ls7a Membrane Transport Review Question

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

The random movement of molecules within a solution is referred to as:

diffusion

solution; has a lower solute concentration than that of inside the cell. - Cell also inflates/bursts because there is too much solute (ex. Water) entering

hypotonic,

Tonicity

The ability of a solution surrounding a cell to cause that cell to gain or lose water.

Isotonic

a solution; when the solute concentration is the same as that of the cell. A balance. - Cell remains the same

Why does active transport of molecules across a membrane require ATP?

An input of energy is needed to allow the movement of molecules from an area of low concentration to one of higher concentration.

During osmosis, water moves from a region of _____ to a region of _____.

Both "high solvent concentration; low solvent concentration" AND "low solute concentration; high solute concentration" are correct answers.

Osmosis

Diffusion of water through a selectively permeable membrane

Secondary Active Transport

Form of active transport which does not use ATP as an energy source; rather, transport is coupled to ion diffusion down a concentration gradient established by primary active transport.

when a solute solution has a higher concentration than that of inside the cell (the solvent). - Cell shrinks because of the difference in solute concentration of the outside and inside (water leaves the cell).

Hypertonic "more of something and less of water"

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration. (to balance the sides)

Can Macromolecules (ex. Proteins) and polysaccharides (sugar) pass through the phospholipid bilayer?

No, too big

A beaker contains two solutions of salt dissolved in water. The two solutions have different concentrations of salt (measured by molarity, M) and are separated by a membrane that is permeable to both salt and water. The salt and water will move through the membrane by diffusion. Which statement is true about the diffusion of these solutions?

There will be a net movement of salt from side B to side A and net movement of water from side A to side B.

selectively permeable

a property of cell membranes that allows some substances to pass through, while others cannot (ex. protein cant too big).

The plasma membranes of some plant cells use transport proteins to move protons out of the cell against their concentration gradient. This is an example of:

active transport

Primary Active Transport

active transport that moves ions or small molecules across a membrane and may create a difference in charge across that membrane

Which molecules can easily diffuse across a plasma membrane?

gases like O2 and CO2

Some plant cells create a high concentration of protons outside the cell to move solutes, such as sucrose, across the plasma membrane into the cell where the sucrose concentration is already relatively high. This type of transport is an example of:

secondary active transport.

Can Gases (o2, CO2), nonpolar (where electronegativity is evenly distributed) molecules like lipids can?

yes