HLSC 128 Microbiology

What are the two types of prokaryotes?

1. Eu-bacteria/”True bacteria”

   • Group that causes disease

   • Local environment

2. Archaebacteria/”Ancient bacteria”

   • Don’t cause disease

   • Isolated and extreme environment

What are the four types of eukaryotes?

1. Fungi

2. Protozoa

3. Multicellular animal parasites

4. Algae

Who made the quote: “Life only comes from life”?

Louie Pasteur

Describe the experiments Louie Pasteur had done to determine that life did not arise spontaneously from nonliving matter.

In his trials, he had heated flasks filled with broth with air and removed air (open and closed), and found that the broth was infested when the flask was open with air. He then heated the neck of the flask into an S-shape and left the flask open for air. Pasteur found that the broth was not present with microbes as they had gotten suck in the bends.

What is pasteurization?

It is a heating process to remove the bacteria from food and beverages. The purpose is to make them safe for consumption and extend shelf life.

What is fermentation?

It is the metabolic process of bacteria and yeast where they convert sugars into alcohol.

Who is the scientist that discovered the bacterium that causes anthrax?

Robert Koch

What are the Koch’s Postulates?

Experimental steps to prove that a specific microbe causes a specific disease.

What was Edward Jenner known for?

Edward Jenner was known for creating the first vaccine. In his time smallpox was a epidemic. He inoculated a subject with cowpox virus (fluid from a blister) and found that the subject had complete immunity from smallpox.

What are the building blocks of proteins called?

Amino acids

What are the four structures of a protein?

1. Primary structure

• Polypeptide chain

2. Secondary structure

• Helical shape made of a-helix sheets

3. Tertiary structure

• Pleated structure made up of beta sheets

4. Quaternary structure

• 3D mix of a-helix and b-sheets

What prime carbon does ribose lose oxygen from?

2’

What are the five prokaryote shapes?

1. Spiral

2. Bacillus

3. Coccus

4. Coccobacillus

5. Pleomorphic

What shape is this? Describe it.

Spiral Vibrio, it is tender

What shape is this? Describe it.

Spiral Spirillum, it is rigid and moves by means of flagella

What shape is this? Describe it.

Spiral Spirochete, it flexible and moves by means of appendages called axial filaments which curve around its structure

What shape is this?

It is a single bacillus

What shape is this?

It is a diplobacilli

What shape is this?

It is a streptobacilli

What shape is this? Describe it.

It is a diplococci. Produced when cocci divide and remain attached to eachother.

What shape is this? Describe it.

It is a streptococci. If cocci divides and forms a chain-like structure.

What shape is this? Describe it.

It is a staphylococci. Happens when cocci divide and bunch together into a grape-like structure

What does the glycocalyx do for a prokaryote?

• Increases virulence

  • By its sugar sticky nature

• Evades phagocytosis

Describe the structure of a flagella in a prokaryote.

1. Made up of filaments which are made up of flagellin

2. Attached to a rotating protein hook

3. Anchored to the cell wall and plasma membrane by the basal body (two set of rings)

What are the four types of flagellum?

1. Monotrichous (singular/whip)

2. Amphitrichous (double sided whip)

3. Lophotrichous (bundle on one side)

4. Petrichous (arrangement is all around the cell)

What does it mean when flagella like to “run”?

This means that flagella keep moving and moving till they hit a barrier, where they tumble and change direction. They regain themselves from tumbling and start moving again to another direction repeating the tumbling motion against barriers.

Describe axial filaments/endoflagella.

• Found in spirochetes

• Anchored at one end of a cell

• Rotate and wrap around cell with powerful spiral movements

What are pili?

Projections that connect from one cell to another to facilitate DNA transfer

What are fimbriae?

They are tiny projections from outside a cell’s surface, being shorter and thinner than flagella

Describe the “peptido” portion of Peptidoglycan.

Polypeptide that connects the sugar backbone by peptide bonds with side-chains and cross-bridge amino acids

Describe the “glycan” portion of Peptidoglycan.

• It is a polymer of glucose

• Makes up sugar backbone that is NAM and NAG which form a wall

Describe a Gram-positive cell wall.

• Contains several thick layers of peptidoglycan

• Contain Teichoic acids

Describe Teichoic acids.

• Mix of alcohol and phosphate

• Two types

1. Ribityl (5 carbons)

2. Glycerol (3 carbons)

• If remaining in wall they are called Lipoteichoic acids

• Provide antigen specific nature and attract positive ions

Describe a Gram-negative cell wall. 

• Outer membrane

  • Contains lipoproteins, porin protein channels, and lipopolysaccharides

  • Lipopolysaccharide is an endotoxin, which contains Lipid A that when released causes inflammatory response

• Thin layer of peptidoglycan

• Periplasmic space

What is an Acid-fast cell wall?

It is a waxy lipid later bound to PG that is made up of Mycolic acid

What is a mycoplasma’s cell wall?

No cell wall and only plasma membrane with sterols present

What is an archaea’s cell wall?

Archaea do not have cell walls, and the rare case they do is pseudo PG (false PG)

What does lysozyme digest when damaging peptidoglycan?

It digests the disaccharide, the backbone of glycan

A Gram-positive devoid of cell wall is called a _______, while a gram-negative devoid of cell wall is called a _____

“protoplast”, “spheroplast”

Ribosome: ___S +__S = Complete 70S ribosome

30S + 50S