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The ultimate source of nearly all energy available to life on Earth is


Which one of the following is not a
function of the plasma membrane? The plasma membrane

is the control center of the cell

The act of a white blood cell engulfing a bacterium is


In lab, you use a special balloon that is
permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?

Water will leave the balloon

In the reaction A → B + C + heat,

the potential energy of the products is less than that of the reactant

When two aqueous solutions that differ
in solute concentration are placed on either side of a semipermeable membrane, and osmosis is allowed to take place, the water will

exhibit a net movement to the side with lower water concentration

Bacterial production of the enzymes
needed for the synthesis of the amino acid tryptophan declines with increasing levels of tryptophan and increases as tryptophan levels decline. This is an example of

feedback inhibition

The active site of an enzyme is

the region of an enzyme that attaches to a substrate.

Phagocytosis is to eating as pinocytosis
is to


Small, nonpolar, hydrophobic molecules
such as fatty acids

easily pass through a membrane's lipid bilayer.

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

the second law of thermodynamics.

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

All of the choices are correct.

Which of the following is not a true
statement about diffusion? Diffusion

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

According to __________, energy cannot
be created or destroyed.

the first law of thermodynamics

The more heat released by a reaction, the

greater the increase in entropy.

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

passive transport.

The cholesterol associated with cell membranes

helps to stabilize the cell membrane at body temperature.

Kinetic energy differs from chemical
energy in that

kinetic energy is the energy of a moving object, whereas chemical energy is the potential
energy of molecules.

When an enzyme catalyzes a reaction

it lowers the activation energy of the reaction.

Osmosis can be defined as

the diffusion of water across a membrane

Which one of the following is true?

Enzymes catalyze specific reactions.

When physicians perform an organ
transplant, they choose a donor whose tissues match those of the recipient as closely as possible. Which of the following cell components are being matched?

cell-surface carbohydrates

Most of a cell's enzymes are


The fluid mosaic model describes the
plasma membrane as consisting of

individual proteins and phospholipids that can drift in a phospholipid bilayer.

Which one of the following processes could result in the net movement of a substance into a cell, if the substance is more concentrated in the cell than in the surroundings?

active transport

Which of the following substances could
be a cofactor?

a zinc atom

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

All of the choices are correct.

What is the basic difference between
exergonic and endergonic reactions?

Exergonic reactions release energy; endergonic reactions absorb it.

Anything that prevents ATP formation will
most likely

result in cell death

Living systems

decrease their entropy while increasing the entropy of the universe.

If placed in tap water, an animal cell will
undergo lysis, whereas a plant cell will not. What accounts for this difference?

the relative inelasticity and strength of the plant cell wall

Heating inactivates enzymes by

changing the enzyme's three-dimensional shape.

Plasma membranes are selectively
permeable. This means that

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

What type of bond joins the phosphates of ATP?


Substrates bind to an enzyme's __________ site.


The molecules responsible for
membrane transport are


Ultimately, nearly all animals are
dependent on __________ as their source of energy.


Which one of the following is a typical
feature of an ATP-driven active transport mechanism?

None of the choices are correct

Membrane phospholipids

None of the choices are correct.

A child is brought to the hospital with a
fever of 107°F. Doctors immediately order an ice bath to lower the child's temperature. Which explanation offers the most logical reason for this action?

Elevated body temperatures may denature enzymes. This would interfere with the cell's
abilities to catalyze various reactions

Most of the functions of a cell membrane
are performed by


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

chemical energy into kinetic energy

The energy required to initiate an
exergonic reaction is called

the energy of activation.

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


Where in are eukaryotic cell enzymes
typically located?

in plasma membranes and inside organelles

Which one of the following processes is

the synthesis of glucose from carbon dioxide and water

Active transport

All of the choices are correct.

Which one of the following is true about
the ATP molecule?

It contains a nitrogenous base molecule called adenine

Some protozoans have special
organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment

is hypotonic to the protozoan.

Which one of the following is false?

Enzymes are used up in chemical reactions.

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