Cell Signalling: Master the Language of Cells

Question 1

Identify the type of cell signaling in which cells release chemical messengers that travel over short distances to affect neighboring cells.

Accepted Answer

Paracrine signaling

Answer

Endocrine signaling

Answer

Autocrine signaling

Answer

Sympathetic signaling

Question 2

Which of the following is classified as a neurotransmitter?

Accepted Answer

Epinephrine

Answer

Insulin

Answer

Testosterone

Answer

Cortisol

Question 3

Which mechanism is involved in the amplification of signals within cells?

Accepted Answer

Utilization of second messengers

Answer

Feedback loops

Answer

Binding of multiple receptors

Answer

Synthesis of new ligands

Question 4

Which of the following is NOT a step in the standard sequence of events in cell signaling?

Accepted Answer

Transcription of new genes

Answer

Binding of a ligand to a receptor

Answer

Transduction of the signal within the cell

Answer

Cellular response to the signal

Question 5

Which characteristic best describes paracrine signaling?

Accepted Answer

Signals act on cells in close proximity to the signaling cell

Answer

Signals travel over long distances

Answer

Signals are transported via the bloodstream

Answer

Signals are amplified through multiple rounds of receptor binding

Question 6

Which of the following is an example of an autocrine signalling molecule?

Accepted Answer

Prostaglandin

Answer

Epinephrine

Answer

Insulin

Question 7

Which of the following best describes a characteristic of paracrine signalling?

Accepted Answer

Signals act locally over short distances

Answer

Signals act over long distances

Answer

Signals are universally non-specific

Question 8

What is the primary role of G proteins in cell signalling?

Accepted Answer

To link signals from receptors to effector proteins

Answer

To bind to signalling molecules and trigger responses

Answer

To synthesize second messengers

Answer

To transport signalling molecules across the cell membrane

Question 9

Which of the following is an instance of a hormone that acts as a second messenger?

Accepted Answer

Cyclic AMP

Answer

Testosterone

Answer

Estrogen

Answer

Thyroid hormone

Question 10

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

Accepted Answer

Enzyme

Answer

Hormone

Answer

Neurotransmitter

Answer

Ligand

Question 11

What is the primary role of a receptor in cell signaling?

Accepted Answer

To bind to a signaling molecule and trigger a response

Answer

To produce the signaling molecule

Answer

To break down the signaling molecule

Answer

To transport the signaling molecule

Question 12

What is the second messenger involved in the cAMP signaling pathway?

Accepted Answer

cAMP

Answer

IP3

Answer

DAG

Answer

Ca2+

Question 13

Which of the following is a characteristic of endocrine signaling?

Accepted Answer

Long-range

Answer

Slow

Answer

Paracrine

Answer

Autocrine

Question 14

What is the primary function of protein kinases in cell signaling?

Accepted Answer

To phosphorylate proteins and alter their activity

Answer

To dephosphorylate proteins and alter their activity

Answer

To bind to DNA and regulate gene expression

Answer

To produce signaling molecules

Question 15

How can the activation of one cell signalling pathway influence or interact with other signalling pathways? Provide specific examples to illustrate your explanation.

Accepted Answer

Activation of one pathway can inhibit another, preventing conflicting cellular responses. (Example: Insulin signalling inhibiting glucagon signalling in glucose metabolism)

Accepted Answer

Activation of one pathway can amplify the effects of another, leading to synergistic cellular responses. (Example: Epinephrine signalling enhancing the effects of glucagon signalling in glycogen breakdown)

Answer

Signalling pathways are completely independent and do not interact with each other.

Answer

Signalling pathways only interact with each other through physical contact between receptors.

Question 16

Why is a thorough understanding of cell signalling essential for comprehending physiological processes in living organisms?

Accepted Answer

Cell signalling coordinates and regulates complex physiological functions

Answer

Cell signalling is only important for understanding hormonal regulation

Answer

Cell signalling is only studied in the nervous system

Question 17

What is a function of protein kinases in cell signalling?

