Quiz 4: Cellular Metabolism

Enzymes are nucleic acidsthat catalyze specific chemical reactions.

A cofactor is a nonprotein component with which some enzymes must combine in order to be active.

The oxidation of glucose, as occurs with cellular respiration, results in its complete breakdown.

The type of energy used by most metabolic processes is chemical energy.

An ATP molecule includes three phosphate groups.

Of the 32 molecules of ATP generated in one round of the reactions of cellular respiration, only two come from glycolysis.

Complete oxidation of glucose results in the production of nitrogen and water.

A metabolic pathway is a sequence of enzyme-catalyzed reactions.

A genome is a section of DNA in which the nitrogenous base sequence encodes a specific sequence of amino acids.

The four nitrogenous bases occurring in DNA are adenine, cytosine, guanine, and uracil.

A codon is a series of three nucleotides within an mRNA molecule that corresponds to a particular amino acid.

The process of translation involves the assembly of an amino acid chain according to the sequence of base triplets in a transfer RNA molecule.

Anticodon sequences are found in transfer RNA molecules.

Describe anabolism. A) The building of larger molecules from smaller ones B) The total of all chemical processes occurring in cells C) The processes that decompose structures within cells D) The breakdown of larger molecules into smaller ones E) The transport of proteins through the cell membrane

What is an example of dehydration synthesis? A) Converting a protein into amino acids B) Converting monosaccharides into glycogen C) Converting water molecules into hydrogen and hydroxyl ions D) Converting a triglyceride into cholesterol

A piece of bread held in the mouth begins to taste sweet as large carbohydrate molecules are broken down into smaller sugars. This is an example of what type of chemical reaction? A) Cellular respiration B) Dehydration synthesis C) Catabolism D) DNA replication E) Hydrolysis

How is water involved in the process of hydrolysis? A) A water molecule is released. B) A water molecule is consumed.

What is an example of catabolism? A) Converting hydrogen and hydroxyl ions into water B) Converting glycogen into glucose molecules C) Converting amino acids into proteins D) Converting fatty acids and glycerol into triglyceride molecules

By definition, anabolism and catabolism together constitute __________. A) metabolism B) protein synthesis C) dehydration synthesis D) hydrolysis E) cellular respiration

What is the function of enzymes? A) To increase activation energy B) To slow metabolic reactions C) To function as catalysts D) To act as reactants in chemical reactions E) To convey the genetic code for a cell

How are enzymes able to catalyze chemical reactions so that they proceed fast enough to sustain life? A) By transporting the product(s) of the reaction out of the cell B) By decreasing the activation energy of the reaction C) By creating more efficient metabolic pathways D) By providing energy in the form of ATP E) By removing cofactors and coenzymes that slow reactions

Each enzyme acts only on specific chemicals. What are these chemicals called? A) Genes B) Catalysts C) Activators D) Cofactors E) Substrates

What is the substrate for the enzyme called protease? A) Hydrogen peroxide B) Proteins C) Protons D) Sugars, such as glucose E) Cholesterol

The part of an enzyme called the __________ combines with a specific part of the substrate. A) polar site B) active site C) terminal site D) nucleus E) cofactor

What are the steps for an enzyme-catalyzed reaction? A) Substrate + enzyme→ enzyme-substrate complex→ product + enzyme B) Enzyme→ substrate + product→ enzyme-substrate complex + enzyme C) Product + enzyme-substrate complex→ enzyme→ substrate + enzyme D) Enzyme-substrate complex→ enzyme + substrate→ product + enzyme E) Enzyme + product→ enzyme-product complex→ substrate + enzyme

An enzyme exposed to certain chemicals, heat, extremes of pH, electricity, or radiation can become __________, potentially inactivating it. A) unnatural B) genetically modified C) denatured D) mutated E) catabolized

Where in the cell does the anaerobic phase of cellular respiration occur? A) In the cytosol B) In the mitochondria C) In the nucleus D) In the Golgi apparatus E) In specialized vesicles

Cellular respiration occurs in three distinct series of reactions. What is the correct order of these reactions? A) Electron transport chain; glycolysis; citric acid cycle B) Glycolysis; electron transport chain; citric acid cycle C) Citric acid cycle; glycolysis; electron transport chain D) Glycolysis; citric acid cycle; electron transport chain E) Electron transport chain; citric acid cycle; glycolysis

