Cell Walls

What is the function of cell walls?

gives cell more strength, helps cell hold shape, bacterial cell walls can contribute to pathogenicity (causing disease), bacterial cell walls can be a target to kill bacteria with antibiotics

What types of cells have cell walls?

bacteria, archaea, some protozoa, algae, fungi {and plants}

What types of cells do not have cell walls?

helminths, most protozoa, humans {and all animal cells]

Where are cell walls located in a cell?

outside of the plasma membrane

"Gram-positive" and "Gram-negative" suggests specific structures of what bacterial cell structure?

cell wall

Both Gram-positive and Gram-negative bacterial species have what substance in their cell walls that is only found in bacterial cell walls?

peptidoglycan

What is the cell wall structure of Gram-positive bacteria?

periplasm outside the plasma membrane, outside the periplasm is a thick layer of peptidoglycan with teichoic acid

What is the cell wall structure of Gram-negative bacteria?

outside of the plasma membrane is periplasm, then thin layer of peptidoglycan, then periplasm, then an outer membrane that has lipopolysaccharide (aka endotoxin)

Peptidoglycan is partly made of a polysaccharide called _______.

glycan

Glycan is made of two alternating sugars. If we abbreviate the sugar names, how would we describe the structure of glycan?

NAG-NAM-NAG-NAM-NAG-NAM

Peptidoglycan is made of glycan and short _______.

proteins / peptides

The peptide component of peptidoglycan are short peptide chains composed of _____ amino acids bonded together.

4 (tetrapeptide)

What is the Gram stain?

A laboratory procedure used to identify whether bacteria have Gram-positive cell walls or Gram-negative cell walls. It is an important tool for distinguishing between different bacterial species.

Gram-positive bacteria will stain _____ (color) as a result of the Gram stain.

purple

Gram-negative bacteria will stain ______ (color) as a result of the Gram stain.

pink

What part of a Gram-negative cell walls can protect these bacterial species from antimicrobial drugs?

outer membrane

How does penicillin interfere with bacterial cell walls?

Penicillin interferes with the synthesis of peptidoglycan.

Penicillin tends to be more effective at killing Gram-_______ bacteria.

positive

Lysozyme is an antibacterial enzyme made by the human body and found in ______.

tears, saliva, mucus, milk, blood

How does lysozyme interfere with bacterial cell walls?

Lysozyme destroys the glycan in peptidoglycan

Lysozyme tends to be more effective at killing Gram-______ bacteria.

positive