2.3 Bacterial Cell Membrane

Question 1

What structures are components of the cell envelope?

Answer 1

Cytoplasmic membrane
Peptidoglycan layer
Outer membrane

Question 2

Bilayer immediately surrounding the cytoplasm of a cell composed primarily of phospholipids is the ______________

Answer 2

plasma membrane

Question 3

the cytoplasmic membrane is composed of …….

Answer 3

a phospholipid bilayer with embedded proteins

Question 4

The cell membrane has a ____________ core and a __________ surface

Hint: philic/phobic

Answer 4

hydrophobic core

hydrophilic surface

Question 5

The cell membrane’s hydrophilic surface is due to __________

Answer 5

the polar head groups of phospholipids

Question 6

The cell membrane’s hydrophobic core is due to __________

Answer 6

fatty acid side chains of phospholipids

Question 7

bacterial and eukaryotic cell membranes have ________ linkages. Archaeal cell membranes have _________ linkages

Answer 7

B,E : Ester linkages

A: Ether linkages

Question 8

What are hophanoids?

Answer 8

Sterol-like molecules in the cell membrane that help with stability across temperature ranges.

Increase rigidity of the plasma membrane

Question 9

What are aquaporins?

Answer 9

Protein channels that enable water to flow down its concentration gradient by osmosis

Question 10

__________ allow water to enter and exit bacterial cell across the membrane

Answer 10

aquaporins

Question 11

Water passing through aquaporins is a form of ________ diffusion

Answer 11

facilitated

Question 12

Explain how facilitated diffusion works and how much energy it requires.

Answer 12

• Protein channel enables particles to move WITH a concentration gradient
• Does not require ATP energy

Question 13

What are the two types of co-transport?

Answer 13

Symport

Antiport

Question 14

What is the difference between symport and antiport?

Answer 14

Symport: using a substance at a high concentration OUTSIDE the cell to bring in a substance with low concentrations OUTSIDE the cell

Antiport: Using a substance at high concentrations INSIDE the cell to bring in a substance with low concentrations OUTSIDE the cell

Question 15

How come co-transport and facilitated diffusion take no additional energy in the form of ATP?

Answer 15

Bc they involve moving particles using concentration gradient

Question 16

Co-transport moves substances into the cell ________ their concentration gradients

Answer 16

against

Question 17

Unlike facilitated diffusion and co-transport, active transport requires ________

Answer 17

ATP

Question 18

Explain how active transport works

Answer 18

1. cell sends solute-binding protein outside the cell

2. active transport transport solutes into cell against concentration gradient using ATP as energy source

Question 19

Which nutrient transport mechanism enables protein secretion?

Answer 19

Active transport

Question 20

Which of the following is NOT a function normally associated with cytoplasmic membrane proteins?

Controlling access of nutrients into and out of the cell

Controlling access of peptides out of the cell

Sensing environmental signals that trigger reactions in the cytoplasm

Capturing and storing energy

Provides membrane strength and rigidity

Answer 20

Provides membrane strength and rigidity

Question 21

Mechanism of co-transport that couples the movement of one substance across the plasma membrane with movement of another in the same direction

Answer 21

symport

Question 22

Which of these does NOT use ATP?

Facilitated diffusion
Protein secretion
ParM
Active transport

Answer 22

Facilitated diffusion

Question 23

Apart from acting as a permeability barrier, what roels does the cell membrane play?

Answer 23

• Can be used for respiration/photosynthesis
• Can be used to derive energy for motion (flagella)
• Embedded proteins can detect environment changes, alter gene expression in response
• Electron transport chains create proton motive force (PMF)