Session 2 Flashcards by Margaret Quaid

A gene
A. Contains information necessary for the synthesis of proteins
B. Is a sequence of nucleotides in DNA
C. Is composed of many molecules of DNA
D. Contains information necessary for the synthesis of proteins and is a sequence of nucleotides in DNA
E. All of the choices are correct

D. Contains information necessary for the synthesis of proteins and is a sequence of nucleotides in DNA

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A genome is
A. A cluster of genes that are all regulated in the same manner
B. A measure of the genetic variability in a population
C. A region of DNA that codes for a single protein
D. All of the DNA and RNA in a cell at a given point in time
E. The total genetic information in a typical cell of an organism

E. The total genetic information in a typical cell of an organism

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A codon is
A. A triplet of deoxyribonucleotides
B. A triplet of ribonucleotides
C. A sequence of ribonucleotides on tRNA
D. A triplet of ribonucleotides and a sequence of ribonucleotides on tRNA
E. None of the choices are correct

B. A triplet of ribonucleotides

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Transfer RNA
A. Functions to transport mRNA out of the nucleus
B. Binds specifically to mRNA and nonspecifically to amino acids
C. Binds specifically to amino acids and nonspecifically to mRNA
D. Binds specifically to mRNA and to amino acids
E. None of the choices are correct

D. Binds specifically to mRNA and to amino acids

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A certain protein receptor is capable of binding the neurotransmitter epinephrine but does not bind to the neurotransmitters dopamine, glutamate or serotonin. This is because the receptor displays
A. Saturation
B. Inhibition
C. Specificity
D. Acclimatization
E. All of the choices are correct

C. Specificity

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The affinity a binding site has for a ligand
A. Can be influenced by the shape of the binding site
B. Can be influenced by the presence of charged groups on the ligand and the binding site
C. Is a measure of how readily a bound ligand can be released from the protein
D. Both can be influenced by the shape of the binding site and can be influenced by the presence of charged groups on the ligand and the binding site are correct
E. All of the choices are correct

E. All of the choices are correct

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A competitive antagonist for a ligand
A. Does not interfere with the action of the ligand
B. Blocks the binding of the ligand to its binding site and prevents activation of the protein
C. Causes covalent modulation of the ligand, usually by phosphorylation or dephosphorylation
D. Both blocks the binding of the ligand to its binding site and prevents activation of the protein and causes covalent modulation of the ligand, usually by phosphorylation or dephosphorylation are correct
E. None of the choices are correct

B. Blocks the binding of the ligand to its binding site and prevents activation of the protein

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Phosphorylation or dephosphorylation of proteins is a common means of
A. Covalent modulation of the proteins
B. The activation or inactivation of kinases
C. Allosteric modulation of the proteins
D. Covalent modulation of the proteins and the activation or inactivation of kinases
E. All of the choices are correct

D. Covalent modulation of the proteins and the activation or inactivation of kinases

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The term “metabolism”
A. Refers to all the chemical reactions that occur in the body
B. Includes the synthesis of complex molecules from simpler molecules
C. Includes the breakdown of complex molecules into simpler molecules
D. Includes anabolism and catabolism
E. Is described by all of the choices

E. Is described by all of the choices

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A chemical catalyst increases the rate of a reaction by
A. Acting as one of the reactant molecules
B. Decreasing the energy of activation
C. Increasing the energy content of the product molecules
D. Increasing the temperature of a solution
E. All of the choices are correct

B. Decreasing the energy of activation

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With regard to chemical reaction rates, which of the following statements is true?
A. Increasing the concentration of the reactants will increase the reaction rate
B. Increasing the temperature will increase the reaction rate
C. Increasing the activation energy will increase the reaction rate
D. Both increasing the concentration of the reactants will increase the reaction rate and increasing the temperature will increase the reaction rate
E. All of the choices are correct

D. Both increasing the concentration of the reactants will increase the reaction rate and increasing the temperature will increase the reaction rate

