Microbial Cell Flashcards
Prokaryote
No membrane bound organelles (contain nucleoid though, irregularly shaped region that contains most of the genetic material)
No mitosis
No organelles
Cell shape
Determined by MREB, actin like protein
Example of a spherical shape bacteria and why it’s spherical
Spherical shape - No MREB, default shape
Eg. streptococcus
Example of a rod shape
E. coli
What is a spirillum? Give an example
One curvature, eg. Helicobacter pylori
What is a spirochete? Give an example
Spirochete (multiple curvature) - eg. Treponema pallidum (syphilis)
For cell size, why is small good?
A small cell means a higher surface area to volume ratio, allows the cell to be more efficient and thus take in more nutrients.
Gives the cell a high metabolic rate and because of that, it allows a high growth rate in the population -> easier to adapt to the environment
More surface = more transport possibilities you have
Why do big cells need membrane bound organelles?
The outside surface is not enough to have efficient metabolism, need membrane bound organelles so that you can increase surface area inside the cell
What are the functions of the cytoplasmic membrane?
Permeability barrier - prevents leakage and functions as a gateway for transport of nutrients into and waste out of the cell
Protein anchor - site of many proteins that participate in transport, bioenergetics and chemotaxis
Energy conservation - site of generation and use of proton motive force
What are Dong’s 3 functions for the cytoplasmic membrane?
Respiration
Photosynthesis
Selective permeability
What structure is also known as liquid crystal and why is it called a liquid crystal?
Cytoplasmic membrane. Ordered like a crystal but fluid so liquid.
What determines how fluid are the liquid crystals?
The fatty acid tails - whether they saturated or unsaturated.
What kind of fatty acid tails do psychrophiles have? Thermophiles? Why?
Psychrophile - unsaturated
Thermophiles - saturated
Unsaturated allows the cell membrane to be more fluid, so it can get to a lower temperature before the membrane gets rigid
What holds the liquid crystal structure together?
Hydrogen bonds and hydrophobic interactions
What is the linkage in Archaea bacteria?
Ether bonds - stronger than ester bonds
What is the tail component of Archaea?
Phytanyl, biphytanyl
What is the function of sterols and hopanoids and what group has what?
Function - interacalate into the phospholipid bilayer and increase rigidity
Bacteria: hopanoids
Eukarya: Sterols
Archaea: none
What are the two types of transport?
Diffusion and active transport
What are characteristics of carrier-mediated transport?
Specificity, saturable, highly regulated (cell decides how much of the transport proteins to make)
What is the energy source of carrier-faciliated transport?
Proton motive force or ATP
What are the three types of simple tranporters?
Uniporter, symporter, antiporter
What is group translocation and what is the energy source for it? Give an example where it is used.
Group translocation is a transport that couples metabolism with transport. Energy source is PEP, through a series of enzymatic steps, the phosphorus on PEP is transferred to glucose so it can be transported into the cell. Eg. uptake of glucose by E. coli
What does ABC stand for and what are the three components of this transporter?
ABC = ATP binding cassette, three components are integral membrane protein, the channel, and the substrate specific protein on outside to capture specific proteins and bring to other side through hydrolysis
What is the function of the cell wall?
To maintain cell shape under turgor pressure
What is a cell without a cell wall called?
protoplast, spheroplast if there is still some cell wall
What are the sugars that make up peptidogylcan?
N-actylglucosamine and N-actyl muramic acid
Where is peptidogylcan found?
Cell wall
How many layers of ptg does gram + have? -?
+ is 20, 90% of cell wall, - is 1, 10% of cell wall
What unusual amino acid does the cell wall contain?
D-alanine
What are the glycosidic bonds that are in present in peptidogylcan?
B 1-4 glycosidic bonds
What are the bonds present in archaea cell wall?
B 1-3 glycosidic bonds, not responsive to B lactome class of antibiotics