BIO 1308 (Cell membrane/Transport)

Aquaporins

Allow water to cross the plasma membrane via facilitated diffusion

Which of the following processes can move a solute against its concentration gradient? Facilitated diffusion Passive transport Osmosis Active transport

Active transport

Which one of the following statements regarding active transport is false? Active transport is driven by the concentration gradient Active transport uses ATP as an energy source Active transport requires the cell to expand energy Active transport can move a solute against its concentration gradient

Active transport is driven by the concentration gradient

Membrane phospholipids... Remain fluid because they are tightly packed against one another. Have hydrophilic tails that face outward and are exposed to water. Are able to drift about in the plasma membrane. Have hydrophobic heads that face the center of the membrane and are shielded from water.

Are able to drift about the plasma membrane.

How do fatty acids travel through a cell membrane? Active transport Diffusion Carrier proteins Endocytosis

Diffusion

Which of the following statements regarding diffusion is false? Diffusion is a result of the thermal energy of atoms and molecules Diffusion occurs even after equilibrium is reached and no net change is apparent Diffusion requires no input of energy into the system Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated

Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated

The fluid mosaic model describes the plasma membrane as consisting of.. A phospholipid bilayer with embedded carbohydrates Two layers of phospholipids with cholesterol sandwiched between them Diverse proteins embedded in a phospholipid bilayer Carbohydrates and phospholipids that can drift in the membrane

Diverse proteins embedded in a phospholipid bilayer

A cell that has neither a net gain of water nor net loss of water when it is immersed in a solution must be... Hypotonic to its environment Isotonic to its environment Hypertonic to its environment

Isotonic to its environment

Which of the following statements regarding membrane protein function is false? Membrane proteins serve as enzymes. Membrane proteins form junctions between cells. Membrane proteins produce phospholipids. Membrane proteins act as receptors to molecules like hormones.

Membrane proteins produce phospholipids.

Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of Endocytosis Passsive Transport Active transport Exocytosis

Passive transport

Oxygen crosses a plasma membrane by Osmosis Active transport Endocytosis Passive transport

Passive transport

Most of the functions of a cell membrane, including transport and enzymatic function, are performed by Proteins Cholesterol Glycolipids Phospholipids

Proteins

The molecules responsible for membrane transport are Proteins Steroids Carbohydrates Phospholipids

Proteins

Osmosis can be defined as... The diffusion of water. The diffusion of nonpolar molecules The diffusion of a solute Active transport

The diffusion of water.

Plasma membranes are selectively permeable this means that... Glucose cannot enter the cell Plasma membrane must be very thick Anything can pass into or out of the cell as long as the membrane is intact and the cell is healthy The plasma membrane allows some substances to enter or leave a cell more easily than others

The plasma membrane allows some substances to enter or leave a cell more easily than others

Which of the following statements regarding membrane function is false? The plasma membrane plays a role in transferring signals to the cell's interior. The plasma membrane has receptors for chemical messages. The plasma membrane is the control center of the cell. The plasma membrane forms a selective barrier around the cell.

The plasma membrane is the control center of the cell

Which of the following is a typical feature of an ATP-driven active transport mechanism? The transport protein must cross to the correct side of the membrane before the solute can bind to it. The solute moves against the concentration gradient. The transport protein catalyzes the conversion of ADP to ATP

The solute moves against the concentration gradient.

facillitated diffusion across a biological membrane requires_____and moves a substance_____its concentration gradient. Transport proteins; against Transport proteins; down

Transport Proteins; down

The cholesterol associated with animal cell membranes Helps solidify the membranes when the room temperature is below freezing Helps keep phospholipids from being too close to one another Is attached to membrane proteins and extends into the watery environment surrounding the cell. Is abnormally resulting from a diet in high cholesterol

helps to keep phospholipids from being too close to one another.

The process of a white blood cell engulfing a bacterium is

phagocytosis