Which of the following statements about ion channel is not true? A) Ion channel

Question

Which of the following statements about ion channel is not true? A) Ion channel are gated B) Ion channels allow some ions to pass nut not others C) Ion channels allow more than a million ions to pass each second D) Ion channels change conformation as each ion passes What would be the outcome if gut epithelial cells were missing the glucose Na^+ symport? A) Glucose would not be transported from the gut lumen into the gut epithelial cells B) There will be no effect no glucose transport into or out of the gut of epithelial cells C) Food cannot be broken down into glucose in the gut D) Glucose would not be exported out of the gut epithelial cells Conversion of a chemical signals to an electrical signal in the post synaptic cell requires which of the following?' A) Depolarization of the membrane B) Binding of the neurotransmitter to its receptor C) Activation of ligand gated channels D) All of the above True or false 1. Electrons donated by NADU to the electrons tra

Explanation / Answer

1.Ion channels are those membrane protein complexes whose function is to facilitate the diffusion of ions across biological membranes.These are gated which means that they open when required to allow the specific ions to pass and get closed when not needed and hence regulate the entry of ions. These ion channels can allow 106 ions per second.

The answer is 'D', since ion channels open they allow the needed number of ions to pass through at once, hence there is no conformation change to pass each ion.

2.Symport means cotransport where carriers bind two dissimilar solutes (substrates) and transport them together across a membrane. Transport of the two solutes is obligatorily coupled. A gradient of one type of ion, may drive uphill (against the gradient) transport of a another type of ion. It is sometimes referred to as secondary active transport.

eg.the glucose-Na+ symport found in plasma membranes of some epithelial cells and the bacterial lactose permease, a H+ symport carrier.

if glucose-Na+symport was missing in gut epithelial cells then the glucose molecules would not be trasported from the gut lumen into the epithelial cells.

3.During the conversion of electrical signal to chemical signal ,the post synaptic neuron receives the neurotransitters from presynaptic neuron, which undergoes depolarization of the membrane so as to prepare the cell to be ready to recieve syngnal where neurotransmitters bind to their respective receptors and further there will be activation of the ligand gated channels to open.

hence the answer is D,All of the above.

4) 1. The electrons donated by NADH in ETC( electron transport chain) gets in O2 and not H2o.

hence the answer is false

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