Q: Which equation best represents the action of the Na+-K+ pump in maintaining the resting membrane potential?

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

Question 1

Which of the following best explains why the inside of a resting cell membrane is more negative than the outside?

Accepted Answer

K+ diffuses out of the cell through leakage channels, while negatively charged proteins remain inside, creating a negative charge on the inner membrane surface.

Question 2

A neuron is experimentally treated so that its membrane is equally permeable to both K+ and Na+. What would happen to the resting membrane potential?

Accepted Answer

It would become less negative, approaching 0 mV.

Question 3

Which equation best represents the action of the Na+-K+ pump in maintaining the resting membrane potential?

Accepted Answer

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

Question 4

Which organelle is responsible for producing most of the cell’s ATP via aerobic respiration, and what unique feature does it possess?

Accepted Answer

Mitochondrion; contains its own DNA, RNA, and ribosomes

Question 5

A mutation prevents the formation of ribosomes in a cell. Which process would be directly affected?

Accepted Answer

Protein synthesis

Question 6

Which of the following best describes the role of the Golgi apparatus in protein processing?

Accepted Answer

It modifies, concentrates, and packages proteins and lipids received from the rough ER.

Question 7

During which phase of mitosis do chromosomes align at the cell’s equator, and what is this region called?

Accepted Answer

Metaphase; metaphase plate

Question 8

Which of the following is a function of lysosomes?

Accepted Answer

Digestion of ingested bacteria, viruses, and toxins

Question 9

A cell is observed to have an extensive network of smooth endoplasmic reticulum. Which function is this cell likely specialized for?

Accepted Answer

Lipid metabolism and detoxification

Question 10

Which of the following best describes the flow of genetic information during protein synthesis?

Accepted Answer

DNA $$ \rightarrow $$ mRNA $$ \rightarrow $$ protein

Question 11

Which of the following statements about chromatin is correct?

Accepted Answer

Chromatin consists of DNA, RNA, and histone proteins.

Question 12

What is the primary function of microvilli on the surface of certain cells?

Accepted Answer

Increase surface area for absorption

Question 13

Which of the following is true regarding the role of tRNA in protein synthesis?

Accepted Answer

tRNA carries amino acids to the ribosome during translation.

Question 14

A cell is exposed to a toxin that inhibits the Na+-K+ pump. What is the most likely immediate effect on the cell?

Accepted Answer

The resting membrane potential will decrease as Na+ accumulates inside and K+ outside.

Question 15

Which of the following best describes the function of the centrosome during cell division?

Accepted Answer

It organizes microtubules and forms the basis of the mitotic spindle.

Question 16

Which of the following is a correct statement about the cell cycle?

Accepted Answer

Interphase includes G1, S, and G2 phases, where S is the phase of DNA synthesis.

Question 17

Which of the following is a real-life example of the importance of contact inhibition in cell division?

Accepted Answer

Cancer cells lose contact inhibition, leading to uncontrolled cell division.

Question 18

Which of the following best explains why the same ligand can cause different responses in different cells?

Accepted Answer

Different cells have different receptor pathways that determine the cellular response.

Question 19

Which of the following is a function of peroxisomes in the cell?

Accepted Answer

Neutralization of free radicals and detoxification of harmful substances

Question 20

A patient has a genetic disorder that prevents the formation of the sarcoplasmic reticulum in muscle cells. Which process would be most directly affected?

Accepted Answer

Release and storage of calcium ions during muscle contraction

BIO111 Lecture 6: Cells, Membrane Potential, Organelles, Cell Cycle, and Protein Synthesis

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