Topic 3: Prokaryotic Cells Flashcards
Pairs of bacteria
Diplo-
ex: diplococci, diplobacilli
Clusters of bacteria
Staphylo-
Ex: staphylococci
Chains of bacteria
Strepto-
Ex: Streptococci
Which type of bacteria produce endospores?
Bacilli
Average prokaryotic cell size
1 um
Two components of the cell envelope
- Plasma membrane
- Cell wall
3 roles of the plasma membrane
- Permeability & transport
- Cell wall biosynthesis
- Respiratory reactions
Where are chromatophores located?
Within the plasma membrane of photoautotrophic bacteria
Non-polar substances & the plasma membrane
Non-polar substances can pass through the plasma membrane without assistance
Membrane proteins that help water pass through plasma membrane
Aquaporins
Membrane proteins that help lactose pass through plasma membrane
Permease
Membrane proteins that help glucose pass through the plasma membrane
Group translocation
Simple diffusion
Movement of a solute from an area of high concentration to an area of low concentration
Facilitated diffusion
Solute combines with a transporter protein in the membrane
Active transport
Requires a transporter protein and ATP
Group translocation
A form of active transport
- (glucose phosphorylated to G6P)
In prokaryotes, where does the electron transport occur?
on the plasma membrane
Hypertonic
Higher concentration of solutes on outside of cell
Isotonic
Same concentration of solutes on inside and outside
Hypotonic
Lower concentration of solutes outside of cell
What part of a prokaryote is the site of cell wall biosynthesis?
Plasma membrane
What is a prokaryotes cell wall made of?
Peptidoglycan
- NAG and NAM in polymer that is delivered by a carrier protein
Gram positive bacteria cell wall
- Thick layer of peptidoglycan
- Regulates autolysins
Gram negative bacteria cell wall
- Thin layer of peptidoglycan
- Also has an outer
membrane
Important antimicrobials
Lysozyme: digests disaccharide of the cell wall
Penicillin: inhibits formation of peptide bridges
Glycocalyx
A sheath of polysaccharides or protein outside the cell wall
- Good for adherence & protection
Flagella
Responsible for bacterial motility
- Composed of filament, hook, basal body.
Axial filaments
Attached to the surface of spirochaete bacteria and anchored at one end
- Propulsion
Fimbriae
Adherence
Pilus/Pili
Some provide motility and some facilitate DNA transfer between bacterial cells (sex pilus)
Endospores
Produced by Bacillus and Clostridium
- Resistant to heat & Pasteurization
- Need to be killed by autoclaving or harsh chemicals
How are endospores produced?
- Copy of the bacterial chromosome & cytoplasm is surrounded by a double membrane close to an end of the cell
- Peptidoglycan is deposited between the membranes
- Spore coat is deposited on the outside
- Endospore is released
