a&p chp 4
A example of genetic change is the presence of certain DNA sequences occurring in different numbers of copies in different individuals.
TRUE
A metabolic pathway is a particular sequence of enzyme-controlled reactions.
TRUE
A mutation may occur spontaneously or by exposure to a mutagen.
TRUE
A mutation that changes a CGC codon to CGA would not affect health because the encoded amino acid is unchanged.
TRUE
All of the genetic information in a cell is a genome.
TRUE
An ATP molecule consists of an adenine, a ribose, and three phosphates.
TRUE
Codons are three contiguous mRNA bases.
TRUE
DNA and RNA differ in number of strands, type of sugar, and types of nitrogenous bases.
TRUE
Enzymes are proteins that promote specific chemical reactions.
TRUE
Exposure to UV radiation can cause changes in DNA and can therefore be considered a mutagen.
TRUE
In glycolysis, the enzyme phosphofructokinase catalyzes the slowest part of this metabolic process and can therefore be considered a rate-limiting enzyme.
TRUE
Oxidation of glucose is important because it releases energy.
TRUE
The part of the tRNA that binds mRNA is the anticodon.
TRUE
The portion of a DNA molecule that contains the genetic information for making a protein is called a gene.
TRUE
The two strands of a DNA molecule have opposite orientation.
TRUE
Three types of RNA participate in protein synthesis.
TRUE
A mutation is A) a change in a DNA sequence in less than 1% of a population that affects anatomy and/or physiology. B) a common genetic variant. C) always beneficial to health. D) always harmful to health.
a change in a DNA sequence in less than 1% of a population that affects anatomy and/or physiology.
A cofactor is ________. Examples are ________. A) an inorganic molecule that all enzymes require; cholesterol and calcium B) an inorganic molecule that some enzymes require; vitamin B12 and B6 C) a necessary part of some enzymes; copper, iron, and zinc D) a molecule that destabilizes substrates; carbonic acid
a necessary part of some enzymes; copper, iron, and zinc
When a sucrose molecule is broken down to yield a glucose molecule and a fructose molecule, A) dehydration synthesis occurs. B) a water molecule is released. C) a water molecule is used. D) starch is consumed.
a water molecule is used.
The term metabolism refers to A) the reactions in the body that synthesize proteins and nucleic acids. B) the reactions in the body that break down proteins and nucleic acids. C) all of the chemical reactions in a cell. D) the breakdown of glucose molecules to release energy.
all chemical reactions in a cell
Anaerobic reactions of cellular respiration A) break down glucose into 2 pyruvic acid molecules. B) occur in the absence of oxygen. C) transfer energy to ATP molecules. D) all of the answer choices are correct.
all of the answer choices are correct.
The metabolome includes A) all of the genes that encode protein in the genome. B) the DNA that does not encode protein in the genome. C) all of the small molecules that are part of metabolism. D) all of the enzymes that take part in aerobic respiration.
all of the small molecules that are part of metabolism.
Synthesis of a protein stops when A) any of three specific anticodons are encountered in the mRNA. B) there is no more DNA. C) any of three "stop" codons are encountered in the mRNA. D) the ribosome becomes fatigued.
any of three "stop" codons are encountered in the mRNA.
The enzyme catalase acts on the substrate A) oxygen. B) hydrogen. C) hydrogen peroxide. D) peroxidase.
hydrogen peroxide.
In dehydration synthesis of a carbohydrate, A) larger molecules are broken down into smaller ones. B) monosaccharides are joined. C) water molecules bond to monosaccharide molecules. D) the molecule is broken down into carbon dioxide and water.
monosaccharides are joined.
Three types of genetic changes are A) replication, transcription, and translation. B) A to C, G to C, and U to A. C) mutations, SNPs, and changes in copy number. D) adenine, guanine, and cytosine.
mutations, SNPs, and changes in copy number.
An important mechanism that controls metabolic pathways under physiological conditions is A) positive feedback. B) signal transduction. C) negative feedback. D) genetic control.
negative feedback.
The term catabolism refers to A) chemical reactions that acquire energy. B) chemical reactions that release energy. C) synthesis of large molecules. D) the formation of genetic material.
chemical reactions that release energy.
The correspondence between a unit of DNA information and an amino acid is the genetic ________.
code
DNA profiling A) sequences the entire genomes of criminals. B) sequences genes that cause disease. C) compares the most variable parts of the genome for a variety of applications. D) analyzes 64 highly variable regions of the human genome.
compares the most variable parts of the genome for a variety of applications.
