$$V_m = V_{\text{inside}} - V_{\text{outside}}$$

Question 1

Which of the following best describes the three main stages of cell signalling as illustrated in the signal transduction pathway?

Accepted Answer

Signal reception, signal transduction, cellular response

Question 2

In the context of the fight-or-flight response in an impala, which of the following is the correct sequence of events for adrenaline signalling?

Accepted Answer

Adrenaline binds to receptor → relay molecules transmit signal → enzyme breaks down glycogen → glucose fuels muscles

Question 3

Which process allows Myxococcus xanthus bacteria to survive unfavorable conditions?

Accepted Answer

Aggregation of cells into a fruiting body and formation of spores

Question 4

In yeast cell mating, what is the role of the 'a' and 'α' factors?

Accepted Answer

They are chemical signals that bind to receptors on the opposite mating type, initiating fusion

Question 5

Which of the following is an example of local signalling in animal cells?

Accepted Answer

Paracrine signalling via local regulators

Question 6

Which statement about G-protein coupled receptors (GPCRs) is correct?

Accepted Answer

GPCRs activate G-proteins by facilitating the exchange of GDP for GTP

Question 7

What is the primary function of the Na-K-ATPase pump in neurons?

Accepted Answer

To maintain the resting membrane potential by moving 3 Na$$^+$$ out and 2 K$$^+ in $$per ATP hydrolyzed

Question 8

Which equation correctly describes the membrane potential ($$V_m) of a $$cell?

Accepted Answer

$$V_m = V_{	ext{inside}} - V_{	ext{outside}}$$

Question 9

What would be the effect of ouabain, a Na-K-ATPase inhibitor, on glucose uptake in intestinal cells over time?

Accepted Answer

Glucose uptake would decrease due to the loss of the Na$$^+$$ gradient

Question 10

Which of the following best explains why action potentials propagate in only one direction along an axon?

Accepted Answer

Inactivation of voltage-gated Na$$^+$$ channels prevents backward propagation

Question 11

If tetrodotoxin, a voltage-gated Na$$^+$$ channel blocker, is applied to a neuron, what will happen to the action potential?

Accepted Answer

The action potential will not be generated due to lack of Na$$^+$$ influx

Question 12

Which of the following is a direct result of the activation of receptor tyrosine kinases?

Accepted Answer

Phosphorylation of tyrosine residues on the receptor

Question 13

Which ion channel is primarily responsible for the repolarization phase of the action potential?

Accepted Answer

Voltage-gated K$$^+$$ channels

Question 14

Which of the following best describes the role of myelin in action potential propagation?

Accepted Answer

It insulates the axon, allowing saltatory conduction between nodes of Ranvier

Question 15

Which of the following is a correct statement about intracellular receptors?

Accepted Answer

They are found in the cytoplasm or nucleus and bind lipid-soluble signals like steroid hormones

Question 16

Which of the following is a real-life example of long-distance signalling?

Accepted Answer

Adrenaline released into the bloodstream during a stress response

Question 17

Which equation is used to calculate the equilibrium potential ($$E_X) $$for an ion X?

Accepted Answer

$$E_X = \frac{RT}{zF} \ln \left( \frac{[X]_{	ext{outside}}}{[X]_{	ext{inside}}} ight)$$

Question 18

Which of the following is true about the specificity of cell signalling?

Accepted Answer

The same signalling molecule can produce different responses in different cell types due to different relay proteins

Question 19

Which of the following best describes the effect of tetraethylammonium, a voltage-gated K$$^+$$ channel blocker, on the action potential?

Accepted Answer

It prolongs the repolarization phase, making the action potential last longer

Cell Signalling and Neuronal Communication: Receptors, Ion Channels, and Action Potentials

Study Guide - Practice Questions