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208 Cards in this Set
- Front
- Back
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what are examples of Histones? what is their function?
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H2A, H3A, H4 (2 of each= 8 total), DNA wraps outside of protein (like a ball) & H1 holds all DNA together (acts as connector)
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what is a Solenoid?
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coil wound into tightly packed helix
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what is a nucleosome?
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complex made of 8 hsitones with DNA wrapped around it approx. twice
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What happens if a mutation occurs in topoisomerase?
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cause them not to work properly or not work at all causing the cell to die (lethal)
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what do researchers want to use to kill cancer cells?
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modified topoisomerase
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how is a plasmid different from regular prokaryotic DNA?
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has DNA not in nucleus (circular plasmid- prokaryotic), & plasmid is genetically modeified from normal prokaryotic DNA (add/ remove DNA from plasmid- genes)
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Do all proteins function in cytoplasm of cell?
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no
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how does cloning occur for lacZ+ gene?
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lacZ+ gene has multiple cloning sites, has different enzymes when you cut and have lacZ+ gene in vector, you have sticky ends on plasmid and sticky ends on DNA that attach together
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i have a blue colony and its the one i want. How is it possible that the blue colony is actually the one that im interested in? How is it possible I can do cloning (usually looking for white colonies) but I realize later that I actually want blue colony all along?
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want gene to be intact (truly interested in B- gal.), major assumption made (if still blue)--> ignore blue because it is uncut, if did cut & fragment went in it and still made blue (cut with different restriction enzyme, doesn't frame shift lacZ gene, keeps it in gene) still makes functional protein, inserted so that didn't make B-gal. stop funcioning, different cut site & kept lacZ gene active
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you have done PCR reaction & generated 400 bp fragment, run it on gel. A normal person, 2 abnormal people. Run gel on these people (100 bp marker) how would u interpret the gel?
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conclude PCR worked for all 3 samples, if end up with multiple sections of colour on gel, can conclude that this lane is not giving reults you expect, repeat reaction (error). If you get different results, repeat again. Only need 1 bad copy of gene to show result. (results show 1 line at 400 bp and 1 at 200bp- autosomal dominant disorder). can be caused by deletion of 200bp or insertion. location of 200 bp deletion is in fragment that you PCR amplify and is located between primers
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What happens if PCR works?
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gene/area of interest must be between 2 primers after amplification, just by looking at gene you CAN'T pinpoint exact area location of deletion/ insertion in between 2 primers
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What happens if PCR doesn't work?
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assume that there is a problem with primers.
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If mom has 1 400bp (normal) & dad has 2- 1 at 200bp and 1 at 400bp (abnormal), if child is abnormal what does this mean?
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child has inherited mutation from dad (abnormal)
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If mom has 1 400bp (abnormal) & dad has 2- 1 at 200bp and 1 at 400bp (normal), if child is carrier what does this mean?
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child has inherited mutation from mom (carrier)
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what happens if you have a SNIP on mom's chromosome?
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alter primer and cause amplification not to work
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what does a larger band mean?
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insertion
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what does a smaller band mean?
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deletion
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if run gel on normal person who had thick band and abnormal personal had thinner band (1/2 amount of normal person after magnification- both are 400bp fragments) what does this mean?
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may not have enough protein, must transcribe DNA, PCR (has primers), assume chromosome 7 (1 inherited from each parent), primers bind to chromosome 7 & amplify, if deletion was present (large) & included 400 bp fragment, such that primers can't bind to 1 of chromosomes you will get 1/2 amount of product (PCR only worked on 1 chromosome instead of 2)
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what can you expect from a negative control (PCR)?
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not to amplify, give negative results, would show NO lines on gel
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what can you expect from a positive control (PCR)?
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to amplify, give positive results, would show lines on gel where predicted
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what is the function on ladders?
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help to size fragments (base positive control against this to ensure correct size), bought from manufacturing companies
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what would you do if you set up PCR reaction, ran results and saw a band in negative control?
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PCR didn't work because of contamination, repeat experiment, have no faith in results when no line in gel (both controls (+) & (-) must work*)
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how many PCR primers can you have at once to be amplified? why?
