13

What factors are involved in the phospholipase C cell signaling pathway

Answer 13

Question 14

Kinesins vs dyneins

Answer 14

Kinesins and dyneins have similarities, but an important difference is that most kinesins travel toward the plus end of the microtubule that they are on (i.e., away from the center of the cell), while dyneins travel toward the minus end of the microtubule (towards the center of the cell).

Question 15

Type II collagen is located in

Answer 15

Car-TWO-lage

vitreous humor

nucleus pulposus

Question 16

Type I Collagen

Answer 16

found in many tissues besides cartilage,

where Type II collagen is found

Question 17

dynein vs Kinesin

Answer 17

Microtubules can also serve as a substrate along which dynein and kinesin can move. This process requires hydrolysis of ATP.

• Dynein moves retrograde: the “minus” end of the microtubule
• Kinesin moves anterograde: the “plus” end of the microtubule, where new subunits are added

Mnemonics: “Dyne-in or taKe out?” Also, the “K” of kinesin looks like a “+” → kinesin moves to the “plus” end.

Question 18

What features of the small intestines make them
a favorable place for drug absorption?

Answer 18

high surface area because of villi

long residence time

low pH (but not too low)

highly vascularized

Question 19

What features of the stomach makes it an
unfavorable place for drug absorption?

Answer 19

pH sis very low

mucous membranes

short residence time

thick wall