What substance becomes more abundant as a result of cellular respiration? A) Oxygen B) Glucose C) Citric acid D) Glycogen E) ATP

An ATP molecule that has given up its terminal phosphate in order to provide energy for the cell becomes what molecule? A) AMP B) Cyclic AMP C) Glucose D) ADP E) Activated ATP

What is the fate of a glucose molecule during the anaerobic phase of cellular respiration? A) Glucose is broken down to yield two molecules of pyruvic acid. B) Glucose combines with another glucose molecule to yield one molecule of pyruvic acid. C) Glucose combines with oxygen to form a molecule of pyruvic acid. D) Glucose is broken down to yield one molecule of pyruvic acid and one molecule of lactic acid. E) Glucose remains unchanged.

What part of an ATP molecule holds the energy that can then be used in metabolism? A) Chemical bonds of the adenosine group B) Chemical bonds of the nitrogen-containing base C) Chemical bonds between the phosphate groups D) Chemical bond attaching the adenosine group to the first phosphate group

Glycolysis is classified as the ____________ phase of cellular respiration. A) anaerobic B) aerobic

For each molecule of glucose that is completely oxidized, how many ATP molecules are produced? A) 2 B) 4 C) 25 D) 32 E) 48

In what cellular location do the reactions of aerobic respiration occur? A) In mitochondria B) In the nucleus C) In the Golgi apparatus D) In lysosomes E) In the cytoplasm

What compound combines with a 4-carbon oxaloacetic acid molecule to begin the citric acid cycle? A) ATP B) Acetyl CoA C) Pyruvic acid D) Glucose E) Carbon dioxide

What are the DNA segments called that encode for proteins? A) Nitrogenous bases B) Genomes C) Amino acids D) Genes E) Nucleotides

Of the human genome, about __________ percent encodes protein. A) 1.5 B) 10 C) 33.3 D) 50 E) 98

What is the "genetic code"? A) A sequence of amino acids that instructs cells how to make specific nucleic acids B) A sequence of nucleotide bases that instructs cells how to make specific protein molecules C) A sequence of amino acids in proteins that act as enzymes D) A sequence of proteins embedded in the cell membrane E) A sequence of enzymes located within the mitochondria

What is the term for the complete set of genetic instructions for an individual? A) Gene B) Nucleus C) DNA D) Genome E) Messenger RNA

A segment of a DNA strand has the base sequence T, C, G, A, T, C. What is the base sequence of the complementary strand? A B) A, G, C, T, A, G C) U, C, G, A, U, C D) A, G, C, U, A, G E) C, T, A, G, C, T

Identify the complementary base pairs in DNA. A) A - G and C - T B) A - G and C - U C) A - A, G - G, C - C, and T - T D) A - T and G - C

Which statement describes a DNA molecule? A) A triple helix B) Chains of nucleotides C) Single-stranded molecule D) Made up of RNA E) Chains of amino acids

When is it necessary for DNA replication to occur? A) When a cell divides B) When protein synthesis occurs C) Immediately prior to formation of messenger RNA D) When a gene is activated E) When a cell dies

The transfer of genetic information from the nucleus into the cytoplasm is a function of what molecule? A) DNA B) Ribosomal RNA C) Messenger RNA D) Transfer RNA E) ATP

What is the base sequence of an mRNA molecule produced using a gene with the base sequence T-T-A-C-G-A? A) A-A-U-G-C-U B) A-A-T-G-C-T C) T-T-A-C-G-A D) U-U-T-G-C-T E) A-G-C-A-T-T

During protein synthesis, what determines the amino acid order in the newly produced polypeptide chain? A) Ribosomal RNA B) Transfer RNA C) Messenger RNA

What phase of protein synthesis involves the copying of information from DNA into RNA? A) Translation B) Transcription C) Replication D) Deamination

The breakdown of starch to maltose is an example of what type of reaction? A) Anabolic reaction B) Catabolic reaction

What are the net end products of glycolysis? A) 4 ATP, 2 acetyl groups B) 2 ATP, 2 pyruvic acids C) 32 ATP, 2 acetyl groups, 2 pyruvic acids D) 32 ATP, 6 H ₂O, 6 CO ₂ E) 2 ATP, 2 H ₂O, 2 CO ₂

A cell has burned one glucose molecule, resulting in the net production of 2 ATP. What can be said about the process that occurred? A) Glucose was burned anaerobically. B) Glucose was burned aerobically.

