Card Set Information
Lab week 2&3
What is an endospore
Cell formed within cells of certain bacteria.
Inner protective shell
Why do bacteria form endospores?
To protect themselves from
Lack of nutrients
Two major Genera that form endospores
studied in lab
G(+), soil organism
Botulin toxin (a neurotoxin)
Used in BOTOX
studied in class
Used to make Anthrax
Phases of bacterial growth
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
plate find the CFU
=370,000 = 3.7x10
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
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
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 (-NH
) 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 (NH
What happens during the creation of a peptide bond?
one water molecule is released
What are the 4 levels of protein structure
1st level of protein structure
Amino acids are
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
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