Cellular Transport

What is the primary function of the cell membrane?

• To produce energy for the cell

• To store genetic material

• To regulate the passage of substances into and out of the cell

• To provide structural support to the entire organism

Which three main components make up a phospholipid molecule?

• Protein, carbohydrate, and water

• Glycerol, phosphate, and fatty acids

• DNA, RNA, and amino acids

• Glucose, fructose, and sucrose

How do phospholipid molecules arrange themselves in a bilayer within the cell membrane?

• Water-loving heads face inwards, and water-hating tails face outwards

• They randomly scatter throughout the membrane

• Water-loving heads face outwards, and water-hating tails face inwards

• They form a single layer with tails exposed to water

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Which type of membrane protein helps the immune system distinguish between the body's own cells and harmful invaders?

• Transport proteins

• Receptor proteins

• Glycoproteins

• Junction proteins

What is the primary function of junction proteins in cell membranes?

• To receive chemical signals from outside the cell.

• To help chemical reactions occur.

• To link to proteins on nearby cell membranes.

• To transport substances across the membrane.

Which of the following best describes diffusion?

• Movement of a chemical from where it's less concentrated to where it's more concentrated.

• Movement of a chemical from where it's more concentrated to where it's less concentrated.

• Movement of water across a semi-permeable membrane.

• Movement of substances that requires energy.

What is facilitated diffusion?

• A type of active transport that uses ATP.

• The movement of water across a membrane.

• Passive transport that requires a transport protein.

• The direct passage of nonpolar substances through the membrane.

What is a key characteristic of active transport?

• It moves substances from a high concentration to a low concentration.

• It does not require energy.

• It uses ATP to move substances in a needed direction.

• It only transports water molecules.