6 Questions
What is the characteristic of the peptidoglycan layer in Gram positive bacteria?
It is thick and composed of multiple layers
What is the function of teichoic acids in Gram positive bacteria?
They are covalently linked to peptidoglycan
Which of the following is an example of Gram positive bacteria?
Bacillus subtilis
What is the purpose of lipoteichoic acids in Gram positive bacteria?
They are anchored to the membrane and extend into the peptidoglycan layer
Why are some Gram positive bacteria beneficial?
All of the above
What is the result of Gram staining on Gram positive bacteria?
They stain purple
Study Notes
Characteristics
- Peptidoglycan (also known as murein) layer is thick (up to 50 layers)
- Teichoic acids and lipoteichoic acids are present in the cell wall
- Have a single membrane (monoderm)
- Stain purple with Gram stain due to the thick peptidoglycan layer
Cell Wall Structure
- Peptidoglycan layer:
- Made up of repeating units of N-acetylglucosamine and N-acetylmuramic acid
- Cross-linked by peptide chains
- Teichoic acids:
- Polymers of glycerol or ribitol phosphate
- Covalently linked to peptidoglycan
- Lipoteichoic acids:
- Amphipathic molecules
- Anchored to the membrane and extend into the peptidoglycan layer
Examples of Gram Positive Bacteria
-
Firmicutes:
- Bacillus (e.g. B. subtilis, B. anthracis)
- Clostridium (e.g. C. difficile, C. perfringens)
- Staphylococcus (e.g. S. aureus, S. epidermidis)
- Streptococcus (e.g. S. pneumoniae, S. pyogenes)
-
Actinobacteria:
- Mycobacterium (e.g. M. tuberculosis)
- Corynebacterium (e.g. C. diphtheriae)
Importance of Gram Positive Bacteria
- Some are pathogenic, causing diseases such as tuberculosis, pneumonia, and food poisoning
- Others are beneficial, used in food production (e.g. cheese, yogurt), biofuel production, and bioremediation
- Some produce antibiotics and other secondary metabolites
Characteristics of Gram Positive Bacteria
- Thick peptidoglycan (murein) layer, up to 50 layers
- Presence of teichoic acids and lipoteichoic acids in the cell wall
- Single membrane (monoderm)
- Stain purple with Gram stain due to thick peptidoglycan layer
Cell Wall Structure of Gram Positive Bacteria
- Peptidoglycan layer composed of repeating units of N-acetylglucosamine and N-acetylmuramic acid
- Peptidoglycan layer cross-linked by peptide chains
- Teichoic acids are polymers of glycerol or ribitol phosphate, covalently linked to peptidoglycan
- Lipoteichoic acids are amphipathic molecules, anchored to the membrane and extending into the peptidoglycan layer
Examples of Gram Positive Bacteria
- Firmicutes:
- Bacillus (e.g. B. subtilis, B. anthracis)
- Clostridium (e.g. C. difficile, C. perfringens)
- Staphylococcus (e.g. S. aureus, S. epidermidis)
- Streptococcus (e.g. S. pneumoniae, S. pyogenes)
- Actinobacteria:
- Mycobacterium (e.g. M. tuberculosis)
- Corynebacterium (e.g. C. diphtheriae)
Importance of Gram Positive Bacteria
- Some species are pathogenic, causing diseases such as tuberculosis, pneumonia, and food poisoning
- Others are beneficial, used in food production (e.g. cheese, yogurt), biofuel production, and bioremediation
- Some species produce antibiotics and other secondary metabolites
Learn about the unique features of Gram positive bacteria cell walls, including peptidoglycan layer, teichoic acids, and more.
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