Microbial Cell

Question 1

Prokaryote

Answer 1

No membrane bound organelles (contain nucleoid though, irregularly shaped region that contains most of the genetic material)
No mitosis
No organelles

Question 2

Cell shape

Answer 2

Determined by MREB, actin like protein

Question 3

Example of a spherical shape bacteria and why it’s spherical

Answer 3

Spherical shape - No MREB, default shape

Eg. streptococcus

Question 4

Example of a rod shape

Answer 4

E. coli

Question 5

What is a spirillum? Give an example

Answer 5

One curvature, eg. Helicobacter pylori

Question 6

What is a spirochete? Give an example

Answer 6

Spirochete (multiple curvature) - eg. Treponema pallidum (syphilis)

Question 7

For cell size, why is small good?

Answer 7

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

Question 8

Why do big cells need membrane bound organelles?

Answer 8

The outside surface is not enough to have efficient metabolism, need membrane bound organelles so that you can increase surface area inside the cell

Question 9

What are the functions of the cytoplasmic membrane?

Answer 9

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

Question 10

What are Dong’s 3 functions for the cytoplasmic membrane?

Answer 10

Respiration
Photosynthesis
Selective permeability

Question 11

What structure is also known as liquid crystal and why is it called a liquid crystal?

Answer 11

Cytoplasmic membrane. Ordered like a crystal but fluid so liquid.

Question 12

What determines how fluid are the liquid crystals?

Answer 12

The fatty acid tails - whether they saturated or unsaturated.

Question 13

What kind of fatty acid tails do psychrophiles have? Thermophiles? Why?

Answer 13

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

Question 14

What holds the liquid crystal structure together?

Answer 14

Hydrogen bonds and hydrophobic interactions

Question 15

What is the linkage in Archaea bacteria?

Answer 15

Ether bonds - stronger than ester bonds

Question 16

What is the tail component of Archaea?

Answer 16

Phytanyl, biphytanyl

Question 17

What is the function of sterols and hopanoids and what group has what?

Answer 17

Function - interacalate into the phospholipid bilayer and increase rigidity
Bacteria: hopanoids
Eukarya: Sterols
Archaea: none

Question 18

What are the two types of transport?

Answer 18

Diffusion and active transport

Question 19

What are characteristics of carrier-mediated transport?

Answer 19

Specificity, saturable, highly regulated (cell decides how much of the transport proteins to make)

Question 20

What is the energy source of carrier-faciliated transport?

Answer 20

Proton motive force or ATP

Question 21

What are the three types of simple tranporters?

Answer 21

Uniporter, symporter, antiporter

Question 22

What is group translocation and what is the energy source for it? Give an example where it is used.

Answer 22

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

Question 23

What does ABC stand for and what are the three components of this transporter?

Answer 23

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

Question 24

What is the function of the cell wall?

Answer 24

To maintain cell shape under turgor pressure

Question 25

What is a cell without a cell wall called?

Answer 25

protoplast, spheroplast if there is still some cell wall

Question 26

What are the sugars that make up peptidogylcan?

Answer 26

N-actylglucosamine and N-actyl muramic acid

Question 27

Where is peptidogylcan found?

Answer 27

Cell wall

Question 28

How many layers of ptg does gram + have? -?

Answer 28

+ is 20, 90% of cell wall, - is 1, 10% of cell wall

Question 29

What unusual amino acid does the cell wall contain?

Answer 29

D-alanine

Question 30

What are the glycosidic bonds that are in present in peptidogylcan?

Answer 30

B 1-4 glycosidic bonds

Question 31

What are the bonds present in archaea cell wall?

Answer 31

B 1-3 glycosidic bonds, not responsive to B lactome class of antibiotics