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
Sporadic
occasional cases and irregular intervals in widely dispersed locations
pandemic
worldwide spread of disease
ICeberg Effect of disease
All cases of a disease are not reported because of a lack of access to care or people not going to the doctor with symptoms
Morbidity
Number of people afflicted with infectious diseases
Mortality
Number of deaths in a population due to a certain disease
Epidemiology
The effects of diseases on the community
Disease Etiology
Cause, set of causes, or manner of causation of a disease or condition
Fomites
An inanimate object that harbors and transmits pathogens
Oral-Fecal Route of disease transmission
Contaminated feces from an infected person are somehow ingested by another person
Food route of disease transmission
Food Poisoning, foodborne pathogens, recreational drinking water, animals, or their environment, and person to person spread
Air Droplet Nuclei route of disease transmission
Spread when droplets of pathogens are expelled into the air from coughing, sneezing, or talking
Nosocomial infection
Hospital-Acquired Infection (HAI)
PPE (Personal Protective Equipment)
Gloves, masks, gowns, etc. to help prevent the spead of disease from patient to Healthcare provider and vice versa
Physical control of microbial growth
heating, refrigeration, freezing, high pressure, autoclave
Chemical control of micribial growth
antiseptic, antibiotics, disinfectants
How to clean an inanimate object
Disinfectant
How to clean live tissue
Antiseptics
Antibiotics are used where and how?
inside the body
Antiseptics are used where and how?
Outside the Body
Koch’s 1st postulate
The microorganism must be found in abundance in all organisms suffering from the disease, but not be found in healthy organisms.
Koch’s 2nd Postulate
The microorganism must be isolated from a diseased organism and grown in a pure culture.
Koch’s 3rd postulate
The cultured microorganism should cause disease when introduced into a healthy organism.
Koch’s 4th postulate
The microorganism must be reisolated from the inoculated, diseased host and identified as being identical to the original microbe.
Skin/Mucosa as an entry portal for a microbes
Broken skin, eyes, mouth, ears, nose
Urogenital Mucosa as an entry portal for microbes
Urination, sexual transmission (fluid), sexual contact
Gastrointestinal Mucosa as an entry portal for microbes
Food, Water
Placenta as an entry portal for microbes
Certain diseases can pass from the mother through the placenta to the child (Rubella, Mumps, Syphilis, Malaria, CMV, and Herpes.
Respiratory Tract/Mucosa as an entry portal for microbes
Breathing in the pathogen to the respiratory tract
Stages of the infection process
Exposure Invasion Symptoms Adherence Multiplication Exit
Exposure in the infection process
First encoutner with the pathogen at an entry site (Portal of entry_
Invasion in the infection process
Dissemination of a pathogen throughout local tissues or the body pathoens may produce exotoxins/exoenzymes, which increase virulence
Symptoms in the infection process
Coughing, sneezing, runny eyes, vomiting, etc. as documented and reported by the patient
Adherence in the infection process
Pathogen adheres to the portal of entry. Capability of microbes to attach using adhesion (Fimbriae, Biofilm, slime layer)
Multiplication in the infection process
Local, focal, or systemic infection
Exit in the infection process
Pathogen exits the host and is transmitted to a new host
Latent infections
Asymptomatic infection capable of manifesting symptoms under circumstances or if activated
Asymptomatic Infections
The patient is a carrier for a disease, but no symptoms are present
Subclinical infection
No recognizable clinical findings
Source of infection
The Pathogen
Reservoir of infection
environment the pathogen lives in normally and reproduces
Carrier of infection
Infected but asymptomatic/ Can be the vector
Vector
Caused by a parasite
Primary vs Secondary infection
Primary infection is present and reduces immune response. Secondary infection can be more deadly due to weakened immune system (Pneumonia secondary to HIV was cause of death)
Communicable dieases
Infectious agent caused the disease
non-communicable diease
genetic or chronic disease with no infectious agent
Localized infection
An infection that affects only one body part or organ is called a localized infection
Systemic Infection
An infection that is in the bloodstream or organ system
Direct transmission of disease
Direct contact required
Indirect transmission of disease
Airborne or Droplet
Acute infection
new onset symptoms
Chronic infection
Long-Developing condition
Sign of an infection/disease
observable by others
Symptom of an infection/disease
only subjective evidence of a disease, noted by the affected individual
Living Reservoir of a pathogen
Humans, Animals, Plants
Nonliving reservoir of a pathogen
Water, soil, food
What is the importance of mosquitos, ticks, and fleas in the transmission of disease
Parasites which can transmit pathogens during their life cycles
Minimun infectious dose
As the dose increases, the severity of the pathological effects increases (Dose- # of bacteria) = Concentration (# of bacteria/gram) x Mass (grams)
Structures used by pathogens in the process of adherence
Flagellae, fimbriae, glycocalyx, slime layer, capsule, hooks, suckers
Hooks and suckers are only present in what type of cells?