Accepted Answer

To phosphorylate proteins

Answer

To dephosphorylate proteins

Answer

To bind to specific DNA sequences

Answer

To generate small molecules

Question 18

What is the primary function of a cell surface receptor?

Accepted Answer

To bind to a specific molecule, called a ligand

Answer

To amplify a signal

Answer

To produce a cellular response

Answer

To transport molecules across the cell membrane

Question 19

Which of the following hormones is primarily responsible for regulating blood sugar levels?

Accepted Answer

Insulin

Answer

Testosterone

Answer

Estrogen

Answer

Adrenaline

Question 20

Which of the following neurotransmitters is known to play a crucial role in mood regulation?

Accepted Answer

Serotonin

Answer

Dopamine

Answer

Acetylcholine

Answer

Glutamate

Question 21

Which of the following experimental techniques is commonly used to study the binding of ligands to receptors?

Accepted Answer

Radioligand binding assay

Answer

Western blotting

Answer

Immunohistochemistry

Answer

Flow cytometry

Question 22

Which of the following molecules acts as a second messenger in both protein kinase A and protein kinase G signalling pathways?

Accepted Answer

cAMP

Answer

IP3

Answer

DAG

Answer

Ca2+

Question 23

Which step initiates the cell signalling process?

Accepted Answer

Ligand binding to a receptor

Answer

Second messenger generation

Answer

Protein kinase activation

Answer

Target gene transcription

Question 24

Which cell signalling type involves direct contact between adjacent cells?

Accepted Answer

Juxtacrine

Answer

Endocrine

Answer

Paracrine

Answer

Autocrine

Question 25

Which characteristic is unique to G protein-coupled receptors (GPCRs)?

Accepted Answer

Seven transmembrane helices

Answer

Intracellular catalytic domain

Answer

Ion channel linkage

Answer

Direct DNA binding

Question 26

Which second messenger is associated with protein kinase A (PKA) activation?

Accepted Answer

cAMP

Answer

IP3

Answer

DAG

Answer

Ca2+

Question 27

Which neurotransmitter is implicated in the "fight-or-flight" response?

Accepted Answer

Noradrenaline

Answer

GABA

Answer

Glutamate

Answer

Dopamine

Question 28

Which receptor type is located within the cell nucleus?

Accepted Answer

Steroid hormone receptor

Answer

Ligand-gated ion channel

Answer

G protein-coupled receptor

Answer

Receptor tyrosine kinase

Question 29

Which neurotransmitter is known for its inhibitory effects on neuronal activity?

Accepted Answer

GABA

Answer

Dopamine

Answer

Serotonin

Answer

Glutamate

Question 30

Which type of receptor is directly coupled to an ion channel?

Accepted Answer

Ion channel-linked receptor

Answer

G protein-coupled receptor

Answer

Tyrosine kinase receptor

Answer

Nuclear receptor

Question 31

Which molecule acts as a second messenger in cell signalling?

Accepted Answer

Cyclic AMP

Answer

Guanine nucleotide-binding protein

Answer

Receptor tyrosine kinase

Answer

Steroid hormone

Question 32

Which of the following is NOT a potential consequence of dysregulated cell signalling?

Accepted Answer

Normal development

Answer

Cancer

Answer

Diabetes

Answer

Heart disease

Question 33

What is the primary function of hormone-sensitive lipase?

Accepted Answer

Degradation of triglycerides to release fatty acids

Answer

Synthesis of cholesterol

Answer

Regulation of blood sugar levels

Answer

Activation of adenylyl cyclase

Question 34

Which hormone is secreted from the adrenal glands in response to stressful stimuli?

Accepted Answer

Epinephrine

Answer

Insulin

Answer

Thyroid hormone

Answer

Testosterone

Question 35

Describe the molecular events that occur when a ligand binds to a G protein-coupled receptor (GPCR), leading to the activation of a signalling cascade.