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Which of the following does not affect the rate of synthesis of a protein in a cell?
A. The rate of its gene’s transcription
B. The rate of initiating protein assembly on ribosomes
C. The rate of mRNA degradation
D. The presence or absence of transcription factors
E. The rate of its tRNA synthesis

E. The rate of its tRNA synthesis

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Which of the following is commonly used to regulate enzyme-mediated reactions in a cell?
A. Altering the enzyme concentration in the cell
B. Altering the enzyme’s activity
C. Altering the cell’s temperature
D. Both altering the enzyme concentration in the cell and altering the enzyme’s activity
E. All of the choices are correct

D. Both altering the enzyme concentration in the cell and altering the enzyme’s activity

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ATP is
A. Formed during the hydrolysis of ADP
B. Used by cells for the storage of energy
C. Used to transfer energy within a cell
D. A protein
E. Both used by cells for the storage of energy and used to transfer energy within a cell

C. Used to transfer energy within a cell

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The site where most of the ATP is generated in a cell is the
A. Nucleus
B. Plasma membrane
C. Endoplasmic reticulum
D. Golgi apparatus
E. Mitochondria

E. Mitochondria

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Which of the following metabolic pathways does not require oxygen?
A. Glycolysis
B. Oxidative phosphorylation
C. Krebs cycle
D. The breakdown of fatty acids to CO2 and H2O
E. None of the choices are correct

A. Glycolysis

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Which of the following is not a product of glycolysis?
A. Carbon dioxide
B. ATP
C. Pyruvate
D. NADH
E. All of the choices are products of glycolysis

A. Carbon dioxide

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Oxidative phosphorylation
A. Requires the presence of coenzymes
B. Requires phosphorylated organic molecules
C. Produces the great majority of useable energy for cell functions
D. Both requires the presence of coenzymes and produces the great majority of useable energy for cell functions
E. Both requires phosphorylated organic molecules and produces the great majority of useable energy for cell functions

D. Both requires the presence of coenzymes and produces the great majority of useable energy for cell functions

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Fatty acid catabolism
A. Takes place in the cytosol of cells
B. Is initiated by the binding of a molecule of coenzyme A
C. Proceeds by a process called beta-oxidation
D. Generates one molecule of acetyl coenzyme A for every carbon atom in the fatty acid
E. Both is initiated by the binding of a molecule of coenzyme A and proceeds by a process called beta- oxidation are correct

E. Both is initiated by the binding of a molecule of coenzyme A and proceeds by a process called beta- oxidation are correct

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Before an amino acid can be broken down for energy
A. The side chain must be removed
B. The carboxyl group must be removed
C. It must be converted to NAD+
D. The amino group must be removed
E. It must be phosphorylated

D. The amino group must be removed

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Glucose cannot be synthesized from fatty acids because the reaction converting pyruvic acid to acetyl coenzyme A is not reversible.

True

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Human beings can synthesize all twenty amino acids the body must have.

False

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An essential nutrient is one necessary for good health that may or may not be synthesized by the body.

false

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The continuous expression of housekeeping genes is said to be constitutive.

True

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The expression of most genes is regulated gene at the level of transcription.

True

The codon that corresponds to the DNA sequence A-T-G is A. U-A-C B. A-T-G C. C-A-T D. C-A-U E. T-A-C

A. U-A-C

27. RNA synthesis from a DNA template A. Is called translation of the message B. Occurs in the cytoplasm C. Is regulated D. Occurs in the nucleolus E. None of the choices are correct

C. Is regulated

28. Allosteric proteins A. Contain more than one kind of binding site B. Undergo a change of shape when a ligand binds to the regulatory binding site C. Are always activated when a modulator molecule binds to the regulatory site D. Both contain more than one kind of binding site and undergo a change of shape when a ligand binds to the regulatory binding site are correct E. All of the choices are correct

D. Both contain more than one kind of binding site and undergo a change of shape when a ligand binds to the regulatory binding site are correct

