A Gram-negative cell is moving uric acid across the cytoplasmic membrane against its chemical gradient. Which of the following statements is true?

a. The exterior of the cell is probably electrically negative compared to the interior of the cell.
b. The acid probably moves by a passive means such as facilitated diffusion.
c. The acid moves by an active process such as active transport.
d. The movement of the acid requires phagocytosis.

Question

A Gram-negative cell is moving uric acid across the cytoplasmic membrane against its chemical gradient. Which of the following statements is true?

a. The exterior of the cell is probably electrically negative compared to the interior of the cell.

b. The acid probably moves by a passive means such as facilitated diffusion.

c. The acid moves by an active process such as active transport.

d. The movement of the acid requires phagocytosis.

Accepted Answer

Hello, everyone. Let's take a look at the next question. A bacterial cell moves lactose molecules from a region of low concentration outside the cell to a region of high concentration inside the cell. Which statement below accurately describes this scenario. A the movement of lactose requires phagocytosis. B the exterior of the cell is probably electrically positive compared to the interior C, the lactose moves by an active process such as active transport or D the lactose probably moves by a passive means such as simple diffusion. So let's just keep in mind what's going on here. The molecule that's moving is lactose. So this is a polar molecule but it's not charged and it's moving against a concentration gradient. Well, what do we know when we move something against the concentration gradient? We know that we need to put in energy, we need to do work to make this go against the direction it would naturally flow and that requires an active means of transport. So when we look at our answer choices, what involves an active process? Choice? C the lactose moves by an active process such as active transport. And again, this is because it requires energy to move against the gradient. When we look at our other answer, choices, choice D the lactose moves by a passive means into simple diffusion. This would only be the case if it were moving down the concentration gradient. So that's why choice D is not going to be our answer here. Choice A the movement of lactose requires phagocytosis. Voc cytosis is a means of bringing things into a cell. But it's the means by which cells bring specifically used by some eukaryotic cells to engulf large particles or entire cells. It's not used for the movement of small particles or small molecules. So it wouldn't be used to move a sugar molecule like lactose. So that would not be our answer choice. And then finally, choice B the exterior of the cell is probably electrically positive compared to the interior. Well, first of all, in general, the interior of the cell is generally electrically negative with regard to the exterior. But in addition, lactose is not a charged molecule, it's not an ion. And so it wouldn't be moving down an electrochemical gradient. So choice B not going to be our answer, but they there would be no electrochemical gradient explaining the movement of lactose. So once again, if we have a situation where a cell is moving lactose molecules from a region of low concentration outside the cell to a region of high concentration inside the cell, which statement accurately describes this scenario and the answer is choice C the lactose moves by an active process such as active transport. See you in the next video.

Verified Solution

Key Concepts

Gram-negative Bacteria

Active Transport

Chemical Gradient