Prokaryotic Genetics and Immunology Flashcards
What are the four base pairs of DNA? What are the two categories? which one is which? Which one pairs which which?
Bases = GCAT = Guanine, cytosine, Adenine, Thymine
Purines = double ring, adenine and guanine
Pyrimidines = single ring, cytosine and thymine
What is the difference between a guanosine, a guanine base, a guanine nucleotide (dGMP), and a guanosine triphosphate deoxyribosnucleotide (dGTP)? which become DNA?
Guanosine= a guanine base + a deoxyribose
Guanine base = just the nitrogen ring
dGMP = base + deoxyribose + 1 phosphate (this is what becomes the DNA stucture)
dGTP= full building block. This is used in synthesis
which way is new DNA synthesized? 3’ and 5’
synthsised 5’ to 3’
What three functions does DNA methylation serve? which nucleotide is typically methylated?
Adenines are typically methylated. Methylation controls genetic expression, initiation of DNA replication, and protects against viral infection
What is the limiting metabolite in binary fission?
nucleotides
What is the difference between RNA primers, mRNA, rRNA and tRNA?
RNA primer = created by primase, starts DNA replication by allowing DNApol to start
mRNA = carries genetic info from the DNA to the ribosome. Created by RNApol (complementary to OG DNA)
rRNA = a structural component of ribosomes
tRNA = carries specific amino acids to ribosome
What are the three steps of transcription?
1) initiation
2) elongation
3) termination
What are the two types of transcription termination?
1) self-termination: DNA terminator causes RNA to fold (C-G rich hairpin loop)
2) Enzyme-dependent termination: Rho protein pushes between pol and DNA along the RNA strand
What are four differences between Eukaryotic transciption and prokaryotic transcription?
1) Occurs in the nucleus of Eurkaryote, mitochondria, or chloroplast
2) Three types of RNApol
3) numerous transcription factors
4) mRNA processing : capping, polyadenylation, splicing
Bacterial DNA replication begins at the :
orgin
Where does transcription happen (in prokaryotes)
nucleoid
What are special features of a bacterial mRNA strand?
1)Multiple genes per a mRNA
2) multiple polypeptides per a gene
3) no capping or splicing of mRNA once complete
4)Ribosomal splicing sites for cutting
5)Multiple ribosomes per an mRNA molecule
What are the two components of rRNA? what is the prokaryotic and eukaryotic forms?
prokaryotic: 70S (Smaller and odd)
Eukaryotic: 80S (larger and even)
Large and small subunits
What’s an operon?
An operon is a set of promoter, operator, and genes regulated by an up steam regulatory gene
What is conjugation (prokaryote)? Transduction? Transformation?
Conjugation: transfer of genetic material (plasmid) between bacterial cells via cell (F+ to F- cell) to cell contact
Transduction: when a bacteriophage infects the genome of the bacterial cell. Typically its bacterial genome that has been picked up in the phage formation
Transformation: When bacteria uptake genetic material from environment. Only component bacteria can do this.
What are the two types of mutations?
1)Point mutations: silent, missense, nonsense
2) frameshift mutations
What is the innate and adaptive immune reponse?
Innate: non-specific, rapidly mobilized, lack memory
Adaptive: specific to pathogen, can confer protective immunity (antibody response), Specific pathogen recogition
Which three components are used by both innate and adaptive immunity
Major histocompatibility complex(MHC), cytokines, and the complement system
What is the difference between MHC I and II?
-both mediate leukocyte - leukocyte interaction
-MCH I: displays endogenous antigens. Common with CD 8 T cells/cytotoxic
-MCH II: displays exogeneous antigen, Common with CD4 T cells/helper T cells
what is the complement system?
- A collection of proteins in the blood that start the immune system activation in areas of infection
What are the four MOAs of the complement system
-Chemotaxis: makes phagocytes move to soluble factor
-cytolysis: lysis of infected cells release fragments that B and T cells can use
-Opsonization: microorganism and/or antigen+antibody complexes are phagocytized
-Anaphylatoxin: promotes vasodilation and vascular permeability via C3a and C5a protein
What are the four types of cytokines
1) Interferons (IFNs)/immunoregulatory: important against viruses/intracellular pathogens
2)Proinflammatory:
3)anti-inflammatory
4)colony stimulating factors (CSF) and stem cell factors : for immune cell growth and differentiation
What are the three complement pathways? what do they do?
All form a membrane attack complex that causes infected cell lysis, sets infected cells up for phagocytosis
1) classical pathway: triggered by antibodies bound to antigen
2) alternative pathway: activated by microbial surfaces
3) lectin pathway: activated by proteins binding to lectin on pathogen surface
What are the main function of Cytokines
low-molecular but potent signaling chemicals for cell defense
WHat are the three key features of the innate immune reponse?
Rapid, non-specific, short duration
What are the components of the innate immune reponse
1)Physiological: skin, membranes, secretions
2) immne components: cells and stuff
What does lysozyme do?
dissolves bacterial cell walls. On/near skin surface
What is secreted from glands to stop bacterial infection?
pH acidic, fatty acids
What are the three MOA that the respirtory tract use to stop infection?