29. When a chemical reaction is at equilibrium A. The rate of the reaction in one direction is equal to the rate in the reverse direction B. The concentration of the reactants is equal to the concentration of the products C. The ratio of reactants to products varies according to the amount of energy released in one direction D. The rate of the reaction in one direction is equal to the rate in the reverse direction and the concentration of the reactants is equal to the concentration of the products occur E. The rate of the reaction in one direction is equal to the rate in the reverse direction and the ratio of reactants to products varies according to the amount of energy released in one direction occur

E. The rate of the reaction in one direction is equal to the rate in the reverse direction and the ratio of reactants to products varies according to the amount of energy released in one direction occur

30. A catalyst for a chemical reaction A. Lowers the activation energy of the reaction B. Is modified by the reaction C. Changes the energy content of the reactants D. Both lowers the activation energy of the reaction and is modified by the reaction are correct E. Both lowers the activation energy of the reaction and changes the energy content of the reactants are correct

A. Lowers the activation energy of the reaction

3. Which of the following statements is true? A. NAD+ and FAD are coenzymes derived from B- vitamins B. At the initiation of translation mRNA binds to a small ribosomal subunit. C. The initiation complex positions appropriate tRNA opposite the mRNA codon signaling the start site for assembly to begin. D. A and B E. A, B and C

E. A, B and C

4. The codon that corresponds to the DNA sequence G-T-A is A. G-T-A B. A-T-G C. C-A-T D. C-A-U E. T-A-C

D. C-A-U

5. Which of the following statements about RNA transcription and translation is true? A. All of the nucleotide sequences in a gene are transcribed into RNA B. The entire transcribed message of a gene is translated into amino acid sequences C. The mRNA that enters the cytosol is considerably shorter than that synthesized during transcription D. Both all of the nucleotide sequences in a gene are transcribed into RNA and the mRNA that enters the cytosol is considerably shorter than that synthesized during transcription are correct E. All of the choices are correct

C. The mRNA that enters the cytosol is considerably shorter than that synthesized during transcription

6. The segments of primary RNA that are cleaved off by spliceosomes are called A. Codons B. Introns C. Exons D. Anticodons E. None of the choices are correct

B. Introns

7. A binding site on a protein is A. An area of the protein with a shape complementary to that of a ligand B. Determined by the amino acid sequence of the protein C. Formed by a region of amino acids that must be adjacent to each other on a polypeptide chain D. An area of the protein with a shape complementary to that of a ligand and determined by the amino acid sequence of the protein E. All of the choices are correct

D. An area of the protein with a shape complementary to that of a ligand and determined by the amino acid sequence of the protein

8. Binding site A requires twice the concentration of ligand to achieve saturation as does binding site B. From this one can conclude that A. Binding site A has a higher affinity for the ligand than does binding site B B. Binding site B has a higher affinity for the ligand than does binding site A C. Both binding sites have the same affinity for the ligand D. Site B is a competitive antagonist of site A E. None of the choices are correct

B. Binding site B has a higher affinity for the ligand than does binding site A

9. Two receptors, A and B, can bind the same chemical signaling molecules but the concentration of those molecules required to reach 50 percent saturation is twice as great for receptor B. Therefore the receptors have the same ________, but different ________. A. Specificity, affinity B. Specificity, saturation C. Affinity, specificity D. Affinity, competition E. Saturation, affinity

A. Specificity, affinity

10. A chemical catalyst increases the rate of a reaction by A. Acting as one of the reactant molecules B. Decreasing the energy of activation C. Increasing the energy content of the product molecules D. Increasing the temperature of a solution E. All of the choices are correct

B. Decreasing the energy of activation

11. Consider the reaction: M + N -> Y + Z Which of the following statements is true? A. The reaction is reversible B. At chemical equilibrium, increasing the concentration of M will drive the reaction to the left C. At chemical equilibrium, decreasing the concentration of M will drive the reaction to the left D. Both the reaction is reversible and at chemical equilibrium, increasing the concentration of M will drive the reaction to the left E. Both the reaction is reversible and at chemical equilibrium, decreasing the concentration of M will drive the reaction to the left

