Find study materials for any course. Check these out:
Browse by school
Make your own
To login with Google, please enable popups
To login with Google, please enable popups
Don’t have an account?
To signup with Google, please enable popups
To signup with Google, please enable popups
Sign up withor
Which term describes the process by which gene expression can be downregulated by introduction of
double-strand RNA into a cell?
A. RNA targeting.
B. RNA blocking.
C. RNA obstruction.
D. RNA interference.
E. RNA disposal.
You put a cell in glucose solution and measure the concentration of glucose inside the cells after 30 minutes. You repeat the experiment using double the concentration of glucose in the solution and find that the concentration of glucose inside the cells also doubled. This result suggests that glucose enters the cells by means of:
A) facilitated diffusion B) endocytosis
C) active transport D) osmosis
1) Which would NOT be found in a bacterium?
2) Which statement is CORRECT?
A) Plants do not have mitochondria
B) Animals cells do not have a central
C) Nuclei do not contain proteins
D) The lysosome is only found in
Which statement is CORRECT?
A) During exocytosis, vesicles in the cytoplasm discharge their contents outside the cell.
B) During endocytosis, particles enter the cytoplasm through a pore in the plasma membrane.
C) Human cells do not undergo exocytosis since the elimination of waste products is carried out by the excretory system.
D) Exocytosis transports waste but no other materials outside of the cell.
Within a closed system, as entropy increases the free energy must:
A) increase then decrease
B) be constant
Some viruses have a phospholipid envelope that originates from the
A) nucleus of the host cell.
B) plasma membrane of the host cell.
C) synthesis of proteins and lipids inside the virus.
D) synthesis of lipids in the virus and proteins in the host cell
Which statement about enzymes is FALSE?
A) They do not change the chemical reactions they promote.
B) They catalyze specific chemical reactions
C) Their speed up chemical reactions by providing activation energy
D) They function best at a particular pH
Which statement about cell respiration is
A) animals and plants both perform cell respiration
B) All ATP production takes place in the mitochondria
C) CO2 is made in the Citric Acid Cycle
D) Glycolysis and fermentation both occur in the absence of O2
Which statement is FALSE?
A) NADH is last electron accepter of the electron transport chain.
B) Electrons harvested from the oxidation of pyruvate are eventually given to O2.
C) Oxidation of glucose produces two ATP, 2 NADH, and 2 pyruvate molecules.
D) The ETC uses electrons from oxidation of glucose to drive proton pumps
When electrons move closer to a more electronegative atom, what happens?
A) The more electronegative atom is oxidized, and entropy decreases.
B) The more electronegative atom is oxidized, and energy is released.
C) The more electronegative atom is reduced, and entropy decreases.
D) The more electronegative atom is reduced, and energy is released.
Which of the following would NOT be considered to be energetically spontaneous?
A) triglyceride --> fatty acids and glycerol
B) movement of ions through a membrane channel from an area of high to an area of low concentration.
C) an exergonic reaction
D) the energy of the products is greater than the energy of the reactants
C3H8 + 5O2 --> 3CO2 + 4 H2O
Which statement best describes this reaction?
A) endergonic, C3H8 is oxidized
B) exergonic, C3H8 is oxidized
C) endergonic, C3H8 is reduced
D) exergonic, C3H8 is reduced
During aerobic respiration, electrons travel
downhill in which sequence?
A) food → NADH → ETC → oxygen
B) food → krebs cycle → ATP → NAD+
C) glucose → pyruvate → ATP → oxygen
D) glucose → ATP → electron transport chain → NADH
E) food → glycolysis → krebs cycle → NADH → ATP
Mammals that hibernate have "brown fat” cells that contain many mitochondria. These cells contain an protein that allows hydrogen ions to freely cross membranes. The most likely function of these cells is:
A) to make and store fat
B) to produce large amounts of ATP
C) to produce heat
D) to conserve energy
The ETC pumps hydrogen ions from the stroma to the intermembrane space. If this process is disrupted, you should see
A) an increase in the pH of the intermembrane space
B) a drop in the pH of the intermembrane space and an increase in the stroma
C) no change in the pH of the intermembrane space
D) a drop in the pH of the intermembrane space
Yeast cells that have defective mitochondria incapable of respiration will be able to grow by catabolizing which of the following carbon sources for energy?
