B2.1 & D2.3 Plasma Membrane

Identify cholesterol molecule

• structure a

• structure b

• structure h

• structure i

Identify a peripheral protein

• structure a

• strucure b

• structure g

• structure h

Plasma membranes are selectively permeable. This means

• anything can pass in and out

• the membrane regulates the passage of the material in and out of the cell

• glucose cannot enter the cell

• cholesterol cannot enter

Small, nonpolar, hydrophobic molecules such as fatty acids

• easily pass through the membrane's bilayer

• very slowly diffuse through the bilayer

• require transport proteins

• enter through endocytosis

What do diffusion and osmosis have in common?

• They only happen in living cells.

• They require transport proteins in the membrane.

• They are passive transport mechanisms.

• Net movement of substances is against the concentration gradient.

What is the difference between simple diffusion and facilitated diffusion?

• A

• B

• C

• D

Which one of the following is not a function performed by a membrane protein?

• Cell adhesion

• Enzyme

• Hormone (Receptor) binding sites

• Vesicle Transport

Which of the following is a feature of exocytosis but not endocytosis?

• Shape changes of a membrane

• Vesicle formation

• Use of ATP

• Secretion

What is essential for diffusion?

• A concentration gradient

• A selectively permeable membrane

• A source of energy

• A protein

Which pair of characteristics are correct for the cellular processes of exocytosis and endocytosis?

• A

• B

• C

• D