E. Both the reaction is reversible and at chemical equilibrium, decreasing the concentration of M will drive the reaction to the left

12. Consider the reaction: H2CO3 CO2 + H2O + 4 kcal/mol Which of the following statements is true? A. The reaction is anabolic B. The reaction is catabolic C. The energy content of the reactants is greater than the energy content of the products D. A and C E. Band C

E. Band C

13. Enzymes A. Are catalysts in chemical reactions B. Can be carbohydrate molecules C. Are broken down during chemical reactions they catalyze D. Have names generally ending in the suffix "-ose." E. Are described by all of the choices

A. Are catalysts in chemical reactions

15. The probability of a reaction occurring is increased A. By decreasing reactant concentrations B. By increasing the activation energy C. By increasing the product concentration D. If the reaction uses a great deal of energy E. By none of the choices

E. By none of the choices

16. Which of the following is true concerning the rate-limiting step in a metabolic pathway? A. It is likely to be the slowest reaction in the pathway B. It is likely to be the fastest reaction in the pathway C. It may be subject to end-product inhibition D. Both it is likely to be the slowest reaction in the pathway and it may be subject to end-product inhibition E. Both it is likely to be the fastest reaction in the pathway and it may be subject to end-product inhibition

D. Both it is likely to be the slowest reaction in the pathway and it may be subject to end-product inhibition

17. Glucose A. Is the only carbohydrate utilized as an energy source B. Must be phosphorylated before it can be metabolized C. Can be synthesized from other types of molecules, including amino acids and triacylglycerol D. A and B E. B and C

E. B and C

18. Ammonia is A. A waste product of fatty acid metabolism B. Excreted by the kidneys into urine C. Processed by the liver to form a less toxic compound D. A waste product of fatty acid metabolism and excreted by the kidneys into urine E. None of the choices are correct

C. Processed by the liver to form a less toxic compound

19. In the absence of oxygen, cells can derive energy to form ATP from the metabolism of fatty acids. A) True B) False

False

20. The reactions of the Krebs cycle A. Take place in the cytosol within mitochondria B. Generate ATP directly by substrate phosphorylation C. Generate ATP indirectly through production of the coenzymes, NADH and FADH2 which will, subsequently, deliver electrons to the electron transport chain D. A and C E. All of the choices are incorrect

D. A and C

21. Glucose cannot be synthesized from fatty acids because the reaction converting pyruvic acid to acetyl coenzyme A is not reversible. A) True B) False

True

22. When glucose is catabolized in the absence of oxygen, A. Pyruvate formed in glycolysis will generally be converted to lactate B. Pyruvate formed in glycolysis will generally be converted to acetyl coenzyme A, which will enter the Krebs cycle C. The number of ATP molecules formed per molecule of glucose will be less than the number formed in the presence of oxygen D. A and C E. B and C

D. A and C

23. A coenzyme A. Is an organic cofactor B. May be a metal such as iron C. Is a substrate for a catalyzed reaction D. Both is an organic cofactor and is a substrate for a catalyzed reaction E. Both may be a metal such as iron and is a substrate for a catalyzed reaction

D. Both is an organic cofactor and is a substrate for a catalyzed reaction

24. Which of the following is a way that the activity of an enzyme can be modified? A. Allosteric activation B. Allosteric inhibition C. Covalent activation (e.g., by phosphorylation) D. Covalent inhibition (e.g., by phosphorylation) E. All of the choices are correct

E. All of the choices are correct

25. Which of the following statements concerning energy storage in the body is true? A. Most is stored in the form of ATP B. Most is stored in the form of glucose C. Most is stored in the form of fat D. Most is stored in the form of protein E. Most is stored in the form of DNA

C. Most is stored in the form of fat

1. The RNA codon that corresponds to the DNA sequence A-T-C is A. A-U-C B. U-A-G C. T-A-G D. C-A-U E. T-A-C

B. U-A-G

2. Which of the following statements is FALSE concerning RNA synthesis from a DNA template A. The process is termed transcription B. Occurs in the endoplasmic reticulum C. Is often regulated by the activity of protein transcription factors binding to DNA regulatory elements D. A and B E. B and C