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when sequencing, can ONLY have 1 primer, define points of what you have amplified, when sequenced, in reactio you can only have 1 primer NOT 2
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what happens if you have 2 primers?
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electropharagram becomes really messy when used on 2 different reactions
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where are your PCR primers?
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surrounding the SNP, 3 main parts--> marker/ladder, positive and negative controls
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If this PCR is successful, what do you expect to see on an ethidium bromide stained gel?
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a 300bp band/ fragment, trick question*, don't usually use PCR to cut
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how do you interpret fel with no "PCR negative control"?
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can't interpret PCR results because there is no PCR on gel at all
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Assuming all controls are correct, how do you interpret a lane on gel, loaded with a sample's PCR product, that shows 2 bands (i.e. 100bp and 200bp)?
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unsuccessful PCR, trick question, unsuccessful PCR because doesn't say it was cut, only 300bp is correct if not cut
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Assuming all controls are correct, how do you interpret a lane on gel, loaded with a sample's PCR product, that shows one band (30bp)?
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successful PCR, only amplified PCR, trick question, can't assume everything worked
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Assume all controls are correct, how do you interpret a lane on gel, loaded with a sample's PCR product cut with EcoR1, that shows one 300bp band?
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person is homozygous for adenine at the SNP site, trick question, assume everything worked, PCR is cut
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Assume all controls are correct, how do you interpret a lane on gel, loaded with a sample's PCR product cut with EcoR1, that shows 2 bands (100bp and 200bp)?
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person is homozygous for guanine at the SNP site
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Assume all controls are correct, how do you interpret a lane on gel, loaded with a sample's PCR product cut with EcoR1, that shows 3 bands (100bp, 200bp, 300bp)?
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person has guanine and adenine at the SNP site, autosomal recessive--> 2 chromosomes, either 1 can have G or A (mom & dad) always have option of having SNP (A) and not have SNP (G)
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Assume all controls are correct, how do you interpret a lane on gel, loaded with a sample's PCR product cut with EcoR1, that shows 3 bands (100bp, 200bp, 300bp) & incomplete digestion?
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heterozygous, 1 chromosome from mom and dad, assume 50% from both, 300bp should give 1 intensity and 100bp and 200bp would be half of 300bp but same intensity (complete digestion), if incomplete digestion occurs, then 100 & 200bp would be different intensities
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Assume all controls are correct, how could you improve your PCR if your gel shows 2 bands (i.e. pale 300bp and bright 450bp bands) reather than 300bp band?
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increase primer annealing temperature= GOOD IDEA, binding occurs, harder for primers to bind, only things more complementary can bind under more stressful conditions, CAN'T use more PCR cycles because more amplification which is NOT good, more primer used= more binding, decrease denature temp= primers won't bind= no product for PCR
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what does Totipotent mean?
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ability to give rise to ALL the cell types of the body plus all of the cell types that make up the extra-embryonic tissues (placenta) such as the placenta
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what does Pluripotent mean?
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ability to give rise to all of the various cell types of the body but can NOT make extra-embryonic tissues such as the amnion, chorion, & other components of the placenta
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what does Multipotent mean?
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ability to gievrise to a number of closely related family of cells
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what does Olgiopotent mean?
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ability to give rise to only a few cells i.e. lymphoid or myleoid stem cells
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what does Unipotent mean?
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ability to produce ONLY one cell type, their own
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what does the term "Ectoderm" refer to?
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outer most layer; nervous system & skin
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what does the term "Endoderm" refer to?
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inner most layer; gut tube & lungs
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what does the term "Mesoderm" refer to?
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middle layer; muscle, bone, blood
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what are the 2 kinds of stem cells based on their site of origination & degree of specialization?
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embryonic stem cells, somatic or adult stem cells
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what are embryonic stem cells (ESC)?
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most research done on mouse & human embryonic stem cells, in vitro (test tube) mESC are NOT identical to hESC, 1998--> able to derive stem cells from human embryos (discarded watse of IVF donated to research),
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what are hESC (human embryonic stem cell)?
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isolated from inner cell mass of blastocyst
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how do you identify embryonic stem cells?
