Question

active transport across the cell membrane requires: * 1 point
energy in the form of atp.
no energy input from the cell.
movement of substances down their concentration gradient.
movement of water from high to low concentration.

cells in the root hairs of a plant need to absorb mineral ions from the soil, where the concentration of these ions is lower than inside the root hair cells. this process requires energy and is called: * 1 point
facilitated diffusion.
simple diffusion.
osmosis.
active transport.

a scientist observes a cell shrinking when placed in a particular solution. this indicates that * 1 point
the solution is:
hypotonic to the cell.
isotonic to the cell.
in equilibrium with the cell.
hypertonic to the cell.

Explanation:

1. Active transport across the cell - membrane moves substances against their concentration gradient and requires energy in the form of ATP.
2. When root - hair cells absorb mineral ions from soil where ion concentration is lower outside, moving ions against the concentration gradient with energy input is active transport.
3. A cell shrinks when placed in a solution because water moves out of the cell. This occurs when the solution is hypertonic (has a higher solute concentration) compared to the cell.

Answer:

1. Energy in the form of ATP.
2. Active transport.
3. Hypertonic to the cell.