Cell Signaling: Interactive Quizzes for Medical Students

Question 1

Which of the following is NOT a type of cell signaling?

Accepted Answer

Electrical signaling

Answer

Endocrine signaling

Answer

Paracrine signaling

Answer

Autocrine signaling

Question 2

Which of the following is a primary function of protein kinases within cell signaling cascades?

Accepted Answer

Phosphorylating specific proteins, altering their activity

Answer

Dephosphorylating specific proteins, modulating their function

Answer

Binding to specific DNA sequences, regulating gene expression

Answer

Degrading specific proteins, controlling their abundance

Question 3

Which of the following is a key difference between endocrine and paracrine signaling?

Accepted Answer

The range over which the signal acts

Answer

The nature of the signaling molecule employed

Answer

The specificity of the signal

Answer

The duration of the signal

Question 4

Which type of receptor undergoes a conformational change upon ligand binding, directly opening or closing an ion channel?

Accepted Answer

Ion channel-linked receptor

Answer

Enzyme-linked receptor

Answer

G protein-coupled receptor

Answer

Nuclear receptor

Question 5

Which of the following is a second messenger that activates protein kinase A?

Accepted Answer

cAMP

Answer

DAG

Answer

IP3

Answer

Ca2+

Question 6

Which type of protein kinase is activated by the phosphorylation of its tyrosine residues?

Accepted Answer

Mitogen-activated protein kinase

Answer

Protein kinase A

Answer

Protein kinase C

Answer

Protein kinase B

Question 7

Which of the following is a characteristic feature of a G protein-coupled receptor?

Accepted Answer

Seven transmembrane domains

Answer

Direct ion channel activation

Answer

Binding to nuclear hormone receptors

Answer

Tyrosine kinase domain

Question 8

Which of the following is a key difference between paracrine and endocrine signalling?

Accepted Answer

Distance of signal transmission

Answer

Molecule type transmitted

Answer

Specificity of target cells

Answer

Duration of signal

Question 9

Which of the following techniques is used to investigate protein-protein interactions in signal transduction?

Accepted Answer

Co-immunoprecipitation

Answer

Western blotting

Answer

Gene sequencing

Answer

Flow cytometry

Question 10

Which of the following is a primary role of the nucleus in cell signalling?

Accepted Answer

Transcription of genes

Answer

Translation of proteins

Answer

Synthesis of lipids

Answer

Storage of DNA

Question 11

Which of the following is a positive regulator of cell signalling?

Accepted Answer

Protein kinase A

Answer

Protein phosphatase 1

Answer

Ubiquitin ligase

Answer

Caspase

Question 12

What is the function of protein kinases in cell signaling?

Accepted Answer

Protein phosphorylation

Answer

Protein degradation

Answer

DNA binding

Answer

Membrane transport

Question 13

Which of the following is an example of a ligand-activated transcription factor?

Accepted Answer

Steroid hormone receptor

Answer

Growth factor receptor

Answer

G protein-coupled receptor

Answer

Ion channel

Question 14

Which of the following is NOT a type of cell signaling molecule?

Accepted Answer

Enzymes

Answer

Hormones

Answer

Neurotransmitters

Answer

Cytokines

Question 15

What is the main function of a G protein-coupled receptor (GPCR)?

Accepted Answer

To transmit signals across the plasma membrane

Answer

To activate transcription factors

Answer

To hydrolyze GTP

Answer

To synthesize hormones

Question 16

Which of the following is a second messenger that activates protein kinase A (PKA)?

Accepted Answer

cAMP

Answer

DAG

Answer

IP3

Answer

Ca+2

Question 17

What is the mechanism of action of tyrosine kinase receptors?

Accepted Answer

They form dimers and activate each other's kinase domains

Answer

They phosphorylate serine and threonine residues on target proteins

Answer

They bind to G proteins and activate downstream effectors

Answer

They hydrolyze GTP to release energy

Question 18

What is the main role of ubiquitination in cell signaling?

Accepted Answer

To target proteins for degradation

Answer

To activate transcription factors

Answer

To inhibit protein synthesis

Answer

To regulate protein trafficking

Question 19

What is the significance of cross-talk between cell signaling pathways?

Accepted Answer

It allows for coordinated cellular responses

Answer

It prevents signaling pathways from interfering with each other

Answer

It ensures that only one signaling pathway is active at a time

Answer

It is a rare occurrence that does not have a significant impact on cellular function

Question 20

In the phospholipase C signaling pathway, which molecule acts as a second messenger?

Accepted Answer

Inositol triphosphate (IP3)

Answer

Cyclic AMP (cAMP)

Answer

Diacylglycerol (DAG)

Answer

Calcium ions (Ca2+)

Question 21

A mutation in a receptor tyrosine kinase (RTK) prevents its autophosphorylation. What is the most likely outcome of this mutation?

Accepted Answer

The receptor will be unable to activate downstream signaling molecules.

Answer

The receptor will be unable to bind its ligand.

Answer

The receptor's signaling activity will be enhanced.

Answer

The receptor will become constitutively active, leading to uncontrolled cell growth.

Question 22

Which signaling pathway is primarily responsible for mediating cellular responses to growth factors?

Accepted Answer

MAP kinase pathway

Answer

JAK/STAT pathway

Answer

cAMP/PKA pathway

Answer

Notch signaling pathway

Question 23

What is the role of GTPase-activating proteins (GAPs) in G protein-coupled receptor (GPCR) signaling?

Accepted Answer

They accelerate the hydrolysis of GTP bound to G proteins, terminating the signal.

Answer

They act as second messengers, relaying signals from activated GPCRs.

Answer

They enhance the binding of G proteins to GPCRs.

Answer

They activate G proteins by promoting GDP exchange for GTP.

Question 24

Which of the following is a defining characteristic of apoptosis?

Accepted Answer

Controlled dismantling of cellular components

Answer

Inflammatory response

Answer

Cell swelling and lysis

Answer

Random DNA degradation

Question 25

Nitric oxide (NO) is a signaling molecule involved in various physiological processes. How does it exert its effects?

Accepted Answer

It diffuses across cell membranes and activates guanylyl cyclase.

Answer

It binds to cell surface receptors and activates downstream signaling cascades.

Answer

It acts as a second messenger, amplifying signals within the cell.

Answer

It directly modifies the activity of target proteins.

Question 26

Which statement best describes the concept of signal amplification in cell signaling?

Accepted Answer

A single activated receptor can trigger the activation of multiple downstream effector molecules.

Answer

Different cell types respond differently to the same signal.

Answer

Cells become more sensitive to a signal after prolonged exposure.

Answer

Signals can be transmitted over long distances within the cell.

Question 27

What is the primary role of scaffolding proteins in signal transduction?

Accepted Answer

They organize groups of interacting signaling molecules into signaling complexes.

Answer

They amplify signals by activating multiple downstream molecules.

Answer

They act as second messengers, relaying signals from activated receptors.

Answer

They terminate signals by dephosphorylating activated kinases.

Question 28

Which of the following is a mechanism by which cells can desensitize themselves to a signal?

Accepted Answer

Receptor sequestration

Answer

Signal amplification

Answer

Positive feedback loop

Answer

Increased receptor synthesis

Question 29

Mutations in which type of genes are most commonly associated with the development of cancer?

Accepted Answer

Genes encoding components of cell signaling pathways

Answer

Genes encoding metabolic enzymes

Answer

Genes encoding structural proteins

Answer

Genes encoding DNA repair proteins