Deck 4: Cellular Metabolism

Question 1

An important mechanism that controls metabolic pathways under physiological conditions is

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

Answer 1

C

Question 2

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.

Answer 2

A

Question 3

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

Answer 3

D

Question 4

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 5

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 6

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.

Question 7

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 8

"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 9

Dehydration synthesis reactions _____, whereas hydrolysis reactions _____.

Question 10

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)
C) They are most active at temperatures above 53 degrees
D) They have active sites and interact with specific substrates.

Question 11

"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 12

"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 13

One reason 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 14

The name of an enzyme ends in

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

Question 15

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 16

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.

Question 17

The enzyme catalase acts on the substrate

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

Question 18

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 19

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.

Question 20

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 21

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 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

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 24

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

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

Question 25

A molecule that is a storage form of carbohydrate is

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

Question 26

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 27

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 28

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 29

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 30

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 31

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 32

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 33

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 34

How many codons specify the twenty types of amino acids?

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

Question 35

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

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

Question 36

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 37

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 38

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

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

Question 39

The anaerobic reactions of cellular respiration take place in the

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

Question 40

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 41

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 42

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 43

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 44

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

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

Question 45

Three types of genetic changes are
A)

A) replication, transcription, and translation.
B) A to C, G to C, and U to
C) mutations, SNPs, and changes in copy number.
D) adenine, guanine, and cytosine.

Question 46

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 47

A DNA sequence AACGGTGCACCACGG encodes an mRNA of sequence

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

Question 48

Copying DNA information into an mRNA molecule is called

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

Question 49

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 50

Codons are part of

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

Question 51

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

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

Question 52

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 53

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 54

The genome sequences of different individuals are

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

Question 55

The codon that will signal where to begin making a polypeptide is ___________.

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

Question 56

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 57

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 58

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 59

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 60

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 61

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

Question 62

Oxidation of glucose is important because it releases energy.

Question 63

MicroRNAs

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

Question 64

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 65

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

Question 66

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.

Question 67

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

Question 68

Oxidation forms chemical bonds.

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

The synthesis of an ATP molecule requires two ADP molecules.

Question 71

Dehydration synthesis is catabolic and hydrolysis is anabolic.

Question 72

Proteins are critical to metabolism because all proteins are enzymes.

Question 73

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

Question 74

A cell may contain hundreds of different types of enzymes.

Question 75

Enzymes are proteins that promote specific chemical reactions.

Question 76

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

Question 77

Catabolism builds up molecules and anabolism breaks down molecules.

Question 78

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

Question 79

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

Question 80

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