The anaerobic reactions of cellular respiration occur in the ________ , whereas the aerobic reactions of cellular respiration occur in the ________. A) mitochondria with O2 required; cytoplasm with O2 required B) cytoplasm without O2 required; cytoplasm with CO2 required C) mitochondria without O2 required; mitochondria with O2 required D) cytoplasm without O2 required; mitochondria with O2 required
cytoplasm without O2 required; mitochondria with O2 required
The anaerobic reactions of cellular respiration take place in the A) cytoplasm. B) mitochondria. C) nucleus. D) ribosomes.
cytoplasm.
Which choice lists structures in order of increasing size? A) nitrogenous base - nucleotide - gene - chromosome - genome B) nitrogenous base - nucleotide - gene - genome - chromosome C) genome - nucleus - chromosome - nucleotide - gene D) cell - organelle - tissue - organ
nitrogenous base - nucleotide - gene - chromosome - genome
Three factors that increase the rates of enzyme-controlled reactions are the A) number of enzyme molecules, number of substrate molecules, and efficiency of the enzyme. B) temperature of the reaction, number of H2O molecules, and bond strength. C) number of enzyme and substrate molecules formed, and strength of the enzyme. D) size of the enzyme compared to the substrate, the number of active sites, and the ratio of enzyme to substrate molecules.
number of enzyme molecules, number of substrate molecules, and efficiency of the enzyme.
ATP is important to cellular processes because it A) is formed by muscles contracting or whenever cellular work occurs. B) provides energy for cellular work when the terminal, high-energy bond is broken. C) releases oxygen when high-energy phosphate bonds are broken. D) is a by-product of all catabolic reactions.
provides energy for cellular work when the terminal, high-energy bond is broken.
Adenine and guanine are ________ and cytosine and thymine are ________.
purines; pyrimidines
In the DNA damage response, A) repair enzymes replace mismatched nucleotides in DNA. B) repair enzymes replace mismatched nucleotides in RNA. C) repair enzymes replace mismatched amino acids in protein. D) more than one codon encodes one type of amino acid.
repair enzymes replace mismatched nucleotides in DNA.
The process that extracts energy from glucose and makes it available is cellular ________.
respiration
The basic steps of an enzyme-catalyzed reaction are A) substrate and product combine, forming an S-P complex. The reaction occurs, enzymes are released, and the unchanged substrate is released and recycled. B) substrate and enzyme combine, forming an E-S complex. The reaction occurs, products are released, and the unchanged enzyme is released and recycled. C) substrate, enzyme, and product combine, forming an S-E-P complex. The reaction occurs, products are released, and the unchanged enzyme is released and recycled. D) enzyme and product combine, forming an E-P complex. The reaction reverses, enzymes are released, and the unchanged substrate is released and recycled.
substrate and enzyme combine, forming an E-S complex. The reaction occurs, products are released, and the unchanged enzyme is released and recycled.
A molecule that carries energy in a form the cell can use is A) glucose. B) glycogen. C) vitamin C. D) ATP.
ATP.
The codon that will signal where to begin making a polypeptide is ________. A) TAC B) AGG C) AUG D) TTA
AUG
Name the molecule that is common to carbohydrate and lipid metabolic pathways and connects these two pathways metabolically. A) Glucose B) Pyruvic acid C) Acetyl coenzyme A D) Glycogen
Acetyl coenzyme A
MicroRNAs A) are 21 or 22 bases long. B) control gene expression. C) are noncoding RNAs. D) All of these answer choices are correct.
All of these answer choices are correct.
A DNA sequence AACGGTGCACCACGG encodes an mRNA of sequence A) AACGGUGCACCACGG. B) UUGCCACGUGGUGCC. C) AACGGTGCACCACGG. D) UUCGGAGCUCCUCGG.
B) UUGCCACGUGGUGCC.
Which DNA sequence can encode the amino acid sequence ile-asp-ser-cys-his-tyr? A) TAGCTGTCAACAGTGATA B) TAACTGTCGACGGTGATG C) TAACTAAGTACGGTGATG D) All of the answer choices are correct
C) TAACTAAGTACGGTGATG
A DNA molecule is a double helix in which A pairs with C and T pairs with G.
FALSE
A DNA strand of ACTTCGCATG, when replicated, would yield a strand of the same sequence.
FALSE
A single nucleotide polymorphism is a very rare genetic variant that affects health.
FALSE
An active site is the part of a substrate molecule that binds an enzyme.
FALSE
Phospholipids are critical structures in cell membranes and are therefore enzymes.
FALSE
The synthesis of an ATP molecule requires two ADP molecules.
