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OBJECTIVES

CHAPTER 4 – CELLULAR METABOLISM

1. Distinguish between anabolism and catabolism. Cite examples using the following terminology: amino acid hydrolysis carbohydrate hydroxyl group dehydration synthesis monomer dipeptide monosaccharide disaccharide peptide bond

fat molecule polypeptide fatty acid polymer glycerol protein hydrogen atom water

2. Describe the role of enzymes. Incorporate the following terminology in the description:

activation energy product active site rate limiting enzyme enzyme substrate complex substrate metabolic pathway specificity negative feedback

3. Explain how enzymes are named. Incorporate the following terms into your

explanation: amylase maltase lactase protease lipase sucrase

4. Distinguish among cofactors, coenzymes and vitamins. 5. Define energy and list common forms.

6. Discuss the three distinct, yet interconnected, series of reactions in cellular respiration..

Incorporate the following terminology in your discussion: acetyl CoA (acetyl coenzyme A) lactic acid adenosine diphosphate (ADP) flavine adenine dinucleotide (FAD) adenosine triphosphate (ATP) nicotinamide adenine dinucleotide (NAD) aerobic respiration NADH anaerobic respiration mitochondria ATP synthetase oxaloacetic acid carbon dioxide oxidative phosphorylation citric acid oxygen citric acid (Krebs) cycle oxygen debt

(continued on next page)

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6. (continued from previous page) cytosol phosphorylation FADH2 pyruvic acid energy substrate level phosphorylation electron transport chain water glucose

7. Explain the anabolic and catabolic pathways of carbohydrates, proteins and lipids in the human body.

8. Define the following terms: gene genetic code

genome 9. Describe the chemical structure of a nucleic acid, a nucleotide, and the four nucleotides

of DNA and RNA. Incorporate the following terminology into your description: adenine phosphate covalent bond purine cytosine pyrimidine double helix sugar guanine thymine hydrogen bond uracil nitrogenous base

10. Explain what is meant by "base pairing." 11. Describe DNA replication. Incorporate the following terminology in your description: code nucleotide chain complementary chain template hydrogen bonds triplet 12 Discuss the role of nucleic acids in protein synthesis. Incorporate the following

terminology into your discussion: amino acid nucleus anticodon peptide bond codon ribosome cytoplasm RNA (ribonucleic acid) DNA (deoxyribonucleic acid) transfer RNA (tRNA) DNA replication triplet messenger RNA (mRNA)

13. Describe the following steps in protein synthesis - synthesis of mRNA (transcription); sequencing of amino acids at the ribosomal site by transfer RNA; and formation of polypeptide chain (translation)

14. Define the term "mutation" and explain the factors that can cause this to occur.

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4-5

CLASS NOTES

CHAPTER 4 – CELLULAR METABOLISM

I. Two Types of Metabolic Reactions

A. Anabolism – large organic molecules (polymers) are constructed from the covalent bonding of many repeating small molecules or building blocks (monomers) requiring an input of energy. (Know figs. 4-1 to 4.3 - when reaction is going to the right)

1. In dehydration synthesis (an example of anabolism), two monomers join

together and the reaction involves the elimination of a hydrogen atom from one monomer and the hydroxyl group from the other; the hydrogen atom and the hydroxyl group join to form water.

2. Complex carbohydrates (polymers) are synthesized from

monosaccharides fats (polymers) are synthesized from glycerol and fatty acids (monomers), and proteins (polymers) are synthesized from amino acids (monomers).

B. Catabolism – larger molecules (polymers) are broken down into smaller ones

(monomers) causing the release of energy. (Know figs. 4-1 to 4.3 - when reaction is going to the left)

1. In hydrolysis (an example of catabolism), a water molecule is use to split a

polymer into two parts (monomers). The water molecule supplies a hydrogen atom to one monomer and a hydroxyl group to the other monomer.

2. Complex carbohydrates (polymers) are hydrolysed into monosaccharides

(monomers), fats (polymers) are hydrolysed into glycerol and three fatty acids (monomers), and proteins (polymers) are hydrolysed into amino acids (monomers).

