Mastering Bio questions ch 5

Which of the following is an accurate comparison of active transport and facilitated diffusion

Active transport moves solutes against their concentration gradient; facilitated diffusion moves substances down their concentration gradient.

Green olives may be preserved in brine, which is a 30% salt solution. How does this method of preservation prevent microorganisms from growing in the olives?

Bacteria can't survive because they would loose water in a hypertonic solution

In a hypothetical world, how could you increase the amount of energy that could be stores in a molecule of ATP.

Increase the negative charge of each phosphate group

Macrophages are white blood cells that roam the body searching for invading microbes. These invaders are destroyed inside macrophage vacuoles. How do the macrophages bring the microbes inside.

Microbes are engulfed into the macrophage via phagocytosis

Which of the following statements is true about passive transport

Passive transport requires no expenditure of cellular energy.

The lipid in a cell membrane are arranged so

The nonpolar parts of two lipids point toward each other

According to the second law of thermodynamics, which of the following is true

The ordering of one system depends on the disordering of another.

A pharmaceutical company wishes on focus's on an enzyme to develop new medications. What type of initial study would be the greatest benefit.

Understanding the key structure so it could design molecules that fit to the binding site and alter activity.

The phosphorylation of ADP to form ATP is an ___ reaction that ___ energy

endergonic ... requires an input of

Which of the following is a difference between active transport and facilitated diffusion

Active transport requires the expenditure of cellular energy, and facilitated diffusion does not.

cellular respiration is an example of

And exergonic process

Antibiotics-for example, penicillin-cannot be used to treat viral infections, such as the common cold. Why?

Antibiotics inhibit enzymes that are essential to the survival/reproduction of bacteria only, not enzymes important to humans

Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B; cell B is actively converting oxygen to water in cellular respiration. Oxygen will diffuse more rapidly into cell __________ because __________.

B ... the diffusion gradient in cell B is steeper

In plant cells, carbon dioxide and water are joined to form carbohydrates. Plant cells can also break down carbohydrates such as glucose, releasing carbon dioxide, water, and energy. No one has ever observed such reactions between water and carbon dioxide outside of living cells. What allows living cells to assemble and disassemble complex molecules, which is not possible in nonbiological environments?

Cells couple energy-releasing reactions to energy requiring reactions

Cells store energy that they can access when needed by converting it to ATP. This energy is stored in the form of ___

Chemical energy within molecules

ATZ is an antiretroviral drug used in the treatment of HIV. It shares a structural similarity to a nucleotide. What might be the mode of action for this drug

Competitive inhibition

The movement of atoms, ions or molecules from a region of higher to lower concentration

Diffusion

Frequently, transplanted organs are rejected by the recipient's body. How is this reaction related to plasma membranes?

Each person has a unique set of carbohydrate chains attached to his or her plasma membranes.

Which of these statement describes what occurs in facilitated diffusion

Facilitated diffusion of solutes occurs through protein pores in the membrane

Which statement regarding enzyme function is true

High temperatures can cause many enzymes to denature

Other than some possible side effects, why doesn't the antibiotic penicillin harm humans

Humans dont have cell walls

The synthesis of an amino acid follows this pathway: precursor A -› intermediate B -> amino acid C. Each reaction is catalyzed by a different enzyme. This metabolic pathway is controlled by feedback inhibition with amino acid C inhibiting the conversion of precursor A to intermediate B. Amino acid C acts as a of the first enzyme in the pathway.

Non competitive inhibitor

passive transport

Passive transport can transport molecules without the assistance of proteins from an area of high concentration to low concentration

The hydrolysis of DNA into nucleotides constitutes an exergonic reaction. Yet, DNA is quite stable. Why is this the case?

The activation energy required to initiate this reaction is seldom reached.

Which of the following is an example of the second law of thermodynamics

The aerobic respiration of glucose generates heat which is dissipated from the cells

The transport of molecules of a particular solute from inside an animal cell across the cell membrane to the extra cellular fluid always requires energy when

The concentration of the solute is lower inside than the cell around it

What controls the net direction of the movement of oxygen molecules in passive transport

The direction of the oxygen concentration gradient

Which of the following statements is true of an ex ergo if reaction but not of an endergonic reaction

The potential energy of the products is less than the reactants

When in solution, a molecule that moves slowly across an artificial membrane moves rapidly across a plasma membrane. This occurs regardless of whether the concentration of this molecule is higher inside or outside the cell. Using this information, which transport mechanism is most likely to be responsible for the movement of the molecule across a plasma membrane?

active transport

Utah's Great Salt Lake has an average salinity seven times higher than that of the oceans. Very few multicellular organisms live in this harsh environment. An example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. These brine shrimp must _____.

actively pump water back into their cells to counter its loss due to osmosis

Fluidity of an animal cell plasma membrane is enhanced by __________.

cholesterol molecules

In the process of osmosis, water displays a net movement from an area of ____ water concentration to an area of ____ water concentration

higher, lower

New drugs are being developed to lower levels of circulating cholesterol. A successful drug would be one that _____.

increases the rate of LDL receptor-mediated endocytosis

Light is _____ energy, which is converted by plants into molecules, which possess _____ energy.

kinetic ... chemical

The mechanism of enzyme action is to

lower the energy of the activation of a reaction

The diffusion of water across a selectively permeable membrane is called

osmosis

The plasma membrane is selectively permeable. Which of the following can pass freely through the membrane with no assistance

oxygen and carbon dioxide

Overall, membranes seem to have a great deal in common, but on closer inspection it is revealed that membranes of different cells have unique properties. What is the primary component of membranes that gives membranes cell-specific properties?

proteins

Which of the following enables a cell to pick up a concentrate a specific kind of molecule

receptor-mediated endocytosis

When placed in a hypotonic environment, where the solute concentration is below that of the cell, a houseplant will _____.

remain standing upright

For an enzyme to catalyze a reaction there must be a specific fit between the __________ and the enzyme's __________.

substrate, active site

Osmosis is often viewed incorrectly as a process driven directly by differences in solute concentration across a selectively permeable membrane. What really drives osmosis?

the difference in water concentration across a selectively permeable membrane