A) fatty acids
C) Such yeast cells will not be capable of catabolizing any food molecules, and will therefore die.
E) glucose, proteins, and fatty acids
All cells have
A) a nucleus and chloroplasts
B) a cell wall and nucleus
C) ribosomes and nucleus
D) a cell membrane and cytoplasm
For a protein to be an integral membrane protein, it must be
A) exposed on only one surface of the membrane.
B) amphipathic, with at least one hydrophobic region.
D) completely covered with phospholipids.
Which mode of transport does NOT require a protein?
A) simple diffusion
B) facilitated diffusion
C) active transport
If ΔG of a chemical reaction is negative and ΔS is positive, you can conclude that
A) it is in equilibrium
B) it is endergonic
C) it is exergonic
D) it requires energy
E) it is anabolic
Which is characteristic of the lytic cycle?
A) The virus- host relationship usually lasts for generations.
B) A large number of new virus particles are released at a time.
C) The viral genome replicates without destroying the host.
D) Many bacterial cells containing viral DNA are produced.
E) Viral DNA is incorporated into the host genome.
Which statement is FALSE?
A) Pyruvate from glycolysis is converted to acetyl- CoA in the mitochondria.
B) For each glucose molecule, the citric acid (Kreb's) cycle produces more ATP than glycolysis.
C) The energy to make ATP comes from a proton gradient across the mitochondrial membrane.
D) Some energy from ATP is required to begin glycolysis.
Which is NOT a product of glycolysis?
You have a friend who lost 7 kg (about 15 pounds) of fat on a regimen of strict diet and exercise. How did the fat leave her body?
A) It was broken down to amino acids and eliminated from the body.
B) It was released as CO2 and H2O.
C) It was converted to urine and eliminated from the body.
D) It was converted to ATP, which weighs much less than fat.
E) It was converted to heat and then released.
The size cells can grow to is limited. Of the
cells shown below, which one is likely to
experience the greatest difficulty as it grows
larger assuming it retains the same shape?
You add cyanide to an animal cell to stop aerobic respiration. Which of the following is most likely to be affected?
A) hydrolysis of proteins into amino acids
B) lateral movement of phospholipids in the cell's plasma membrane
C) facilitated diffusion of water across the cell membrane
D) movement of K+ into the cell up its concentration gradient
The ΔG of reaction is + 3.6 kCal/mol. If you add an enzyme to catalyze this reaction the ΔG should now be:
A) + 3.6 kCal/mol
B) < + 3.6 kCal/mol
C) it can't be determined without additional information
D) > + 3.6 kCal/mol
E) Most of the energy of respiration is converted to heat.
A metabolic poison that would most directly interfere with glycolysis is one that
A) reacts with oxygen and depletes its concentration in the cell
B) oxidizes NADH to NAD+
C) blocks passage of electrons along the electron transport chain
D) closely mimics the structure of glucose but is not metabolized
E) binds to pyruvate and inactivates it
A) must break down more glucose using less efficient anerobic respiration to maintain ATP levels
Which of the following most accurately
describes what happens in the ETC?
A) Energy of the electrons increases at each step.
B) Each electron carrier alternates between being reduced and being oxidized.
C) Molecules in the chain give up some of their potential energy.
D) ATP is generated at each step.
If a cell contains enzymes, DNA, ribosomes, a plasma membrane, and mitochondria. It could be a cell from
A) nearly any eukaryotic organism.
B) a plant or an animal.
C) an animal, but not a plant.
D) a bacterium.
E) any kind of organism.
Which structure is NOT composed of phospholipid?
Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
A) membrane proteins
D) cellulose fibers in the cell wall
E) cytoskeletal structures
Which would likely move through the lipid bilayer of a plasma membrane most rapidly?
D) an amino acid
The ATP is made during glycolysis by
A) oxidation of NADH to NAD+ .
B) electron transport.
C) substrate- level phosphorylation.
Which is (are) true for anabolic pathways?
A) They consume energy to make polymers from monomers.
B) They are usually highly spontaneous chemical reactions.
C) They release energy as they degrade polymers to monomers.
D) They do not depend on enzymes.
*Which statement is FALSE?
