Lecture 3 - Prokaryotes vs. eukaryotes & C.Diff Flashcards
what is the starting amino acid for prokaryotic protein?
formylmethionine
what is the starting amino acid for eukaryotic proteins?
methionine
What organisms encompass eukaryotes?
fungi, plant cells, protozoa, metozoa, and human cells
11 characteristics of prokaryotic cells?
- 0.2- 2.0 micrometers in size
- no nuclear membrane (nucleoli)
- no membrane bound organelles
- simple flagella
- complex cell wall
- plasma membrane lacks carbohydrates and sterols
- no cytoskeleton
- small ribosomes (70S)
- single circular chromosomes
- reproduce via binary fission
- not capable of meiosis
11 characteristics of eukaryotic cells?
- 10-100 micrometer in size
- true nucleus nucleoli
- organelles present (i.e. has a golgi, mitochoondria, ER)
- complex flagella
- Simple cell wall (if present)
- plasma membrane contains sterols and carbohydrates
- Has Cytoskeleton
- larger ribosomes (80S) with the exception of mitochondria which has 70S
- Multiple linear chromosomes
- replicates via mitosis
- capable of meiosis (sexual reproduction)
Where is the energy produced in the bacterial cell?
plasma membrane (because it contains ATP)
6 characteristics of gram negative bacteria?
- thin layer of peptidoglycan
- no teichoic acid (provides rigidity to cell wall by anchoring to lipid membranes)
- Lipopolysaccharide (endotoxins)
- contains an outer membrane and periplasm
- LESS SUSCEPTIBLE TO PENICILLIN
- Pink/red when stained
6 characteristics of gram positive bacteria?
- thick layer of peptidoglycan
- has teichoic acid
- does not have lipopolysaccharide
- does not have an outer membrane or periplasm
- MORE SUSCEPTIBLE TO PENICILLIN
- Dark blue/purple when stained
Why are gram positive bacteria more susceptible to penicillin than gram negative?
Gram-positive bacteria are more sensitive to penicillin than Gram-negative bacteria because the peptidoglycan is not protected by an outer membrane and it is a more abundant molecule
Two bacteria that are not stained by Gram Staining?
- mycobacterium i.e. M. tuberculosis (causes tuberculosis) –> the cell wall has peptidoglycan however, it has mycolic acid which prevents stain from penetrating
- Mycoplasma i.e. M.pneumoniae (causes pneumonia) –> has no cell wall (peptidoglycan) and contains alot of sterols
What is the Ziehl-Neelsen / Acid Fast Stain? Which organisms is it used for?
its a stain used to detect mycobacterium tuberculosis and other organisms with high lipid/wax content in their cell walls
- i.e. cryptosporidium (found in the north saskatchewan river; causes diarrhea)
What is gangrene?
gangrene is tissue death that is caused by an infection
often times the area is amputated or the part is cut open to remove the dead tissue and then treated with antibiotics
What are axial filaments?
axial filaments are flagella inside of the cell wall of spirochaetes (gram negative, spiral bacteria);
they allow them to move through tissues
what are the two functions of bacterial pili/fimbrae?
- attachment to cells and tissues
2. sex pilus (transfer of plasmids between bacteria called conjugation)
What is the process of conjugation between two bacteria?
Horizontal transmission of genes from one bacteria to another;
The process by which a bacteria stretches their pili out and attaches it to neighboring bacteria to form a bridge; then it’s plasmid will replicate and send a copy to the neighboring bacteria; since plasmids contain the bacterial chromosomes, then the neighboring bacteria will make copies and have the same DNA as the original bacteria.