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can grow/ subculture for many months, presence of transcription factors & cell surface antigens, cytogentic assessment to confirm absence of numerical & structural changes to chromosomes, tissue culture to confirm cultues frozen, thawed & replated will grow & subculture
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how can you confirm cells are pluripotent?
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allowing spontanteous differentiation in cell culture, inducing differentiaion, (in vivo) intro. of stem cells into immunodepressed mouse & observe how they grow & differentiate
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why are Oct-4, NANOG & Sox2 transcription factors used to mark for undifferentiated hESC?
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suppression of genes that lead to differentiation, maintenance of pluripotency (maintain this state)
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what happens if abnormal oligodendrocytes are present?
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leads to demyelination & dysfunction within CNS (MS & leukodystrophies), spinal cord injuries have damage to these oligodendrocytes but specifially at site of injury (focus on measurable results)
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what are Somatic/ adult stem cells?
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rare, undifferentiated cell found among differentiated cells in a tissue or organ, since 2006 able to reprogram differentiated/ specialized cells to stem cell like state
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where are adult stem cells found?
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skeletal muscle, heart, bone marrow, skin, teeth, blood vessels, umbilical cord blood, etc.
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what are most adult stem cells ? (unipotent, multipotent, etc.)
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lineage restricted (multipotent)
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what has the point of San Diego Zoo & Israeli scientists research? ("stem cell zoo")
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perserve skin cells & other tissues from 800 species to save extinct species
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what are Hematopoietic stem cells (HSC)?
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form all types of blood cells in body and immune system
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what are bone marrow stromal stem cells or Mesenchymal stem cells/ skeletal stem cells?
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form the bone, cartilage, fat, cells that support the formation of blood, & fibrous connective tissue
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what diseases can be treated by use of cord blood & tissue?
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cancers, blood disorders, immune disorders, metabolic disorders
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what is immunology?
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study of immune system, collective name for organs, tisses and cells of body that work to prevent/ heal disease
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what are the 3 lines of defense against invasion?
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physical barrier, innate immune system, adaptive/ acquired (not born with) immune system
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What is a physical barrier line of defense?
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1st line of defense, many body cavities lined by mucus membranes, have environments that are hostile to pathogens, ie. acidic stomach, reproductive tract, epithelium
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what is the innate immune system?
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2nd line of defense, generalized internal chemical, physical & cellular reactions against pathogens that have survived the 1st line of defense, immediate, nonspecific response targets invading pathogens & has NO memory of prior exposure to that specific pathogen; inherited
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what is the adaptive/ acquired (not born with) immune system?
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found ONLY in vertebrates, inherited mechanisms that lead to the synthesis of antibodies, reaction to infection takes several days
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how does the body make antibodies?
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inherited, depends on what you have been exposed to, differs for all people
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what is inflammation?
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creates an internal condition that inhibits/ kills many pathogens
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what is the 1st step of action to get rid of pathogen for specialized cell?
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break in skin introduces bacteria, which reproduces at the wound site
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what is the role of a specialized cell?
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engulf/ kill pathogens or infected body cells (i.e. macrophages, neutrophils, etc.)
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what is the 2nd step of action to get rid of pathogen for specialized cell?
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activated macrophages engulf pathogen & secrete cytokines & chemokines
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what are pathogens?
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highly conserved molecular patterns present on their surface that are NOT on host cells, which allows for recognition of foreign material
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what is a monocyte?
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differentiates into macrophage when released from blood into damaged tissue
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what is the function of a monocyte after it enters the damaged tissue?
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differentiates into macrophages (big eaters)
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what is the role of a macrophage receptor?
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recognize & bind to surface molecules of the pathogens & initiate phagocytosis
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what happens if there is not enough macrophages?
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secrete cytokines to attract other immune cells
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how does the body recognize foreign substances and know when to attack?
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bacteria and other foreign substances have different patterns on membranes different from body cells
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what is the 3rd step of action to get rid of pathogen for specialized cell?
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activated mast cells release histamine which dilate local blood vessels & increase their permeability
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what does the death of cells caused by pathogens lead too?
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infection site activates cells that are dispersed through out the connective tisse (mast cells)
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what are neutrophils?
