Question

osmosis occurs since cells by finding a potential current in its cell membrane, which from a higher concentration to a lower concentration gradient. through this process does not require energy. this is an example of:

a) facilitated diffusion (is a type of passive transport)
b) simple diffusion.
c) active transport.

active transport across the cell - membrane requires:
a) movement of substances down their concentration gradient.
b) energy in the form of atp
c) no energy input from the cell.
d) movement of water from high to low concentration.

a cell is placed in a solution where the concentration of solutes is lower outside the cell than inside the cell. this type of solution is called:
a) hypertonic
b) hypotonic
c) isotonic

the cell membranes role in maintaining homeostasis is directly related to its ability to:
a) produce enzymes for metabolic reactions.
b) synthesize proteins for cell structure.
c) store genetic information.
d) control the movement of substances into and out of the cell.

the sodium - potassium pump moves cells across sodium ions out of the cell and potassium ions into the cell, both against their concentration gradients. this process requires:
a) passive transport
b) atp

Explanation:

1. Osmosis is the movement of water across a semi - permeable membrane from an area of high water concentration to an area of low water concentration. Facilitated diffusion involves the use of transport proteins to move substances down their concentration gradient and does not require energy. Simple diffusion is the movement of substances from an area of high concentration to an area of low concentration without the use of energy or transport proteins. Active transport moves substances against their concentration gradient and requires energy in the form of ATP.
2. Active transport moves substances against their concentration gradient and requires energy in the form of ATP. It is used to move substances into or out of the cell against the natural flow.
3. Hypotonic solutions have a lower solute concentration compared to the cell, causing water to move into the cell. Hypertonic solutions have a higher solute concentration, causing water to move out of the cell. Isotonic solutions have the same solute concentration as the cell, resulting in no net movement of water.
4. The cell membrane's role in maintaining homeostasis is directly related to its ability to control the movement of substances into and out of the cell.
5. The sodium - potassium pump moves sodium ions out of the cell and potassium ions into the cell against their concentration gradients and requires ATP for energy.

Answer:

1. A. Facilitated diffusion (it is a type of passive transport)
2. C. Energy in the form of ATP
3. A. Hypotonic
4. D. Control the movement of substances into and out of the cell
5. B. ATP