2.3 Bacterial Cell Membrane Flashcards
What structures are components of the cell envelope?
Cytoplasmic membrane
Peptidoglycan layer
Outer membrane
Bilayer immediately surrounding the cytoplasm of a cell composed primarily of phospholipids is the ______________
plasma membrane
the cytoplasmic membrane is composed of …….
a phospholipid bilayer with embedded proteins
The cell membrane has a ____________ core and a __________ surface
Hint: philic/phobic
hydrophobic core
hydrophilic surface
The cell membrane’s hydrophilic surface is due to __________
the polar head groups of phospholipids
The cell membrane’s hydrophobic core is due to __________
fatty acid side chains of phospholipids
bacterial and eukaryotic cell membranes have ________ linkages. Archaeal cell membranes have _________ linkages
B,E : Ester linkages
A: Ether linkages
What are hophanoids?
Sterol-like molecules in the cell membrane that help with stability across temperature ranges.
Increase rigidity of the plasma membrane
What are aquaporins?
Protein channels that enable water to flow down its concentration gradient by osmosis
__________ allow water to enter and exit bacterial cell across the membrane
aquaporins
Water passing through aquaporins is a form of ________ diffusion
facilitated
Explain how facilitated diffusion works and how much energy it requires.
- Protein channel enables particles to move WITH a concentration gradient
- Does not require ATP energy
What are the two types of co-transport?
Symport
Antiport
What is the difference between symport and antiport?
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
How come co-transport and facilitated diffusion take no additional energy in the form of ATP?
Bc they involve moving particles using concentration gradient
Co-transport moves substances into the cell ________ their concentration gradients
against
Unlike facilitated diffusion and co-transport, active transport requires ________
ATP
Explain how active transport works
- cell sends solute-binding protein outside the cell
2. active transport transport solutes into cell against concentration gradient using ATP as energy source
Which nutrient transport mechanism enables protein secretion?
Active transport
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
Provides membrane strength and rigidity
Mechanism of co-transport that couples the movement of one substance across the plasma membrane with movement of another in the same direction
symport
Which of these does NOT use ATP?
Facilitated diffusion
Protein secretion
ParM
Active transport
Facilitated diffusion
Apart from acting as a permeability barrier, what roels does the cell membrane play?
- 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)