A) Enzymes can catalyse both exergonic and endergonic reactions
B) An exergonic reaction is one in which energy is released
C) The first steps of glycolysis are endergonic reactions
D) Catabolism refers to the breakdown of complex molecules into more simple molecules
E) Activation energy refers the total energy released by a reaction
A) The covalent bond in O2 is unstable
and easily broken by electrons from
B) Electrons are being moved from atoms
that have a lower affinity for electrons
(such as C) to atoms with a higher
affinity for electrons (such as O).
In the absences of oxygen, cells capable of fermentation
A) accumulate pyruvate
B) no longer produce ATP
C) accumulate glucose
D) oxidize NADH to produce NAD+
Which statement is FALSE?
A) Most biochemical reactions in your body are irreversible.
B) The products of a reaction can have less energy than the reactants.
C) Even exergonic reactions require some activation energy
D) The products of a reaction can have more energy than the reactants.
C) Proteins secreted by prokaryotes are
made by ribosomes bound to the
cytoplasmic side of the cell membrane.
A) One type of protozoa had functional mitochondria, the other did not.
Most CO2 from catabolism is released during
A) electron transport.
C) oxidative phosphorylation.
D) lactate fermentation.
E) the citric acid cycle.
Viagra blocks activity of phosphodiesterase- 5
(PDE5) in the following reaction:
cGMP --PDE5-> GMP
Blocking the enzyme results in a buildup of
B) cGMP and GMP
During a laboratory experiment, you discover
that an enzyme- catalyzed reaction has a ΔG
of - 20 kcal/mol. If you double the amount of
enzyme in the reaction, what will be the ΔG
for the new reaction?
A) + 40 kcal/mol
B) 0 kcal/mol
C) - 40 kcal/mol
D) + 20 kcal/mol
E) - 20 kcal/mol
All of the following occur during completely anaerobic breakdown of glucose in muscle cells, EXCEPT:
A) release of CO2
B) production of pyruvate
C) lactic acid production
D) NADH converted to NAD+
E) creation of ATP
When a plant cell, such as one from a peony stem, is submerged water containing very little solute, what is likely to occur?
A) The cell breakdown in the water.
B) It will neither gain nor lose water.
C) The cell will lose water.
D) The cell will take up water.
E) The cell membrane will lyse.
Which statement is CORRECT regarding a fasting cell performing aerobic respiration?
A) Entropy of the system decreases.
B) The free energy of the system increases.
C) The free energy remains constant.
D) Entropy is converted into free energy.
E) Entropy of the system increases.
*Most cells observed in nature fall within certain size ranges due to the
A) limited strength and integrity of the plasma membrane, large cells can't be structurally supported
B) need for a surface area sufficient to support the cell's metabolic needs
C) differences in plasma membranes between prokaryotes and eukaryotes
D) rigid cell walls that limit the expansion of cells
E) evolutionary progression in cell size; more primitive cells have smaller sizes
You treat an animal cell with a chemical. The cell rounds up and materials in the cell stop moving but cell respiration continues. The chemical most likely affects the cell's:
D) cell wall
Which of the following is NOT a basic difference between plant and animal cells?
A) Plants have cell walls, and animal cells do not.
B) The cell wall plays a major role in determining plant cell shape while the cytoskeleton plays a major role in determining animal cell shape.
C) Animal cells have mitochondria but plant cells do not.
D) Plant cells contain chloroplasts, but animal cells do not.
If cytokinesis failed during cell division, this will result in
A) cells that are unusually small.
B) cells lacking nuclei.
C) destruction of chromosomes.
D) cells with more than one nucleus.
E) cell cycles lacking an S phase.
Which statement IS TRUE of proto-oncogenes?
A. They can acquire somatic mutations that result in reduced function of their gene product.
B. They are introduced to a cell initially by retroviruses.
C. Some of them encode proteins that stimulate the cell cycle.
D. They are expressed at much lower levels in cancer cells than in normal cells.
E. Some of them encode proteins that inhibit the cell cycle
Which would probably have the LEAST
difficulty diffusing across a cell membrane?
C) ethyl alcohol
Zinc, an essential trace element, is present in the active site of carboxypeptidase enzyme. The zinc most likely functions as a(n)
A) cofactor necessary for enzyme activity.
