Unit 3: Practice Questions Flashcards
Between Tryptophan (charged) and indole (uncharged) which is more soluble?
Indole is more soluble because not ion
The porin proteins utilize the _____ structural motif
a) alpha helix
b) beta sheet
b) beta sheet
What role do van der Waals interactions play in membranes?
a) favor the self assembly of the lipid bilayer
b) decrease the melting temperature
c) increase membrane fluidity
d) decrease the membrane fluidity
d) decrease membrane fluidity
Association of proteins with membranes that do NOT exist are:
a) integral membrane spanning beta sheet with nonpolar side groups outside
b) integral membrane spanning alpha helices with polar side groups outside
c) integral membrane spanning nonpolar alpha helices
d) peripheral polar interactions with phospholipid heads
If Lipid A has a higher Tm than lipid B, which of the following differences between A and B may exist?
a) A has short fatty acid chains than B
b) A has longer fatty acid chains than B
c) A has more unsaturated fatty acid chains than B
d) A has more saturated fatty acid chains than B
e) A has trans unsaturatd fatty acid chains wheras B has cis saturated fatty acid chains
Secondary transporters (or cotransporters) can be divided into symporters and antiporters. What is the basis for this distinction?
a. Symporters allow the same molecule to be moved in both directions, while antiporters allow it to move in only one direction.
b. Symporters use the energy from one molecule moving down its concentration gradient to drive the movement of a second molecule in the opposite direction against its concentration gradient, while antiporters drive the movement in the same direction.
c. Symporters use the energy from one molecule moving down its concentration gradient to drive the movement of a second molecule, wheras antiporters use the energy from both molecules for transport
d. Symporters use the energy from one molecule moving down its concentration gradient to drive the movement of a second molecule in the same direction against its concentration gradient, while antiporters drive the movement in the opposite direction.
d. Symporters use the energy from one molecule moving down its concentration gradient to drive the movement of a second molecule in the same direction against its concentration gradient, while antiporters drive the movement in the opposite direction.
The Na+ - K+ pumps in active transport that
a) pumps Na+ into the cell and K+ out of the cell
b) pumps Na+ out of the cell and K+ into the cell
c) provides energy such as Na+ and K+ can move freely in either direction
d) pumps both Na+ and K+ into the cell
b) pumps Na+ out of the cell and K+ into the cell
Which of the following would be expected to lower the Tm for a phospholipid bilayer?
a) replacing a lipid containing carbon 18 fatty acids with one containing carbon 16 fatty acids
b) adding ions that bind to charged groups in the polar head groups
c) replacing a lipid containing unsaturated fatty acids with one containing saturated fatty acids
d) decreasing the concentration of phospholipids
a) replacing a lipid containing carbon 18 fatty acids with one containing carbon 16 fatty acids
The common way in which integral membrnae proteins span the membrane is in
a) alpha helical segments
b) single strands with no secondary structure
c) paired alpha helical and beta sheet segments
d) beta sheet structures
a) alpha helical segments
Select the fundamental properties of all ion channels
- rapid transport
- selectivity
- use active transport
- voltage gated
1 and 2
What is a receptor protein?
a) a protein that spans the plasma membrane
b) a plasma membrane protein that binds with first messengers
c) a vesicle that transports large particles across the plasma membrane
d) an intracellular chemical that activates intracellular enzymes
e) an extracellular ligand that signals intracellular activity to change
b) a plasma membrane protein that binds with first messengers
Select the structural features common to all membrane bound receptors
- seven membrane bund receptors
- intracellular domain undergoes structural changes upon extracellular ligand binding
- signal molecule binding site on extracellular domain
- kinase domain
2 and 3
What factor does not contribute to the high phosphoryl transfer potential of ATP?
a) adenine ring structure
b) charge repulsion
b) ability of water to interact more favorably with products of ATP hydrolysis than with ATP itself
d) resonance stabilization
a) adenine ring structure
What statement correctly describes metabolic reactions?
a) Anabolic processes break down material and transform fuels in cellular energy, wheras catabolic processes require energy for biosynthesis
b) Metabolism breaks down material and transforms fuels in cellular energy, wheras intermediary metabolism requires energy for biosynthesis
c) Catabolic processes break down material and transforms fuels in celular energy, wheras anabolic processes require energy for biosynthesis
c) Catabolic processes break down material and transforms fuels in celular energy, wheras anabolic processes require energy for biosynthesis
What needs to be invested for glucogenesis
Invest 4 ATP, 2 GTP, 2 NADH
Dr. Kim has discovered a molecule she believes to be a signaling molecule associated with signal transduction. This molecule is hydrophilic; therefore, you expect it to interact with a receptor ____.
a) in the nucleus of the cell
b) within the cytoplasm of the cell
c) on the cell surface
d) on the cytoplasmic surface of the plasma membrane
c) on the cell surface
