Deck 4: Energy and Cellular Metabolism

Question 1

A competitive inhibitor binds to

A) a region of the enzyme other than the active site.
B) the active site.
C) the substrate.
D) the product.
E) the surrounding tissue.

Answer 1

B

Question 2

A reversible reaction is one where

A) there are large changes in the net free energy from substrate to product.
B) there are small changes in the net free energy from substrate to product.
C) there is no change in the net free energy from substrate to product.
D) a reaction between products is unlikely due to the high activation energy.

Answer 2

B

Question 3

Organic molecules that act as receptors/carriers for the cleaved portion of the substrate are

A) vitamins.
B) isoenzymes.
C) coenzymes.
D) modulators.

Answer 3

C

Question 4

When an enzyme's activity is destroyed by heat or a change in pH, the enzyme is said to be

A) broken.
B) toxic.
C) conjugated.
D) tertiary.
E) denatured.

Question 5

Phosphate groups may be transferred from one molecule to another during

A) hydrolysis reactions only.
B) addition reactions only.
C) dehydration reactions only.
D) exchange reactions only.
E) addition and exchange reactions.

Question 6

According to the second law of thermodynamics,

A) the amount of entropy in living systems increases without the input of energy.
B) entropy decreases in living systems that are not receiving energy.
C) energy can be converted, but not be created nor destroyed.
D) the total amount of energy in the universe never changes.

Question 7

When a chemical reaction is in equilibrium,

A) there is no net change in the amount of substrates or products.
B) the reaction is proceeding at its maximum rate.
C) the reaction has stopped.
D) there are equivalent amounts of substrates and products.

Question 8

An enzyme that transfers chemical groups among substrates is a

A) hydrolase.
B) lipase.
C) transferase.
D) ligase.
E) kinase.

Question 9

An enzyme that adds or subtracts water molecules is a

A) hydrolase.
B) lipase.
C) transferase.
D) ligase.
E) kinase.

Question 10

Isozymes

A) are enzymes with a slightly different structure that catalyze the same reaction.
B) are enzymes with the same structure that catalyze different reactions.
C) are inorganic molecules that bind to and thereby activate enzymes.
D) are the inactive form of an enzyme.

Question 11

Energy is defined as

A) doing tasks that make you tired.
B) the capacity to do work.
C) the light and heat from the sun.
D) using glucose to synthesize ATP.

Question 12

An allosteric modulator binds to

A) a region of the enzyme other than the active site.
B) the active site.
C) the substrate.
D) the product.
E) the surrounding tissue.

Question 13

The addition of a phosphate group to a substrate is called ________.The enzyme that catalyzes this reaction is referred to as a ________.

A) proteolysis, phosphatase
B) phosphorylation, phosphatase
C) proteolysis, kinase
D) phosphorylation, kinase

Question 14

The activity of an enzyme is changed by environmental factors such as temperature or pH; these factors are referred to as

A) specificity.
B) common bond.
C) modulators.
D) isozyme.
E) product.

Question 15

Activation energy is

A) the energy lost or gained in a reaction.
B) the energy required for an endergonic reaction.
C) the energy required to bring molecules into a position where they can interact.
D) required to convert an endergonic reaction to an exergonic reaction.

Question 16

An enzyme that joins two substrates using energy is a

A) hydrolase.
B) lipase.
C) transferase.
D) ligase.
E) kinase.

Question 17

The general term that describes energy stored in chemical bonds is

A) thermodynamics.
B) bioenergetics.
C) entropy.
D) kinetic energy.
E) potential energy.

Question 18

The ________ of glycogen from many glucose molecules is an ________ reaction.

A) decomposition, endergonic
B) synthesis, exergonic
C) decomposition, exergonic
D) synthesis, endergonic

Question 19

Enzymes increase reaction rate by

A) lowering the activation energy of a reaction.
B) increasing the free energy in the products.
C) raising the activation energy of a reaction.
D) converting an endergonic reaction to an exergonic reaction.

Question 20

Chemical reactions in a living system function to

A) only transfer energy from one molecule to another.
B) create new energy.
C) only use energy stored in a molecule.
D) transfer energy from one molecule to another or use energy stored in a molecule.

Question 21

A molecule that loses electrons during a reaction is

A) reduced.
B) oxidized.
C) dehydrated.
D) hydrated.

Question 22

The explanation for how ATP bonds are actually formed during oxidative phosphorylation is called

A) the Krebs hypothesis.
B) the second law of thermodynamics.
C) the proton principle.
D) the chemiosmotic theory.
E) Murphy's law.

Question 23

In the aerobic metabolism of glucose, ________ acts as the final electron acceptor.

