Q: A solution contains 150 mM NaCl. What is its osmolarity, considering complete dissociation of NaCl?

$$150 \, \text{mM} \times 2 = 300 \, \text{mOsm}$$

Question 1

Which of the following best describes the relationship between osmolarity and tonicity in a clinical scenario where a patient receives an intravenous solution of 200 mOsm NaCl?

Accepted Answer

The solution is hypo-osmotic and hypotonic; water will enter the patient's cells, causing them to swell.

Question 2

A cell is placed in a solution containing 400 mOsm of non-penetrating solute. What will happen to the cell, and why?

Accepted Answer

The cell will shrink because the solution is hypertonic, causing water to leave the cell.

Question 3

Which of the following best illustrates the concept of negative feedback in human physiology?

Accepted Answer

An increase in blood glucose stimulates insulin release, which lowers blood glucose back toward normal.

Question 4

Which of the following is a correct statement about the first law of thermodynamics as it applies to human physiology?

Accepted Answer

Energy in the body is transformed from one form to another, but the total amount is conserved.

Question 5

A patient is given a drug that acts as an antagonist at a specific membrane receptor. What is the most likely effect of this drug?

Accepted Answer

It will block the receptor and prevent the normal ligand from eliciting a response.

Question 6

Which of the following best explains why glucose requires a carrier protein to cross the plasma membrane?

Accepted Answer

Glucose is polar and cannot diffuse freely through the lipid bilayer.

Question 7

Which of the following is an example of mechanical work performed by a cell?

Accepted Answer

Muscle contraction moving a limb.

Question 8

A solution contains 150 mM NaCl. What is its osmolarity, considering complete dissociation of NaCl?

Accepted Answer

$$150 \, 	ext{mM} 	imes 2 = 300 \, 	ext{mOsm}$$

Question 9

Which of the following best describes the role of membrane proteins in cell function?

Accepted Answer

They act as channels, carriers, receptors, and enzymes, facilitating communication and transport.

Question 10

A cell is placed in a solution that is iso-osmotic but contains a high concentration of permeable solute. What will happen to the cell?

Accepted Answer

The cell will swell because permeable solute enters, water follows, increasing cell volume.

Question 11

Which of the following is a correct example of local cell-to-cell communication?

Accepted Answer

Gap junctions allowing ions to pass directly between adjacent heart muscle cells.

Question 12

Which of the following best describes the difference between hydrostatic pressure and osmotic pressure in capillaries?

Accepted Answer

Hydrostatic pressure pushes fluid out of capillaries, while osmotic pressure pulls fluid in.

Question 13

Which of the following is NOT a function of proteins in the plasma membrane?

Accepted Answer

Storing genetic information.

Question 14

Which of the following best describes the specificity of ligand-receptor binding?

Accepted Answer

It is determined by the shape and structure of both the ligand and the receptor, like a puzzle piece.

Question 15

Which of the following is an example of a covalent bond in biological molecules?

Accepted Answer

The bond between two hydrogen atoms in a water molecule ($$\mathrm{H}_2\mathrm{O}).$$

Question 16

Which of the following best explains why water moves through aquaporins in the plasma membrane?

Accepted Answer

Water is polar and cannot freely cross the lipid bilayer, so it uses protein channels called aquaporins.

Question 17

Which of the following is a correct statement about the second law of thermodynamics as it applies to living systems?

Accepted Answer

Living systems must use energy to maintain order and counteract entropy.

Question 18

A patient has a genetic defect in a membrane carrier protein responsible for glucose uptake. Which of the following is a likely consequence?

Accepted Answer

Glucose will accumulate outside the cell, leading to high blood glucose levels.

Question 19

Which of the following best describes the difference between organic and inorganic molecules in the human body?

Accepted Answer

Organic molecules contain carbon and include proteins, lipids, and nucleic acids; inorganic molecules include water and salts.

Anatomy & Physiology: Foundations, Homeostasis, and Cellular Mechanisms

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