Accepted Answer

Ligand binding induces a conformational change in the GPCR, causing the exchange of GDP for GTP on the G protein.

Answer

Ligand binding directly activates the G protein, bypassing the GPCR.

Answer

Ligand binding causes the GPCR to dissociate from the G protein, activating the G protein.

Answer

Ligand binding triggers phosphorylation of the GPCR, which then activates the G protein.

Question 36

Which type of cell signalling is characterized by the release of hormones that travel through the bloodstream to reach target cells?

Accepted Answer

Endocrine signalling

Answer

Paracrine signalling

Answer

Autocrine signalling

Answer

Synaptic signalling

Question 37

What is the name for the molecule that initiates cell signalling by binding to receptors on the target cell?

Accepted Answer

Ligand

Answer

Effector

Answer

Transducer

Answer

Second messenger

Question 38

What is the primary function of second messengers in cell signalling?

Accepted Answer

To amplify the signal from the receptor

Answer

To directly activate target proteins

Answer

To transport ligands across the membrane

Answer

To synthesise new proteins

Question 39

Which endocrine gland is responsible for releasing growth hormone?

Accepted Answer

Pituitary gland

Answer

Adrenal gland

Answer

Pancreas

Answer

Thyroid gland

Question 40

What is the primary role of a hormone?

Accepted Answer

To transmit signals over long distances

Answer

To regulate gene expression

Answer

To initiate a rapid cellular response

Answer

To amplify the effects of neurotransmitters

Question 41

Which of the following is NOT a characteristic of a neurotransmitter?

Accepted Answer

Mediates long-distance communication

Answer

Released from synapses

Answer

Stimulates or inhibits post-synaptic cells

Answer

Binds to specific receptors

Question 42

What is the purpose of a receptor in cell signalling?

Accepted Answer

To bind ligands and initiate a response

Answer

To amplify the signal

Answer

To regulate gene expression

Answer

To transport molecules

Question 43

Which of the following is an example of a negative feedback mechanism in cell signalling?

Accepted Answer

Hormone B inhibits the release of hormone A

Answer

Hormone A stimulates the release of hormone B

Answer

Receptor downregulation

Answer

Ligand-receptor complex formation

Question 44

What is the principal function of a receptor in cell signalling?

Accepted Answer

To bind specific molecules and trigger intracellular responses

Answer

To transmit signals between cells

Answer

To intensify signals within a cell

Answer

To inhibit the effects of signals

Question 45

Identify an example of a paracrine signalling molecule:

Accepted Answer

Histamine

Answer

Insulin

Answer

Epinephrine

Answer

Serotonin

Question 46

Which of the following is NOT a function of cell signalling?

Accepted Answer

Phototaxis

Answer

Coordination of cellular activities

Answer

Regulation of growth and differentiation

Answer

Protection against stress

Question 47

The hormone adrenaline acts on cells by increasing the concentration of:

Accepted Answer

cAMP

Answer

cGMP

Answer

IP3

Answer

DAG

Question 48

The binding of a ligand to a nuclear receptor triggers:

Accepted Answer

Transcription of new genes

Answer

Activation of G proteins

Answer

Hydrolysis of GTP

Answer

Release of second messengers

Question 49

What is the main function of G proteins in cellular signalling?

Accepted Answer

Relaying signals

Answer

Amplifying signals

Answer

Binding to receptors

Answer

Gating ion channels

Question 50

Which neurotransmitter is associated with muscle contraction and mental alertness?

Accepted Answer

Epinephrine

Answer

Dopamine

Answer

Serotonin

Answer

GABA

Question 51

How do steroid hormones primarily exert their effects on target cells?

Accepted Answer

Directly binding to DNA

Answer

Activating protein kinases

Answer

Modifying membrane permeability

Answer

Inhibiting gene transcription

Question 52

What acts as the primary second messenger in the cAMP signalling pathway?

Accepted Answer

Cyclic AMP

Answer

Inositol 1,4,5-trisphosphate

Answer

Diacylglycerol

Answer

Calcium