B) allosteric activator of the enzyme.
C) competitive inhibitor of the enzyme.
D) noncompetitive inhibitor of the enzyme.
E) coenzyme derived from a vitamin.
Which statement is representative of the second law of thermodynamics?
A) Every energy transformation by a cell decreases the entropy of the universe.
B) Heat is a form of energy that can be used by most organisms to do work.
C) Conversion of energy from one form to another is always accompanied by some gain of free energy.
D) Cells need a constant input of energy to maintain a high level of organization.
Which statement is CORRECT regarding aerobic respiration?
A) the energy for oxidative phosphorylation comes from ATP.
B) energy to make ATP comes from protons moving down a concentration gradient.
C) glucose is first converted to pyruvic acid in the mitochondrion.
D) The electron transport chain makes ATP by pumping electrons across the cell membrane.
Which statement best describes this reaction?
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
A) CO2 is reduced and O2 is oxidized.
B) O2 is oxidized and H2O is reduced.
C) C6H12O6 is oxidized and O2 is reduced.
D) C6H12O6 is reduced and CO2 is oxidized.
E) O2 is reduced and CO2 is oxidized
Oxidative phosphorylation is performed during which stage(s) of cell respiration?
II. pyruvate --> Acetyl- CoA
III. Citric Acid Cycle
A) I, II, and III C) I only
B) IV only D) I and III
You measures the average tail length of a wild population of birds. Several generations later, you measure the birds again and see an increase in average tail length. Which process could account for this increase?
i. Genetic drift iii. Natural selection
ii. Emigration iv. Immigration
A) iii only D) iii and iv only
B) i and iii only E) i, ii, iii, and iv
C) ii and iv only
CO2 produced during aerobic respiration in
A) the mitochondria only
B) both the cytoplasm and mitochondria
C) the cytoplasm only
During intense exercise, as skeletal muscle cells switch to anerobic respiration, the human body will increase its catabolism of
A) fats only.
B) proteins only.
C) fats, carbohydrates, and proteins.
D) fats and proteins only.
E) carbohydrates only.
*Protozoans living in pond water must use exocytosis to get rid of excess water in their cytoplasm? Why might this be necessary?
A) Protozoans take up water by endocytosis; therefore, they must expel it by exocytosis.
B) Pond water is hypotonic to the protozoan cytoplasm.
C) Pond water is isotonic to the protozoan cytoplasm.
D) Water cannot diffuse across the protozoan plasma membrane.
E) Pond water is hypertonic to the protozoan cytoplasm.
Which of the following reactions would
A) converting CO2 and H2O into glucose
B) adding a phosphate group to ADP to form ATP
C) converting lactose into glucose and galactose
D) A and B would release energy.
E) All of the above would release energy.
What accepts the electrons from NADH during fermentation in humans?
D) pyruvic acid
How do eukaryotic and prokaryotic codons compare?
A) The translation of codons is mediated by tRNAs in eukaryotes, but translation requires no intermediate
molecules such as tRNAs in prokaryotes.
B) Prokaryotic codons usually have different bases than those of eukaryotes.
C) Prokaryotic codons usually specify different amino acids than those of eukaryotes.
D) Codons in prokaryotes and eukaryotes
code for the same amino acids.
D) Codons in prokaryotes and eukaryotes code for the same amino acids.
Extracellular glucose inhibits transcription of
the lac operon by _____.
A) weakening the binding of repressor to the operator
B) strengthening the binding of repressor to the operator
C) reducing the levels of cAMP in the cell
D) increasing the levels of cAMP in the cell
Which is a protein?
Which modification is least likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis?
A) decreasing the length of the DNA fragment
B) increasing the length of the DNA fragment
C) altering the nucleotide sequence of the DNA fragment
D) neutralizing the negative charges within the DNA fragment
Which of the following sequences is most
likely to be cut by a restriction enzyme?
If the DNA code for an amino acid is AGT, then the anticodon on the tRNA would be:
A) TCA B) AGU
C) UCA D) AGT
Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?
A) a deletion of two nucleotides
B) an insertion of a codon
C)a substitution of the first nucleotide of a GGG codon
D) a deletion of a codon
E) a substitution of the third nucleotide in an ACC codon
The expression of many genes is tightly regulated but some genes are expressed at roughly constant rates. Which of the following genes would you predict to be constitutively (constantly) expressed?