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phagocyte that engulfs pathogens & tissue debris in damaged tissues, sticks to membrane walls and makes walls sticky
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what happens to the blood vessel when histamine is released by mast cell?
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dilates, becomes more permeable
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what is the 4th step of action to get rid of pathogen for specialized cell?
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chemokines (secreted by macrophage) attract neutrophils, which pass between cells of the blood vessel wall & migrate to infection site
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how many complement proteins are in a complement system?
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more than 30 proteins, many different combinations
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what are complement proteins?
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insert themselves ito membrane of pathogens, creating a pore
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what is a complement system?
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normally inactive, interacting soluble plasma proteins that circulate in blood & interstitial fluid, activated when recognize molecules on surface of pathogens (when they see foreign object)
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what are heat, redness and swelling during inflammation due to?
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dilation of local blood vessels (ie. macrophage and mast cells release cytokines & histamine respectively)
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what is pus composed of?
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mostly dead & dying neutrophils
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What is pain caused by during inflammation?
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migration of macrophages & neutrophils
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what is the 5th step of action to get rid of pathogen for specialized cell?
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neutrophils engulf pathogens & destroy them
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what is the function of natural killer cells (NK)?
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part of innate immunity to kill virus-infected cells and some cancerous cells of host
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what is programmed cell death?
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normal phenomenon of cells, growth & death of cells both required for normal development
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what is apoptosis?
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highly important through evolution (conserved), pathogens trigger abnormal cellular activity that activates responses, ie. programmed cell death
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what is interferon?
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viral dsRNA may cause infected host cell produce 2 cytokines, binds to cell surface receptors triggering cascade of changes to gene expression pattern in cell, ribonucleases degrade most cellular RNA interfering with protein synthesis which inhibits replication of viral genome
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what is the role of RNA interference (RNAi)?
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interfers with cell's ability to transcribe/ translate genes, triggered by dsRNA (ssRNA folded), most viruses have dsrNA as part of life cycle, inhibit dsRNA in many viruses & eliminate impact of viral infection
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what are common strategies to identify viruses within the body?
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RNA interference, interferon, apoptosis, natural killer cells
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what is a pathogen virus?
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innate immunity system often unable to distinguish between viral pathogen & host cells (go undetected)
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what is RNA interference?
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double stranded RNA (single stranded, then folds back on itself to make double strand --> affects translation of protein)
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what is a macrophage?
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phagocyte that engulfs infected cells, pathogens. and cellular debris in damaged tissues, helps activate lymphocytes in carrying out immune response
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what is the immune system made up of?
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physical barrier, innate immunity & adaptive immunity, product of long term coevolutionary interactions between pathogens & their hosts
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how does adaptive/ acquired immunity work within the body?
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very specific to foreign substances, body retains memory of first exposure to that pathogen, enabling it to respond more quickly if pathogen is encountered again in future (reaction to pathogen is SPECIFIC to type of pathogen present in body); most complex line of defense, reaction is specific to foregin substance, attack to neutralize/ eliminate pathogen, triggered by specific molecules on pathogen that are recognized as being foreign "nonself" to body
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what do Natural Killer cells secrete?
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granules containing perforin & proteases
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what is the function of proteases?
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degrade proteins, activate enzymes that degrade DNA and trigger apoptosis
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what is the function of perforin?
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creates pores in cell membrane which allows unregulated diffusion of ions through the pores (affects osmotic pressure)
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does central node of tumor have to be effected for cancer to spread to other parts of the body?
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no, any node may be effected
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what is the function of a tumor node?
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if even 1 node on tumor shows sign of cancer, cancer can spread to rest of body, even if CENTRAL node hasn't been effected yet
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what do lymphocytes function as?
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adaptive immunity, produce antibodies, destroy infected and cancerous body cells, and stimulate macrophages & other leukocyte types to engulf infected cells, pathogens & cellular debris
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what is a lymphocyte?
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main substances involved in innate and adaptive immunity are natural killer cells, B cells, plasma cells, helper T cells, and cytotoxic T cells
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what is the function of basophil?
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respond to IgE antibodies in an allergy response by secreting histamine, which stimulates inflammation
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what is the function of eosinophil?