A) water
B) oxygen
C) carbon dioxide
D) lactate
E) ATP

Question 24

An enzyme that transfers phosphates from ATP to a substrate molecule is a

A) hydrolase.
B) lipase.
C) transferase.
D) ligase.
E) kinase.

Question 25

Which of these results in a REDUCED molecule?

A) loss of phosphate
B) gain of phosphate
C) loss of electrons
D) gain of electrons

Question 26

Aerobic metabolism of glucose

A) requires oxygen.
B) produces more ATP per glucose than anaerobic pathways.
C) is the fastest way to produce glucose.
D) requires oxygen and produces more ATP per glucose than anaerobic pathways.

Question 27

The reactions of glycolysis occur in the cell's ________; the reactions of the citric acid cycle occur in the ________.

A) cytoplasm, cytoplasm
B) mitochondria, mitochondria
C) cytoplasm, mitochondria
D) mitochondria, cytoplasm

Question 28

The process of forming mRNA is called

A) replication.
B) transcription.
C) translation.
D) ribolation.
E) protein synthesis.

Question 29

When an enzyme is working as fast as it can because its active site is continually refilled with substrate, the condition is referred to as

A) allosteric modulation.
B) equilibrium.
C) saturation.
D) the Ricardo-Mertz phenomenon.
E) specificity.

Question 30

After forming a complex with the ribosome, mRNA interacts with a third molecule.This molecule is called

A) DNA.
B) an amino acid.
C) rRNA.
D) tRNA.
E) rough ER.

Question 31

For each NADH molecule that moves through the electron transport system, what is the potential yield of ATP molecules?

A) 1
B) 2
C) 2.5
D) 3.5
E) 4

Question 32

ATP synthase transfers the ________ energy of the H⁺ ions to the high-energy phosphate bond of ________.

A) potential, NADH
B) potential, ATP
C) kinetic, NADH
D) kinetic, ATP
E) None of the answers are correct.

Question 33

End-product inhibition describes the process whereby

A) decreasing amounts of substrate reduce activity of the enzyme.
B) decreasing amounts of product reduce activity of the enzyme.
C) increasing amounts of substrate reduce activity of the enzyme.
D) increasing amounts of product reduce activity of the enzyme.
E) increasing amounts of product reduce activity of all enzymes in the vicinity.

Question 34

Which can serve as substrates for ATP production?

A) glucose only
B) amino acids only
C) fatty acids only
D) glucose and fatty acids only
E) glucose, amino acids and fatty acids

Question 35

Compartmentation refers to

A) pairing together isozymes that perform similar reactions.
B) grouping related enzymes into specific organelles.
C) separating substrates into chemical classes.
D) dividing metabolic reactions into groups for better understanding.

Question 36

When energy is released during catabolism, it is temporarily trapped in high energy bonds or electrons of certain compounds.Which of the following is NOT associated with carrying energy?

A) ATP
B) DNA
C) NADH
D) FADH₂
E) NADPH

Question 37

What is the potential yield of ATP molecules for each FADH₂ molecule entering the electron transport system?

A) 1
B) 1.5
C) 2
D) 2.5
E) 3

Question 38

The binding sites of enzymes are

A) products of an enzymatic reaction.
B) regions of an enzyme that are involved in bringing substrates together.
C) bonds between the substrate and certain amino acids.
D) not necessarily involved in a reaction.

Question 39

Why is there a range of 30-32 ATP molecules produced from one glucose molecule?

A) Sometimes the electron transport system is more efficient than other times.
B) The NADH molecules produced during glycolysis are in the cytoplasm; occasionally, electrons are carried by the lower energy FADH₂ instead of NADH.
C) Individual variation is normal among cells.
D) Any of these answers may work under different cellular conditions.

Question 40

An example of transamination is

A) removing an amine group from one molecule and binding it to a different molecule.
B) removing an amino group and putting it into the bloodstream for the kidneys to discard.
C) removing a phosphate group from a molecule.
D) finding a brand new sports car in your driveway with your name on it.

Question 41

Transcription occurs in the ________ of the cell.

A) nucleus
B) cytoplasm
C) Golgi apparatus
D) smooth endoplasmic reticulum
E) plasma membrane

Question 42

Match the specific enzyme to its class.
A.oxidoreductase
B.hydrolase
C.transferase
D.ligase
E.Lyase
lipase

Question 43

Match the specific enzyme to its class.
A.oxidoreductase
B.hydrolase
C.transferase
D.ligase
E.Lyase
dehydratase

Question 44

In the reaction shown, identify the role of each of the participants.
CO₂ + H₂O H₂CO₃
A.enzyme
B.substrate(s)
C.product(s)
CO₂ + H₂O

Question 45

Following post-translational modification, any misfolded protein will be destroyed by

A) ubiquitin.
B) chaperones.
C) methylation.
D) ribonucleases.