II. Control of Metabolic Reactions is by Enzymes

A. Enzyme Action

1. Metabolic reactions require energy before they can proceed. Enzymes are usually globular proteins that promote specific chemical reactions within cells by lowering the activation energy required to start these reactions.

2. An enzyme acts upon a molecule (called a substrate) by temporarily

combining with it (forming an enzyme-substrate complex).

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3. Each enzyme has “specificity,” meaning it acts on only a particular substrate. The shape of the substrate molecules must precisely fit the shape of the enzyme’s “active site.”

4. A chemical reaction occurs and the result is a product molecule and an

unaltered enzyme that can the function repeatedly. (Know fig. 4.4)

5. Enzymes are usually named according to their substrates, ending in “-ase.”

B. Regulation of Metabolic Pathways (Know fig. 4.6)

1. The rate at which a metabolic pathway functions is often determined by a regulatory enzyme that catalyzes one of its steps.

2.. As a rule, a rate-limiting enzyme is the first enzyme in the series. This is

important because it prevents the accumulation of intermediate products. a. Often the product of the pathway inhibits the rate-limiting regulatory

enzyme.

b. This is a negative feedback reaction. Accumulating product inhibits the pathway, and synthesis of the product falls. When the concentration of product increases, the inhibition lifts and more product is synthesized. In this way, a single enzyme can control a whole pathway, stabilizing the rate of production.

C. Cofactors and Coenzymes

1. Often an enzyme is inactive until it combines with a non-protein component (called a cofactor) that either helps the active site maintain its shape or helps bind the enzyme to its substrate.

2. A cofactors can be an ion of an element, such as copper, iron, or zinc, or it

may be a small organic molecule (called a coenzyme).

3. Vitamins, which are sources of coenzymes, usually can’t be synthesized by cells in adequate amounts and therefore must come from the diet.

D. Factors that Alter Enzymes

1. Enzymes are proteins and can be denatured.

2. Factors that denature enzymes include excessive heat, radiation, electricity, certain chemicals, and extreme pH values.

III. Energy for Metabolic Reactions – all metabolic reactions involve energy in some form.

A. Energy is the capacity to change something; it is the ability to do work.

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B. Common forms include heat, light, sound, electrical energy, mechanical energy, and chemical energy.

1. In the human body, energy is held in the chemical bonds that link atoms

into molecules, and it is released when these bonds break. 2. In cells, enzymes decrease the activation energy. In cellular respiration

energy is transferred to special energy-carrying molecules, thereby allowing those cells to capture almost half of the energy released in the form of chemical energy; the rest escapes in the form of heat

C. Cellular respiration is the process that releases energy from molecules such as

glucose and makes it available for cellular use.

1. The chemical reactions in cellular respiration are controlled by enzymes that are in the cytoplasm and mitochondria of the cell.

2. Each reaction is controlled by a different enzyme.

IV. Cellular Respiration – enzymes in the cytoplasm and the mitochondria control cellular

respiration, which is a process where energy is released from the breakdown of the chemical bonds in glucose. That energy is used to promote metabolism. A sequence of enzyme-controlled reactions, as seen in cellular respiration, is called a metabolic pathway. A. ATP is the stored form of chemical energy in the human body. The molecule is

made up of adenine, a ribose, and three phosphates. The 3rd phosphate in ATP is attached by a high-energy phosphate bond and the energy stored in that bond may be released when that bond is broken and it can be quickly transferred to another molecule in a metabolic process. (Know fig. 4.7)

B. An ATP molecule that loses its terminal phosphate becomes an ADP (adenosine

diphosphate) molecule, which has only 2 phosphates. However, ATP can be resynthesized from ADP by using energy released from cellular respiration to reattach a phosphate in phosphorylation. (Know fig. 4.8)

C. Steps in Cellular Respiration - (Know fig. 4.9) 1. Glycolysis – Three Main Phases occur in the cytoplasm: (Know fig. 4.10)

a. Priming - Glucose is phosphorylated by the addition of two phosphate groups, one at each end of the molecule. This requires ATP but it primes the molecule for some of the energy releasing reactions that require later.

b. Cleavage - The 6-carbon glucose molecule is split into two 3-

carbon molecules. This occurs in the cytosol and does not require oxygen.

