Question 1

Which statement best describes the principle of complementarity of structure and function in cells?

Accepted Answer

The biochemical functions of cells are dictated by their shape and specific subcellular structures.

Question 2

A scientist observes that a cell is unable to divide and suspects a malfunction in a specific protein. Which type of membrane protein is most likely involved in this process?

Accepted Answer

Peripheral proteins that function as receptor proteins for shape change during cell division.

Question 3

Which of the following best explains why oxygen and carbon dioxide can easily diffuse across the plasma membrane?

Accepted Answer

They are small, nonpolar, and lipid-soluble molecules.

Question 4

A patient receives an intravenous solution that causes their red blood cells to swell and burst. What type of solution was administered?

Accepted Answer

A hypotonic solution, which has lower osmolarity than the cell interior.

Question 5

Which equation correctly represents the relationship between osmolarity ($$O$$), number of solute particles ($$n$$), and volume of solvent ($$V$$)?

Accepted Answer

$$O = \frac{n}{V}$$

Question 6

Which type of cell junction would be most important in preventing leakage of digestive enzymes between cells lining the stomach?

Accepted Answer

Tight junctions, which form impermeable barriers between adjacent cells.

Question 7

A muscle cell needs to rapidly transmit electrical signals to neighboring cells. Which cell junction facilitates this function?

Accepted Answer

Gap junctions, which allow ions and small molecules to pass between cells.

Question 8

Which of the following best describes the role of cholesterol in the plasma membrane?

Accepted Answer

It increases membrane stability by interacting with phospholipids.

Question 9

A cell is placed in a hypertonic solution. What is the most likely outcome for the cell?

Accepted Answer

Water will leave the cell, causing it to shrink (crenation).

Question 10

Which process requires energy input from the cell to move substances across the plasma membrane?

Accepted Answer

Active transport

Question 11

Which of the following is a function of integral membrane proteins?

Accepted Answer

They act as transport proteins, enzymes, or receptors.

Question 12

A cell is exposed to a solution with the same osmolarity as its cytoplasm. What will happen to the cell?

Accepted Answer

There will be no net movement of water; cell volume remains unchanged.

Question 13

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of polar molecules across the membrane with the help of carrier or channel proteins.

Question 14

Which equation best represents the equilibrium condition for water movement across a cell membrane, where hydrostatic pressure ($$P_{hydro}) $$equals osmotic pressure ($$P_{osm}$$)?

Accepted Answer

$$P_{hydro} = P_{osm}$$

Question 15

Which of the following is NOT a function performed by membrane proteins?

Accepted Answer

Synthesis of DNA within the nucleus

Question 16

A cell's glycocalyx is important for which of the following functions?

Accepted Answer

Cell-to-cell recognition and immune system identification of 'self' vs. 'nonself'

Question 17

Which of the following best explains why cells without cell walls are at risk of bursting when placed in hypotonic solutions?

Accepted Answer

They cannot counteract osmotic pressure with hydrostatic pressure, leading to excessive water intake.

Question 18

Which of the following statements about desmosomes is correct?

Accepted Answer

They provide anchoring strength and allow 'give' between cells, preventing tearing under tension.

Question 19

Which of the following is true regarding the movement of water by osmosis?

Accepted Answer

Water moves from areas of low solute concentration to areas of high solute concentration.

Question 20

A cell is placed in a solution and both solute and water diffuse across the membrane until equilibrium is reached. What type of membrane is this?

Accepted Answer

A membrane permeable to both solute and water.

Lecture Exam 1: Chapter 3 Cells

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