Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
61 Cards in this Set
- Front
- Back
|
What is the disease triangle?
|
Host/Organism/Environment
|
|
|
Name the HOST factors that affect the disease triangle?
|
- age
-sex -immune status -pregnancy -genetics |
|
|
What ORGANISM factors affect the disease triangle?
|
-size of inoculum (dose)
-site of inoculum -virulence determinants |
|
|
What ENVIRONMENTAL factors affect the disease triangle?
|
-temperature
-humidity -ventilation -overcrowding -diet |
|
|
List key differences between eukaryotes & prokaryotes.
|
EUKARYOTES (ANIMALIA)
Multi-cellular Membrane-bound organelles Chromosome in organelles Cytoskeleton NO cell wall Large (5 to 20 μM) PROKARYOTES (EUBACTERIA) UNIcellular NO membrane bound organelles in cytoplasm Chromosome in cytoplasm Transcription/translation take place in cytoplasm NO cytoskeleton Cell wall contains peptidoglycan (unique to prokaryote) Exception: Mycoplasma Small (0.1 to 5 μM) |
|
|
Name the 4 types of prokaryotic cells.
|
Coccus
Bacillus Spirochete Pleomorphic |
|
|
Describe the shape of each of the following cells.
a. Coccus b. Bacillus c. Spirokette d. Pleomorphic (all possible) |
a. sphere
b. rod c. spiral d. Coccobacillus Curved Rod club-shaped rod filamentous |
|
|
Name the 3 different types of prokaryotic cell arrangements.
|
Pairs:Diplococcus
Chains: Dashed line Clusters: bunch of grapes |
|
|
The cell envelope is made up of what structures?
|
Cell wall
Periplasm Inner cell membrane |
|
|
Name 5 important functions/properties of the cytoplasm.
|
Contains chromosome(s)
DNA replication RNA synthesis Protein synthesis Metabolic processes |
|
|
What is important about the cells inner membrane?
|
contains the lipid bilayer
Permeability barrier Uptake system (e.g. nutrients, minerals, ions, amino acids, etc) Export systems (e.g. minerals, ions, antibiotics, etc) Electron transport Cell wall synthesis Protein translocation |
|
|
What are the key characteristics of the periplasm.
|
Contains enzymes catalyzing formation of disulfide bonds
Contains proteins participating in small molecule transport or break down of polymers to bite-size compounds Contains protein-folding and trafficking factors that build and maintain cell envelope Sensing domains of histidine-kinases reading environmental cues Viscous, oxidizing environment |
|
|
What important molecule is found in the prokaryotic cell wall.
|
Peptidoglycans
|
|
|
Describe the structure of a Peptidoglycan.
|
Alternating molecules of two sugars:
N-acetyl glucosamine (NAG) N-acetyl muramic acid (NAM) Linked to one another through ß (1,4) glycosidic bond Pentapeptide linked to NAM NAG-NAM strands linked to one another through pentapeptides |
|
|
What is NAG?
|
N-acetyl glucosamine
|
|
|
What is NAM?
|
N-acetyl muramic acid
|
|
|
NAG-NAM strands are linked to one another by _________.
|
pentapeptides
|
|
|
What is the functions of the cell wall?
|
Gives cell shape and structural strength counteracts osmotic pressure from cytoplasm and prevent cell from blowing up
cell division |
|
|
What substance is found in the cell wall of Gram positve bacteria?
|
Lipoteichoic acid
|
|
|
Which is thicker, the cell wall of a gram negative or gram positive bacteria?
|
Gram positive cell wall is thick
|
|
|
Which type of bacteria has a thin outer membrane beyond the cell wall?
|
Gram Negative
|
|
|
What is LPS and what is its significance?
|
LSP= lipopolysaccharides
Essential component of gram negative bacteria outer membrane, acting as a barrier for toxic compounds. Upon death or degredation of the cell, LPS becomes an endotoxin to eukaryotes |
|
|
What is the gram stain protocal?
|
Fixation> Crystal Violet> Iodine>Decolorization> Safranin
|
|
|
Name the 3 prokaryote growth characteristics
|
Temperature
Nutrients Atmosphere |
|
|
What is a ...
a. Thermophile b. Hyperthermophile c. Mesophile d. Psychrophile |
An organism whos prefered temperature for growth is
a. >45°C b. >80°C c. 25-40°C d. 0-20°C |
|
|
The vast majority of infectious agents prefer which temperature gradient for growth?
|
Mesophile 25-40°C
|
|
|
A FASTIDIOUS organism requires no supplemental nutrition for growth. TRUE or FALSE?
