chapter 5 Mastering biology
Which is a true statement about the ATP cycle?
A single muscle cell needs only about one minute to recycle all of its ATP.
Which of the following molecules spontaneously form membranes when mixed in water and most likely were one of the first organic compounds formed on Earth?
Phospholipids
What best explains the observation that enzymes are selective in the reactions they catalyze?
There is a precise compatibility between an enzyme's active site and the substrate molecule.
Which 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
Active transport ________.
all of the answer options
Which are materials found in a molecule of ATP?
an organic molecule called adenosine plus three phosphate groups
In a hypotonic solution, a plant cell will ________.
become turgid
How do some inhibitors slow down metabolic pathways when the products of the pathways are not needed but still allow a pathway to proceed when the products are needed?
feedback regulation
In osmosis, water always moves toward the __________ solution, that is, toward the solution with the __________ solute concentration.
hypertonic ... greater
Which term is used to describe an animal's ability to survive if the cells are exposed to a hypotonic or hypertonic environment?
osmoregulation
Diffusion is an example of ________.
passive transport
The act of a white blood cell engulfing a bacterium is ________.
phagocytosis
Which one of the following terms is sometimes called "cell eating"?
phagocytosis
Energy is transferred from ATP to other molecules by transferring a(n) ________.
phosphate group
A rock on the top of a mountain contains ________ energy.
potential
Entropy means that __________.
the quantity of usable energy declines with each energy transformation
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
ATP drives work in cells by __________.
transferring its phosphate group to other cell molecules
Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.
transport proteins... down
Ten kilocalories are equivalent to ________ calories.
10,000
Humans convert approximately ________ of the energy stored in food to useful work.
34%
Cells use this molecule to store the chemical energy released by the breakdown of food molecules during cellular respiration.
ATP
What compound directly provides energy for cellular work?
ATP
Which one of the following is TRUE?
An enzyme's function depends on its three-dimensional shape
When cells are placed in hypotonic solutions, both animal and plant cells accumulate water as a result of osmosis. This causes the cells to swell. Why can plant cells better tolerate hypotonic solutions?
Animal cells can burst in such situations. In plants, however, rigid cell walls limit how far cells can expand and exert a back pressure to limit further water uptake.
Which one of the following statements about energy is correct?
Energy cannot be created or destroyed
Which one of the following is TRUE?
Enzymes catalyze specific reactions.
You are riding on your bike and stop pedaling, coasting along the road. Eventually, your bike slows down and stops. What happened to the energy of your motion when your bike stopped?
It was released as heat.
A balloon permeable to water but not to glucose contains a 10% glucose solution. A beaker contains a 5% glucose solution. Which of the following is TRUE?
The solution in the balloon is hypertonic relative to the solution in the beaker.
A balloon permeable to water but not to glucose contains a 10% glucose solution. A beaker contains a 5% glucose solution. What will happen when the balloon is submerged in the beaker?
The volume of water in the beaker will decrease.
Which one of the following is an example of osmosis?
Water enters a plant by passing through the root cell membranes.
Which of the following is an example of potential energy?
a bowling ball placed on the top shelf of a closet
The region of an enzyme to which a substrate binds is called the ________ site.
active
The concentration of calcium in a cell is 0.3%. The concentration of calcium in the surrounding fluid is 0.1%. How could the cell obtain more calcium?
active transport
The use of energy to move molecules across a membrane defines __________.
active transport
An enzyme is a protein that __________.
changes the rate of a metabolic reaction without being consumed by the reaction
Molecules of food have a form of potential energy called __________
chemical energy
Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing ________.
chemical energy into kinetic energy
The principle that energy cannot be created or destroyed is known as ________.
conservation of energy
Enzymes increase the rate of a reaction by ________.
decreasing activation energy
The passive movement of molecules from an area of higher concentration to an area of lower concentration is called __________.
diffusion
Which choice describes a laboratory technique that scientists might use to mimic a natural genetic process of cells?
directed evolution
Calories are units of __________.
energy
Activation energy can be described as __________.
energy needed to activate the reactants and trigger a chemical reaction
Which of the following is a measure of randomness in a system?
entropy
Every time energy is converted from one form to another, _________
entropy increase
Substances that plug up an enzyme's active site are ________.
enzyme inhibitors
When two solutions that differ in solute concentration are placed on either side of a selectively permeable membrane, and osmosis is allowed to take place, the water will ________.
exhibit a net movement to the side with lower water concentration
Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. Which of the following processes could be responsible for its secretion?
exocytosis
When a person cries, tears are exported from cells through the process of ________.
exocytosis
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
A cell that neither gains nor loses a net amount of water at equilibrium when it is immersed in a solution is ________.
isotonic to its environment
Which one of the following is most similar to the mechanism of an enzyme inhibitor?
keeping someone from parking by parking in their designated spot
An object at rest has no ________ energy, but it may have ________ energy resulting from its location or structure.
kinetic... potential
An animal cell placed in a hypertonic solution will __________.
lose water by osmosis and shrivel
Scientists are exploring an area of modern science called nanotechnology that involves __________.
manipulation of materials at the molecular level
The sum total of all the chemical reactions that occur in organisms is called ________.
metabolism
Diffusion ________.
proceeds until equilibrium is reached
Usually, enzymes are ________.
proteins
Anything that prevents ATP formation will most likely ________.
result in cell death
A characteristic of phospholipids that makes them a candidate for the first organic compounds on Earth to be related to life is their ability to __________.
self-assemble into simple membranes
An enzyme's function is most dependent on its ________.
shape
Which component of the following reaction is the enzyme? sucrose + sucrase + water → sucrase + glucose + fructose
sucrase
Which component of the following reaction is the substrate? sucrose + sucrase + water → sucrase + glucose + fructose
sucrose
What is energy?
the capacity to cause change
Which is the best definition of energy?
the capacity to cause change
Osmosis can be defined as ________
the diffusion of water across a selectively permeable membrane