B. Occurs in the endoplasmic reticulum

3. A triplet is the term given to a 3 base mRNA sequence coding for one of 20 amino acids. TRUE FALSE

False

4. Which of the following is a mechanism of regulating gene expression? A. Regulation gene transcription B. Regulating mRNA degradation C. Regulating protein degradation D. A and B E. A, B, and C

E. A, B, and C

8. Which of the following is TRUE concerning regulation of ligand binding to protein? A. Ligand bindings sites can be regulated by altering (modulating) their shape. B. The shape of ligand binding site on a protein can be altered by either non-covalent or covalent modification. C. Allosteric modification refers to the change in shape of a protein that occurs when a modulator molecule binds to its regulatory site. D. Allosteric and covalent modification can change the activity of the functional site by either increasing or decreasing its affinity for ligand E. All of the choices are correct

E. All of the choices are correct

9. Enzymes A. Are lipid catalysts B. Increase the activation energy of a reaction C. Are not modified by the reaction they catalyze D. A and B E. B and C

C. Are not modified by the reaction they catalyze

10. The forward rate of an enzyme-mediated chemical reaction can be increased by A. Increasing the substrate concentration B. Increasing the product concentration C. Increasing enzymatic activity D. A and B E. A and C

E. A and C

11. Which of the following is TRUE? A. A metabolic pathway is a sequence of enzyme mediated reactions results in the formation of a specific product. B. Flow of a metabolic pathway can be regulated by changing the concentration of the rate-limiting enzyme of the pathway C. Catabolism refers to the synthesis of organic molecules, whereas anabolism refers to the breakdown of organic molecules. D. A and B E. A and C

D. A and B

12. Which of the following is FALSE concerning cellular respiration? A. Is the process by which chemical energy from nutrient molecules is released and partially captured in the form of ATP B. Results in formation of ATP, the energy source which provides fuel for cellular biosynthetic reactions and processes. C. Glycolysis acts on carbohydrates and lipids. D. A and B E. None of the statements are false.

C. Glycolysis acts on carbohydrates and lipids.

13. Which of the following is TRUE concerning glycolysis? A. Takes place in the cytoplasm B. Always requires the presence of O2 C. May result in the formation of lactate D. A and B E. A and C

E. A and C

14. Which of the following statements is FALSE concerning glucose synthesis. A. Glucose can be synthesized from fatty acids. B. Glucose can be synthesized by the breakdown of glycogen. C. Glucose can be synthesized from amino acids. D. A and B E. A and C

A. Glucose can be synthesized from fatty acids.

15. Which of the following is TRUE? A. Proteins can be broken down and then used to form steroids. B. Ammonia is formed when an amino group is removed from an amino acid C. The amino group of an amino acid can be transferred to a keto acid to form a new type of amino acid. D. A and B E. B and C

E. B and C

16. The rate-limiting reaction in a metabolic pathway is one that occurs at a slower rate than the other steps in the pathway.

True

NADH and FAD are enzymes that participate in biochemical reactions by donating electrons to a substrate.

Fale

The Krebs cycle and oxidative phosphorylation both occur in the mitochondria but only oxidative phosphorylation requires oxygen

False

Catabolism of one gram of carbohydrate results in more ATP than catabolism of one gram of fat.

False

During cellular respiration, coenzymes that are oxidized during glycolysis and the Krebs cycle are oxidized during oxidative phosphorylation.

False

Fatty acid catabolism occurs by the process of beta-oxidation during which the fatty acid is broken down two carbon atoms at a time. The process occurs in the mitochondria and requires oxygen.

True

Some amino acids cannot be synthesized in the body.

True

Vitamins are a family of essential nutrients.

True

Ammonia is converted to urea in the kidneys.

False

Keto acids derived from amino acids can enter glycolysis or the Krebs cycle to yield ATP.

True

Session 2 Flashcards

(74 cards)