Deck 4: Cellular Metabolism

Question 1

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.

Answer 1

D

Question 2

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.

Answer 2

A

Question 3

An active site of an enzyme is

A)the part of the enzyme that binds ATP.
B)a sequence of DNA nucleotides that encodes a protein molecule.
C)the part of a substrate that combines with an enzyme.
D)the part of an enzyme that combines with a substrate.

Answer 3

D

Question 4

One reason that protein synthesis is important is that

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.

Question 5

The name of an enzyme ends in

A)-ese.
B)-ose.
C)-gen.
D)-ase.

Question 6

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 3 fatty acid molecules to yield water and proteins.
D)glycogen breaking down into many monosaccharides.

Question 7

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,enzymes 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.

Question 8

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.

Question 9

The enzyme catalase acts on the substrate

A)oxygen.
B)hydrogen.
C)hydrogen peroxide.
D)peroxidase.

Question 10

In dehydration synthesis of a carbohydrate,

A)larger molecules are decomposed into smaller ones.
B)monosaccharides are joined.
C)water molecules bond to monosaccharide molecules.
D)the molecule is decomposed into carbon dioxide and water.

Question 11

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.

Question 12

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.

Question 13

A cofactor is ______ and 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

Question 14

An enzyme is

A)a molecule,usually a protein,that speeds the rate of a biochemical reaction by lowering the activation energy.
B)the genetic material.
C)a protein that promotes metabolic reactions by slowing reactions that are too fast.
D)usually a vitamin.

Question 15

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.

Question 16

Dehydration synthesis reactions _____,whereas hydrolysis reactions _____.

A)lose H₂O to break bonds;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 to break bonds
D)lose H₂O to form bonds;use H₂O to break bonds

Question 17

"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.

Question 18

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.

Question 19

When a sucrose molecule is decomposed 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.

Question 20

An important mechanism that controls metabolic pathways under physiological conditions is

A)positive feedback.
B)signal transduction.
C)negative feedback.
D)genetic control.

Question 21

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.

Question 22

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.

Question 23

In the citric acid cycle

A)carbon dioxide is released.
B)oxygen atoms are released.
C)4 ATP molecules are formed.
D)hydrocholoric acid is releaseD.

Question 24

A molecule that is common to carbohydrate and lipid metabolic pathways and connects these two pathways metabolically is

A)glucose.
B)pyruvic acid.
C)acetyl coenzyme A
D)glycogen.

Question 25

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.

Question 26

A molecule that carries energy in a form the cell can use is

A)glucose.
B)glycogen.
C)vitamin C
D)ATP.

Question 27

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.

Question 28

Oxidation during cellular respiration differs from burning in that respiration

A)doesn't use enzymes to lower the activation energy.
B)requires a relatively large amount of energy to start the process.
C)uses enzymes to lower the activation energy.
D)releases more energy as heat and light.

Question 29

A molecule that is a storage form of carbohydrate is

A)glycogen.
B)glycerol.
C)DNA.
D)an amino aciD.

Question 30

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

Question 31

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 where hydrogen bonds join base pairs,and new nucleotides are brought in,forming two double helices.

Question 32

A glucose molecule is broken down into two pyruvic acid molecules in

A)glycolysis.
B)the citric acid cycle.
C)gluconeogenesis.
D)the electron transport system.

Question 33

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.

Question 34

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.

Question 35

Which of the following substances increases in abundance during cellular respiration?

A)Oxygen
B)Glucose
C)ATP
D)Glycogen

Question 36

How many codons specify the twenty types of amino acids?

A)61
B)23
C)46
D)3

Question 37

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

Question 38

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)do all of the above.

Question 39

DNA replication occurs

A)when a cell requires energy.
B)outside of the nucleus.
C)during interphase of the cell cycle.
D)during mitosis.

Question 40

The anaerobic reactions of cellular respiration take place in the

A)cytoplasm.
B)mitochondria.
C)nucleus.
D)ribosomes.

Question 41

Copying DNA information into an mRNA molecule is called

A)translation.
B)synthesis.
C)replication.
D)transcription.

Question 42

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.

Question 43

Which of the nitrogenous bases is part of RNA but not DNA?

A)Cytosine
B)Thymine
C)Guanine
D)Uracil

Question 44

Which of the nitrogenous bases is part of DNA but not RNA?

A)Uracil
B)Thymine
C)Guanine
D)Cytosine

Question 45

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.

Question 46

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.

Question 47

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.

Question 48

The genome sequences of different individuals are

A)always identical.
B)always different.
C)about 90% alike.
D)about 99.9% alike.

Question 49

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.

Question 50

A part of a gene that is a DNA sequence 333 nucleotides long encodes ___ amino acids.

A)333
B)111
C)999
D)444

Question 51

A chaperone protein

A)brings amino acids to the appropriate tRNAs.
B)brings a tRNA to the appropriate codon on mRNA.
C)helps a protein to fold.
D)attracts ATP.

Question 52

A DNA sequence AACGGTGCACCACGG encodes an mRNA of sequence

A)AACGGUGCACCACGG.
B)UUGCCACGUGGUGCC.
C)AACGGTGCACCACGG.
D)UUCGGAGCUCCUCGG.

Question 53

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.

Question 54

Codons are part of

A)mRNA.
B)tRNA.
C)rRNA.
D)proteins.

Question 55

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.

Question 56

DNA transcribed to mRNA always begins with the sequence

A)TAC.
B)AGG.
C)AUG.
D)TTA.

Question 57

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.

Question 58

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.

Question 59

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.

Question 60

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

Question 61

A different enzyme may catalyze the formation and the breakdown of the same molecule.

Question 62

An active site is the part of a substrate molecule that binds an enzyme.

Question 63

Dehydration synthesis is catabolic and hydrolysis is anabolic.

Question 64

Oxidation of glucose is important because it releases energy.

Question 65

In adipose tissue,fat molecules form when fatty acid molecules and glycerol join by hydrolysis.

Question 66

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.

Question 67

A rate-limiting enzyme usually acts at the end of a metabolic pathway.

Question 68

MicroRNAs

A)are 21 or 22 bases long.
B)control gene expression.
C)are noncoding RNAs.
D)are all of the above.

Question 69

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.

Question 70

Catabolism builds up molecules and anabolism breaks down molecules.

Question 71

A metabolic pathway is a particular sequence of enzyme-controlled reactions.

Question 72

A cell may contain hundreds of different types of enzymes.

Question 73

Proteins are critical to metabolism because all proteins are enzymes.

Question 74

An ATP molecule consists of an adenine,a ribose,and three phosphates.

Question 75

Metabolism refers to all of the chemical reactions in a cell.

Question 76

The synthesis of an ATP molecule requires two ADP molecules.

Question 77

Enzymes are proteins that promote specific chemical reactions.

Question 78

Releasing the energy in glucose molecules is an example of catabolism.

Question 79

Oxidation forms chemical bonds.

Question 80

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.