FALSE
Transcription yields protein and translation produces RNA
FALSE
If a cell was unable to produce pyruvate, this cell may have a mutation in an enzyme in which process? A) Glycolysis B) The citric acid cycle C) Gluconeogenesis D) The electron transport system
Glycolysis
The electron transport chain is a series of enzyme complexes that pass electrons one-to- another, releasing energy that is used to phosphorylate ADP to ATP on the inner mitochondrial membrane.
TRUE
The genetic code is the correspondence between DNA sequence and amino acid sequence of a protein.
TRUE
Humans require vitamins in their diets because these nutrients A) provide energy. B) are broken down by catabolic reactions. C) bond with minerals. D) act as coenzymes.
act as coenzymes.
A peptide bond forms between A) a tRNA and an mRNA. B) adjacent amino acids. C) an mRNA and an rRNA. D) a gene and a protein.
adjacent amino acids
Building up large molecules is called ________.
anabolism
If the DNA triplet ACA mutates to GCA, then the encoded amino acid changes from ________ to ________.
cysteine; arginine
In cellular respiration, A) mitochondria release glucose molecules. B) energy is released from molecules and is transferred to other molecules. C) cells breathe, or take in, O2 and give off CO2. D) energy is absorbed from glucose and is transferred to CO2.
energy is released from molecules and is transferred to other molecules.
One reason why protein synthesis is important is A) enzymes are proteins and enzymes are essential to metabolism. B) proteins release energy for metabolic reactions. C) proteins encode DNA sequences. D) the diet does not provide the building blocks of protein.
enzymes are proteins and enzymes are essential to metabolism.
The complete set of genetic instructions in an individual is the ________.
genome
A molecule that is a storage form of carbohydrate is A) glycogen. B) glycerol. C) DNA. D) an amino acid.
glycogen.
Anaerobic respiration and aerobic respiration begin with the process of ________ , in which glucose is broken down.
glycolysis
Releasing the energy in glucose molecules is an example of catabolism.
TRUE
The DNA damage response replaces mismatched nucleotides.
TRUE
The aerobic reactions of cellular respiration occur in the mitochondria.
TRUE
The molecule that an enzyme affects is its ________.
substrate
Metabolism refers to all of the chemical reactions in a cell.
TRUE
A part of a gene that is a DNA sequence 333 nucleotides long encodes ________ amino acids. A) 333 B) 111 C) 999 D) 444
111
How many codons specify the twenty types of amino acids? A) 61 B) 23 C) 46 D) 3
61
Which of the following would NOT be an example of an enzyme? A) A molecule that remains unchanged after assisting in a chemical reaction B) A molecule that assists in the breakdown of proteins into amino acids in the stomach C) A molecule that helps to form the cytoskeleton of a cell D) A molecule that breaks down sucrose into glucose and fructose
A molecule that helps to form the cytoskeleton of a cell
Which of the following substances increases in abundance during cellular respiration? A) Oxygen B) Glucose C) ATP D) Glycogen
ATP
Which of the following is not true regarding RNA? A) It is transcribed in the nucleus and enters the cytoplasm. B) It includes ribose, a 5-carbon sugar. C) It is double-stranded. D) It has cytosine as one of its four nitrogenous bases.
It is double-stranded.
Lactose is a disaccharide found in milk. Individuals who are lactose intolerant lack the enzyme to break this sugar down into monosaccharides. Based on enzyme nomenclature, what enzyme is deficient in these individuals? A) Lact ese B) Lact ose C) Lacto gen D) Lact ase
Lact ase
Which of the following is true? A) The genome consists of entirely protein-encoding genes. B) An amino acid encodes a gene. C) DNA has five types of nucleotide bases. D) Much of the genome does not encode proteins.
Much of the genome does not encode proteins.
A DNA sequence of CGCTTACGATTG would be transcribed into an RNA sequence of GCGAAUGCUAAC.
TRUE
A cell may contain hundreds of different types of enzymes.
TRUE
Which of the following is an example of catabolism? A) The assembly of the cell membrane from precursor molecules B) The increase in muscle tissue with exercise C) The formation of secretory proteins in the pancreas D) The breakdown of glucose in the cytoplasm and mitochondria
The breakdown of glucose in the cytoplasm and mitochondria
If an E. coli bacterium were to have a protein with the correct amino acid sequence, but not the correct shape, which of the following is a logical explanation for what could be wrong?A) Peptide bonds were not able to form between the amino acids. B) The shape-coding region of the DNA sequence related to this protein is mutated. C) The chaperone protein associated with protein folding is not functional. D) An error in transcription occurred.
The chaperone protein associated with protein folding is not functional.
