Unit 4- Bacterial Genetics+Epidemiology Flashcards
Define Lariate
A ring of intron segments that have been spliced out of mRNA by enzymes
5’ Guanosine Cap Function
protects the nascent mRNA from degradation and assists ribosomes in binding during translation
Spliceosome (Function)
RNA-Protein complex that recognizes the exon-intron junctions and enzymatically cuts through them (RNA Splicing)
Poly-A Tail Function
@ the 3’ end, the Poly A Tail is added when elongation is complete. It protects mRNA from enzyme degradation
Role of Transcription factors and RNA Polymerase in transcription
A Family of proteins that function in a multi-subunit complex that can bind to the promoter on DNA or directly to RNA Polymerase. They can activate or repress transcription
Sense Strand of a gene
The strand that holds the coding sequence for a particular gene
The antisense strand of a gene
the strand that holds the complement of the coding sequence for a gene
Define Codon
A Sequence of 3 nucleotides that together form a unit of genetic code in a DNA or RNA molecule
Define Anticodon
a sequence of 3 nucleotides forming a unit of genetic code in a tRNA molecule corresponding to a complementary codon in mRNA
Structure of ribosomes
Made of rRNA (Ribosomal RNA), site of translation, form ribosome-protein complex
A Site on the Ribosome
Aminoacyl site, which adds the amino acid to the polypeptide chain
P Site on the Ribosome
Where the Peptidyl tRNA is formed in the ribosome
E Site on the Ribosome
Exit site for the polypeptide chain
How are Amino Acids linked togehter by the ribosome?
Translation: Amino Acids opposite the codon (tRNA) will align at the A, P, and E Site to create a polypeptide chain out of amino acids.
Wobble in the Genetic Code
The Genetic Code’s third codon is usually coding for the same amino acid, relating to the degeneracy of the code
Point Mutation
Single-nucleotide switches/replacements
Silent Mutation
Codes for the same amino acid with a nucleotide switch
Missense Mutation
Cause another Amino Acid to be coded
Frameshift Mutation
Can cause a reading frame offset and cause a nonsense or missense mutation
Nonsense Mutation
Causes a stop codon to be generated
Back Mutation
Reverses a mutation from its abberant state back to its normal state
Ames Test
A test to determine the mutagenic activity of chemicals by observing whether they cause mutations in simple bacteria
Define Operon
A section of DNA that contains one or more structural genes along with a corresponding operator gene that controls transcription
Regulator in an operon
Turns the operon on/off in response to lactose and glucose levels
Repressor in an operon
Stops transcription and acts as a lactose sensor , will come off when the activator is present
Inducers
Triggers expression of a gene or operon
Semiconservative replication
The strand that serves as a template is an original parental DNA strand that is retained in the daughter molecule
DNA Template
The strand in a DNA Molecule that is used as a model to synthesize a complementaty strand of DNA or RNA during replication or transcription
Replication Fork
Y-Shaped point on a replicating DNA molecule where DNA polymerase is synthesizing new strands of DNA
Leading strand
Strand being replicated continuously
Lagging strand
strand replicated backwards in Okazaki fragments
Continuous strand
Replicated smoothly in one piece
Discontinuous strand
Replicated in Okazaki Fragments
How are Okazaki fragments put together
DNA Ligase
Okazaki Fragments
A Segment formed on the lagging strand where biosynthesis is conducted in a discontinuous manner as required by DNA polymerase’s orientation
DNA Polymerase I role in DNA Replication
Removes RNA Primers, replaces gaps in Okazaki fragments
DNA Polymerase II role in DNA Replication
Adds bases to new DNA Chain; Proofreads the chain for mistakes
DNA Ligase role in DNA Replication
Binds Okazaki fragments together
DNA Gyrase/topoisomerase role in DNA Replication
performs a double-stranded cut to prevent supercoiling when the Double-Helix is unwound for replication
RNA Primase role in DNA Replication
Synthesizes an RNA Primer
DNA Helicase role in DNA Replication
Unzips DNA double-Helix for replication
SSBP-Single-Stranded binding proteins’ role in DNA Replication
Binds to single-stranded DNA and prevents annealing of single-stranded DNA into double-stranded DNA, also prevents single-stranded DNA from degredation
Plasmids
Small, circular pieces of DNA, can bear genes that code for adaptive traits
Resistance Plasmids
Bear genes for resisting antibiotics
Virulence Plasmids
Increase Virulence (adherence), turn the bacteria into pathogens
Fertility Plasmids
Directs the synthesis of a sex pilus
Restriction Enzymes
Cleaves DNA molecules at or near a sequence of bases usually create overhangs
Restriction Site
Sites where restriction enzymes will cut the DNA (Double-Stranded cut)
Degenerative Disease
Common non-infectious diseases whose incidences increase with age.
Genetic Disease
An inherited medical condition caused by a DNA abnormality.
Infectious Disease
A disease caused by a pathogen and can be transmitted in many ways
Direct Mode of Transmission of a disease
Direct contact or Droplet spread
Indirect Mode of Transmission of a disease
Airborne, Vehicle Borne, or vector-borne(mechanical or Biological)
Mechanical Vector
a vector that does not require the host to complete its life cycle (Flies)
Biological Vector
a vector that requires the host to complete its life cycle (Mosquitoes, Ticks)
Source of Resivoir
The habitat in which the infectious agent normally lives, grows, and multiplies/ Can include humans, animals, and the environment
Communicable Disease
Can be transmitted by direct contact or indirect contact (Infectious agent)
Non-Communicable Disease
A medical condition whose disease is not caused by an infectious agent. can be chronic diseases which last a long time and progress slowly
Type I Survivorship curve
High probability of surviving through early and middle life, but die later
Type II Survivorship curve
Consistent mortality throughout life. Chances of dying are independent of age.
Type III Survivorship curve
Few individuals live to adulthood and die as they get older. Most death is early
Factors responsible for increased survivorship (Type II to Type I) in the U.S. in the 20th Century
Cleaner Water Cleaner sanitation/ Septic systems Cleaner personal Hygeine
Describe the role of the CDC in tracking and limiting the spread of infectious diseases
All cases of transmitted diseases are reported by physcians and practitioners by law, and they’re documented in a weekly report
MMWR by the CDC
Morbidity and Mortality weekly report- Weekly epidemiological digest for the U.S. published by the CDC. It contains notifiable diseases and mortality table
Prevalence of a disease
accumulated total of existing cases with respect to the entire population (# of cases/person)*100
Incidence of disease
of new cases over a certain time period, as compared with the general healthy population ( New Cases/# Susceptible)
Endemic
Exhibits a steady and predictable frequency over a long time and is contained in a geographic locale
Epidemic
Region or nationwide spread of disease