Eukaryotic pathogens
Extoxins are produced by what type of cells
Both Gram (+) and (-)
Endotoxins are produced by what type of cells
Gram (-) Only
Neurotoxins
Affect the Brain, Spinal Cord, and nerves
Hepatotoxins
Affect the Liver
Hemotoxins
Affect the blood
Enterotoxins
Affect the GI Tract
Nephrotoxins
Affect the Kidneys
Myotoxins
Affect the muscles
Exoenzyme
enzyme that acts outside the cell that produces it; begins the process of extracellular digestion. Digests molecules via hydrolysis
Mucinase
Hydrolyzes Mucins
Keratinase
Degrades insoluble Keratin Substances
Collagenase
Breaks peptide bonds in collagen (Virulence factor), destroys the extracellular structures in pathogens
Hyaluronidase
degrades hyaluronic acid
Coagulase
Brings about coagulation of blood or plasma, caused by stapylococcus
Steps in the progression of disease states
Incubation Prodrome Invasion Period Covalescent Period
Incubation period of disease progression
After entry of the pathogen into the host, it multuplies
Prodrome period of disease progression
The Pathogen continues to multiply, host experiences signs and symptoms of illness, immune responses
Invasion period of disease progression
Signs and symptoms are most obvious and severe
Convalescent period of disease progression
Patient returns to normal functions, though some diseases may inflict permanent damage the body cannot repair
Define Sequelae
A condition that is the consequence of a previous diease or injury( Chronic condition resulting from an acute condition)
Inflammation in the infection process
Indicates an immune response in the prodrome period of disease progression
Identify the Lesion Type
Bullae
Identify the Lesion Type
Carbuncle
Identify the disease
Meningitis/Encephalitis
Identify the Lesion Type
Furuncle
Identify the Lesion Type
Hematoma
Identify the Condition
Hepatitis
Identify the Lesion Type
Macule
Identify the Condition
Meningitis/Encephalitis
Identify the Skin Lesion
Papule
Identify the Lesion Type
Petichiae
Identify the Lesion Type
Pustule
Identify the Lesion Type
Ulcer
Identify the Lesion Type
Urticaria (Hives)
Identify the Lesion Type
Verruca (Warts)
Ignaz Semmelweis
Hungarian Physician - Estabished a connection between the incidence of pueperal fever (Streptococcus) and mortality and suggested changes in hygiene that reduced the rate of the latter.
Joseph Lister
Developed methods for reducing the incidence and severity of hospital-acquired infections through improvements in hygiene
and aseptic practices.
Alexander Fleming
Discovered lysozyme and penicillin; awarded a Nobel Prize in 1945.
Louis Pasteur
Demonstrated the chirality of molecules; verified the germ theory of disease; developed a method to prevent the spoilage of liquids through heating; played important roles in the development of anthrax and rabies vaccines.
Robert Koch
Made advances in the isolation and culturing of micro-organisms; helped to identify the causative agents of anthrax, tuberculosis and cholera; played an important role in the development of epidemiology with his “postulates.
Ferdinand Cohn
Created a system for classifying bacteria based on their morphology; demonstrated that a bacterium (Bacillus) can produce a very resistant cell (endospore) when subjected to stressful environmental conditions.
Paul Ehrlich
Established the fields of immunology/hematology; developed an effective treatment for syphilis through careful screening of compounds; awarded a Nobel Prize in 1908.
Martinus Beijernick
Established the field of virology (working with tobacco mosaic virus); discovered nitrogen fixation and (anaerobic) cell respiration in bacteria; made improvements in bacterial culture methods.
