Microbiology- Midterm I Flashcards
Properties of Microorganisms M I C R O
M- all microscopic I- independent C- complexity (less) R- rapid growth rate O- omnipresent (almost)
Prokaryotes
- Location of genetic material
- number of DNA
- number of organelles
- presence of cell wall
- type of replication
“before nucleus”
- genetic material floats freely in cytoplasm
- one DNA molecule
- no organelles except ribosomes
- distinct cell wall
- Binary Fission
Two Examples of Prokaryotes
- Archaebacteria
2. Eubacteria (ecoli)
Eukaryotes
- location of genetic material
- number of DNA molecules
- number of organelles
- presence of cell wall
- type of cell division
“True-nucleus”
- genetic material in nucleus
- several varying DNA molecules
- several organelles
- no cell wall
- mitosis and meiosis
Examples of Eukaryotes
- fungus
- algae
- parasite
- protozoan
What is a Virus?
Absolute parasite
- e.g. HIV, Herpes, Hepatitis, Skin viruses
Who Was Louis Pasteur?
- Biogenesis
- life comes from life
- beef broth bent neck flask experiment
- aseptic technique
- pasteurization and fermentation
Who was Robert Koch?
- discovered Anthrax
- causing cattle and human disease
- idea that every unique disease is caused by a unique microbe
Who was Edward Jenner?
- small pox
- fluid from cow pox injected into subject (early vaccination)
Bacillus anthracis
Anthrax
Amino Acids
- how many
- what do they make up?
- around 20
- subunits of proteins
How are proteins formed?
when 2 amino acids connect *usually 250-300 amino acids
Primary Structure
chain of amino acids
Secondary Structure
spiral or accordion structure to save space
Tertiary Structure
3D structure, strengthens protein
Quaternary Strucuture
two or more tertiary structures intertwined
What is an example of Quaternary Structure?
Hemoglobin or collagen
What governs Primary Structure?
Genetics
What are the three components of a nucleotide?
Base, Sugar, Phosphate
What are the purines?
Adenine
Guanine
What are the Pyramidines
Thymine
Cystonine
What base pairs with Adenine and with how many H bonds?
Thymine, 2
What base pairs with Guanine and with how many H bonds?
Cystonine, 3
Ribonucleicacid
- single strand
- sugar, phophate, base (Uracil, Cytosine, Adenine, Guanine)
What are the three types of RNA?
messenger
ribosomal
transfer
Spiral Shaped Eubacteria
- Vibrio (cholera)
- rigid with Fagella
- Spirillum
- Spirochete (syphilis)
- axial filament moving in spiral motion
Vibrio cholerae
cholera
Treponema pallidum
syphilis
Bacillus Shaped Eubacteria
- rod shaped
- no flagella
- anthrax
Coccus Shaped Eubacteria
- Streptococci
- chain
- strep throat
- chain
- Diplo-Cocci
- Staphylococcus
- cluster
- MRSA, TSS
Glycocalyx
- capsule
- escapes phagocytes
- increases virulence
- attachment
- pneumonia
- tooth, dental strep
Flagella
“run, tumble, run”
4 Arrangements of Flagella
- Monotrichous
- one flagella
- Amphitrichous
- one flagella at each end
- Lophotrichous
- many from one end
- Peri-Trichous
- many all over
Axial Filament
run lengthwise between the bacterial inner membrane and outer membrane causing twisting motion and movement of bacteria
Fimbria
- number varies
- look like hairs on a kiwi
- used for attachment
- e.g. gonorrhoea
Pilus
- one or two
- attach between cells for DNA transfer
- “bridge”
- E-coli
Endospores
- internal
- formed when water/nutrients are unavailable
- clinically more problematic
- formed by one gram-ve (pneumonia Q-fever) but mostly gram +ve ( anthrax, tetanus, botulism, gangrins, C.diff)
Cell Wall
- peptidoglycan (protein+glucose changed into glycan)
- also called Murein
Gram Positive
- several layers of peptidoglycan
- has teichoic acid (alcohol+phosphate)
- various alcohols
- recognize bacteria antigenic specifically
Gram Negative
- no teichoic acid
- one MAYBE two layers of peptidoglycan
- phospholipid, lipoprotein, porin protein, lipopolysaccharides
- periplasm composed of outer membrane and plasma membrane separated by layer of pep
What is Periplasm and is it found in gram+ve or gram-ve?
