AP Biology Topic 4.2*: Signal Transduction

What is the first step of signal transduction?

• Response

• Reception

• Transduction

Answer explanation

The first step of the signal transduction pathway is reception. This occurs when the ligand binds to the receptor which leads to a confirmational shape change.

What is a signaling molecule called?

• Activator

• Enhancer

• Ligand

• Repressor

How does the polarity of the ligand affect the location of the receptor?​

Answer explanation

If the ligand is polar – the receptor will be membrane bound. Polar substances are unable to pass through the membrane.​

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If the ligand is nonpolar – the receptor will be intracellular. Nonpolar substances are able to pass through the membrane (so the receptor must be inside).​

Which of the following is NOT a function of transduction?

• To bring the message to its location for response​

• To amplify the signal/message​

• To regulate the signal​

• To stop the signal

All cells respond to the same ligand with the same response

• True

• False

What happens if the receptor is a ligand gated receptor?​

Answer explanation

Conformational change opens the gate and allows for the specific ions for that channel to flow down their concentration gradient.​

What are the three steps in signal transduction pathway?

Answer explanation

Reception​

Transduction​

Response​

What is the signaling molecule & where does it bind?​

• Ligand; Enzyme

• Ligand; Receptor

• Substrate; Enzyme

• Substrate; Receptor

Which of the following acts as a secondary messanger

• ATP

• ADP

• GTP

• cAMP

Plants diffuse signals between other cells by using..

• Gap Junctions

• Phosphatases

• Plasmodesmata

• Paracrine Signaling