Question 46

In the absence of a signal sequence, a newly synthesized protein localizes to the

A) mitochondria.
B) cytoplasm.
C) peroxisome.
D) nucleus.
E) plasma membrane.

Question 47

All of the triplet codes needed to produce exactly one functional piece of RNA are found in one

A) chromosome.
B) gene.
C) codon.
D) anticodon.
E) None of the answers are correct.

Question 48

In the reaction shown, identify the role of each of the participants.
CO₂ + H₂O H₂CO₃
A.enzyme
B.substrate(s)
C.product(s)
H₂CO₃

Question 49

Match the specific enzyme to its class.
A.oxidoreductase
B.hydrolase
C.transferase
D.ligase
E.Lyase
deaminase

Question 50

The enzymes that synthesize mRNA from the start codon are called

A) ribonucleases.
B) RNA polymerases.
C) DNA polymerases.
D) ATP synthases.
E) lactate dehydrogenases.

Question 51

Once synthesized, the ________ of mRNA are removed through ________, which results in the formation of the coding sequence of a protein.

A) exon, RNA interference
B) exon, alternative splicing
C) intron, RNA interference
D) intron, alternative splicing

Question 52

Information stored in the nucleus is translated into

A) carbohydrates.
B) lipids.
C) proteins.
D) phospholipids.
E) None of the answers are correct.

Question 53

Match the specific enzyme to its class.
A.oxidoreductase
B.hydrolase
C.transferase
D.ligase
E.Lyase
synthetase

Question 54

The tRNA molecule contains the three-base sequence called the

A) codon.
B) anticodon.
C) semicodon.
D) aminocodon.

Question 55

Match the specific enzyme to its class.
A.oxidoreductase
B.hydrolase
C.transferase
D.ligase
E.Lyase
kinase

Question 56

Match the specific enzyme to its class.
A.oxidoreductase
B.hydrolase
C.transferase
D.ligase
E.Lyase
aminase

Question 57

In the reaction shown, identify the role of each of the participants.
CO₂ + H₂O H₂CO₃
A.enzyme
B.substrate(s)
C.product(s)
carbonic anhydrase

Question 58

The TAC sequence of DNA is the ________ of a coding sequence that is preceded by the ________ that regulates transcription.

A) start, promoter region
B) start, intron
C) stop, promoter region
D) stop, intron

Question 59

Match the specific enzyme to its class.
A.oxidoreductase
B.hydrolase
C.transferase
D.ligase
E.Lyase
dehydrogenase

Question 60

To activate a regulated gene, the formation of mRNA is ________ by the binding of ________ to the promoter.

A) repressed, transcription factors
B) repressed, translation factors
C) induced, transcription factors
D) induced, translation factors

Question 61

A molecule of ________ consists of all the codons needed to produce a specific polypeptide chain at the ribosome.

Question 62

The enzyme ________ and ________ ions are required for the synthesis of mRNA.

Question 63

Metabolic intermediates use ________ bonds to transfer energy to the high-energy bonds of ATP, NADH, FADH₂ or NADPH.

Question 64

Amino acids are carried to the ribosomes to be incorporated into polypeptide chains by ________.

Question 65

________ describes how much product is generated or substrate destroyed within a period of time.

Question 66

In the process of ________ a phosphate group is attached to a molecule.

Question 67

Chemical reactions that require an input of energy are said to be ________.

Question 68

The activity of metabolic pathways is influenced by the ratio of ________.

Question 69

The rates of chemical reactions that occur in the human body are controlled by a particular type of proteins called ________.

Question 70

A molecule positioned on the high-concentration side of a concentration gradient stores ________ energy.

A) chemical
B) potential
C) kinetic

Question 71

A chemical reaction that can proceed in both directions is called a ________ reaction.

Question 72

________ generated in the ________ enter the electron transport system to generate 2.5 ATP molecules.

Question 73

Chemical reactions that release energy are said to be ________.

Question 74

Glucose is phosphorylated to ________ with a phosphate from ________.

Question 75

During the synthesis of proteins, amino acids are assembled in the proper sequence because the tRNA molecules that bring them to the ribosome have a(n)________ that is complementary to a specific codon in the mRNA.

Question 76

mRNA is created in a process called ________.It then leaves the ________ and enters the cytosol to direct ________, the assembly of amino acids into protein.

Question 77

Energy released by electrons moving through the electron transport system is stored as ________ by H⁺ ions concentrated in the ________.

Question 78

The availability of ________ determines if pyruvate continues into the citric acid cycle.

Question 79

The electron transport system is located in the ________ and includes enzymes and iron-containing proteins known as ________.

Question 80

A certain molecule that participates in more than one biochemical pathway and acts as a branch point for channeling substrate in one direction or another is called a ________.