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c. Formation of ATP and Release of High Energy Electrons

(1) Two 3-carbon pyruvic acid molecules result.

(2) Some of the energy that is released is transferred to 4ATP (which are synthesized). After subtracting the 2 molecules that are used in the priming stage, there is a net gain of 2 ATP in glycolysis (substrate level phosphorylation)

(3) The rest of the energy that is released is in the form of high-

energy electron carrier, NADH. Some of the reactions in glycolysis release hydrogen atoms. The electrons of these hydrogen atoms contain much of the energy associated with the chemical bonds of the original glucose molecule. To keep this energy in a form the cells can use, these hydrogen atoms are passed in pairs to of the hydrogen carrier NAD+ (nicotinamide dinucleotide) as follows:

NAD+ + 2H NADH + H+

(4) Anaerobic Reactions – if oxygen is present (aerobic conditions) the next step in cellular respiration (the citric acid cycle) takes place. But if oxygen is NOT present, the electron transport chain has nowhere to unload its electrons and it can no longer accept new electrons from NADH.

(a) Anaerobic reactions occur and NADH and H+ instead

donate electrons to pyruvic acid, forming lactic acid. (b) Lactic acid builds up and diffuses into the blood and

eventually inhibits glycolysis and ATP formation. When oxygen returns, liver cells convert lactic acid to pyruvic acid, which can finally enter the aerobic pathway.

2. Citric Acid (Krebs) Cycle (Know fig. 4.11 but you do NOT need to know

the names of the intermediate compounds that are formed as citric acid is converted to oxaloacetic acid) – in the mitochondrial matrix

a. The three carbon pyruvic acids generated by glycolysis enter the

mitochondria. Each loses a carbon (generating CO2) and is combined with a coenzyme to form a 2-carbon acetyl coenzyme A (acetyl CoA). More high energy electrons are released.

b. Each acetyl CoA combines with a 4-carbon oxaloacetic acid to form

the 6-carbon citric acid and CoA. The CoA can be used again to form acetyl CoA.

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c. The citric acid is changed through a series of reactions back into oxaloacetic acid. The cycle repeats as long as oxygen and pyruvic acid are supplied to the mitochondria.

d. Consequences of the citric acid cycle:

(1) One ATP is produced directly for each citric acid molecule

that goes through the cycle (substrate level phosphorylation)

(2) For each citric acid molecule, eight hydrogen atoms with high energy electrons are transferred to NAD+ and the related FAD (flavine adenine dinucleotide):

NAD+ + 2H NADH + H+ FAD + 2H FADH2

(3) As the 6-carbon citric acid reacts to form 4-carbon

oxaloacetic acid, two carbon dioxide molecules are formed.

(4) NOTE: For each turn of the citric acid cycle, (two “turns” or citric acids per glucose), one ATP is produced directly, eight hydrogens with high energy electrons are released, and two CO2 molecules are produced. The CO2 dissolves in the cytoplasm, diffuses from the cell, enters the bloodstream and is eventually excreted by the respiratory system.

3. Electron Transport Chain – in inner membrane of mitochondrion

a. The hydrogen and high-energy electron carriers (NADH and

FADH2) generated by glycolysis and the citric acid cycle now hold most of the energy contained in the original glucose molecule.

b. In order to couple this energy to ATP synthesis, the high-energy

electrons are handed off to the electron transport chain, which is a series of enzyme complexes that carry and pass electrons along from one to another.

c. The electron transport chain passes each electron along, gradually

lowering the electron’s energy level and transferring that energy to ATP synthase, an enzyme complex that uses this energy to phosphorylate ADP to form ATP. (Know fig. 4.12)

d. The requirement of oxygen in this last step is why the overall

process is called aerobic respiration.

