AP Biology Review

White blood cells engulf bacteria using _______________.

• phagocytosis

• pinocytosis

• osmosis

• receptor-mediated exocytosis

Which of the following factors would tend to increase membrane fluidity?

• a greater proportion of unsaturated phospholipids

• a greater proportion of saturated phospholipids

• a lower temperature

• a relatively high protein content in the membrane

According to the fluid mosaic model of cell membranes, phospholipids___________________.

• can shift laterally along the plane of the membranee

• frequently flip-flop from one side of the membrane to the other

• occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane

• have hydrophilic tails in the interior of the membrane

Which of the following types of molecules are hydrophilic and therefore excluded from the hydrophobic portion of the phospholipid bilayer?

• transmembrane proteins

• integral membrane proteins

• peripheral proteins

• cholesterol

In what way do the membranes of a eukaryotic cell vary?

• Phospholipids are found only in certain membranes

• Certain proteins are unique to each membrane

• Only certain membranes of the cell are selectively permeable

• Some membranes have hydrophobic surfaces exposed to the cytoplasm while others have hydrophilic surfaces facing the cytoplasm.

Which of the following processes is an "umbrella" term for the others?

• Osmosis.

• Facilitated diffusion.

• Passive transport.

• Transport of an ion down its electrochemical gradient.

Which of the following membrane activities requires energy from ATP?

• Facilitated diffusion of chloride ions through a chloride channel.

• Movement of Na⁺ ions from lower concentration in a mammalian cell to a higher concentration in the extracellular fluid.

• Movement of glucose molecules into a bacteria cell from a medium containing a higher concentration of glucose than inside the cell.

• Movement of carbon dioxide out of a paramecium.

An animal cell lacking in carbohydrates on the external surface of its plasma membrane would likely be impaired in which function?

• transporting ions against an electrochemical gradient

• cell-cell recognition

• attaching the plasma membrane to the cytoskeleton

• establishing a diffusion barrier to charged molecules

Which 4 elements make up most of all living matter?

• Carbon, Hydrogen, Nitrogen, Oxygen

• Carbon, Oxygen, Sodium, Potassium

• Carbon, Hydrogen, Calcium, Nitrogen

• Carbon, Oxygen, Nitrogen, Sulfur

Which of the following describes covalent bonds?

• Bonds form because of opposite charges

• electrons are shared to fill outer electron shells

• Electrons are transferred between atoms

• Covalent bonds are magical