Question

question 7
in which situation would passive transport not use a transport protein for entry into a cell?
water flowing into a hypertonic environment
glucose being absorbed from the blood
an ion flowing into a nerve cell to create an electrical potential
oxygen moving into a cell after oxygen deprivation
none of these answer choices are correct.
question 8
active transport must function continuously because __________.
plasma membranes wear out
not all membranes are amphiphilic
facilitated transport opposes active transport
diffusion is constantly moving solutes in opposite directions
none of these answer choices are correct.
question 9
how does the sodium - potassium pump make the interior of the cell negatively charged?
by expelling anions
by pulling in anions
by expelling more cations than are taken in
by taking in and expelling an equal number of cations
none of these answer choices are correct.

Explanation:

Question 7

Passive transport includes simple diffusion where small, non - polar molecules like oxygen can cross the cell membrane without a transport protein. Oxygen is small and non - polar, so it can move into a cell by simple diffusion after oxygen deprivation. Water movement in a hypertonic environment may involve aquaporins (a type of transport protein), glucose absorption requires transporters, and ion movement for electrical potential involves ion channels or transporters.

Question 8

Active transport must function continuously because diffusion is constantly moving solutes in opposite directions. Diffusion tends to move substances down their concentration gradients, while active transport moves substances against their concentration gradients to maintain concentration differences across the membrane. Plasma membranes don't directly cause the need for continuous active transport, not all membranes being amphiphilic is not related to the continuous function of active transport, and facilitated transport doesn't oppose active transport in a way that requires continuous active transport.

Question 9

The sodium - potassium pump makes the interior of the cell negatively charged by expelling more cations than are taken in. It pumps 3 sodium ions out of the cell and 2 potassium ions into the cell for each ATP molecule hydrolyzed, resulting in a net loss of positive charge inside the cell.

Answer:

Question 7: oxygen moving into a cell after oxygen deprivation
Question 8: diffusion is constantly moving solutes in opposite directions
Question 9: by expelling more cations than are taken in