4. The remaining products are heat and water.

5. Overall net yield of ATP per molecule of glucose in aerobic respiration (Know fig. 4.13):

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a. Glycolysis – 2 ATP (in cytoplasm)

b. Citric Acid Cycle and Electron Transport Chain – 32-34 ATP (in mitochondrion)

D. Carbohydrate Storage - Carbohydrate molecules from foods may enter catabolic

pathways and be used to supply energy sources or they may enter anabolic pathways and be stored or converted to amino acids. (Know fig. 4.14)

E. Carbohydrates, Lipids, and Protein Catabolism – lipids and proteins can also be broken down to release energy for ATP synthesis. The most common entry point is into the citric acid cycle as acetyl-CoA. (Know fig. 4.15)

V. Nucleic Acids and Protein Synthesis – nucleic acids (DNA and RNA) are made up of

chains of nucleotides. The information that instructs a cell to synthesize a particular protein is held in a series of building blocks of deoxyribonucleic acid (DNA), the genetic code. A. Definitions

3. Genetic Code – the correspondence between a unit of DNA information (3 nitrogenous bases or a “triplet”) and a particular amino acid

4. Gene – the portion of a DNA molecule that contains the genetic

information for making a protein

5. Genome – the complete set of genetic instructions in a cell B .

DNA is a Double Chain of Nucleotides: Each Nucleotide has Three Parts (Know figs. 4.16 –4.19)

Part Description Location

Sugar (Deoxyribose)

Alternates with phosphate groups

“Uprights” or backbones of DNA “ladder”

Phosphate Group

Alternates with sugars “Uprights” or backbones of DNA “ladder”

Nitrogenous Base

Rungs are formed by the bonding of complementary bases by weak hydrogen bonds (base pairing) Adenine (A) - bonds only to (T) Guanine (G) - bonds only to (C) Cytosine (C) - bonds only to (G) Thymine (T) - bonds only to A

“Rungs” of DNA “ladder”

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C. DNA Replication - when a cell divides, each newly formed cell must have a copy of the cell’s genetic information (DNA) so it will be able to synthesize the proteins necessary to build cellular parts and carry on metabolism. DNA replication is the process that creates an exact copy of a DNA molecule.

D. Steps in DNA Replication (Know fig. 4.20)

1. DNA helix unwinds 2. DNA separates into its two nucleotide chains

3. Each strand acts as a template (set of instructions) for building a new

complementary strand (order of nucleotides on template strand determines the order on the new strand - i.e. A-T, C-G)

4. End results - two DNA molecules formed that are identical to the original

DNA helix; each DNA molecule now consists of one “old” strand and one “new” strand

E. Similarities and Differences Between DNA and RNA – (Know table 4.1 and figs.

4.21-4.22) F.

Types of RNA and Their Function (Know fig. 4.23)

Types of RNA Function

Messenger RNA (mRNA) – Codon

Carries the “message” containing instructions for protein synthesis from the DNA in the nucleus to the ribosomes out in the cytoplasm

Ribosomal RNA (rRNA)

Forms part of the “ribosomal” structure and helps coordinate the protein building process

Transfer RNA (tRNA) – Anticodon

Transports an amino acid to the ribosome site; recognizes the mRNA codons

G.

Protein Synthesis (Know Tables 4.2-4.3 and figs. 4.23-4.24)

Step Description

Uncoiling of DNA DNA segment or gene specifying one polypeptide or protein uncoils

Transcription (DNA-directed synthesis of mRNA)

One strand of DNA acts as a template for the synthesis of complementary mRNA molecule and there is a transfer of information from DNA’s base sequence (code) into the complementary base sequence of mRNA (codon).

(continued on the next page)

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G. (continued from the previous page)

Step Description

Translation (RNA-directed synthesis of poly-peptide or protein)

- mRNA leaves nucleus and attaches to ribosomes - tRNA (anticodon) transports an amino acid to the mRNA

strand and recognizes a mRNA (codon); the codon and anticodon bind

- the ribosome moves the mRNA strand along as each

codon is read sequentially - as each amino acid is bound to the next by a peptide

bond, its tRNA is released; the polypeptide or protein chain is released when the termination (stop) codon is read

H. Changes in Genetic Information – A DNA molecule contains a great deal of

information. A change in the genetic information is a mutation and the agent causing the change is called a mutagen. Not all mutations are harmful. 1. Nature of Mutations (fig 4.25)

a. Mutations include several kinds of changes in DNA. b. A protein synthesized from an altered DNA sequence may function

abnormally or not at all. c. Repair enzymes can repair some forms of DNA damage.

