Micro Biology Review/Study Questions (Lecture 4-6)

What can act as sources of energy for prokaryotes?

Energy Sources: Sun or organic compounds

What do human pathogens use as a source of energy?

Glucose, Amino Acids, lipids, and nucleic Acids AKA Carbon, Hydrogen, and Oxygen and Nitrogen

What can act as sources of carbon for prokaryotes?

Carbon dioxide and Organic compounds,

What do human pathogens use as a source of carbon?

Organic Compounds (Sugars, amino acids, etc)

Which nitrogen source can be used only by prokaryotes?

Nitrogen Fixation (Turning N_2 into NH_3 for use)

Some cyanobacteria can fix both carbon dioxide and N2. Which nutrient likely limits the growth of these bacteria in aquatic environments?

Phosphorus (In warm environments excess phosphorus in water drive their blooms)

Define the term nutritional immunity.

Nutritional Immunity: Hiding or Isolating of iron in the human body to control microbial growth

Why would people who have a genetic defect in transferrin/lactoferrin production be more susceptible to certain infections?

They are more susceptible because their immune system does not have the ability to hide iron from the pathogenic bacteria, virus, or fungi.

What are siderophores?

They are high-affinity iron chelating compounds secreted by microorganisms that bind free or bound iron

Neisseria gonorrhoeae is fastidious. What does this mean?

They have complicated nutritional requirements

When would you use a defined medium rather than a complex medium?

When you want to control the bacteria’s environment. If your using a complex medium it already has Peptone, Beef extract, and water which all bacteria love to grow in it. If you need to see what that certain bacteria needs to grow you use defined medium.

What characteristic of a bacterial growth medium makes it differential? Give an example of such a medium.

Blood Agar as a differential, and the characteristics are it includes one or more ingredients that can be changed by certain bacteria in a recognizable way.

What characteristic of a bacterial growth medium makes it selective? Give an example of such a medium

Example is Antibiotic-Containing medium, which includes one or more ingredients that inhibits the growth of many unwanted organisms

Describe MacConkey medium and how it is a selective and differential medium.

Selective and differential, includes one or more ingredients that inhibit the growth of many unwanted organisms. Also includes one or more ingredients that can be unchanged by certain bacteria in a recognizable way. For example MacConkey Agar used to selectively grow gram-negative bacteria from mixed samples and differentiate them by lactose fermentation.

Selective: bile salts + dye

Differential: lactose + pH indicator

Is blood agar a selective medium? Yes or No.

NOOO Differential

Describe a medium will you use to isolate acidophiles from a mixed population. Is it selective or differential or both

Both because Acidophiles are bacteria that love pH below 5.5 I should select something along the lines of pH 2.4. I would also differentiate them by color and by colony morphology.

What is a Psychrophile?

Temperature based bacteria that lives between the temperatures of -5 degree celsius and 15 degrees celsius

What is a Mesophile

Temperature based bacteria that lives between the temperatures of 25 degree celsius and 45 degrees celsius

What is a Thermophile?

Temperature based bacteria that lives between the temperatures of 45 degree celsius and 70 degrees celsius

What is a Obliagte aerobe?

Oxygen availability based bacteria that Requires Oxygen

What is a Facultative anaerobe?

Oxygen availability based bacteria that Grows best in Oxygen (If present) but can also grow without it (Slower)

What is a Obligate anaerobe?

Oxygen availability based bacteria that Can’t grow in the presence of Oxygen

What is a Neutrophile?

pH based bacteria that grows only between the pH’s of 5 to 8

What is a Acidophile?

pH based bacteria that grows only between the pH’s of 5.5 and below

What is a Alkalophile?

pH based bacteria that grows only between the pH’s of 8.5 and above

What is a Halotolerant?

Water availability bacteria that grow in relatively high salt solution

What is a Halophile?

Water availability bacteria that requires high levels of sodium chloride to grow

How do Pathogens steal Iron??

1. They express receptors that bind sequestering proteins (Molecular minicry - Copying ADP)

2. Express Siderophores

What are the Three iron sequestering proteins in our body??

Ferritins - Stores excess iron inside of cells

Transferrin - Binds and transports iron in the blood

Lactoferrin - binds iron in tissue fluids so iron is not free

What are 5 mechanisms of drug resistance in Biofilms

1. Restricted penetration of antimicrobial agents

2. Decreased growth rates

3. Over expression of efflux pumps

4. Quorum sensing

5. Outer membrane protein

What are the two ways bacteria can grow?

1. Planktonic

2. Biofilms

What is an operon? How is it advantageous to prokaryotic cells?

Operon - A set of regulated genes transcribed as a single mRNA molecule, along with the sequences that control its expression. It is advantageous to prokaryotic cells because it allow multiple genes to be transcribed together into a single, polycistronic RNA molecule.