MBIO 1220 Microscopy/Cell Structure (2)

Slide 15 from CLASS 4 slides

What is happening here, from steps 1-4?

1. “Donor” contains sex pilus (F plasmid)

2. Merge

3. Instructions on how to make sex pilus goes from donor → recipient

4. Now are both donors (old + new) that both have sex pilus

What is the semi-rigid structure giving shape to the bacterial cell?

Bacterial cell wall

What is the major function of the bacterial cell wall?

Prevent rupture of the cell (protects against environment changes)

The bacterial cell wall is composed of what macromolecule?

Peptidoglycan

Peptidoglycan is a mesh-like structure composed of what 2 things?

Polysaccharide + amino acids

Polysaccharide portion of a peptidoglycan is composed of what 2 alternating monosaccharides?

1. N-acetyl glucosamine (NAG)

2. N-acetyl muramic acid (NAM)

Tetropeptide can only attach to which of the 2 monosaccharides as part of the polysaccharide portion of peptidoglycan?

N-acetyl muramic acid (NAM)

Polysaccharide chains run parallel, with ______ chains linking the polysaccharides together

“peptide”

The gram-positive cell wall is made of thick layers of peptidoglycan where?

Outside of plasma membrane

Gram-positive cell wall also contains _______ acids

“teichoic”

What are the 2 types of teichoic acids?

Wall + lipteichoic

Wall teichoic acids are attached to?

Peptidoglycan

Lipoteichoic acids are attached to?

Plasma membrane, extend through the peptidoglycan

Gram-positive bacteria only have 1 membrane, called the?

Cytoplasmic membrane

The gram-negative cell wall is made of thin layers of peptidoglycan where?

Sandwiched between 2 membranes

What is the outer membrane made of (3)?

Lipids (phospholipids), proteins, lipopolysaccharides (LPS)

The polysaccharide portion of LPS in the outer membrane is composed of?

O-sugars

O-sugars are what’s useful for distinguishing…?

Gram-negative bacteria

What is special about the lipid portion of LPS in the outer membrane?

It’s toxic (= endotoxin, “endo” meaning within as it’s in the membrane)

In gram-negative cells during a gram stain, the thin peptidoglycan will not trap crystal violet, and the outer membrane gets disrupted by _______

“alcohol”

Many __________ have been discovered tha act against peptidoglycan

“antibiotics”

What is the most known inhibitor of peptidoglycan production (you should know by now)?

Penicillin

Peptidoglycan can be degraded by which of our own natural defenses in the body?

Lysozyme

In what 3 places are lysozymes found?

Tears, saliva, mucous

The cytoplasmic membrane exists in a semi-_____ state

“fluid”

Antimicrobial agents are _______ that disrupt the membrane

“alcohols”

Antimicrobial agents can be used as?

Disinfectant

What are the 5 internal components of a prokaryote?

Cytoplasm, nucleoid, ribosomes, storage granules, endospres

What is the nucleoid?

Circular bacterial chromosome that contains all of the cell’s genetic information (DNA)

The nucleoid is/isn’t surrounded by a nuclear membrane

ISN’T

The nucleoid may also contain plasmids, which are?

Smaller, double-stranded DNA molecules containing non-essential genes (essentially just extra information)

Plasmids, for example, can contain genes for?

Antibiotic resistance

pg. 25