Exam 2: Humoral response 2

Question 1

Naive B lymphocytes express which two classes of membrane bound antibodies that function as teh receptors for antigens?

Answer 1

IgM and IgD

Question 2

One activated B cell can generate up to how many plasma cells?

Answer 2

4000 plasma cells

Question 3

One activated B cell can generate up to how many antibody molecules?

Answer 3

10^12 antibody molecules per day

Question 4

High affinity antibodies are characterized by:

Answer 4

regions that match epitopes with the antigen

Question 5

What is the flow of B cells in the lymph node?

Answer 5

efferent blood vessel, high endothelial venule, b cells then get trapped in t cell zone- paracortex, primary focus forms, germinal centers form in the cortex, B cells proliferate, leave node via efferent lymph vessel

Question 6

What are the effector mechanisms of antibodies?

Answer 6

neutralization, opsonizaiton, complement activation

Question 7

Neutralization

Answer 7

bacterial toxins bind to cell with receptors for toxin, antibodies neutralize the toxin and is ingested by macrophage

Question 8

Opsonization

Answer 8

bacteria in extracellular space, antibodies bind to bacteria, macrophage Fc receptor binds to antibodies on bacteria, macrophage ingests and lysis the bacteria

Question 9

What information is needed to make all proteins, including antigen receptors?

Answer 9

the genome

Question 10

Mammals can express up to how many different antigen binding receptors on B and T cells?

Answer 10

10^15

Question 11

How many genes do mammals use to create antigen binding receptors?

Answer 11

fewer than 500 genes

Question 12

How many genes code for the variable region of antigen binding receptors?

Answer 12

several genes

Question 13

How many genes code for the constant region of the antigen binding receptor?

Answer 13

one gene

Question 14

Somatic hypermutation

Answer 14

increased mutation rate in the region in and around rearranged Ig genes, occurs in germinal centers

Question 15

Gene conversion

Answer 15

Process in which portions of one gene are change to another

Question 16

Gene recombination

Answer 16

offspring cells with combinations of traits different than traits of their parental cell DNA

Question 17

What accounts for antigen binding receptors gene diversity?

Answer 17

gene recombination, somatic mutation, gene conversion

Question 18

Process of Gene recombination will results in:

Answer 18

The deletion of unwanted genes by excising a loop that is destroyed and a wanted V and J gene segment

Question 19

Steps in Gene recombination of the Ig light chain

Answer 19

Desired DNA segment undergoes rearrangment, transcription, RNA splicing and translation

Question 20

Steps in Gene recombination of the Ig heavy chain

Answer 20

Desired Gene segment, DNA rearrangment 1, rearrangment 2, Transcription, RNA splicing, Translation

Question 21

Somatic mutation involves teh replacement:

Answer 21

of one nucleotide change from C to T

Question 22

Somatic mutations undergo selection and require:

Answer 22

enhanced antigen binding