1) mucous: bacteria sticks to it. Lysozymes dissolve it, and cilia move it to the stomach
2) IgA (on most mucosal tracts): prevents bacterial attachment (binds to IgA instead of host)
3)Normal flora: outcompetes bad flora
What are the protective mechanisms of the GI tract?
1)Salivary glands: hydrolytic enzymes
2) stomach: low pH
3) small intestines: proteolytic enzymes
4)Normal flora
What are microbial sensors (innate immunity)
-present on macrophages/phagocytic cells.
-Three group: TLRs, NLR, RIG-1-like helicases
-patter recognition receptors (PRRs) that can recognize pathogen associated molecular patterns (PAMPs)
-help innate inflammatory response
- Can be on surface (TLRs) or in cytoplasm looking for products (NOD-like)
What are the three types of phagocytic cells?
1)macrophages
2) Granulocytes (PMN leukophytes)
3) Dendritic
What are the four functions of phagocytic cells
1)Chemotaxis
2) Migration
3) ingestion
4) microbial killing
What is a monocyte? what is a macrophage?
1)Monocyte: Small nacecent macrophage. leukocyte. in blood
2) macrophage: regulate immune activity (cytokine and chemokine activity), FINISH
Which granulocyte is phagocytic
-PMNs (neutophils)
What are the function of Dendritic cells?
-phagocytic: should eat and degrade pathogens
-activating T cells via regulatory cytokines and antigen presenting
What are the functions of natural killer cells?
-large granular lymphocytes
-part of the adaptive immune response as well as the innate
- recognized virus infected cells and tumor cells and triggers apoptosis
What are the two major types of cells in adaptive immunity?
1)B cells : turn into plasma or memory B cells
2) T cells: become adapted to specific pathogens. Become cytotoxic or helper cells
WHat is the cell-mediated response of the adaptive immunity
-activation of phagocytes, helper (CD4) T cells, CD8 (antigen specifc) Tcells)
What is the humoral response of the adaptive immunity
-Phagocytosis leads to antigen production and formation.
-Antigens created by B cells neutralizes the pathogen and marks them
What is cell-mediated adaptive immunity?
-T-cells directly attack infected cells, leading to apoptosis
What does IgG do?
-Small, but most abundant in blood and ECF
-mediates opsonization of antigens, complement system, and toxin neutralization. Can cross to fetus
WHat does IgM do?
-Found in blood and lymph
-First antibody produced during a new infection. Activates complement system
What does IgA do?
-Found in mucosal areas
-protects vulnerable areas by allowing pathogen attachment to it instead
What is the primary immune response? what is the order of antibody production
When you encounter a brand new antigen.
Order of antibody production: IgM, IgG, IgA
Which immunoglobulin is ussed in aggulination assays?
IgM. Very strong response due to five binding sites
What does IgE do?
-Found in skin and mucous membranes
-important in allergen medation
What are the protective functions of antibodies? (6) Give examples
-Neutralization: think IgA and mucosal immunity, as well as toxin neutralization
-opsonization: coating pathogens for phagocytes later
-complement activation: IgM and IgG
-agglutination
-cellular cytotoxicity: NK cells
-complemented mediated lysis
What are the characteristics of a secondary immune response?
-Rapid response, higher antibody titre
-IgM production is consistent, IgG is produced more and longer
what is the difference between CD8 and CD4 T cells? What are there roles?
CD8: cytotoxic T cells. Recognize MHC I via T cell Receptors (TCRs)
CD4: helper T cells. Activates B cells to produce plasma cells (effector cells) and memory cells
Differences (3) between NK T cells and CD8/cytotoxic T cells?
NK: not antigen specific, typically go after tumors/virus infected cells because of this
Cytotoxic: antigen specific (must be correct antigen in MHC I),
Does tissue injury or fever use cytokines or endotoxins
injury -> cytokines, prostaglandins, leukotrienes
fever -> endotoxins
What are the five mechanisms of innate immunity?
-Microbial sensors:
-Phagocytosis:
-NK cells:
-complement system:
-cytokines:
Where would obligate aerobes, obligate anaerobes, facultative anaerobes, and aerotolerant anaerobes lie in a tube of agar?
obligate aerobes: at the head of the agar
obligate anaerobes: at the butt of the agar
facultative anaerobes: concentrated at the head, but diffuse throughout
aerotolerant anerobes: diffuse growth throughout
Fermentation takes ___ from glycolysis and turns it into ___ and ____
It takes pyruvic acid and turns it into lactic acid and ethanol
What are the three tRNA binding sites inside of the ribosome?
E, P, A.
E- where tRNA exits
P- where amino acid is linked to it
A - where new tRNA enters and amino amino acid is linked to polypeptide chain
what MHC receptor does NK cells recognize? What do they do if they do find the receptor?
MHC I. If they do find the receptor, they do nothing. If they don’t find the receptor, they are activated to release cytokines and cytotoxic mediators
What are the similarities and differences between TLRs, NLRs, and RLRs?
Toll-like receptors: detect exogenous PAMPs. Leads to cytokine production
NOD-like receptors: Detect intracellular PAMPS and DAMPs. Leads to inflammation
RIG-like receptors: detect viral intracellular RNA. starts interferon and cytokine production
