Question 1

Below is a list of molecules with different chemical characteristics.Knowing that all molecules will eventually diffuse across a phospholipid bilayer, select the option below that most accurately predicts the relative rates of diffusion of these molecules (fastest to slowest) .
Alanine estrogen propanol sodium

Accepted Answer

A)  alanine > propanol > sodium > estrogen
B)  sodium > propanol > alanine > estrogen
C)  estrogen > propanol > sodium > alanine
D)  estrogen > propanol > alanine > sodiumE) C) and D)
F) None of the above

Question 2

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
$\begin{array}{lll}
\text { active } & \text { hydrophilic } & \text { noncovalent } \
\text { amino acid } & \text { hydrophobic } & \text { passive } \
\text { amphipathic } & \text { ion channels } & \text { transporter proteins }
\end{array}$

A molecule moves down its concentration gradient by __________ transport, but requires __________ transport to move up its concentration gradient.Transporter proteins and ion channels function in membrane transport by providing a __________ pathway through the membrane for specific polar solutes or inorganic ions.__________ are highly selective in the solutes they transport, binding the solute at a specific site and changing conformation so as to transport the solute across the membrane.On the other hand, __________ discriminate between solutes mainly on the basis of size and electrical charge.

Accepted Answer

A molecule moves down its concentration ...

Question 3

Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell.Which of the following negatively charged ions is NOT primarily used to buffer positive charges inside the cell?

Accepted Answer

A)  PO43−
B)  OH−
C)  Cl−
D)  HCO3−E) A) and B)
F) None of the above

Question 4

Describe the process by which gut epithelial cells use transporters to take up ingested glucose (against the concentration gradient) and to distribute glucose to other tissues by moving it back out of the cell (down the concentration gradient).

Accepted Answer

Gut epithelial cells use two different t...

Question 5

Match between columns Premises: The primary mechanism by which Ca²⁺ acts as a signaling molecule is by increasing the net charge in the cytosol.
The extracellular concentration of Ca²⁺ is approximately 10⁴-fold higher than the concentration of Ca²⁺ in the cytosol.
Cytosolic Ca²⁺ concentration is kept low by the use of chelators such as EDTA.
The low cytosolic Ca²⁺ concentration sensitizes the cell to an influx of Ca²⁺, ensuring a rapid response to environmental stimuli.

Accepted Answer

The Answer of False and True is...

Question 6

The Na+-K+ ATPase is also known as the Na+-K+ pump.It is responsible for maintaining the high extracellular sodium ion concentration and the high intracellular potassium ion concentration.What happens immediately after the pump hydrolyzes ATP?

Accepted Answer

A)  Na+ is bound
B)  ADP is bound
C)  The pump is phosphorylated.
D)  The pump changes conformation.E) C) and D)
F) A) and B)

Question 7

The toxicity of mercury depends greatly upon the formulation of the metal.Which of them (elemental, metal ion, or methyl-mercury) is more likely to be absorbed through the skin? Explain your answer.

Accepted Answer

Organo-mercury compounds such as methyl-...

Exam 12: Transport Across Cell Membranes

Describe the process by which gut epithelial cells use transporters to take up ingested glucose (against the concentration gradient) and to distribute glucose to other tissues by moving it back out of the cell (down the concentration gradient).

Correct Answer
verified
Gut epithelial cells use two different t...
View Answer

Correct Answer
verified
A molecule moves down its concentration ...
View Answer

The toxicity of mercury depends greatly upon the formulation of the metal.Which of them (elemental, metal ion, or methyl-mercury) is more likely to be absorbed through the skin? Explain your answer.

Correct Answer
verified
Organo-mercury compounds such as methyl-...
View Answer

Correct Answer
verified

Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell.Which of the following negatively charged ions is NOT primarily used to buffer positive charges inside the cell?

Correct Answer
verified

The Na⁺-K⁺ ATPase is also known as the Na⁺-K⁺ pump.It is responsible for maintaining the high extracellular sodium ion concentration and the high intracellular potassium ion concentration.What happens immediately after the pump hydrolyzes ATP?

Correct Answer
verified

Indicate whether the statements below are TRUE or FALSE.If a statement is false, explain why it is false

Exam 12: Transport Across Cell Membranes

Describe the process by which gut epithelial cells use transporters to take up ingested glucose (against the concentration gradient) and to distribute glucose to other tissues by moving it back out of the cell (down the concentration gradient).

Correct AnswerverifiedGut epithelial cells use two different t...View AnswerShow Answer

Correct AnswerverifiedA molecule moves down its concentration ...View AnswerShow Answer

The toxicity of mercury depends greatly upon the formulation of the metal.Which of them (elemental, metal ion, or methyl-mercury) is more likely to be absorbed through the skin? Explain your answer.

Correct AnswerverifiedOrgano-mercury compounds such as methyl-...View AnswerShow Answer

Correct AnswerverifiedShow Answer

Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell.Which of the following negatively charged ions is NOT primarily used to buffer positive charges inside the cell?

Correct AnswerverifiedShow Answer

The Na+-K+ ATPase is also known as the Na+-K+ pump.It is responsible for maintaining the high extracellular sodium ion concentration and the high intracellular potassium ion concentration.What happens immediately after the pump hydrolyzes ATP?

Correct AnswerverifiedShow Answer

Indicate whether the statements below are TRUE or FALSE.If a statement is false, explain why it is false

Correct Answer
verified
Gut epithelial cells use two different t...
View Answer

Correct Answer
verified
A molecule moves down its concentration ...
View Answer

Correct Answer
verified
Organo-mercury compounds such as methyl-...
View Answer

Correct Answer
verified

Correct Answer
verified

The Na⁺-K⁺ ATPase is also known as the Na⁺-K⁺ pump.It is responsible for maintaining the high extracellular sodium ion concentration and the high intracellular potassium ion concentration.What happens immediately after the pump hydrolyzes ATP?

Correct Answer
verified