Lecture 1: The Bacterial Cell Flashcards
What are the characteristics of Staphylococci?
Staphylococci are cocci bacteria that form bunches of bacteria. Examples are Staphylococcus Epidermidis (found on the skin)
What are Diplococci? Give one example
Diplococci are cocci bacteria that form pairs of bacterial cells, includes bacteria such as streptococcus pneumoniae.
Characteristics of Streptococci? Give one example
Streptococci are cocci bacteria that form chains of cells. An example being streptococcus pyogenes.
Other characteristics include:
- Gram-positive
- Non-motile
-Don’t form spores
- Most are facultative anaerobes, some are obligate anaerobes.
Where on the body are group A streptococci found?
The throat and skin, usually causing mild infections.
Why are certain bacteria grouped differently?
Different bacteria will divide in different ways, for example in every plane or in just one plane.
What are the characteristics of Bacilli?
Bacilli are bacterial cells that are shaped like rods. A classic example of bacilli is E. Coli.
- Gram-positive.
- Mostly aerobic, under some conditions anaerobic.
An example is Bacillus anthracis
Where will bacilli mainly be located?
As part of your gut flora or on your skin
What are the characteristics of Vibrio?
Vibrio are bacteria that are:
- Curved rod shaped (comma)
- Gram-negative
- Highly motile, has singular or multiple flagella.
- Facultative anaerobes.
What are the characteristics of Spirilla?
Spirilla are bacterial cells that are:
- Shaped in a rigid spiral (thicker than spirochetes)
- Gram-negative
- Has flagella
- Aerobic
What are the characteristics of Spirochetes
Spirochetes are bacterial cells that are:
- Slender coils that look round on cross section (are flexible)
- Gram-Negative
- Motile
- Typically anaerobic
- Have endoflagella
Examples are Syphilis and Lyme disease
What are endoflagella (axial filaments), and how do they work?
Endoflagella are flagella-like structures located in the periplasmic space encased by the outer membrane (between peptodogylcan and outer membrane) wrapped around the cell. The movement of this axial filament results in the whole cell rotating and because of spirochetes’ shape it propels them through a medium effectively.
What are bacterial capsules?
A halo-like sugar coated capsule (usually polysaccharide) that makes a pathogen more virulent, as it can protect these cells getting engulfed by eukaryotic cells such as macrophages.
Can also protect against certain antibiotics, by preventing them from disrupting cell walls.
What are bacterial Fimbriae or Pili?
Fimbriae and Pili are thin protein tubes originating from the cytoplasmic membrane. They help bacterial cells attach to one another and can be used to exchange genetic material with eachother. Found in almost all Gram-negative bacteria not in many Gram-positive bacteria.
What is a typical structure and components of a membrane phospholipid?
Made up of two hydrophobic hydrocarbon chains, with ester linkages to a glycerol molecule, the last hydroxyl group on the glycerol being ester linked to a hydrophilic phosphate group and connected to this by an ester bond is an R group.
Describe the difference between Gram-positive and Gram-negative bacteria.
Gram-negative bacteria have a thin peptidoglycan layer in the periplasm (space between outer cell wall and plasma membrane) of the cell wall and also have an outer lipid membrane. The peptidoglycan layer in Gram-positive bacteria is a lot thicker than Gram-negative, and usually has pentaglycine linkages between monomers whereas Gram-negative bacteria mostly has direct linkages.
