BIO 151 Test 3 Review Questions and Answers
The lipids would be more saturated ** Answ** False,
They would be Less Saturated.
In order to maintain fluidity at low temperatures, you want your hydrocarbon chains to interact
less. Saturated bonds will branch off at angles, decreasing the contact area between the
molecules and therefore decreasing inter molecular forces.
The lipids on the fatty acid tails would be shorter ** Answ** True
They'd be Shorter, for the Above same reason.
The membranes would contain more cholesterol ** Answ** True
Cholesterol stabilizes lipids at high and low temperatures
Glucose is taken up by red blood cells by binding to a specific pocket in a membrane protein
which then allows it to cross the membrane and move down its concentration gradient. What
would be the best definition of this process? ** Answ** Facilitated diffusion using a
transporter.
The glucose is moving DOWN its concentration gradient. Hence it cannot be active transport.
The glucose bonded to a specific pocket. Channels don't have pockets for binding of substrate.
Determine if each statement applies to facilitated diffusion, active transport, or both. **
Answ** Facilitated diffusion:-Molecules move down their
concentration gradient
,Active transport:-Requires energy.
Molecules move against their
concentration gradient.
Both:- Carriers are specific for structures of
individual molecules.
-Molecules move through a protein carrier
in the membrane.
Match each description with the appropriate step in the functioning of the sodium-potassium
pump. ** Answ** 1.Carrier in membrane binds intracellular sodium.
2.ATP phosphorylates protein with bound sodium.
3.Phosphorylation causes conformational change in protein, reducing its affinity for Na⁺. The
Na⁺ then diffuses out.
4.This conformation has higher affinity for K⁺. Extracellular potassium binds to exposed sites.
5.Binding of potassium causes dephosphorylation of protein.
6.Dephosphorylation of protein triggers change back to original conformation, with low affinity
for K⁺. K⁺ diffuses into the cell.
See pic on chegg
, The hormone insulin is a protein produced in the pancreas and then secreted into the blood
stream after a meal to increase glucose uptake by tissues. What cellular process is used to secrete
insulin from the pancreas? ** Answ** Exocytosis
Facilitated diffusion is used to transport ** Answ** sugars and amino acids.
Cells are placed in a solution of glucose. The rate at which glucose enters the cells increases as
the concentration of the glucose solution is increased. Eventually the rate of glucose movement
stops increasing. How is glucose moving into cells? ** Answ** Facilitated diffusion via
carrier protein
What do the processes of active transport and facilitated diffusion have in common? **
Answ** Both use transport proteins to move material across the membrane
A cell using protein-mediated facilitated diffusion is treated with a toxin that prevents
conformation change in the membrane protein. What is the most likely outcome? ** Answ**
Carrier protein dysfunction will increase the gradient.
When taking oral medications, several nonpolar lipid cell membrane barriers will have to be
passed before the polar drug can reach circulation. What is the likely method of transport
mechanism the drug would use to cross the membrane? ** Answ** Facilitated diffusion
The lipids would be more saturated ** Answ** False,
They would be Less Saturated.
In order to maintain fluidity at low temperatures, you want your hydrocarbon chains to interact
less. Saturated bonds will branch off at angles, decreasing the contact area between the
molecules and therefore decreasing inter molecular forces.
The lipids on the fatty acid tails would be shorter ** Answ** True
They'd be Shorter, for the Above same reason.
The membranes would contain more cholesterol ** Answ** True
Cholesterol stabilizes lipids at high and low temperatures
Glucose is taken up by red blood cells by binding to a specific pocket in a membrane protein
which then allows it to cross the membrane and move down its concentration gradient. What
would be the best definition of this process? ** Answ** Facilitated diffusion using a
transporter.
The glucose is moving DOWN its concentration gradient. Hence it cannot be active transport.
The glucose bonded to a specific pocket. Channels don't have pockets for binding of substrate.
Determine if each statement applies to facilitated diffusion, active transport, or both. **
Answ** Facilitated diffusion:-Molecules move down their
concentration gradient
,Active transport:-Requires energy.
Molecules move against their
concentration gradient.
Both:- Carriers are specific for structures of
individual molecules.
-Molecules move through a protein carrier
in the membrane.
Match each description with the appropriate step in the functioning of the sodium-potassium
pump. ** Answ** 1.Carrier in membrane binds intracellular sodium.
2.ATP phosphorylates protein with bound sodium.
3.Phosphorylation causes conformational change in protein, reducing its affinity for Na⁺. The
Na⁺ then diffuses out.
4.This conformation has higher affinity for K⁺. Extracellular potassium binds to exposed sites.
5.Binding of potassium causes dephosphorylation of protein.
6.Dephosphorylation of protein triggers change back to original conformation, with low affinity
for K⁺. K⁺ diffuses into the cell.
See pic on chegg
, The hormone insulin is a protein produced in the pancreas and then secreted into the blood
stream after a meal to increase glucose uptake by tissues. What cellular process is used to secrete
insulin from the pancreas? ** Answ** Exocytosis
Facilitated diffusion is used to transport ** Answ** sugars and amino acids.
Cells are placed in a solution of glucose. The rate at which glucose enters the cells increases as
the concentration of the glucose solution is increased. Eventually the rate of glucose movement
stops increasing. How is glucose moving into cells? ** Answ** Facilitated diffusion via
carrier protein
What do the processes of active transport and facilitated diffusion have in common? **
Answ** Both use transport proteins to move material across the membrane
A cell using protein-mediated facilitated diffusion is treated with a toxin that prevents
conformation change in the membrane protein. What is the most likely outcome? ** Answ**
Carrier protein dysfunction will increase the gradient.
When taking oral medications, several nonpolar lipid cell membrane barriers will have to be
passed before the polar drug can reach circulation. What is the likely method of transport
mechanism the drug would use to cross the membrane? ** Answ** Facilitated diffusion