A) genes involved in the biosynthesis of the amino acid tryptophan
B) genes involved in the transport of the sugar lactose
C) genes involved in protein synthesis
D) genes involved in DNA replication
Which statement IS TRUE of gene annotation?
A. It can be used to identify putative genes and regulatory sequences in DNA.
B. It can be used to tag a gene so that it can be studied in an experimental organism.
C. It can be used to match the corresponding phenotypes of different species.
D. It can be used to describe the functions of noncoding regions of the genome
E. It can be used to create mutations in different genes.
CAP is said to be a positive regulator of the lac operon because _____.
A) CAP binds the operator
B) CAP binds cAMP
C) CAP prevents binding of the repressor to the operator
D) extracellular glucose levels influence the ability of CAP to bind to the CAP binding site
E) CAP binding to the operator increases the frequency of transcription
How would would be the effect of a mutation that interferes with the function of the helicase enzyme?
A) Replication will require a DNA template from another source.
B) No replication fork will be formed.
C) Replication will occur via RNA polymerase alone.
D) More errors will be made during replication.
E) Replication will result in the formation of small fragments being produced instead of long continuous strands.
5' TCATACTACTA 3'
4) If the DNA strand above were used as a template for transcription, which of the following would be produced?
A) 5' TCATACTACTA 3'
B) 3' AGTATGATGAT 5'
C) 5' AGUAUGAUGAU 3'
D) 3' AGUAUGAUGAU 5'
During translation, a codon is read to bring in
a new amino acid in the ___ in the ribosome.
A) P site B) operon
C) E site D) A site
Full induction of the lac operon occurs when:
A) lactose levels are high and glucose levels are low
B) lactose levels are low and glucose levels are low
C) lactose levels are high and glucose levels are high
D) lactose levels are low and glucose levels are high
Which is a nucleotide sequence?
Which of the following best describes the complete sequence of steps occurring during every cycle of PCR?
1. The primers hybridize to the target DNA.
2. The mixture is heated to a high temperature to denature the double- stranded target DNA.
3. Fresh DNA polymerase is added.
4. DNA polymerase extends the primers to make a copy of the target DNA.
The length of DNA that codes fora gene is usually longer than the mRNA molecule actually used for translation. This is because:
A bases are added to the tail of the primary transcript
B the regulatory regions (introns) of the gene are not transcribed
C post- transcriptional modification removes the exons
D post- transcriptional modification removes the introns
The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?
A) The same codons in different organisms translate into the different amino acids.
B) All organisms produce the same sets of proteins.
C) A gene from an organism can theoretically be expressed by any other organism.
D) Different organisms have different numbers of different types of amino acids
In negative control of transcription, a gene is activated when:
A) an activator protein binds to DNA
B) a repressor protein binds to DNA
C) an activator protein is removed from DNA
D) a repressor protein is removed from DNA
A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?
A) DNA ligase B) primase
C) nucleotides D) Okazaki fragments
E) DNA polymerase
All of the following are involved in DNA replication, EXCEPT:
A) DNA polymerase
D) messenger RNA
E) chromosomal DNA
When a DNA molecule is replicated before mitosis the result is
A) two DNA molecules, each with one strand of original DNA and one strand of newly made DNA.
B) two DNA molecules, one of which has all of the original DNA molecule, while the other has all new DNA
C) two DNA molecules consisting of a mixture of old DNA, new DNA, and RNA
D) two DNA molecules in which each DNA strand in each molecule is a mixture of the original DNA and of
Which of the following is associated with
BOTH replication and transcription?
A) DNA template
C) DNA polymerase
D) RNA polymerase
E) base- pairing between A and U.
The goal of the polymerase chain reaction is
A) to duplicate all of the DNA in a cell in preparation for cell division
B) to create many copies of a specific DNA sequence
C) to create many copies of a messenger RNA molecules
D) to correct errors in DNA replication
E) to speed up protein synthesis
Which of these occur in the nucleus?
