Quiz 5-8
decreasing extracellular pH
Based on Figure 7.18, which of these experimental treatments would increase the rate of sucrose transport into a plant cell?
It is probably an enzyme that is regulated by competitive inhibition.
Characterization of the complete three-dimensional structure of a newly purified protein suggests that it catalyzes the breakdown of a large substrate. The protein consists of a single polypeptide chain. It has a large pocket that appears to be the binding site for the substrate and a smaller indentation that appears to be the binding site for a regulatory molecule. What do these structural observations suggest about the mechanism by which the activity of this protein is likely regulated?
exergonic; endergonic
Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ________ is to ________.
mitochondria
Cyanide binds to at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the
None of the statements are true.
During cellular respiration, electrons move through a series of electron-carrier molecules. Which of the following is a true statement about this process?
phosphate group
Energy is transferred from ATP to other molecules by transferring a(n) ______.
decreasing activation energy
Enzymes increase the rate of a reaction by ______.
proteins
Examination of a cell by transmission electron microscopy reveals a high density of ribosomes in the cytoplasm. This observation suggests that this cell is actively producing large amounts of which of the following molecules?
B
Five dialysis bags, constructed of a type of membrane that is permeable to water and impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed), and the percent change in mass of each bag was graphed. Which line or lines in the graph represent(s) bags that contain a solution that is hypertonic at 50 minutes?
chemical energy into kinetic energy
Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing ______.
RNA contains uracil; DNA contains thymine.
How does RNA differ from DNA?
19
How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule?
add more of the enzyme.
If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to
Nothing; the reaction will stay at equilibrium.
If an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur?
NADH ... oxidized
In fermentation, ______ is ______.
provide the energy that establishes the proton gradient.
In mitochondria, exergonic redox reactions
Certain proteins are unique to each membrane.
In what way do the membranes of a eukaryotic cell vary?
the citric acid cycle.
Most CO2 from catabolism is released during
temperature is usually uniform throughout a cell.
Most cells cannot harness heat to perform work because
Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life.
Proton pumps are used in various ways by members of every domain of organisms: Bacteria, Archaea, and Eukarya. What does this fact most probably mean?
their enzymes have high optimal temperatures.
Some bacteria are metabolically active in hot springs because
The mixture needs less oxygen; yeast only produce alcohol in the absence of oxygen
Some friends are trying to make wine in their basement. They've added yeast to a sweet grape juice mixture and have allowed the yeast to grow. After several days they find that sugar levels in the grape juice have dropped, but there's no alcohol in the mixture. The most likely explanation is that: ______.
ATP and heat
The energy released from glucose by the process of cellular respiration is in the form of ______.
glycogen, starch, and amylopectin
The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the _ form. Which of the following could amylase break down?
oxygen
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is
H+ concentration gradient across the membrane holding ATP synthase.
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the
C60H102O51
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?
the amino acid sequence of the polypeptide chain
The primary structure of a protein is ______.
primary level
The structural level of a protein least affected by a disruption in hydrogen bonding is the
The pH with the highest absorbance values would indicate the optimum pH for amylase since this pH does not affect the structure or function of the protein.
The table represents the results of an experiment where the effects of pH buffers on an enzyme found in saliva (amylase) were studied. A spectrophotometer set at 500 nm was used to measure absorbance at the various pH levels every 20 seconds for 2 minutes. The higher absorbance values would indicate greater enzyme activity. All experiments were conducted at the same temperature. Which statement correctly identifies the result that the optimum pH for amylase function is 7?
is the sun
The ultimate source of the energy in food ______.
ATP
What compound directly provides energy for cellular work?
cellulose
What does the term insoluble fiber refer to on food packages?
presence of relatively nonpolar C—H bonds
What makes lipids/fats hydrophobic?
The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water?
The pH of the matrix increases.
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?
glycolysis
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
All of the above - chemical energy to kinetic energy - light energy to potential energy - potential energy to kinetic energy - light energy to chemical energy
Which of the following energy transfers is(are) possible in living systems?
a greater proportion of unsaturated phospholipids
Which of the following factors would tend to increase membrane fluidity?
ribosome
Which of the following is present in a prokaryotic cell?
They have double bonds in their fatty acid chains.
Which of the following is true of unsaturated fats?
The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine.
Which of the following is true with regard to a DNA molecule?
C6H12O6 + 6O2 → 6CO2 + 6H2O
Which of the following metabolic processes can occur without a net influx of energy from some other process?
5′-ATGC-3′ with 5′-GCAT-3′
Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?
passive transport
Which of the following processes includes all the others?
Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.
Which of the following statements about the cytoskeleton is true?
Oxidation is the loss of electrons; reduction is the gain of electrons.
Which of the following statements is completely true?
glycolysis, Citric Acid cycle, electron transport chain
Which one of the following is the correct sequence of stages in cellular respiration?
Enzymes catalyze specific reactions.
Which one of the following is true?
mitochondrion
Which structure is common to plant and animal cells?
chloroplast
Which structure is not part of the endomembrane system?
Cellulose and fructose
You would like to lose weight. Which of the following should be your preferred food group?
a peptide bond
A glycosidic linkage is analogous to which of the following in proteins?
energy is conserved in all processes.
According to the first law of thermodynamics,
embedded in a lipid bilayer.
According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly
result in cell death
Anything that prevents ATP formation will most likely ______.