Deck 3: Essentials of Metabolism

Question 1

When an enzyme has bound to its substrate a(n)_____ is formed.

A)Proteolytic complex
B)Cofactor complex
C)Enzyme-substrate complex
D)Coenzyme complex
E)Carrier complex

Answer 1

Enzyme-substrate complex

Question 2

Which of the following distinguishes an enzyme from an apoenzyme? An apoenzyme_____.

A)Is the mirror image of its enzyme?
B)Cannot bind a competitive inhibitor
C)Cannot form an enzyme-substrate complex
D)Contains no cofactor

Answer 2

Contains no cofactor

Question 3

Which is an example of a phosphorylation reaction?

A)Amino acids to protein
B)DPN to DPNH
C)DPNH to DPN
D)Glycogen to glucose
E)Glucose to phosphoglucose

Answer 3

Glucose to phosphoglucose

Question 4

Which of the following is a mismatched pair?

A)Heterotrophs - CO2
B)Chemo heterotrophs - organic compounds
C)Chemoautotrophs - inorganic molecules
D)Photoautotrophs - sunlight and CO2
E)Infectious organisms - organic compounds

Question 5

What has occurred when a large molecule is broken down into small molecules?

A)Anabolism
B)Anaerobic respiration
C)Catabolism
D)Feedback inhibition

Question 6

Which is an example of a dehydration reaction?

A)Amino acids to protein
B)DPN to DPNH
C)DPNH to DPN
D)Glycogen to glucose
E)Glucose to phosphoglucose

Question 7

Which is an example of a hydrolysis reaction?

A)Amino acids to protein
B)DPN to DPNH
C)DPNH to DPN
D)Glycogen to glucose
E)Glucose to phosphoglucose

Question 8

Which is an example of a reduction reaction?

A)Amino acids to protein
B)DPN to DPNH
C)DPNH to DPN
D)Glycogen to glucose
E)Glucose to phosphoglucose

Question 9

Unlike most pathogens,photoautotrophs

A)Are parasitic
B)Can use organic chemicals for energy
C)Can use organic chemicals as a carbon source
D)Can survive and grow on CO? and sunlight
E)None of the choices

Question 10

The biosynthesis of glycogen,using glucose,is an example of

A)Aerobic respiration
B)Anabolism
C)Glycolysis
D)The Krebs cycle
E)Proton motive force

Question 11

Which of the following statements regarding enzymes is false?

A)Enzymes increase the rate of a chemical reaction
B)The amount of energy required or released when a substrate is converted to a product is known as the allosteric energy
C)Enzymes lower the energy of activation
D)Enzymes are not changed by the reactions in which they participate
E)A chemical reaction will occur only if there is sufficient activation energy to initiate the reaction

Question 12

In a chemical reaction pyruvate has gained one electron.It has therefore been

A)Catabolized
B)Hydrolysed
C)Reduced
D)Phosphorylated
E)Oxidized

Question 13

What always occurs during catabolism?

A)Aerobic respiration
B)Electron rearrangement
C)Feedback inhibition
D)Proton motive force
E)Competitive inhibition

Question 14

In feedback inhibition which reaction in the following pathway would the final product inhibit? W →X → Y → Z

A)W→ X
B)X → Y
C)Y → Z
D)Y
E)Z

Question 15

Microorganisms possessing metabolic pathways that can function in the presence or absence of oxygen are described as

A)Obligate anaerobes
B)Anabolic respirers
C)Facultative anaerobes
D)Catabolic anaerobes
E)None of the above

Question 16

The location where a substrate fits into an enzyme is known as the

A)Cofactor site
B)Plebi site
C)Polar site
D)Active site
E)Carrier site

Question 17

What is the name of a reaction that results from oxidation of one reactant coupled to the reduction of another?

A)Reciprocal
B)A chemoheterotrophic reaction
C)Aerobic respiration
D)Competitive inhibition
E)Redox

Question 18

The chemical process that takes place inside every cell and is responsible for the release of energy is referred to as

A)Competitive inhibition
B)Catabolism
C)Feedback inhibition
D)Allosteric inhibition
E)Anabolism

Question 19

What happens when one molecule of glucose is oxidized completely using the Krebs cycle and the electron transport chain?

A)12 H₂O molecules are formed
B)anaerobic respiration occurs
C)38 ATP molecules are formed
D)3 CO₂ molecules are formed
E)12 O₂ molecules are consumed

Question 20

Which is an example of an oxidation reaction?

A)Amino acids to protein
B)DPN to DPNH
C)DPNH to DPN
D)Glycogen to glucose
E)Glucose to phosphoglucose

Question 21

In a mitochondrion carrying out electron transport,the proton concentration gradient develops

A)Across the inner mitochondrial membrane
B)In the cytosol
C)In the nucleus
D)In the space between the outer membrane and the plasma membrane
E)Across the outer mitochondrial membrane

Question 22

Which of the following is not a characteristic of the Krebs cycle?

A)Aerobic metabolism
B)Conversion of pyruvate to acetaldehyde
C)Transfer of electrons to NAD⁺ and FAD
D)Oxidation of acetyl-coA to CO₂
E)Net production of 1 ATP per one turn of the cycle

Question 23

Use the figure below to answer the following questions.