2. Effects of Mutations

1. The genetic code protects against some mutations.

2. A mutation in a sex cell or fertilized egg or early embryo may have

a more severe effect than a mutation in an adult because a greater proportion of the individual’s cells are affected.

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DRILL

ANATOMY AND PHYSIOLOGY CHAPTER 4 – CELLULAR METABOLISM

Questions 1-51: Use the compounds shown in the key to answer the questions below. a. amino acid h. hydrolysis b. dehydration synthesis i. hydroxyl c. dipeptide j. monosaccharide d. disaccharide k. peptide bond e. fatty acid (3) l. triglyceride f. glycerol m . water g. hydrogen

__ 1. Two reactants in the catabolism of a disaccharide (two answers):

__ 2. __ 3. The products in the catabolism of a disaccharide are two molecules of: __ 4. Type of reaction in questions 1-3: __ 5. In the reaction described in questions 1-4, the bond between the simple sugars in

the polymer breaks and the ___ molecule supplies a ___ atom to one sugar __ 6. molecule and a ___ group to the other sugar molecule: __ 7.

__ 8 Two reactants in the catabolism of a dipeptide (two answers): __ 9. __ 10. The products in the catabolism of a dipeptide are two molecules: __ 11. Type of reaction in questions 8-10: __ 12. In the reaction described in questions 8-11, the ___ in the polymer breaks and

the ___ molecule supplies a ___ atom to one amino acid __ 13. molecule and a ___ group to the other amino acid molecule: __ 14. __ 15.

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Questions 1-51 (continued): Use the compounds shown in the key to answer the questions below. a. amino acid h. hydrolysis b. dehydration synthesis i. hydroxyl c. dipeptide j. monosaccharide d. disaccharide k. peptide bond e. fatty acid (3) l. triglyceride f. glycerol m . water g. hydrogen

__ 16. Two reactants in the catabolism of a lipid (two answers): __ 17. __ 18. The products in the catabolism of a lipid are (two answers): __ 19. __ 20. Type of reaction in questions 16-19: __ 21. In the reaction described in questions 16-21, the bonds in the polymer break and

the ___ molecules supply three ___ atoms to glycerol and three __ groups to __ 22. the three fatty acid chains: __ 23. __ 24. In the anabolism of a disaccharide, the reactants are two molecules of:

__ 25. The products in the anabolism of a disaccharide are a ___ molecule and a

molecule of ___ (two answers): __ 26. __ 27. Type of reaction in questions 24-26: __ 28. In the reaction described in questions 24-27, the ___ units join; a ___ atom from

one ___ molecule and a ___ group of another are removed producing ___. __ 29. __ 30. __ 31. __ 32. __ 33. In the anabolism of a dipeptide, the reactants are two molecules of: __ 34. The products in the anabolism of a dipeptide are a ___ molecule and a

molecule of ___ (two answers): __ 35.

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Questions 1-51 (continued): Use the compounds shown in the key to answer the questions below. a. amino acid h. hydrolysis b. dehydration synthesis i. hydroxyl c. dipeptide j. monosaccharide d. disaccharide k. peptide bond g. fatty acid (3) l. triglyceride h. glycerol m . water g. hydrogen

__ 36. Type of reaction described in questions 33-35: __ 37. In the reaction described in questions 33-36, the ___ units join; an ___ group

from one ___ molecule and a ___ atom of another are removed producing ___. __ 38. __ 39. __ 40. __ 41. __ 42. In the anabolism of a triglyceride, the reactants are ___ molecules and a ___

molecule of: __ 43. __ 44. The products in the anabolism of a triglyceride are three ___ molecules and a

molecule of ___ (two answers): __ 45. __ 46. Type of reaction described in questions 42-45: __ 47. In the reaction described in questions 42-46, the reactants join; three ___ groups

from the ___ molecules and three ___ atoms from the ___ molecule are __ 48. removed producing ___. __ 49. __ 50. __ 51. __ 52. Type of metabolism where large molecules are decomposed to their building

blocks: a. anabolism d. both a and c b. catabolism e. none of the above c. dehydration synthesis