A) transcription and translation
B) DNA replication and transcription
C) DNA replication only
D) DNA replication, transcription and translation
E) transcription only
A single base- pair deletion within an exon in the middle of a protein- coding gene would have what
A) Interfere with Poly- A tail addition to the mRNA.
B) Alter the reading frame leading to a different polypeptide.
C) Prevent tRNAs from adding amino acids to the polypeptide.
D) Interfere with binding of RNA polymerase to the promoter.
The ratio of __________ in DNA is 1:1.
A) adenine to guanine
B) cytosine to guanine
C) thymine to guanine
D) adenine to uracil
If an mRNA sequence is 5'- UCAGCCGUC- 3'
what is the sequence of the DNA template
A) 5'- AGTCGGCAG- 3'
B) 3'- AGTCGGCAG- 5'
C) 5'- TCAGCCGTC- 3'
D) 3'- TCAGCCGTC- 5'
3' TACCGAGGCATGCAGCTCAG 5'
5' CGTACG 3'
16) What would be produced if DNA polymerase
and nucleotides were added to the DNA
molecule shown above?
A) 3' TACCGAG 5'
B) 5' CGTACG 3'
C) 5' TCGAGTC 3'
D) 5' ATGGCAC 3'
E) 3' AGCTCAG 5'
During DNA replication:
A) one parental strand must be degraded to allow the other strand to be copied.
B) the parental strands come back together after the passage of the replication fork.
C) a replication bubble at an origin of replication has one replication fork.
D) the parental strands must separate so that both can be copied.
A frameshift mutation could result from:
A) insertion or deletion of a base
B) a base deletion only
C) a base addition only
D) a base substitution only
E) deletion of three consecutive bases
Which of the following is NOT associated with transcription?
A) DNA polymerase
C) DNA template
E) RNA polymerase
The specific function of restriction enzymes in genetic engineering is to:
A) cut DNA molecules at sequence- specific sites
B) join DNA fragments
C) carry foreign DNA that is to be studied
D) replicate specific DNA sequences.
What is the relationship between any two strands of DNA in a DNA molecule?
A) They are a pair of sister chromatids.
B) They have identical base sequences.
C) One was the template for the synthesis of the other.
D) They are connected to each other by sugar- phosphate bonds.
E) An A base on one always pairs with a G base on the other.
If DNA ligase did not function , how would this interfere with the replication of DNA?
A) Prevent the formation of phosphate bridges between Okazaki fragments
B) Prevent primase from synthesizing an RNA primer
C) Cause DNA polymerase to add nucleotides in the 3ʹ′ to 5ʹ′ direction
D) Prevent unwinding of DNA ahead of the replication fork
3' CCGTTTG 5'
5' ACTCATGGGCAAACGCATTAG 3'
16) What would be produced if DNA polymerase and nucleotides were added to the DNA molecule shown above?
A) 5' ACTCATG 3'
B) 3' CCGTTTG 5'
C) 3' TGAGTAC 5'
D) 3' CGTAATC 5'
E) 5' GCATTAG 3'
In E. coli , what, if anything, will be bound to the control region of the lac operon when glucose and lactose levels are both high?
A) the repressor only
B) Nothing will be bound
C) both the CAP activator and the repressor will be bound
D) the CAP activator only
E) Both Bam HI- cut and Bcl I- cut DNAs would be ligated with no preference for which fragment is ligated to which other.
B) Red fluorescence will move into the cytoplasm as well as remain in the cell membrane after delivering the capsid.
*Fatty acids usually have an even number of carbons in their structures. They are catabolized by a process called beta- oxidation. The end products of the metabolic pathway are two carbon acetyl groups. Where would these groups most likely enter the cell respiration pathway?
A) They directly enter the Krebs cycle.
B) They are directly decarboxylated by pyruvate dehydrogenase.
C) They directly enter the electron transport chain.
D) They directly enter the energy- yielding stages of glycolysis.
*Which of the following is FALSE regarding an enzyme catalyzed reaction?
A) The uncatalyzed reactions requires more activation energy than the uncatalyzed reaction.
B) The free energy change between the reactants and products is the same for both the enzyme catalyzed and uncatalyzed reactions.
C) Both the enzyme catalyzed and uncatalyzed reactions reach equilibrium at the same rate.
D) The enzyme speeds up both the forward and reverse reactions of a reversible reaction.