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secretes substances that kill eukaryotic parasites such as worms
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what does complete blood count (CBC) consist of? (components)
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eosinophil, nuetrophil, basophil, red blood cell, lympocyte, monocyte, platelet
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what are considered to be foreign molecules in the body?
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free, found on surface of virus, cancer cells, pollen, transplanted organs
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what is an antigen?
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any foreign substance that can elicit an adaptive immune response, antibody generator
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what are examples of antigens?
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most are macromolecules, large proteins or polysaccharides, can be nucleic acid or synthesized molecules, bacteria, viruses & parasites
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what is an endogenous?
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an antigen already found in the body
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what is an exogenous?
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antigen that can be taken into the body (i.e. a virus)
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what 2 types of lymphocytes are antigens recognized by?
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B lymphocytes (B cells) & T lymphocytes (T cells)
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what is the function of B lymphocytes?
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differentiate from stem cells in bone marrow, after they differentiate they are released into blood & carried to capillary beds serving tissues & organs of lymphatic system
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what is the function of T lymphocytes?
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produced by division of stem cells in bone marrow, released into blood & carried to thymus where they differentiate
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what did injecting lymphocytes from normal mice into irradiated mice do?
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restore adaptive immune response, injecting other types didn't
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what are the 2 types of adaptive immune response?
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antibody mediated immunity (AMI) or humoral immunity, cell-mediated immunity (CMI)
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how are AMI & CMI similar (in mechanisms)?
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lymphocyte recognizes & binds to antigen, divide to produce large # of clones, activated lymphocyte clears antigen from body, differentiate into memory cells that circulate in blood & lymph ready to initiate rapid immune response upon seeing same antigen, development of immunological memory
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what is an antibody?
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protein produced by body in adaptive immunity to destroy or neutralize an antigen
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what does antibody recognition consist of?
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each B & T cell has thousands of antigen specific, identical receptors on plasma membrane, called B cell receptors (BCR) & T cell receptors (TCR)
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what happens if there is a Disulfide bond present in antibody recognition?
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problem, can't bind to receptors
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what happens if a foreign object binds to a variable region during antibody recognition?
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recognized by specific receptors (antigens)
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what do hematopoietic stem cells form?
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form all blood cells, cells of immune system
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are the receptors for antibody recognition all identical on a cell or are they all different?
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all identical
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what is BCR & TCR antibody diversity?
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proteins are encoded by different genes on different chromosomes, produce diversity, number of different segments are in genes
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what is BCR & TCR composition?
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complex of polypeptide (protein) chains that belong to immunoglobulin (Ig) class of protein
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what does TCR consist of?
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1 alpha chain
1 beta chain |
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what does BCR consist of?
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2 identical heavy chains
2 identical light chains chains held together by disulfide bonds & form "Y" shape |
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what is antigenic determinant or epitope?
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place where BCR & TCR bind on the variable region of an antigen
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what occurs during the binding of BCR & TCR?
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don't bind to entire antigen, variable region of BCR & TCR bind to portion of antigen , many different B cells & T cells bind to different portions of particular antigen
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how is each antigen recognized?
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through many B & T cells
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what is the role of each B & T cell?
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can bind to only one particular antigen, entire population of B & T cells in body can collectively recognize millions of antigens
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what is IgG?
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most abundant, crosses placenta & confers passive immunity from mom to fetus
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what are the 5 classes of antibodies?
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IgM, IgG, IgA, IgE, IgD
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what does the class of antibody reflect?
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antibodies location & function
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what do constant regions of heavy chains determine?
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class of antibody
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what do variable regions of chains combine to produce?
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specific antigen binding site, give antibody their specificity
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what does each antibody type have?
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same AA sequence in constant region of heavy chain & light chain, variable regions differ in heavy & light chains
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what does each protein have when binding?
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constant & variable region
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what is genetic rearrangement or somatic recombination?
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portions of these DNA segments are randomly chosen & joined together, DNA transcribed into mRNA, mRNA is translated into protein (antibody)
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what is IgE?
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levels rise when you have allergic reaction (severe)
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what is the 2nd step in generation of antigen presenting cell?
