Question 13 TRUE or FALSE and please explain 1 With the seco

Question 1-3. TRUE or FALSE. and please explain.

1. With the secondary active transport, energy is directly required by the carrier to move a substance uphill against a concentration gradient.

2. A solution of lower solute concentration has a highe concentration of water, therefore, it has a lower osmotic pressure than does a solution with a higher solute concentration.

3. The only means by which an extracellular chemical message can bring about a desired intracellular response is to activate a second messenger system

question 4: which is not a common step in the process of receptor-mediated endocytosis? and please explain.

a. hormone binds together

b. hormone-recptor complex is taken into the cell via endocytosis

c. hormone is seperated from the receptor and ultimately activates genetic system of the cell leading to a cellular responses

d. hormone is recycled back into the cell membrane

Solution

1. This statement is false. Secondary active transport (cotransport), uses an electrochemical gradient – generated by active transport as an energy source to move molecules against their gradient, and thus does not directly require a chemical source of energy such as ATP.

2. This statement is true. A solution with lower solute concnetration will have higher concentration of water molecules outside a cell than inside.

3. This statement is incorrect. It is not the only means. There are two methods for this process: