bio final review chapters 5 and 6
In cellular respiration, which of the following outcomes is the result of electrons moving through the electron transport chain (or its components)? Oxygen gas is formed. A proton gradient is formed. ADP is phosphorylated to make ATP. Carbon dioxide is formed.
A proton gradient is formed
Which of the following is an accurate comparison of active transport and facilitated diffusion? Facilitated diffusion requires the use of ATP; active transport does not require ATP. Active transport moves solutes against their concentration gradient; facilitated diffusion moves substances down their concentration gradient. Active transport requires membrane proteins; facilitated diffusion does not require membrane proteins. In both types of movement, phosphate groups alter the shape of transport proteins.
Active transport moves solutes against their concentration gradient; facilitated diffusion moves substances down their concentration gradient.
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. Facilitated diffusion involves transport proteins, and active transport does not. Facilitated diffusion can move solutes against a concentration gradient, and active transport cannot. Active transport involves transport proteins, and facilitated diffusion does not.
Active transport requires the expenditure of cellular energy, and facilitated diffusion does not.
Cells A and B are the same size and shape, but cell A is metabolically quiet and cell B is actively consuming oxygen. Oxygen will diffuse more quickly into cell _____ because _____. B ... the diffusion gradient there is steeper A ... its membrane transport proteins will not be saturated B ... the oxygen molecules inside cell B have a higher kinetic energy A ... the diffusion gradient there is shallower
B ... the diffusion gradient there is steeper
Green olives may be preserved in brine, which is a 20-30% salt solution. How does this method prevent contamination by microorganisms? Bacteria can't survive in a hypertonic solution because they lose water. High salt concentrations lower the pH, thus inhibiting the process of glycolysis. Bacterial cell walls are shriveled up by salt, causing the cell to burst. High salt concentrations raise the pH, thus inhibiting the process of glycolysis.
Bacteria can't survive in a hypertonic solution because they lose water.
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 simple molecules to assemble into more complex molecules, and also disassemble, in cells but not in other, nonbiological environments? Cells couple energy-releasing reactions to energy-requiring reactions. Cells possess properties not seen in nonliving things, which allow them to run physical processes in reverse. Cells are subject to only the first law, not the second law, of thermodynamics. Cells are far more efficient in energy transactions than are nonliving substances.
Cells couple energy-releasing reactions to energy-requiring reactions.
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. The fibers of the extracellular matrix differ from individual to individual. Everyone's organs contain different amounts of cholesterol. The phospholipid bilayers become disrupted during transplant and may never re-form, causing the tissues to lose their function.
Each person has a unique set of carbohydrate chains attached to his or her plasma membranes.
Which statement regarding enzyme function is true? Higher temperatures allow greater contact between enzymes and substrates; therefore, the higher the temperature the better the enzyme will function. Excessive salt ions can cause an enzyme to denature. Enzymes cannot function at a pH lower than 6. Most coenzymes are inorganic substances such as ions of iron or potassium.
Excessive salt ions can cause an enzyme to denature.
In a theoretical world where all things are possible, how could you increase the amount of energy that could be stored in a molecule of ATP? Convert the negative charge of the phosphate groups to a positive charge. Increase the negative charge of each phosphate group. Change the middle phosphate group from a negative to a positive charge. Alter the first and third groups to make them positive.
Increase the negative charge of each phosphate group.
As shown below, an electron carrier, such as __________, acts as an energy-storage molecule when it is __________. A pair of redox reactions occurring simultaneously. NADH ... reduced NAD+ ... reduced NADH ... oxidized NAD+ ... oxidized
NADH ... reduced
The hydrolysis of DNA into nucleotides constitutes an exergonic reaction. Yet, DNA is quite stable. Why is this the case? Only endergonic reactions proceed rapidly. The activation energy required to initiate this reaction is seldom reached. No enzymes exist to facilitate DNA hydrolysis. DNA synthesis occurs at the same rate as DNA hydrolysis, so DNA only appears stable.
The activation energy required to initiate this reaction is seldom reached.
Taq polymerase is an enzyme isolated from the organism Thermophilus aquaticus. This organism has been found living in the hot springs of Yellowstone National Park. This enzyme is used to copy human DNA from crime scenes. Most reactions are performed at ranges similar to those of the human body; however, what considerations should be made for optimum use of this enzyme? Nothing should be altered. The temperature should be raised. The pH should be decreased. The enzyme will not work on human DNA.
The temperature should be raised.
A pharmaceutical company wishes to focus on an enzyme to develop new medications. What type of study would be of the greatest benefit? Studying the structure of an enzyme would help pharmaceutical companies determine the enzyme's substrate. Understanding the enzyme's structure would help pharmaceutical companies design molecules that fit to the binding site and alter activity. Studying the structure would help pharmaceutical companies create enzymes that are not destroyed during reactions. Knowing the structure of enzymes may make it possible to design enzymes that raise the activation energy above that of the spontaneous reaction to allow more efficient drug synthesis.
Understanding the enzyme's structure would help pharmaceutical companies design molecules that fit to the binding site and alter activity.
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 actively pump water back out of their cells to counter its inflow due to osmosis actively pump salt back out of their cells to counter its inflow due to osmosis synthesize membranes that are impermeable to substances that upset osmotic balance
actively pump water back into their cells to counter its loss due to osmosis
In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and in a few minutes, radioactive oxygen atoms showed up in __________. carbon dioxide ATP water NADH
carbon dioxide
In nutrient-rich environments (like your mouth), bacteria can use the provided amino acids to synthesize their proteins. However, should the environmental conditions change and become nutrient-poor, bacteria would need to synthesize their amino acids. They can do this using __________. glyceraldehyde-3-phosphate ATP citric acid cycle intermediates glucose
citric acid cycle intermediates
A single glucose molecule produces about 38 molecules of ATP through the process of cellular respiration. However, this only represents approximately 38% of the chemical energy present in this molecule. The rest of the energy from glucose is _____. stored as fat used directly for energy converted to heat used to make water from hydrogen ions and oxygen
converted to heat
A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via _____. active transport osmosis passive transport endocytosis
endocytosis
What condition might result from an excess of aquaporins? fluid retention in pregnant women malaria dehydration hereditary diabetes insipidus
fluid retention in pregnant women
During cellular respiration, glucose is oxidized. However, an intermediate __________ can be siphoned off and used to synthesize fats. pyruvate glyceraldehyde-3-phosphate glucose ATP
glyceraldehyde-3-phosphate
A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to treat people with bacterial infections. However, he can't do this because _____. bacteria do not perform glycolysis glycolysis produces so little ATP that the drug will have little effect bacteria are facultative anaerobes; they usually don't need to perform glycolysis human cells also perform glycolysis; the drug might also poison them
human cells also perform glycolysis; the drug might also poison them
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 increases exocytosis in cells that line blood vessels, especially those of the heart blocks the synthesis of LDL receptors binds to the LDL receptor and blocks receptor-mediated endocytosis
increases the rate of LDL receptor-mediated endocytosis
Sports physiologists at an Olympic training center want to monitor athletes to determine at what point their muscles begin to function anaerobically. They could do this by checking for a buildup of _____. ATP carbon dioxide ADP lactic acid
lactic acid
Recent data suggests that heat-generating brown fat is most active in __________. all individuals exposed to cold temperatures babies obese people exposed to cold temperatures lean people exposed to cold temperatures
lean people exposed to cold temperatures
Lungs are to breathing as _____ are to cellular respiration. alveoli chloroplasts bronchi mitochondria
mitochondria
A scientist wants to study the enzymes of the citric acid cycle in eukaryotic cells. What part of the cell would she use as a source of these enzymes? mitochondrial matrix mitochondrial inner membrane plasma membrane cytoplasm
mitochondrial matrix
You're on the pilot episode of a new reality show called "The Transport Factor." The host hands you three different amino acids, four different sugars, and two different ions. Then the host shouts, "How many different proteins does the cell need to move these molecules across the plasma membrane using facilitated transport?" Quickly, you correctly respond: _____. one nine five three
nine
Bacteria have no membrane-enclosed organelles. However, some still generate ATP through cellular respiration. Where is the electron transport chain found in these organisms? mitochondria plasma membrane nucleoid region cytoplasm
plasma membrane
Succinylcholine is structurally almost identical to acetylcholine, but if combined with the enzyme that normally hydrolyzes acetylcholine, the enzyme is no longer able to hydrolyze acetylcholine. This suggests that _____. succinylcholine must be a competitive inhibitor of acetylcholine succinylcholine must be a noncompetitive inhibitor the active site must have the wrong configuration to permit succinylcholine binding succinylcholine must regulate the activity of this enzyme by negative feedback
succinylcholine must be a competitive inhibitor of acetylcholine
Most NADH molecules generated during cellular respiration are produced during __________. glycolysis the electron transport chain the reduction of oxygen the citric acid cycle
the citric acid cycle
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 sugar or ion concentration across a selectively permeable membrane the first law of thermodynamics the difference in the height of water columns on either side of a selectively permeable membrane the difference in water concentration across a selectively permeable membrane
the difference in water concentration across a selectively permeable membrane
What controls the direction of a molecule, such as oxygen, involved in passive transport? the direction of the oxygen concentration gradient the size of the oxygen molecule the amount of energy available to transport oxygen the type of cell to or from which the oxygen molecule is moving
the direction of the oxygen concentration gradient
In an oil-based, nonpolar environment, phospholipids would arrange themselves so that they __________. would pack more tightly together than they would in a watery environment would stay together but in a reverse orientation, with their tails projecting outward would never associate but instead would remain as individual molecules completely dissolved in the oil would not pack together at all
would stay together but in a reverse orientation, with their tails projecting outward