If an organism is known to have a mutation in the DNA sequence of a gene that codes for an enzyme, but still produces a functional enzyme, which of the following is most likely TRUE? A) The mutation did not lead to a change in the amino acid sequence of the enzyme. B) Chaperone proteins are able to repair the error in the DNA sequence. C) The mutation must have occurred in the part of the sequence coding for the active site. D) Transcription of the gene into RNA is able to repair the mutation.
The mutation did not lead to a change in the amino acid sequence of the enzyme.
Some insecticides, such as chlorpyrifos, work by inhibiting the enzyme acetylcholinesterase (AChE), which normally breaks down the neurotransmitter acetylcholine. Where does this insecticide most likely bind to inhibit the enzyme's activity? A) Any location on the amino acid chain that forms the AChE enyzme B) A sequence of DNA nucleotides that encodes the AChE enzyme protein molecule C) It does not need to bind with the enzyme directly D) The part of an enzyme that combines with acetlycholine
The part of an enzyme that combines with acetlycholine
If the DNA sequence ATGCTCAT was found to have the complimentary strand TACGGGTA, which of the following is possible? A) There was an error during DNA replication. B) The cell correctly copied the DNA strand during replication. C) There was an error during translation where the incorrect nucleotide was brought by the mRNA. D) There was an error during transcription where the incorrect codon on the tRNA molecule.
There was an error during DNA replication.
Which of the nitrogenous bases is part of DNA, but not RNA? A) Uracil B) Thymine C) Guanine D) Cytosine
Thymine
Dehydration synthesis reactions ________ , whereas hydrolysis reactions ________. A) lose H2O as bonds are broken; use H2O to form bonds B) break large molecules into smaller ones; build large molecules from smaller ones C) use H2O to form bonds; lose H2O as bonds are broken D) lose H2O as bonds are formed; use H2O to break bonds
lose H2O as bonds are formed; use H2O to break bonds
In what molecule are codons found? A) mRNA B) tRNA C) rRNA D) Proteins.
mRNA
An example of an anabolic reaction is A) many monosaccharides bonding, forming glycogen. B) a dipeptide breaking down into two amino acids. C) glycerol reacting with three fatty acid molecules to yield water and proteins. D) glycogen breaking down into many monosaccharides.
many monosaccharides bonding, forming glycogen.
A substance that causes a mutation is called a ________.
mutagen
The type of RNA that binds an amino acid is ________ -RNA
t
Copying DNA information into an mRNA molecule is called A) translation. B) synthesis. C) replication. D) transcription.
transcription.
If one strand of DNA has the sequence TCAGGCTATTCCCG, then the complementary sequence of the other strand is A) AGUCCGAUAAGGGC. B) AGTCCGATAAGGGC. C) TCAGGCTATTCCCG. D) UCAGGCUAUUCCCG.
AGTCCGATAAGGGC.
Catabolism builds up molecules and anabolism breaks down molecules.
FALSE
Dehydration synthesis is catabolic and hydrolysis is anabolic.
FALSE
During the anaerobic reactions of cellular respiration, pyruvic acid reacts to form glucose.
FALSE
Each individual has her or his own genetic code.
FALSE
For each acetyl CoA molecule that enters the citric acid cycle, 2 ATPs, 16 H atoms, and 4 CO2 molecules are produced.
FALSE
Genetic information is contained in protein molecules and is passed from one parent to another.
FALSE
In DNA replication, the two strands of the double helix separate and enzymes place A, C, G, and U nucleotides opposite their complements, forming two double helices from one.
FALSE
In adipose tissue, fat molecules form when fatty acid molecules and glycerol join by hydrolysis.
FALSE
Oxidation forms chemical bonds.
FALSE
Which of the following would not be considered a mutagen? A) Ethidium bromide, a chemical that binds directly to DNA and deforms the double helix B) X-rays, which can break the bonds in DNA molecules C) Nitrous acid, which can convert cytosine to uracil D) Flavonoids, a family of compounds which can remove free radicals from cells
Flavonoids, a family of compounds which can remove free radicals from cells
A sequence of DNA is CTGATGTCTA. Its complement is ________.
GACTACAGAT
If you were to sequence the genome of two individuals and found that their DNA is 99.9% similar, what inference could you make? A) These two individuals must be siblings. B) These individuals are likely identical twins. C) These individuals must be from different species. D) No inferences could be made because 99.9% of DNA is shared between all humans
No inferences could be made because 99.9% of DNA is shared between all humans
Which of the following best describes the interaction between an enzyme and its substrate? A) The enzyme surrounds and completely contains the substrate. B) The substrate surrounds and completely contains the enzyme. C) The enzyme temporarily deactivates the substrate. D) Part of the enzyme temporarily binds part of the substrate molecule.