- composed of outer membrane and plasma membrane separated by a layer of peptidoglycan
- gram -ve
Archaebacteria
- no peptidoglycan
- never causes disease
- wall-less
Mycoplasma Species
- no wall (Tb and leprosy)
Magnification of…
- Objective Lense
- Ocular Lense
- Total
- 4 to 100x
- 10x
- OccularxObjective
Why do we always use a basic dye when staining?
- bacteria are negatively charged
- bacteria have a pH of 7
Simple Stain
- pH
- what is it used for
- two examples
- basic
- structure, shape, arrangement, size
- safranin
- methylene blue
What is Mordant?
enhances colour of basic stain
*must match colour of basic stain
Is Gram+ve or Gram-ve harder to treat with antibiotics? Why?
gram-ve, they have two phospholipid bilayers
What is Myoloacterium, and why does it require Acid-Fast Stain?
TB, leprosy. necessary because they have a waxy lipid layer that repels dye
Describe the four steps of an Acid-Fast Stain
- Carbolfuschin Stain
- Heat 10-15 min over boiling H2O to fix bacteria to slide
- Decolorizer
- Acid-Alcohol
- Metheline Blue
What is Mycholic-Acid and how does it effect the dying of TB
- long fatty acids
- causative agent of TB
- TB when stained will always be red
What is the result of an acid-fast stain?
*Acid fast organism will remain original colour while non will be blue
Describe the three steps of negative staining
- Acidic Dye (India Ink)
- stains all but the cell (repels it)
- H2O Wash
- Safranin
- stains cell red with capsule ring
If heating _____ mordant.
do not use
Describe the three steps of Endospore Staining
- Malachite Green
- Dyes cell green
- Heat 15 min
- Safranin
- dyes capsule red
Describe the two steps of Flagella Staining
- Carbolfuschin
2. Mordant- potassium alum
What is the hardest staining process and why?
Flagella, very delicate
Where can a lysozyme be found?
- saliva, mucus, tears, breast milk
How does a lysozyme effect a cell?
- destroys G (glycan, backbone) in PG layer
How does a lysozyme effect a gram+ve and gram-ve best friend?
Gram+ve - breaks thick PG exposing plasma mem. below - broken cell called protoplast Gram-ve - lysozyme removes middle PG layer - PG-less cell called Spheroplast
What is a Protoplast?
Gram+cell broken by lysozyme
What is a Spheroplast?
Gram-cell missing PG from lysozyme
What cell does lysozyme effect more, Gram+ve or Gram-ve? Why?
Gram+ve, more PG to break, exposes only layer of plasma mem
How do antibiotics effect Gram+ve and Gram-ve cells?
- destroy peptide links in Gram+ve cells (more damage)
- destroy single layer in G-ve cells (less damage)
What is Metabolism?
creation and use of energy (sum total of all reactions)
What is Catabolism?
- biodegenerative
- hydrolytic reactions (bond breaking)
- exergonic reactions (release energy)
- produce ATP
What is Anabolism?
- biosynthetic reactions
- dehydration reactions
- endergonic reactions (absorb energy)
- use ATP
Describe ATP
- principle form of energy
- immediate source
- “energy currency”
Describe the structure of ATP
- Adenosine-tri-phosphate
- Adenine base + ribosugar (ribose) + 3 phosphate
Why is ATP unstable?
three negatively charged phosphate repel each other
What is ab enzyme?
- speeds up chemical reactions (catalyst)
- increases likelihood of a reaction by reducing required activation energy
- not consumed in reaction
- proteins and substrates
Simple enzymes are…
proteins (vitamin B, from green veggies and spinach) only that carry one atom to another
Conjugated enzymes are…
proteins (apo-enzyme) and cofactor
Holoenzymes are…
active enzymes with a cofactor
What is a Cofactor?
inorganic (magnesium, magnese, calcium ion) or organic (become co-enzymes)
What are the four enzymatic factors?
- Temperature
- Ph
- Substrate
- Inhibitor
What is a competitive inhibitor?
- has the same size and chemical structure as the substrate
- binds instead of substrate
What is an example of an inhibitor?
- Sulpha Drugs- mimics PABA and
- Adversely effects pregnant women
- used for nucleic acid to carry Folic Acid leading to bacteria cell death
What is non-competitive inhibitor?
- allosentric sites (for feedback inhibitors)
- inhibitors bind to allosteric site (not active site)
- excess product acts as inhibitor to shut down reaction when enough product is produced
What is an Oxidation reaction?
removal of electrons (loss of H+)
What is a Reduction reaction?
gain electrons (gain H+)
What is phosphorylation?
- adding of phosphate
ADP+P–> ATP
Describe Substrate Level Phosphorylation
- substrate level addition of P
- substrate donates P to ADP
Describe Redox Phosphorylation
- Hydrogen is added to coenzyme through redox reaction and goes through ETC to create ATP
Is Redox or Substrate Level Phosphorylation more efficient?
redox
Describe Photophorylation
- conversion of light to ATP
- does not occur in animal cells
What is the net production of ATP in…
- Glycolysis
- Kreb’s Cycle
- ETC
- 2
- 2
- 32
Each FADH2 Produces _____ ATP while each NADH produces _____ ATP.
2, 3
Describe Aerobic Respiration…
- What cycles
- Total ATP
- Final Electron Receptor
- Example
- Glycolysis, Krebs, and ETC
- total ATP (32)
- O2 is final electron acceptor
- most bacteria
Describe Anaerobic Respiration…
- What cycles
- Total ATP
- Final Electron Receptor
- Example
- Glycolysis and Krebs
- ATP from glycolysis varies
- O2 never final electron acceptor (SO4-, NO3-, or NO2-)
- Clostridium tetanus
Describe Fermentation…
- What cycles
- Total ATP
- Final Electron Receptor
- Example
- only glycolysis
- Always 2
- organic molecule
- Bacterium lactobacillus or yeast
Describe an Obligate Aerobe…
- O2 Use
- Total ATP
- Growth Rate
- Example
- needs O2
- ATP varies
- increased growth
- most bacteria
Describe an Obligate Anaerobe…
- O2 Use
- Total ATP
- Examples
- harmed by O2
- ATP varies
- Clostridium sp.
Describe a Facilitated Anaerobe….
- O2 Use
- Growth Rate
- Example
- can switch between using O2 and fermentation
- flexible growth
- ecoli
Describe Aerotderant Anaerobes…
- O2 Use
- Total ATP
- Example
- tolerates O2 but chooses fermentation (Obligate fermented)
- 2
- Lactobacillus sp.
Describe a Microaerophile…
- O2 Use
- Total ATP
- Example
- can use O2 in small amounts (1-20%)
- 34
- Helicoptor pylori (peptic ulcer), Compylobacter jejuni (gastroenteritis)
How does temperature effect Mesophiles, does it pose a health concern, and what is an example?
- can grow 25-40
- optimum is 37
- cannot grow above 50
- health concern (grow in same temps as us)
- strep
How does temperature effect True Psychrophiles, does it pose a health concern, and what is an example?
- can grow at 0
- optimum at 15
- cannot grow above 20-25
- no health concern
- pink on snow
How does temperature effect Facultative/Psychotrophs, does it pose a health concern, and what is an example?
