Bio Chapter 5 Test

The fluid mosaic model describes the plasma membrane as consisting of

A phospholipid bilayer with embedded proteins

Membrane "ghosts"

Are derived from red blood cells, Are a form of pure plasma membrane, Are a result of breaking open cells and washing away the cytoplasm, Have provided much of our knowledge about plasma

Heating inactivates enzymes by

Breaking the hydrogen bonds that give the molecules its three-dimensional shape

A major function of glycoproteins are glycolipids in the cell membrane is to

Communicate with other cells by sending signals

How does inhibition of n enzyme-catalyzed reaction by a competitive inhibitor differ from inhibition by a noncompetitive inhibitor?

Competitive inhibitors bind to the active binding site; noncompetitive inhibitors bind to a different site

Living systems

Decrease their entropy while they increase the entropy of the universe

Phagocytosis is to eating as pinocytosis is to

Drinking

Cellular metabolism can include

Endergonic reactions, Exergonic reactions, Cellular repiration, Fermintation

When a cell uses chemical energy to perform work, it couples a (n) _____ reaction with a (n) _____ reaction

Exergonic ... Endergonic

What is the basic difference between exergonic and endergonic reactions?

Exergonic reactions release energy; endergonic reactions absorb (store) energy

Certain cells that line the stomach synthesizes a digestive enzyme and secrete it into the stomach. This enzyme is a protein. WHich of the following processes could be responsible for its secretion?

Exocytosis

Enzyme(s)

Function depends on its three-dimensional shape, emerged unchanged from the reactions they catalyze

Organic Cofactors

Include minerals

An "energy barrier"

Is equilavent to the energy of activation of a reaction

A plant cell in a hypotonic solution

Is turgid (or filled)

A cell that neither gains not loses water when it is immersed in a solution is

Isotonic to its enviornment

Which of the following is (are) a true statement about the ATP molecule?

It contains three phosphate molecules, It contains a nitrogenous base molecule called adenine

Which of the following is NOT a function of the plasma membrane?

It is the control center of the cell

When an enzyme catalyzes a reaction,

It lowers the activation energy of the reaction, It acts as a reactant but is not decomposed in the reaction

Which of the following is NOT a true statement about diffusion?

It occurs when particles spread from areas of less concentration to areas of greater concentration

The organ that plays a major role in osmoregulation (Regulates fluid level) in humans is the

Kidney

Which of the following energy transfers is (are) possible in living systems?

Light energy to chemical energy, Chemical energy to kinetic energy, light energy to potential energy

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

NA+

The production of insulin increases as blood sugar levels increase. The production of insulin decreases as the blood sugar levels decrease. This is an example of

Negative feedback

Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered

Passive Transport

The act of a white blood cell engulfing a bacterium is

Phagocytosis

The transfer of a phosphate group to a molecule or compound is celled

Phosphorulation

Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing

Potential energy into kinetic energy

Most of a cells enzymes are

Proteins

The molecules responsible for membrane transport are

Proteins

Anything that prevents ATP formation will

Result to cell death

Relaying a message from a membrane receptor to a molecule that performs a specific function within the cell is called

Signal Transduction

Which of the following can affect the rate of an enzyme-catalyzed reaction?

Temperature, pH, Competitive Inhibitors, Noncompetitive Inhibitors

Which of the following pieces of evidence would prove that a substance enters a cell by active rather then passive transport

The breakdown of ATP is needed for transport to occure

Osmosis can be defined as

The diffusion of water across a membrane

According to _____, energy cannot be created or destroyed

The first law o thermodynamics

Plasma membranes are selectively permeable. This means that

The plasma membrane regulates he passage of material into and out of the cell

The "active site" of an enzyme is

The region of the enzyme that attaches to a substrate

A steer must eat at least 100 pounds of grain to gain less then 10 pounds of muscle tissue. This illustrates

The second law of thermodynamics, the fact that energy transformations are never 100% efficient

Which of the following processes is endergonic?

The synthesis of glucose from carbon dioxide and water

Facilitated diffusion across a biological membrane requires _____.

Transport proteins

Active transpirt

Uses ATP as an energy source, Can move solutes up a concentration gradient, Requires the cell to expend energy, Can involve the coupled passage of soultes