Structure and Function of Plasma Membranes

This set of flashcards covers key concepts related to the structure and function of plasma membranes, including types of proteins, transport mechanisms, osmosis, and tonicity.

What moves substances down their concentration gradients across the plasma membrane with the aid of proteins?

Facilitated transport.

What type of proteins facilitate the movement of ions and molecules across the plasma membrane?

Channel proteins and carrier proteins.

What is a characteristic of gated channel proteins?

They control the channel's opening based on certain stimuli.

Which type of protein binds a substance and changes shape to transport it across the membrane?

Carrier protein.

What is the process called that involves the movement of water through a semipermeable membrane?

Osmosis.

What term describes the solution that has a lower osmolarity than the fluid inside a cell?

Hypotonic solution.

In a hypertonic solution, how does the extracellular fluid compare to the fluid inside the cell?

It has a higher osmolarity, causing water to leave the cell.

What happens in an isotonic solution regarding water movement?

There is no net movement of water into or out of the cell.

What mechanism do many living organisms use to control the effects of osmosis?

Osmoregulation.

What is the result of excessive water leaving a red blood cell?

The cell shrinks, or crenates.

What part of the plant cell helps prevent lysis in a hypotonic solution?

Cell wall.

What condition occurs when a plant cell loses turgor pressure due to lack of water?

Plasmolysis.

How do freshwater and saltwater fish manage osmotic pressure in their environments?

Freshwater fish actively take in salt and excrete diluted urine; saltwater fish secrete salt and excrete concentrated urine.

What regulates water amount in vertebrates' bodies?

The kidneys.

What specialized cells in the brain monitor the solute concentration in the blood?

Osmoreceptors.