- can grow at 0
- optimum is 20-30
- cannot grow above 40
- thrive in same conditions as us
- food spoilage, slimy mold, growth slowed in fridge
How does temperature effect Trues&Hyper Thermohiles, does it pose a health concern, and what is an example?
- cannot grow at 45
- optimum at 50-60
- can grow 80-130
- not a health hazard (cannot grow where we find comfort)
What pH does mold survive at?
4-5
What pH does bacteria survive at?
6.5-7
How is an Agar Plate prepared?
- melted at high temp to sterilize it
- cools to liquid at 45
- poured into plate to solidify and be stored at 37
Describe Selective Media
- Bismuth Sulfite Agar
- can only grow salmonella (typhoid fever) and typhus only
- encourages growth of one bacteria and discourages all others
Describe Differential Media
- Blood Agar Plate
- grows streptococcus pyogenes (strep throat)
- used in strep testing
- distinguishes specific colonies
Describe Selective Differential Plate
- Manitol Salt Agar
- can grow staphylococcus aureus (skin infection) TSS
What are the four stages of Binary Fission?
- Lag
- Log
- Stationary
- Death
Describe the Lag phase of Binary Fission
- NOT dormant
- no change in cell number
- metabolically active
Describe the Log Phase of Binary Fission
- straight line increase
- generation time is consistent
- most vulnerable stage
Describe Stationary Phase of Binary Fission
- number of new cells is equal to the number of dying cells
Describe the Death stage of Binary Fission
a resources used or treatment starts to work
- more cells dying than being produced
At what stage is it best to start treatment?
Log
Describe three moist methods to clean using heat
- Boiling
- Autoclaving
- steaming under pressure
- 121 degrees for 15 mins
- Pasteurization
- classic (batch) is 63 degrees for 30 mins
- HTST, (high temp short time), flash is 72 degrees for 15 seconds which does the same thing
- UHT (ultra high temp) is 140 degrees for 1-4 sec
Describe three dry methods to clean using heat
- Loops
- streak
- Incineration
- burning carcass
- biohazard waste
- Hot Air
- 1hr 45 min slower than autoclave
- used in OR
Where is HTST and UHT used? Which is preferred and why?
UHT- 3rd world countries because they don’t have fridges
HTST- North America
UHT changes taste
What are the five types of filtration?
- N-95 Mask
- Vaccines
- Antibiotics
- Enzymes
- HEPA Filters
What are two types of radiation?
- Ionizing
2. Non-Ionizing
Describe Ionizing Radiation
- ionizes water
- forms OH free radical causing cell death
- damages DNA
Describe Non-Ionizing Radiation
- forms thymine dimers
- T should bind to A in DNA bit this causes T to bind to T
- UV light
- faint blue colour
What is Ionizing Radiation used for?
- gloves
- sutures
- pharmaceutics
- dental supplies
- postal units
- supermarkets on veggies to increase shelf life
What is Non-Ionizing Radiation Used for?
- OR
- Nurseries
- cafeterias
What are the five chemical methods of control?
- Phenol and Phenolics
- Halogens
- Alcohols
- Quats
- Gas
Why are Phenolics used more than Phenol? What is an example?
- bad odor
- irritates skin
- lysol
What two Halogens are used for cleaning?
- Iodine
2. Chlorine
Describe Iodine
- combined with amino acid tyrosine to be di-iod- tyrosine
- denaturing agent
- pure I2 stains and causes skin irritation
Describe Cholrine
- combined with water to form HCL
- HCL performs redox
- oxidizing agent
What are two alcohols? Which is better and why?
- Ethanol
- Isopropanol
- Isopropanol because it is less volatile and less expensive
Describe Quats
- used on some surfaces
- bacteria can grow on it
Describe Gas as a chemical method of control
- sterilizes everything it touches
- combines with proteins to become CH2-CH2-OH
- highly penetrating
- many hospital uses (mattresses, dialysis)
- must be used in chamber
- carcinogenic
