MHC and Antigen Presentation

Question 1

what makes the MHC molecules different between individuals

Answer 1

locus: of a particular gene in a chromosome

allele: each common variant of a polymorphic gene in the population

polymorphism: variation at a single genetic locus and its product

Question 2

what does it mean that expression of MHC alleles is codominant

Answer 2

no recessive alleles of MHC
both alleles are expressed equally
heterozygous

Question 3

what is the haplotype

Answer 3

combination of alleles at adjacent loci that are transmitted together
clusters are inherited together

Question 4

what is the effect of geographical distribution of HLA variants

Answer 4

basis of diseases being more prevalent in different parts of the world

Question 5

MHC class I structure

Answer 5

heterotrimer

3 domain heavy alpha chain glycoprotein with transmembrane region and peptide binding groove

light beta2 microglobulin chain
non-covalently attached

peptide antigen
required for function

Question 6

MHC class II structure

Answer 6

heterotrimer with two equal sized alpha and beta chains each making half of the binding groove

peptide antigen

Question 7

which MHC class binds larger antigens

Answer 7

MHC class II