Plasma Membrane and Cellular Transport

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 kinds of molecules pass through a cell membrane most easily?

• ionic

• small and hydrophobic

• large polar

• large and hydrophobic

Which of the following allows water to move faster across cell membranes?

• aquaporins

• ATP

• peripheral proteins

• the sodium-potassium pump

_______ regulates what enters and leaves a cell.  

• Cell Membrane

• Nucleus

• Mitochondria

• Cytoplasm

Tags

NGSS.MS-LS1-2

Identify cholesterol molecule

• structure a

• structure b

• structure h

• structure i

Identify a peripheral protein

• structure a

• strucure b

• structure g

• structure h

Which is NOT a function of the membrane?

• it forms a selective barrier

• it has receptors for chemical messages

• it is the control center of the cell

• it is involved in self recognition

Membrane phospholipids

• have hydrophobic heads that face the center of the membrane and are shielded from water

• have hydrophilic tails that face outward

• remain fluid because they are tightly packed

• none of these

Which of the following substances would have the most trouble crossing the membrane by diffusing through the bilayer?

• water

• oxygen

• carbon dioxide

• a sodium ion