Concept explainers
Introduction: Aquaporins or water channels are the proteins that help in the movement of water across the membrane. They are integral membrane proteins that form pores in the membrane to allow the transfer of water and sometimes small solutes.
Answer to Problem 1TY
Correct answer: Aquaporins are the protein channels that allow the transfer of water across the plasma membrane. Hence, the correct answer is option c.
Explanation of Solution
Reason for correct answer:
Aquaporins are a part of major intrinsic proteins that result in the pore formation. This allow the exchange of water molecules, and in some cases, small solute particles across the plasma membrane.
Option c. is given as “a protein channel in plasma membranes that facilitates the diffusion of water”.
The intrinsic proteins that cause the exchange of water molecules across the membrane are called aquaporins. Hence, the correct answer is option c.
Reasons for the incorrect answer:
Option a. is given as, “a channel protein that allows the influx of K+ into cells, causing water to flow in between the phospholipids of the plasma membrane”.
The aquaporins only allow the transfer of water molecules from extracellular fluid to the cytoplasm and not ions. Hence, option a. is incorrect.
Option b. is given as, “a type of blue-colored pore in the epidermal surfaces of plants”.
The aquaporins are not blue colored and are present in the plasma membrane of the cells for the transport of water. Hence, option b. is incorrect.
Option d. is given as, “a transport protein, or transporter, in plasma membranes that use protons to co-transport water”.
Aquaporins are the primary channels for the transport of water, some small neutral solutes and carbon dioxide through the plant cell membrane. They transfer the water molecules based on the concentration gradient. Hence, option d. is incorrect.
Option e. is given as, “none of the above”.
The aquaporins serve as protein channels that are hydrophobic and allow the transfer of water molecules. Hence, option e. is incorrect.
Hence, the options a., b., d., and e. are incorrect.
Aquaporins are present on the plasma membrane of the plant, animal, and bacterial cells. These protein channels serve as the key transport route for the water molecules. They are hydrophobic and can also transfer some neutral solutes and carbon dioxide across the plasma membrane.
Want to see more full solutions like this?
Chapter 38 Solutions
Connect Access Card for Biology
- How can substances be transported across a membrane against their concentration gradient? A. If the plasma membrane is fully hydrophobic. B. The plasma membrane is permeable to all small molecules. C. Some membrane proteins act as channels for specific molecules to enter the cell. D. Some membrane proteins are ATP-dependent carrier molecules.arrow_forwardOsmosis is a special type of diffusion that ________. a. moves water from an area with a high solute concentration to one of lower solute concentration b. moves sugar from an area with a high solute concentration to a lower solute concentration c. moves water from an area with a low solute concentration to one of higher solute concentrationarrow_forwardTurgor pressure can be measured, in part, by determining the ____________. A. external force of water applied to a bacterial cell's membrane B. external force of water applied to animal cell's membrane C. internal force of water applied to a plant cell's vesicle D. internal force of water applied to a fungal cell's wallarrow_forward
- A solute passively diffuses through a transport protein out of the cell, therefore, ____. a. the concentration of water is higher inside the cell than outside b. the concentration of water is lower inside the cell than outside c. the concentration of the solute is the same inside and outside the cell d. the concentration of the solute is lower inside the cell than outside e. the concentration of the solute is higher inside the cell than outsidearrow_forwardpart 1 Reaching osmotic balance across a semipermeable membrane for non-charged molecules depends on: a.Relative solute concentration gradient across the membrane b.Relative electrical gradient across the membrane c.Relative solute concentration and electrical gradient across the membrane part 2 The equilibrium of a charged molecule across a semipermeable membrane depends on: a.Relative solute concentration gradient across the membrane b.Relative electrical gradient across the membrane c.Relative solute concentration and electrical gradient across the membranearrow_forwardIf placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference? the relative inelasticity and strength of the plant cell wall the relative impermeability of the plant cell membrane to water the relative impermeability of the plant cell wall to water expulsion of water by the plant cell's central vacuolearrow_forward
- Active transport pumps are used to move sodium ions across the membranes of gill cells in freshwater fish species. Which of the following statements about the pumps is accurate?Explain. a) There are specific binding sites for sodium ions on the pump b) They require osmosis to carry the sodium ions into the cell c) This is an example of passive diffusion and ATP is required d) Their lipid based structure allows it to embed in the cell membranearrow_forwardWhich of these statements about ion movement through the plasmamembrane is true?a. Movement of Na+ out of the cell requires energy (ATP).b. When Ca2+binds to proteins in ion channels, the diffusion of Na+into the cell is inhibited.c. Specific ion channels regulate the diffusion of Na+ through theplasma membrane.d. All of these are truearrow_forwardWhen an animal cell is placed on an isotonic solution, water molecules will A) Move out of the cell, resulting in shrinkage B) move into the cell until it bursts C) move into and out of the cell at equal rates D) stop moving need help for this, thanksarrow_forward
- The energy required for active transport can come from: A. A concentration gradient B. A high energy molecule like ATP C. A and B D. Neither A nor Barrow_forwardConsider a plant cell. The value for solute concentration in a plant cell is -0.12 MPa and the turgor pressure is 0.12 MPa. 1- What is the water potential in this plant cell? 2- If this plant cell were placed in a solution with water potential of -0.1 MPa, what would happen to the cell? (Hint: explain where the water goes and what that does to the cell).arrow_forwardThe membrane in the diagram above is not permeable to the sugar in the solution, however it is permeable to water. Which of the following statements would best describe what will happen? Select ALL that apply. [mark all correct answers]a. Sugar molecules will move to side A until the concentrations on both sides are equal.b. There will be no change since the membrane is not permeable to the sugar molecules.c. Sugar molecules will move to side A at the same rate as the water molecules will move to side B.d. Water molecules will move to side B until the concentrations on both sides are equal.arrow_forward
- Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax CollegeBiology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage LearningBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning