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What is an endospore
Cell formed within cells of certain bacteria.
Inner protective shell
Why do bacteria form endospores?
- To protect themselves from
- Desiccation (dehydration)
- UV light
- Lack of nutrients
Two major Genera that form endospores
Clostridium and Bacillus
Species of Clostridium studied in lab
- C. botulinum
- G(+), soil organism
- Botulin toxin (a neurotoxin)
- Used in BOTOX
Species of Bacillus studied in class
- B. anthracisG(+)
- Used to make Anthrax
Phases of bacterial growth
- Leg Phase
- Log Phase
- Stationary Phase
- Death Phase
- First step in bacterial growth curve
- When bacteria are no multiplying but synthesizing enzymes, proteins, RNA ect.
- Second step of the bacterial growth curve
- Bacterial cells multiply rapidly (binary fission)
- Third phase of bacterial growth curve
- Growth of bacterial cells plateau (growth/death =1)
- Towards end of this phase is when endospores are made.
Last phase of growth curve
- The creation of endospores
- (towards the end of stationary phase)
steps to making an endospore stain
- Make smear, air dry and heat fix
- Flood with malachite green(basic)
- Steam for 5 minutes
- Counterstain with safranin(basic) for 2mins
- rinse and oil immersion
Why do you steam the endospore slide?
To allow the malachite green(basic) to penetrate endospore
OCD stand for ____
Original Cell Density
Finding OCD or CFU
- = Colonies counted/DF x Volume plated
Final Dilution Factor
How to find the FDF
DF x volume plated
If 37 colonies were on the 10-4 plate find the CFU
- =370,000 = 3.7x105 CFU/mL
Phenol Red (PR) Broth
- A simple broth that has sugar in it
- PR is a pH indicator
- ph <6.8 it turns yellow
- 6.9<pH<7.3 turns red
- pH > 7.4 it turns pink or magenta
Why is glucose preferred in PR broth
Because it is the preferred carbohydrate of bacterial cells to metabolize
Name the 4 bacilli used in the PR tubes and their similarity
- Escherichia coli
- Enterobacter aerogenes
- Alcaligenes faecalis
- Proteus vulgaris
They are all gram (-) bacilli
What does Oxidation-fermentation (OF) Glucose Test tell us
Differentiates bacteria based on oxidative or fermentative metabolism of carbohydrates
Energy production under anaerobic condition
Dye used in OF tests
- Bromthymol blue dye
- pH 6 it turns yellow
What is a phospholipid?
Complex Lipid/Phospholipid are made up of what?
Contain carbon, hydrogen, and oxygen like simple lipids but also contain phosphorus, nitrogen, and sulfur
What is a complex lipid?
Phospholipid or steroids
Contain P,N and S along with the normal C,H, and O in simple lipids
What are cell membranes primarily made of?
What is a steroid?
A 4 carbon ring with an -OH group attached to one ring
What are proteins made of?
- Carbon, Hydrogen, Oxygen, and Nitrogen
- Amino Acids
Complex, and 3-D shape
What are enzymes?
A type of protein that speed up biochemical reactions
What do amino acids make up?
What make up amino acids?
A carboxyl group (-COOH) and one amino group (-NH2) attached to the same carbon atom
Two stereoisomers of amino acids
- L-amino acid (Left hand; COOH)
- D-amino acid (Right hand; HOOC)
L-forms are most often found in nature
What is a peptide bond?
A bond between amino acids
How are peptide bonds formed? What are they formed from?
- They are formed by dehydration synthesis
- Formed from the carboxyl(-COOH) and the amino acid (NH2)
What happens during the creation of a peptide bond?
one water molecule is released
What are the 4 levels of protein structure
- Primary structure
- Secondary structure
- Tertiary structure
- Quaternary structure
- 1st level of protein structure
- Amino acids are linked together to form a polypeptide chain (protein)
- 2nd protein structure
- Twists and folds; shape held together by H-bonds
- Spirals or helices
- 3rd protein structure
- Irregular folding due to bonding between AA's in the polypeptide chain
- Disulfied bonds
- Hydrogen bonds
- Ionic Bonds
- 4th level of protein structure
- Not in all proteins
- May require covalent, hydrogen, ionic bonds or hydrophobic reactions
- Easily denatured by pH, temp or chemicals
- Consist of a combination of amino acids and other organic molecules.
- Glycoproteins (Contain sugars)
- Nucleoproteins (Contain nucleic acids)
- Lipoproteins (Contain Lipids)
Full name for DNA
Nucleic acids are made from what?
- DNA, RNA, ATP
- Acidic found in nucleus
- Sugar-phosphate backbone
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