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Mastering Biology Unit 2 Questions and Answers 2024
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Mastering Biology Unit 2
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Mastering Biology Unit 2Which of the following statements about a typical plasma membrane is correct? -
answer The two sides of the plasma membrane have different lipid and protein
composition.
Singer and Nicolson's fluid mosaic model of the membrane proposed that
membranes_____. - answer consist of protein molecules embedded in a fluid bilayer of
phospholipids
According to the fluid mosaic model of cell membranes, phospholipids _____. - answer
can move laterally along the plane of the membrane
Which of the following is a reasonable explanation for why unsaturated fatty acids help
keep a membrane more fluid at lower temperatures? - answer The double bonds form
kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.
Which of the following statements about osmosis is correct? - answer The presence of
aquaporins (proteins that form water channels in the membrane) should speed up the
process of osmosis.
What kinds of molecules pass through a cell membrane most easily? - answer small
and hydrophobic
The movement of glucose into a cell against a concentration gradient is most likely to be
accomplished by which of the following? - answer cotransport of the glucose with a
proton or sodium ion that was pumped across the membrane using the energy of ATP
hydrolysis
Active and passive transport of solutes across a membrane typically differ in which of
the following ways? - answerActive transport always involves the utilization of cellular
energy, whereas passive transport does not require cellular energy.
Which of the following membrane activities requires energy from ATP? -
answermovement of Na+ ions from a lower concentration in a mammalian cell to a
higher concentration in the extracellular fluid
Which of the following is most likely true of a protein that cotransports glucose and
sodium ions into the intestinal cells of an animal? - answerA substance that blocks
sodium ions from binding to the cotransport protein will also block the transport of
glucose.
, Ions diffuse across membranes through specific ion channels down _____. -
answertheir electrochemical gradients
Energy is observed in two basic forms: potential and kinetic. Which of the following
correctly matches these forms with a source of energy? - answerthe covalent bonds of a
sugar molecule: potential energy
Which of the following is a statement of the first law of thermodynamics? -
answerEnergy cannot be created or destroyed.
For living organisms, which of the following is an important consequence of the first law
of thermodynamics? - answerThe organism ultimately must obtain all of the necessary
energy for life from its environment.
Living organisms increase in complexity as they grow, resulting in a decrease in the
entropy of an organism. How does this relate to the second law of thermodynamics? -
answerAs a consequence of growing, organisms cause a greater increase in entropy in
their environment than the decrease in entropy associated with their growth.
Which of the following statements is a logical consequence of the second law of
thermodynamics? - answerEvery chemical reaction must increase the total entropy of
the universe.
Which of the following statements about equilibrium of chemical reactions is correct? -
answerA reaction that is at equilibrium is not capable of doing any work.
Which of the following is true of metabolism in its entirety in all organisms? -
answerMetabolism consists of all the energy transformation reactions in an organism.
A system at chemical equilibrium _____. - answercan do no work
Which of the following is most similar in structure to ATP? - answeran RNA nucleotide
Which of the following is NOT a way in which an enzyme can speed up the reaction that
it catalyzes? - answerThe active site can provide heat from the environment that raises
the energy content of the substrate.
According to the induced fit hypothesis of enzyme catalysis, _____. - answerthe binding
of the substrate changes the shape of the enzyme's active site
Increasing the substrate concentration in an enzymatic reaction could overcome which
of the following? - answercompetitive inhibition
Zinc, an essential trace element for most organisms, is present in the active site of the
enzyme carboxypeptidase. The zinc most likely functions as _____ - answera cofactor
necessary for enzyme activity
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