In the figure which step indicates the molecules produced by hydrolysis?

Question 24

When a molecule is oxidized it receives electrons.

Question 25

Negative feedback inhibition works by

A)The product of a metabolic pathway inhibiting a key enzyme early in the synthesis of the product
B) Altering pH and denaturing the enzyme
C)Binding to the binding site of an enzyme and interfering with substrate binding
D)Increasing the energy of activation of a chemical reaction
E)Increasing the free energy of the reaction

Question 26

Which of the following statements regarding NAD? is incorrect?

A)NAD? is a vitamin
B)NAD? is a coenzyme
C)NAD? enters the electron transport chain as NADH
D)In its reduced form NADH becomes NAD?
E)More NADH is formed more often than FADH? in the Krebs cycle

Question 27

Enzyme reactions are affected by

A)Temperature
B)Enzyme concentration
C)Concentration of substrate
D)pH
E)All of the choices

Question 28

What is the result if an enzyme is subjected to extremely high temperatures?

A)The enzyme's rate of reaction will increase
B)There will be an alteration in electrical charges, which will interfere with substrate interaction
C)The substrate concentration will be too low for enzyme activity
D)The hydrogen bonds stabilizing the three-dimensional structure will break and the enzyme will become denatured
E)The enzyme's activity will cease as a result of feedback inhibition

Question 29

Which of the following is a common feature of most fermentation pathways?

A)The production of glucose
B)The formation of lactic acid
C)The provision of electrons by NADH
D)The use of the Krebs cycle
E)The conversion of pyruvate to acetyl CoA

Question 30

The mechanism of competitive inhibition involves

A)Inhibiting the first enzyme in a metabolic pathway
B)Decreasing the pH and denaturing the enzyme
C)Increasing the energy of activation of a chemical reaction
D)Binding to an enzyme at the active site
E)Binding to a site distant from the active site and causing a conformational change of the enzyme

Question 31

Use the figure below to answer the following questions.

In the figure which step indicates the molecules produced by dehydration?

Question 32

An allosteric inhibitor is added to an enzyme substrate mixture.What is likely to happen?

A)The product of the reaction will increase
B)The enzyme will denature
C)The inhibitor will bind the active site of an enzyme and interfere with substrate binding
D)The inhibitor will bind to a site other than the active site and cause a conformational change of the enzyme

Question 33

Which of the following is required to fuel anabolic reactions in cells?

A)Triglycerols
B)Proteins
C)ATP
D)Carbohydrates
E)Nucleic acids

Question 34

During alcoholic fermentation the intermediate _____ is synthesized from pyruvic acid.

A)NAD?
B)Acetaldehyde
C)Lactic acid
D)ATP
E)Acetyl CoA

Question 35

_____ can be inorganic,whereas _____ is always organic.

A)An enzyme; an allosteric inhibitor
B)A substrate; a product
C)FAD; NAD?
D)An oxidation reaction; a reduction reaction
E)A cofactor; a coenzyme

Question 36

Use the figure below to answer the following questions.

In the figure which step would produce a polysaccharide?

Question 37

Which of the following statements regarding eukaryotic electron transport is true?

A)Electron transport occurs in the cytoplasm
B)A consequence of electron transport is the formation of a concentration gradient of protons
C)Generates a concentration gradient of electrons
D)NADH and FADH₂ are reduced during electron transport

Question 38

Which of the following is not a characteristic of glycolysis?

A)Anaerobic metabolism
B)Substrate-level phosphorylation
C)Net production of 2 ATP
D)Glucose is oxidized to 2 pyruvate molecules
E)Takes place on microbial cell membranes or on the inner membrane of the mitochondrion

Question 39

Use the figure below to answer the following questions.

In the figure which step would produce carbon dioxide?

Question 40

Nearly all infectious organisms are chemoheterotrophs.

Question 41

You are working at a biotechnology company that specializes in the scale-up and purification of enzymes derived from bacterial sources for human therapeutics.One of your responsibilities is to ensure that the 180-liter industrial fermenter in the pilot plant does not exceed 37°C during the batch synthesis phase.Explain why attention to this particular detail is important.

Question 42

Why are pharmaceutical industries interested in enzyme inhibition?

Question 43

The regulation of enzymes is illustrated by the ability of the end product of a series of enzymatic reactions to inhibit the first enzyme in the pathway.

Question 44

Enzymes catalyze reactions when they increase the energy of activation of the reaction.

Question 45

Why is regulation of enzyme activity of fundamental importance in biological systems?

Question 46

Enzymes catalyze reactions because they increase the difference in energy between the substrate and the products.

Question 47

Describe three ways in which the cell can regulate enzyme activity.

Question 48

Explain why anabolism is important during the replication of bacteria during an infection.

Question 49

Use the terms provided below to describe how a cell metabolizes glucose in the presence or absence of oxygen.

Question 50

Provide two examples of biological molecules made by anabolism that would be required for the replication of bacteria to occur,identifying the reactants and products.

Question 51

What happens to the rate of glucose consumption if a microorganism is moved from an anaerobic environment to an aerobic growth chamber? Explain why.

Question 52

Cellular respiration can be anaerobic.