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Questions 53-63: Match the terms associated with enzymes in the key with their descriptions below. a. activation energy f. enzyme substrate complex b. active site g. metabolic pathway c. coenzyme h. product d. cofactor i. substrate e. enzyme j. vitamin

__ 53. A non-protein substance that is necessary for the activity of a particular enzyme: __ 54. A small molecule or ion that must combine with an enzyme for activity: __ 55. An organic compound other than a carbohydrate, lipid or protein that is needed

for normal metabolism: __ 56. The energy that is required to initiate a chemical reaction: __ 57. A protein that catalyzes a specific biochemical reaction: __ 58. A series of linked, chemically controlled chemical reactions: __ 59. The substance upon which an enzyme acts: __ 60. The region of an enzyme molecule that temporarily combines with a substrate: __ 61. The result of a chemical reaction: __ 62. Globular protein that lowers the activation energy required for a biochemical

reaction: __ 63. The shape of the substrate molecule must precisely fit the shape of the enzymes

active site in order to form an: __ 64. Regarding anabolic and catabolic reactions:

a. both require energy b. both release energy c. the former requires energy and the latter releases energy d. the former releases energy and the latter requires energy

__ 65. Enzymes usually are named:

a. according to their products, ending in “ase” b. according to their products, ending in “ate” c. according to their substrates, ending in “ase” d. according to their substrates, ending in “ate”

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Questions 66-116: Match the chemicals and energy involved in cellular respiration and photosynthesis in the key with their descriptions below.

a. acetyl Co-A j. flavine adenine dinucleotide b. adenosine diphosphate k. glucose c. adenosine triphosphate l. lactic acid

d. ATP synthetase m. nicotinamide adenine dinucleotide e. carbon dioxide n. NADH f. citric acid o. oxaloacetic acid g. cytosol p. oxygen h. energy q. pyruvic acid i. FADH2 r. water

__ 66. In glycolysis, the reactant is ___ and the product is 2 molecules of ___: __ 67. __ 68. Three products of glycolysis: __ 69. __ 70. __ 71. In the mitochondrion, pyruvic acid is converted to ___: __ 72. Substance that transfers electrons from the glycolysis sequence to the electron

transport chain: __ 73. The cell’s main energy compound: __ 74. The enzyme that is involved in the formation of adenosine triphosphate: __ 75. The 3-carbon containing compound produced in glycolysis enters the Krebs citris

acid cycle after being changed into: __ 76. Two compounds that transport electrons from the Krebs cycle: __ 77. __ 78. The energy compound produced in the Krebs cycle: __ 79. The energy compound produced in the electron transport chain: __ 80. In the first half of glycolysis ATP is used up and is converted to: __ 81. NADH is produced from: __ 82. Citric acid is formed from the union of two compounds: __ 83.

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Questions 66-117 (continued): Match the chemicals involved in cellular respiration and photosynthesis in the key with their descriptions below.

a. acetyl Co-A j. flavine adenine dinucleotide b. adenosine diphosphate k. glucose c. adenosine triphosphate l. lactic acid

d. ATP synthetase m. nicotinamide adenine dinucleotide e. carbon dioxide n. NADH f. citric acid o. oxaloacetic acid g. cytosol p. oxygen h. energy q. pyruvic acid i. FADH2 r. water

__ 84. The two carbon atoms from the acetyl group are eliminated from the Krebs cycle

as two molecules of: __ 85. Four compounds eliminated from the Krebs cycle: __ 86. __ 87. __ 88. __ 89. The 2 compounds that enter the electron transport chain: __ 90. __ 91. Primary energy compound produced in the electron transport chain: __ 92. Compound that is formed in the Krebs cycle when oxaloacetic acid reacts with

acetyl CoA: __ 93. Two reactants in the overall equation for cellular respiration: __ 94. __ 95. Three products in the overall equation for cellular respiration: __ 96. __ 97. __ 98. In the mitochondrion pyruvic acid is converted to: __ 99. Two-carbon containing compound:

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Questions 66-117 (continued): Match the chemicals involved in cellular respiration and photosynthesis in the key with their descriptions below.