Part of the enzyme temporarily binds part of the substrate molecule.
How does oxidation during cellular respiration differ from burning? A) Respiration doesn't use enzymes to lower the activation energy. B) Respiration requires a relatively large amount of energy to start the process. C) Respiration uses enzymes to lower the activation energy. D) Respiration releases more energy as heat and light.
Respiration uses enzymes to lower the activation energy.
A different enzyme may catalyze the formation and the breakdown of the same molecule.
TRUE
Which of the following is not a characteristic of enzymes? A) They speed up the rate of chemical reactions but are not used up in the process. B) Most are proteins. C) They are most active at temperatures above 53 degrees C. D) They have active sites and interact with specific substrates.
They are most active at temperatures above 53 degrees C.
What is the function of ATP molecules in living cells? A) They form a genetic material. B) They capture energy from the oxidation of fuels in their high-energy phosphate bonds, and the energy is used in various cell processes. C) They act as coenzymes so that fats can be synthesized. D) They are an integral part of the cell membrane, important in transporting water molecules.
They capture energy from the oxidation of fuels in their high-energy phosphate bonds, and the energy is used in various cell processes.
The term anabolic metabolism refers to A) biochemical reactions that synthesize compounds. B) all processes required to maintain life. C) biochemical reactions that break down compounds. D) biochemical reactions that release energy from nutrients.
biochemical reactions that synthesize compounds.
In the citric acid cycle, A) carbon dioxide is released. B) oxygen atoms are released. C) 4 ATP molecules are formed. D) hydrochloric acid is released.
carbon dioxide is released.
DNA replication occurs A) when a cell requires energy. B) outside of the nucleus. C) during interphase of the cell cycle. D) during mitosis.
during interphase of the cell cycle.
Arsenic poisoning harms the body by A) unraveling the DNA double helix. B) interfering with cellular extraction of energy from glucose. C) forming more sulfur bonds in proteins. D) rotting the teeth.
interfering with cellular extraction of energy from glucose.
If you were to isolate a molecule containing uracil, all of the following are most likely true EXCEPT A) it contains codons that represent amino acids. B) it is single stranded. C) it also contains guanine. D) it contains deoxyribose sugar.
it contains deoxyribose sugar.
A DNA sequence AACGGTGCACCACGG encodes a portion of a protein of sequence A) ile-gly-ala-pro-arg. B) leu-pro-arg-gly-ala. C) ala-gly-arg-pro-leu. D) arg-pro-ala-gly-ile.
leu-pro-arg-gly-ala.
All of the following are examples of catabolic reactions EXCEPT A) trypsin in the stomach digesting large proteins into smaller ones. B) amylase in saliva breaking down starch into simple sugars. C) the release of energy by converting ATP into ADP during a metabolic reaction. D) synthesizing the enzyme maltase from amino acids.
synthesizing the enzyme maltase from amino acids.
During DNA replication, A) tRNAs bring specific amino acids to an mRNA molecule. B) two single strands of DNA come together, restoring complementary base pairing. C) amino acids are joined. D) the DNA double helix comes apart, and new nucleotides are brought in, forming two double helices.
the DNA double helix comes apart, and new nucleotides are brought in, forming two double helices.
A mutation can cause disease if A) the DNA sequence does not change. B) the DNA sequence changes so that one amino acid is substituted for another in a way that affects the encoded protein's functioning. C) the DNA sequence changes so that one amino acid is substituted for another in a way that does not alter the encoded protein's functioning. D) it attracts mutagens.
the DNA sequence changes so that one amino acid is substituted for another in a way that affects the encoded protein's functioning.
Energy is defined as A) something important for chemical reactions. B) the ability to do work. C) the heat given off from chemical reactions. D) the heat required to start a reaction.
the ability to do work.
The genetic code is A) the correspondence between a sequence of three DNA nucleotides and a specific amino acid. B) the correspondence between a DNA nucleotide and an RNA nucleotide. C) the correspondence between a gene and a genome. D) the correspondence between a specific amino acid and a specific gene.
the correspondence between a sequence of three DNA nucleotides and a specific amino acid.
Transcription and translation differ in that A) transcription produces DNA and translation produces RNA. B) transcription produces RNA and translation produces DNA. C) transcription produces protein and translation produces RNA. D) transcription produces RNA and translation produces protein.
transcription produces RNA and translation produces protein.
If the DNA sequence for an enzyme lacked a stop codon, this would mean A) transcription would not have an end point. B) translation would not have an end point. C) DNA replication would not be possible. D) the incorrect amino acid would be incorporated into the final enzyme at that point.
translation would not have an end point.
