Exam 12: Biosignaling

Correct Answer:

Answered by Examlex AI Copilot

To match the signal input with the result, we need to understand how different sensory cells respond to various stimuli:a) Light typically causes photoreceptor cells in the retina to hyperpolarize. When light hits these cells, it leads to a chemical change that closes ion channels, causing the cell to become more negative inside compared to the outside.
b) Odorant molecules bind to receptors on olfactory sensory neurons, which usually leads to the depolarization of these cells. This depolarization occurs because the binding of the odorant opens ion channels, allowing positively charged ions to flow into the cell.
c) Sweet molecules interact with taste receptors on the tongue, particularly the G protein-coupled receptors that, when activated, initiate a cascade of events leading to depolarization of the taste sensory cells.
d) Epinephrine (adrenaline) binds to adrenergic receptors on various target cells. Depending on the specific receptor type (alpha or beta receptors), the effect can be either depolarization or hyperpolarization. However, in many cases, epinephrine binding leads to a response that does not directly change the membrane potential but instead triggers a signaling cascade that results in physiological changes, such as increased heart rate or breakdown of glycogen.
Based on this information, the matches would be:
a) Light - 2) Sensory cell hyperpolarizes
b) Odorant - 1) Sensory cell depolarizes
c) Sweet molecule - 1) Sensory cell depolarizes
d) Epinephrine - 3) No effect on sensory cell membrane potential (or it could have various effects depending on the cell type, but for simplicity, we'll choose no direct effect on membrane potential)
Please note that the response to epinephrine can vary greatly depending on the cell type and receptor involved, so the answer provided for epinephrine is a simplified generalization.