In the gut, the digestion of a meal to release nutrient molecules is an example of __________. A) catabolism B) anabolism

Name the type of reaction that occurs when two monosaccharides combine to form the disaccharide called sucrose. A) The anabolic reaction called dehydration synthesis B) The catabolic reaction called dehydration synthesis C) The catabolic reaction called hydrolysis D) The anabolic reaction called hydrolysis

What type of reaction results in the release of a water molecule? A) Hydrolysis B) Dehydration synthesis

A chemical reaction in which bonds are broken is associated with __________. A) the consumption of energy B) the release of energy

Enzymes are best described as what kind of molecule? A) Proteins that catalyze chemical reactions B) Nucleic acids that code for protein production C) Compounds that are converted to products during a chemical reaction D) Proteins that increase the activation energy of chemical reactions

What are coenzymes? A) Small organic molecules required by some enzymes to become active B) Small molecules that bind to the active sites of enzymes and undergo chemical changes C) Ions that act to regulate the pace of reactions in a metabolic pathway D) Molecules that stimulate the production of enzymes needed by a cell

What is the fate of the energy released during the reactions of cellular respiration? A) 10% used to produce ATP; 90% lost as heat B) 40% used to produce ATP; 60% lost as heat C) 60% used to produce ATP; 40% lost as heat D) 90% used to produce ATP; 10% lost as heat

Which molecule contains the most chemical energy? A) Adenosine triphosphate B) Adenosine diphosphate

Compare the anaerobic phase of cellular respiration to the aerobic phase. Which results in the greater production of ATP? A) Aerobic phase B) Anaerobic phase

Compare the anaerobic phase of cellular respiration to the aerobic phase. Which one involves the compound called acetyl CoA? A) Aerobic phase B) Anaerobic phase

Compare the anaerobic phase of cellular respiration to the aerobic phase. Which results in the production of pyruvic acid? A) Aerobic phase B) Anaerobic phase

Compare the anaerobic phase of cellular respiration to the aerobic phase. Which one occurs in the cytoplasm? A) Aerobic phase B) Anaerobic phase

Compare the anaerobic phase of cellular respiration to the aerobic phase. Which results in the production of water? A) Aerobic phase B) Anaerobic phase

What is the function of DNA polymerase? A) Forms new DNA strand during DNA replication B) Causes hydrogen bonds between DNA strands to break C) Carries genetic information from nucleus out to ribosomes in cytoplasm D) Forms messenger RNA during protein synthesis

Which enzyme is critical to the process of transcription? A) RNA polymerase B) DNA polymerase

For each DNA molecule, the process of DNA replication results in two identical complete DNA molecules. What is the composition of these two end products of DNA replication? A) Each DNA molecule consists of one old strand from the original DNA molecule and one newly formed strand. B) One DNA molecule consists of the two original strands from the original DNA molecule; the other consists of two newly formed DNA strands.

Each amino acid is represented in a DNA molecule by a particular sequence of __________ nucleotides. A) 2 B) 3 C) 4 D) 6

Compare translation and transcription. Which process relies on codons to accurately complete the process? A) Translation B) Transcription

Compare translation and transcription. Which process results in the production of mRNA? A) Translation B) Transcription

Compare translation and transcription. Which process occurs in the cytoplasm? A) Translation B) Transcription

Compare translation and transcription. Which process relies on ribosomes to complete the process? A) Translation B) Transcription

Codon production depends on what "information"? A) Base sequence on DNA molecule B) Base sequence of anticodon C) Amino acid sequence of ribosome binding site D) Amino acid sequence of RNA polymerase

Where does the binding of an anticodon to a codon occur? A) Within a ribosome B) In the cytosol C) In the nucleus D) In a mitochondrion

The genetic condition called phenylketonuria results from a defect in a gene called PAH which helps create phenylalanine hydroxylase, the enzyme that breaks down the amino acid phenylalanine. What is the outcome of this condition and the lack of this enzyme? A) Phenylalanine accumulates. B) Phenylalanine is completely used up, deleting its stores in the body. C) A different enzyme begins breaking down phenylalanine. D) Phenylalanine hydroxylase accumulates.

The term __________ includes all of the chemical reactions that occur in the body.