Microbiology Unit 6 Flashcards
What 3 non-chromosomal sites contain DNA?
- Mitochondria
- Chloroplasts
- Plasmids
Children inherit their mitochondrial DNA entirely from which parent?
Mother
What form do bacterial chromosomes take?
A single loop of DNA floating in the cytoplasm
3 types of genes
- Structural genes (code for proteins)
- Genes that code for RNA
- Regulatory genes (control gene expression)
What is the base of a DNA nucleotide made of?
Deoxyribose
What are the 3 components of a nucleotide
Nitrogenous base
Sugar (Ribose or deoxyribose)
Phosphate group
Nucleotide
A single unit of DNA or RNA
What are the pairings of nucleic acids?
Guanine/Cytosine (3 hydrogen bonds)
Adenine/Thymine (2 hydrogen bonds) (DNA only)
Adenine/Uracil (2 hydrogen bonds) (RNA only)
Purines
Adenine and guanine
Have 2 carbon loops
Bind to pyrimidines
Pyrimidine
Thymine, Cytosine, and uracil
Have 1 carbon loop
Bind to purine
Gyrase
The enzyme that causes DNA to coil tightly
Nucleosome
DNA coiled around a histone protein in eukaryotic cells
Origin of replication
The site of a chromosome where DNA replication will be initiated
Helicase
The enzyme that unwinds and unzips DNA
Primase
Enzyme that establishes RNA primer in DNA replication
DNA polymerase II
Enzyme that adds nucleotides to an RNA primer
DNA polymerase I
Enzyme that removes RNA primers and fills in open sites of new DNA
Ligase
An enzyme that connects nucleotides of DNA after replication
What is the order of events of DNA duplication?
- Helicase unwinds and unzips DNA
- Primase creates an RNA primer over each strand of DNA
- DNA polymerase II adds new nucleotides to RNA primer
- DNA polymerase I replaces The RNA primer base with DNA base
- Ligase connects nucleotides of DNA strands
- Gyrase re-coils DNA
Which nucleotide is replaced w/ uracil in RNA?
thymine
Codon
A sequence of 3 nucleotides that code for a specific amino acid
(or to stop in the case of a stop codon)
RNA polymerase
An enzyme that creates mRNA
Anticodon
A codon on tRNA that binds to a codon (and allows it to bring the needed amino acid)
Wild Type
A natural, nonmutated characteristic
Substitution mutation
A mutation that occurs when one base is swapped for another
3 types of substitution mutation
- missense mutation (one a. acid swapped for another)
- Nonsense mutation (a. acid swapped for stop)
- Silent mutation (base changes but a. acid stays the same)
Conservative vs. Nonconservative Missense protein
Conservative: The resulting protein is still functional
Nonconservative: The resulting protein is nonfunctional
Inversion Mutation
A mutation that occurs when adjacent bases switch places
Usually lethal
Frameshift mutation
The insertion or removal of a base
Point Mutation
Chromosomal Abberation
A mutation that only affects one or a few nucleotides
A mutation that affects an entire gene
4 Types of chromosomal aberrations
Inversion
Gene Relocation
Gene Deletion
Gene Duplication
DNA Polymerase
Mismatch Repair
Excision Repair
An enzyme that “proofreads” nucleotides during DNA replication
Locates and repairs mismatched nucleotides not caught by DNA polymerase
Locates and repairs incorrect sequences by removing the damaged gene and inserting the correct bases
Ames Test
A test used to detect genetic mutation
Genetic Recombination
(And 3 types)
Acquisition and expression of genes acquired from another organism
- Conjugation
- Transformation
- Transduction
Transformation
Acquisition of chromosome fragments from the environment (from lysed cells, etc.)
Transduction
Transfer of DNA via bacteriophage
Transposons
Segments of DNA that can jump from one segment of the genome to another
Streptomyces
Genus of bacteria that resembles fungi
Used to create many antibiotics, including streptomycin and vanc
What 2 genera of fungi are commonly used to make antibiotics
Penicillium
Cephalosporium
Chemotherapy
Treatment, relief, or prophylaxis of a disease by chemical means
Antibiotic
Substance naturally produced by an organism that inhibits or destroys other organisms
What five methods can an antibiotic use to kill/inhibit dividing cells?