|
FALSE
|
|
|
What are the oxygen requirements of the following:
Aerobe Anerobe Facultative Microaerophile |
requires oxygen
oxygen is toxic not oxygen dependant requires sm amts of oxygen |
|
|
What portion of a prokaryotic cell is composed of polysaccarides and provides protection from immune invasion?
|
Capsule
|
|
|
What function does Flagellum provide for the cell?
|
Motility
|
|
|
What is the difference between Polar and Peritrichous
flagellum? |
Polar are located at either end (pole) of a cell and peritrichous are located all over the body of the cell
|
|
|
What are Pilus and what is its function(s)?
|
Surface associated molecule
Function: cell adherence and up take of DNA |
|
|
Prokaryotes can be divided into groups based on:
|
Shape
Structure of cell envelope Growth Characteristics Surface Associated Molecules |
|
|
Describe the differences between Gram Positive and Gram Negative bacteria
|
Gram +: thick peptidoglycan layer, no OM, lipoteichoic acid
Gram - : thin peptidoglycan layer, outer membrane, LPS (endotoxins) |
|
|
What is acid fast stain?
|
The acid-fast stain is a differential stain which distinguishes organisms with waxy cell walls that can resist decolorization with acid alcohol.
|
|
|
Name an organism that requires identification using an acid fast stain.
|
Mycobacterium
Corynebacterium |
|
|
Surface- Associate molecules
(General) |
- Capsule
- Flagellum - Pilus |
|
|
DNA is
|
- a long, double-stranded, helical molecule composed of building blocks called deoxyribonucleotides
|
|
|
A deoxyribonucleotide is composed of
|
a molecule of the 5-carbon sugar deoxyribose
a nitrogenous base phosphate group |
|
|
deoxyribose (a pentose sugar)
|
|
|
Nitrogenous base
|
Adenine
Cytosine Guanine Thymine (or Uracil) |
|
|
Direction of Bacterial DNA replication
|
bidirectional from a single origin of replication
|
|
|
Steps of bacterial DNA replication
|
1. uncoiling the helix (helicases)
2. Separation of the strand by breaking hydrogen bonds between the complementary bases (single stranded DNA binding proteins) 3. Synthesizing 2 new strands by complementary base pairing (DNA polymerases, 5’→ 3’) 4. DNA gyrase and topoisomerases restore supercoiled state of DNA |
|
|
organization of the bacterial chromosome
|
-Most form one long single molecule of double stranded, helical, supercoiled DNA, forms a physical circle
-Some bacterial are linear - not membrane bound (free floating in the cytoplasm) |
|
|
Bacterial transcription and translation occur simultaneously because
|
there are no nuclear membranes separating ribosomes
|
|
|
Plasmids
|
Extrachromosomal circular DNA molecules capable autonomous replication; independent of chromosome
|
|
|
Why are plasmids important in DNA replication?
|
They are transmissible, specify virulence factors, and or antibiotic resistance
|
|
|
Chromosomal DNA of eukaryote is
|
- diploid
- Membrane-bound - DNA is separated from ribosomes - transcription/translation cannot occur simultaneously - Linear and contains several origins of replication - Plasmids are uncommon |
|
|
GENE
|
a sequence of deoxyribonucleotide bases along one strand of DNA that codes for a functional product (i.e. mRNA, tRNA, or rRNA).
|
|
|
OPERON
|
set of adjacent structural genes whose mRNA is synthesized in one piece, plus the adjacent regulatory signals that affect transcription of the structural genes
|
|
|
REGULON
|
a collection of genes (grouped together in operons) under regulation by the same regulatory protein though they are not physically close to one another on the chromosome
|
|
|
Transcription is initiated by
|
the recruitment of the RNA polymerase to the promoter region of the gene by sigma factors
|
|
|
mRNA is synthesized by
|
complementary base-pairing of ribonucleotides with deoxyribonucleotides by the RNA polymerase (5’→3’)
|
|
|
RNA polymerase initiates and terminates ______________.
|
transcription
|
|
|
The product of a gene is usually
|
RNA
|
|
|
ultimately results in synthesis of a protein
|
mRNA
|
|
|
mRNA is divided up into
|
codons
|
|
|
A codon is
|
a series of THREE consecutive nucleotides coding for one specific amino acid
|
|
|
mRNA is translated into proteins by
|
ribosomes
|
|
|
Ribosomes are made of
|
62% RNA and 38% protein.
|
|
|
2 subunits that make up bacteria ribosomes
|
30S + 50S
|