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large molecules of engulfed bacterium broken down to produce antigens
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what is the 1st step in generation of antigen presenting cell?
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dendritic cell engulds bacterium
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what is a Dendritic cell?
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BM progenitor, WBC of myeloid & lymphoid origin, circulate in blood as immature cell
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what happens during T cell activation?
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Dendritic cell engulfs & degrades pathogen and becomes an APC, APC secretes interleukins which activate T cells to secrete cytokines & then proliferate, producing clones of cell, clonal cells differentiate into helper T cells (assist in activation of B cells)
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what are the phases of the antibody mediated immune response?
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T cell activation & B cell activation/ antibody production
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what is the 7th step in antibody mediated immune response?
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TCR of helper T cell recognizes the specific antigen on B cell & links 2 cells together
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what is the 6th step in antibody mediated immune response?
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BCR binds to antigen on bacterium, bacterium is engulfed and its macromolecules degraded, antigens produced are displayed on cell surface bound to class II MHC proteins
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what are Memory B cells?
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provide immunological memory of antigen encounter
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what are Plasma cells?
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secrete antibodies specific for antigen
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Clonal cells differentiate into which 2 types of cells?
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memory B cells, plasma cells
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what happens during B cell activation/ antibody production?
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recognize antigens on pathogen & engulf it, display antigen on cell surface, TCR on helper T cell activated by same antigen binds to antigen on B cell, Interleukins from T cell stimulate the B cell to produce clone of cells with identical BCRs
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what is the 5th step in antibody mediated immune response?
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cloned cells differentiate into helper T cells
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what is the 4th step in antibody mediated immune response?
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activated T cell secretes cytokines- stimulate T cell to proliferate to produce clone of cells
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what is the 3rd step in antibody mediated immune response?
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The APC secretes an interleukin which activates the T cell
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what is the 2nd step in antibody mediated immune response?
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Bacterial antigens are displayed on APC cell surface bound to class II MHC proteins and presented to CD4 T ccells with TCRs that recognize antigen
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what is the 1st step in antibody mediated immune response?
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bacterium is taken up by phagocytosis and degraded in a lysosome
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what is the 4th step in generation of antigen presenting cell?
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antigen displayed on cell surface bound to MHC protein- cell is now an antigen- presenting cell (APC)
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what is the 3rd step in generation of antigen presenting cell?
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antigens bind to class II MHC proteins
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what is the 9th step in antibody mediated immune response?
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some cloned B cells differentiate into plasma cells, which secrete antibodies specific for antigen, whereas a few differentiate into memory B cells
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what is the 8th step in antibody mediated immune response?
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interleukins stimulate B cell proliferation to produce a clone of cells
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(matching) innate (specificity): nonspecific
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adaptive: specific
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(matching) Innate (memory): has no memory of previous pathogen exposure
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adaptive: remembers previous exposures
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(matching) Innate (response time): within minutes
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adaptive: days
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what is an allergen?
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antigens that elicit hypersensitivity or allergic reaction
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what to allergens induce?
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B cells to secrete an overabundance of IgE antibodies which bind to receptors on mast cells in connective tissue & on basophils
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what do mast cells on connective tissue and basophil secrete?
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histamines
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what is a histamine?
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produces a severe inflammation usually in tissue directly exposed to allergen
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what is step# 1 in response to allergen?
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allergen (antigen) enters the body
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what is step #2 in response to allergen?
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allergen binds to B-cell surface antibodies, B cell now processes the allergen & with stimulation by helper T cell, proceeds through steps leading to cell/ antibody division
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what is step #3 in response to allergen?
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activated B-cell clone produces & secretes IgE antibodies active against allergens
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what is step #4 in response to allergen?
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IgE antibodies attach to mast cells in tissues, which have granules containing histamine molecules. Memory B & T cells capable of recognizing the allergen are also produced
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what is step #5 in response to allergen?
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after first exposure when the allergen enters the body, binds with IgE antibodies on mast cells; binding stimulates the mast cell to release histamine and other substances
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what is a vaccine?
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a biologically safe preparation that induces adaptive (acquired) immunity to a particular disease
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what is an autoimmune reaction?
