BIO 400 Exam 4 Questions With New Update Solutions A+ Pass

BIO 400 Exam 4 Questions With New Update Solutions A+ Pass types of molecules that serve as antigens - Answer- proteins, polysaccharides, glycolipids, nucleoproteins, MAMPs factors that affect immunogenicity - Answer- size, structural complexity, chemical composition, degree of foreignness to host epitope - Answer- the part of the antigen the immune system recognizes and to which the antibody binds methods of immunity acquisition - Answer- natural passive - breast milk/through placenta artificial passive - receiving already made antibodies e.g. antivenom natural active - exposure to disease/having disease artificial active - vaccines types of vaccines - Answer- killed microbes; living, weakened (attenuated) microbes; engineered organisms and their products; or inactivated toxins (toxoids) MHC 1 - Answer- all nucleated cells - presents intracellular antigens and host cell components identifying as host cells MHC 2 - Answer- found on DCs, macrophages, and B cells used to present extracellular foreign antigens to WBC - have longer and deeper groove than MHC 1 (can present larger antigens) CTLs - Answer- cytotoxic T lymphocytes - CD8 - kill cells that have been infected by intracellular pathogens (i.e. only interact with MHC 1), are presenting cancer neoantigens, or have altered MHC proteins cytolytic pathway - release perforin, granzymes, and other substances that form pores in and lyse infected cells apoptotic pathway - causes cell to kill itself T helper cells - Answer- CD4 - cytokines released by DCs trigger development into one of several kinds of TH cells (caused by signal 3 during maturation) only interact with MHC 2 on APCs *need more on fn T cell activation - Answer- 3 signaling processes: 1. interaction with antigen - coreceptors restrict which type of MHC molecule can be involved 2. B7 on APC binds to CD28 receptor on T cell 3. stimulation via cytokines T cell receptor (structure and function) - Answer- detect antigen fragments presented by MHC molecules made up of alpha and beta proteins that form antigen binding pocket that is specific to each antigen and a coreceptor (CD4 or CD8) T cell development - Answer- takes place in thymus where thymic selection picks out alpha-beta T cells, which then receive either CD4 or CD8 coreceptors 98% of CLPs are selected against and forced to undergo apoptosis because they recognize self cells too strongly cells leaving the thymus are mature (fully developed) but naïve (have not yet interacted with an antigen) common lymphoid progenitor (CLP) - Answer- stem cells that give rise to all sorts of lymphocytes - present in bone marrow (B cells) and thymus (T cells) thymic selection - Answer- determines which type of T cells immature cells will become and selects against cells that inappropriately recognize self as nonself types of T cells - Answer- effector and memory immune synapse - Answer- region of contact between T cell and APC at MHC molecule B cell receptor - Answer- complex of antibodies - IgD and IgM - and transmembrane heterodimer proteins that facilitate signal transduction to nucleus 10^13 unique BCRs for different antigens have fixed and variable portions - variable portions are same for all BCRs on a single B cell T cell dependent B cell activation - Answer- B cell must first bind to antigen and present it on an MHC 2 molecule then T helper cell must also bind same antigen elsewhere in body and migrate to B cell and bind to it, then stimulate it to develop into a plasma cell T cell independent B cell activation - Answer- ? IgG - Answer- most common in blood, monomeric, opsonizes pathogens and activates complement (classical), only antibody able to cross placenta replaces IgM over time in immune response IgM - Answer- also present in serum as pentamer and present as BCRs as a monomer, first antibody to respond to infection, levels off over time and gives way to IgG IgA - Answer- present somewhat in serum (monomeric) but mostly in mucus secretions (dimeric) e.g. tears, saliva, intestinal mucus, breast milk, etc. creates immune barrier - immune exclusion IgD - Answer- BCRs IgE - Answer- mostly associated with allergies (mast cells, eosinophils, basophils) overall fn of antibodies - Answer- opsonization - promotes phagocytosis activate classical complement pathway also directly neutralize toxins and viruses agglutinate antigens together for easier phag. enhance fn of NK cells class switching - Answer- switching from IgM to IgG as immune response progresses primary antibody response - Answer- first exposure to antigen - longer lag phase (about 10 days to several weeks) - IgM is secreted first then midway through log phase, class switching to IgG (or sometimes IgA) occurs secondary antibody response - Answer- subsequent exposure to pathogen - high affinity IgG secreted right away (shorter lag phase and log phase is more rapid) clonal selection - Answer- B cells activated by a specific antigen clone themselves somatic hypermutation - Answer- B cells in lymph nodules rapidly mutate creating new sequences - process of creating many unique BCRs for all possible antigens herd immunity - Answer- at least 2/3 of population must be vaccinated in order to protect the unvaccinated community first bacteria in babies - Answer- E. coli and streptococci creates reducing environment to allow anaerobes bifidobacteria and bacteroidetes to grow bifidobacteria - Answer- found in breast fed babies v. bottle fed