Q: Which equation best represents the sodium-potassium pump, a primary active transport mechanism?

$$ 3\ \text{Na}^+_{in} + 2\ \text{K}^+_{out} + 1\ \text{ATP} \rightarrow 3\ \text{Na}^+_{out} + 2\ \text{K}^+_{in} + 1\ \text{ADP} + 1\ \text{P}_i $$

Question 1

Which of the following best describes the function of the plasma membrane in a cell?

Accepted Answer

It acts as a selective barrier, regulating the movement of substances into and out of the cell.

Question 2

A cell is placed in a hypertonic solution. Which of the following will most likely occur?

Accepted Answer

The cell will shrink as water leaves.

Question 3

Which equation best represents the movement of water during osmosis across a semipermeable membrane?

Accepted Answer

$$ \Delta \Psi = \Psi_{outside} - \Psi_{inside} $$

Question 4

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

Accepted Answer

Storage of genetic material

Question 5

A patient is given an intravenous solution that is hypotonic relative to their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

The cells will swell and possibly burst due to water influx.

Question 6

Which of the following best distinguishes primary active transport from secondary active transport?

Accepted Answer

Primary active transport directly uses ATP, while secondary active transport uses the energy from a concentration gradient established by primary transport.

Question 7

Which of the following is a correct description of the structure of the plasma membrane?

Accepted Answer

A double layer of phospholipids with embedded proteins, described by the fluid mosaic model.

Question 8

Which organelle is responsible for ATP production and contains its own DNA?

Accepted Answer

Mitochondrion

Question 9

A cell needs to import large particles such as bacteria. Which process will it use?

Accepted Answer

Phagocytosis

Question 10

Which cytoskeletal element is primarily responsible for cell movement and muscle contraction?

Accepted Answer

Microfilaments

Question 11

Which of the following best describes the function of the Golgi apparatus?

Accepted Answer

Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

Question 12

Which cell extension increases surface area for absorption in the intestine?

Accepted Answer

Microvilli

Question 13

Which of the following is a function of lysosomes?

Accepted Answer

Digestion and waste removal

Question 14

Which equation best represents the sodium-potassium pump, a primary active transport mechanism?

Accepted Answer

$$ 3\ 	ext{Na}^+_{in} + 2\ 	ext{K}^+_{out} + 1\ 	ext{ATP} ightarrow 3\ 	ext{Na}^+_{out} + 2\ 	ext{K}^+_{in} + 1\ 	ext{ADP} + 1\ 	ext{P}_i $$

Question 15

Which of the following best describes the difference between cilia and microvilli?

Accepted Answer

Cilia are motile extensions that move substances across the cell surface, while microvilli are non-motile extensions that increase surface area for absorption.

Question 16

Which of the following is a function of the nucleolus?

Accepted Answer

Synthesizes ribosomal RNA and assembles ribosomes

Question 17

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules through the membrane via carrier proteins, down their concentration gradient, without ATP.

Question 18

Which of the following is a major component of the extracellular matrix?

Accepted Answer

Proteins and polysaccharides that provide structural support and adhesion between cells.

Question 19

A cell is actively secreting hormones into the bloodstream. Which process is primarily responsible for this activity?

Accepted Answer

Exocytosis

Question 20

Which of the following best describes the function of tight junctions between cells?

Accepted Answer

They form a waterproof seal, preventing leakage of extracellular fluid.

Cells: Structure, Function, and Transport Mechanisms

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