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have immune system, BUT normal cells are being recognized as foreign and being attacked (own tissue), Occurs with a faulty immune system, “self” cells are recognized as “nonself” so are destroyed
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what is the role of the agent in a vaccine?
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stimulates the body's immune system to recognize the agent as foreign, destroy it, and "remember" it, so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters
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How is the light chain polypeptide formed?
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Two genes, IGK = Immunoglobulin Kappa , IGL = Immunoglobulin Lambda
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How is the heavy chain polypeptide formed?
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One gene, IGH = Immunoglobulin Heavy
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how is antibody diversity (between 1 million to 100 million specificities) achieved with a limited number of genes?
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protein structure, IGH/IGK/IGL transcription of genes to RNA, IGH/IGK/IGL forms template for transcription
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do genes encode for multiple proteins?
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yes
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where can a heavy chain be bound to?
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light chain
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do the 2 light chains have the same function?
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no
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what is another word for B lymphocyte (white blood cell)?
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B cell
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what is another name for T lymphocyte (white blood cell)?
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T cell
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what is the IGK structure?
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what is the IGL structure?
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what is the IGH structure?
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what is the structure of V,D, J segments in IGH/IGK/IGL genes?
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what is DNA somatic rearrangement?
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pick a V, D, and J. they are cut, re-arranged and therefore affecting your protein. What happens in my cells is different then someone else’s cells, the choices are random.
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what does choosing a certain segment effect?
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protein transcription and translation and affects antibody that is produced
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how many different ways can IGH be formed?
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40 x 25 x 6= 6,000
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How many different ways can IGK be formed?
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40 x 5= 200
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How many different ways can IGL be formed?
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30 x 4= 120
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How many different ways can V(D)J recombination occur & form an antibody with IGH & IGK polypeptides?
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6000 x 200= 1,200,000
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How many different ways can V(D)J recombination occur to form an antibody with IGH & IGL polypeptides?
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6000 x 120= 720,000
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How many different ways can V(D)J recombination occur to form an antibody?
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1,200, 000 + 720, 000= 1,920,000
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how many possible antibodies are their if V,D,J recombination occurs & there are 8 possible combinations for alleles?
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1,920,000 x 8= 15,360,000 or 1.5 x 10^7
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what is DNA recombination?
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Intrachromosomal DNA crossing over (happens inside of the chromosome), deletion of material between, Causes DNA template, RNA transcript & protein to be smaller than expected
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what is mosaicism?
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denotes the presence of two or more populations of cells with different genotypes in one individual who has developed from a single fertilized egg
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is deletion that occurs in DNA recombination the same as splicing introns in RNA?
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no
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what is a T cell receptor?
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multimeric protein
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Is there antibody diversity between different people?
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yes, maternal and paternal chromosomes inherited are NOT identical therefore we are NOT all the same in terms of immune system
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Is there antibody diversity differences between identical twins?
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Yes, as each can pick different V, D, J combos
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Why do we study SNPs in the body?
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Look at SNPS because see association to disease, drug response, etc. in body (which drugs can and can’t take, etc.)
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how are researchers able to distinguish stem cells?
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have 3 transcription factors that are specific to stem cell, repressed genes from differentiating , can differentiate from different types of specialized cells
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what are the basic 3 types of immunology?
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first line of defense (base line), inherited things (innate, hereditary, inflammation, complementary proteins), acquired/ antibody formation
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if you have different foreign objects entering body, how do you defend yourself against these objects?
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antibody is formed, stretch of DNA, at DNA level chunks are added/deleted which alters DNA/ transcripts & proteins (formation of heavy/ light chains are being altered)
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what is Messleson- Stahl Experiment fpr semi- conservative replication?
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1 strand is completely parental, one strand is completely new (parental strand is used as a template)
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what is Messleson- Stahl experiment for conservative replication?
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start with 2 parental strands, somehow at replication fork the parental remain intact and the new strands coming in don't use parental strands as templates (act like clones)
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what is Messleson- Stahl Experiment for dispersive replication?
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parental strands are chopped, each helix has chunks of parental and newly synthesized strands
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