(5 drug targets)
- Inhibition of (peptidoglycan) cell wall synthesis
- Breakdown of cell membrane
- Interference w/ DNA/RNA functions
- Inhibition of protein synthesis
- Inhibition of metabolism
Acyclovir
Ribavirin
AZT
Antivirals that blocks formation of new genetic material
Specific to herpes
Replaces guanine, Specific to RSV and hemorrhagic fever
Replaces thymine, specific to HIV
Most common antimalarial drug
3 most common antiprotozoan drugs
Quinine
Flagyl, sulfonamides, tetracyclines
R Factor
Resistance factor
plasmid encoded with drug resistance
5 Types of antibiotic resistance
1 - Drug inactivation (breaks down drug)
2 - Decreased permeability (changes receptor site that admits drug)
3 - Activation of drug pumps (expels drug from cell)
4 - Change in binding site (alters shape of ribosome drug would bind to)
5 - Use of alternate metabolic pathway
Toxinosis
Toxemia
Intoxication
adverse of an affect of a toxin
Toxin spread via blood
Toxin spread by ingestion
A-B Toxins
A pair of toxins working in tandem
B bonds to a cell and allows A entry, A causes the damage
Prevalence (Epidemiology)
Incidence (Epidemiology)
Total number of cases (as a %)
Number of new cases vs. healthy people over a time period
Point-Source
Common Source
Epidemic Comes from a single source (geographically confined)
Epidemic comes from exposure to the same source (widespread)
Propagated Epidemic
Epidemic with sustained increase over time, indicating person-to-person contact
Nosocomial infections/HAIs
Diseases acquired or developed during a hospital stay
Pseudomonas, staph, E. coli common
From reusing gloves, contaminated equipment, exposure to more resistant pathogens
Lysozyme
An enzyme that hydrolyzes the cell wall of bacteria
Defensins
Peptides that lyse bacteria and fungi
PAMP
Pathogen-Assisted Patterns
Molecules that are shared by microorganisms, can be recognized by WBCs
PRR
Pathogen recognition receptors
Receptors on WBCs that recognize PAMPs, molecules on the outside of pathogens
Mononuclear Phagocyte System
Macrophages that attack and ingest microbes that pass the first line of defense
Serum
Liquid portion of blood after a clot has formed
Difference Between Granulocytes and Agranulocytes
Granulocytes have lobed nucleus
Agranulocytes have rounded nucleus
Hemopoiesis / Hematopoiesis
Production of blood cells
3 Granulocytes
Neutrophils
Basophils
Eosinophils
Neutrophil
Granulocyte that phagocytoses invaders
Basophil
Granulocyte that produces histamine and causes allergic reacgtion
Leukocytes
Agranulocytes
Consist of lymphocytes (T- and B-cells), Monocytes, and macrophages
B Cells / B Leukocytes
Leukocytes that produce antibodies
Macrophages
Leukocytes that absorb pathogens
Diapedesis
Migration of cells out of the blood vessels into the tissues
Pyrogens
Chemicals that prompt the body to induce fever
Toll-Like receptor
Receptor on a macrophage that alerts to a foreign body
Phagolysosome
A foreign body inside a lysosome
Breaks down the foreign body
Phagosome
A vacuole containing a foreign body following phagocytosis
Combines w/ a lysosome to create a phagolysosomes
Interferons
Proteins produced by WBCs and tissue cells
Promote antiviral gene expression and suppress cancerous gene expression
3 Types of interferons
Alpha - Produced by lymphocytes/macrophages (stimulates phagocytes)
Beta - Produced by fibroblasts/epithelium (stimulates phagocytes)
Gamma - Produced by T cells (regulates macrophages and lymphocytes)
Complement
26 blood proteins that work in a cascade reaction to destroy pathogens
Immunocompetence
Ability for the body to interact w/ a wide spectrum of foreign substances
MSC / Major Histocompatibility Complex Molecule / Human Leukocyte Antigen
Proteins found on human cells (except RBCs) that allow the immune system to recognize them as self
Also allow for antigen presenting
2 Classes of MHC genes
Class I - Produced “self” antigens
Class II - Allow for antigen presenting
Interleukin-1 / IL-1
Cytokine produced by atingen-presetning cells to activate helper Ts
Interleukin-2 / IL-2
Cytokine produced by helper Ts to activate B and T cells
Perforins and Granzymes
Secretions from killer/cytotoxic T cells that promote cytolysis
Perforin makes a hole in the cell membrane, granzymes enter through hole and cause cell to lyse
5 Types of Immunoglobulins
IgG - Produced by plasma and memory T cells
IgA - Found in blood and mucous/serous secretions
AgM - First line of defense
IgD - Acts as antigen receptor on B cells
IgE - Allergic reactions and helmithns