a. acetyl Co-A j. flavine adenine dinucleotide b. adenosine diphosphate k. glucose c. adenosine triphosphate l. lactic acid

d. ATP synthetase m. nicotinamide adenine dinucleotide e. carbon dioxide n. NADH f. citric acid o. oxaloacetic acid g. cytosol p. oxygen h. energy q. pyruvic acid i. FADH2 r. water

__ 100. Three requirements in the overall equation for photosynthesis: __ 101. __ 102. __ 103. In the first half of glycolysis ATP is converted to: __ 104. Another name for ATP: __ 105. Another name for ADP: __ 106. Another name for NAD: __ 107. Another name for FAD: __ 108. In the second half of glycolysis ADP is converted to: __ 109. NADH is produced from: __ 110. In the electron transport chain FADH2 produces: __ 111. In the electron transport chain, NADH produces: __ 112. Product of anaerobic respiration: __ 113. Three-carbon containing compound: __ 114. Two six-carbon containing compounds: __ 115. __ 116. One-carbon containing compound: __ 117. Four-carbon containing compound:

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Questions 118-135: Match the terms associated with cellular respiration in the key with their descriptions below. a. cytosol e. mitochondria b. electron transport chain f. oxygen debt

c. glycolysis g. pyruvic acid acetyl Co-A d. Krebs cycle __ 118. Location of glycolysis: __ 119. Location of the electron transport chain: __ 120. Location of the citric acid cycle: __ 121. Another name for the oxidative phosphorylation: __ 122. Another name for the citric acid cycle: __ 123. The process of transferring electrons to form a high energy phosphate bond by

introducing a phosphate group to ADP to form ATP: __ 124. The NADH formed in glycolysis enters the: __ 125. Three sequences where NADH is produced: __ 126. __ 127. __ 128. Sequence where FADH2 is produced: __ 129. Three places where ATP is produced in cellular respiration: __ 130. __ 131. __ 132. Three anaerobic processes: __ 133. __ 134. __ 135. Aerobic respiration:

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Questions 136-140 : Match the part of a nucleotide in the key that best fits the description or location below. a. nitrogenous base c. sugar b. phosphate group

__ 136. Form the “rungs” of the DNA ladder: __ 137. Two “uprights” of the DNA ladder: __ 138. __ 139. Deoxyribose of DNA is its: __ 140. Each of the following compounds in DNA - adenine, thymine, guanine and

cytosine - is an example of a: Questions 141-148: Match the steps of protein synthesis in the key to their descriptions below:

a. transcription c. uncoiling b. translation

__ 141. tRNA transports an amino acid to the mRNA stand and recognizes mRNA

(codon): __ 142. Codon and anticodon bind: __ 143. Two strands of DNA separate in one area: __ 144. Step when each amino acid is bound to the next by a peptide bond and its tRNA

is released: __ 145. Termination code is read and the polypeptide or protein chain is released: __ 146. Transfer of information from DNA’s base sequence (code) into the

complementary base sequence of mRNA (codon): __ 147. The ribosome moves the mRNA strand along as each codon is read sequentially: __ 148. mRNA leaves nucleus and attaches to ribosomes:

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Questions 149-152: Match the type of RNA in the key with its function below. a. messenger RNA c. transfer RNA b. ribosomal RNA

__ 149. Forms part of the “ribosomal” structure and helps coordinate the protein building process:

__ 150. Transports an amino acid to the ribosomal site: __ 151. Recognizes the mRNA codons: __ 152. Carries the instructions for protein synthesis from the nucleus to the ribosomes

out in the cytoplasm: Questions 153-156: Match the terms in the key to their descriptions below.

a. anticodon c. codon b. code d. gene

__ 153. A DNA segment that carries the information for building one protein or

polypeptide chain. The information is in the sequence of bases in the nucleotide strands:

__ 154. The three based sequence that specifies the synthesis of mRNA: __ 155. The corresponding three-based sequence on a mRNA molecule that can bond to

a complementary code: __ 156. The tRNA special three based sequence that can bind to the complementary

codon: Questions 157-164: Match the nitrogenous bases in the key with their descriptions listed

below: a. adenine d. thymine b. cytosine e. uracil c. guanine __ 157. Nitrogenous base of DNA that binds with adenine of DNA: __ 158. Nitrogenous base of DNA that binds with cytosine of DNA: __ 159. Nitrogenous base of DNA that binds with guanine of DNA: __ 160. Nitrogenous base of DNA that binds with thymine of DNA: __ 161. Nitrogenous base of RNA that binds with adenine of DNA: __ 162. Nitrogenous base of RNA that binds with cytosine of DNA:

4-23

Questions 157-164 (continued): Match the nitrogenous bases in the key with their descriptions listed below: a. adenine d. thymine b. cytosine e. uracil c. guanine

__ 163. Nitrogenous base of RNA that binds with guanine of DNA: __ 164. Nitrogenous base of RNA that binds with thymine of DNA: Questions 165-209: Match the correct terms in the key (or write in a number, when

appropriate) to the questions below regarding protein synthesis. a. adenine m. pentose b. codon n. purines c. cytosine o. pyrimidines d. deoxyribonucleic acid (DNA) p. ribonucleic acid (RNA) e. deoxyribose q. ribose f. double helix r. ribosomal RNA (rRNA) g. guanine s. thymine h. messenger RNA (mRNA) t. transcription i. mutagen u. transfer RNA (tRNA) j. mutation v. translation k. nitrogenous base w. uracil l. nucleotide 165. Identify the two main types of nucleic acids: 166. 167. Each of the basic building blocks of nucleic acids is called a: 168. Each nucleotide consists of a sugar, a phosphate group, and one of several

bases. 169. 170. In DNA nucleotides, the pentose sugar is: 171. In RNA nucleotides, the pentose sugar is: 172. Identify the four organic bases that occur in DNA: 173. 174. 175.

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Questions 165-209 (continued): Match the correct terms in the key (or write in a number, when appropriate) to the questions below regarding protein synthesis.

a. adenine m. pentose b. codon n. purines c. cytosine o. pyrimidines d. deoxyribonucleic acid (DNA) p. ribonucleic acid (RNA) e. deoxyribose q. ribose f. double helix r. ribosomal RNA (rRNA) g. guanine s. thymine h. messenger RNA (mRNA) t. transcription i. mutagen u. transfer RNA (tRNA) j. mutation v. translation k. nitrogenous base w. uracil l. nucleotide 176. Number of types of nucleotides that constitute DNA: (Write in a number) 177. Two of the nitrogenous bases of DNA, adenine (A) and guanine (G), have a

double C-N ring structure and are termed: 178. The other two nucleotides that occur in DNA, thymine (T) and cytosine (C), have

a single C-N ring structure and are termed: 179. Identify the four organic bases 181. that occur in RNA: 180. 182. 183. Number of types of nucleotides that constitute RNA: (Write in a number) 184. Term for the structure of DNA, which consists of two polynucleotide strands

joined by hydrogen bonding: __ 185. The hydrogen bonding of DNA is always between complementary base pairs. An

adenine nucleotide in one strand of DNA always pairs up with a nucleotide in 186. the strand. Similarly, a guanine nucleotide always pairs up with a nucleotide. 187. RNA molecules differ from DNA molecules in several ways. First, RNA

molecules are usually made up of (write in a number) strand(s). Second, __ 188. RNA molecules contain the pentose sugar instead of deoxyribose. Third, RNA nucleotides contain in place of thymine. 180. 190. In addition to being able to self-replicate, DNA molecules can direct the formation

of RNA molecules. When a DNA molecule opens up and the sequence of nucleotides one strand codes for the sequence of nucleotides on an RNA strand, the process is called:

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Questions 165-209 (continued): Match the correct terms in the key (or write in a number, when appropriate) to the questions below regarding protein synthesis.

a. adenine m. pentose b. codon n. purines c. cytosine o. pyrimidines d. deoxyribonucleic acid (DNA) p. ribonucleic acid (RNA) e. deoxyribose q. ribose f. double helix r. ribosomal RNA (rRNA) g. guanine s. thymine h. messenger RNA (mRNA) t. transcription i. mutagen u. transfer RNA (tRNA) j. mutation v. translation k. nitrogenous base w. uracil l. nucleotide 191. DNA is capable of self-replication. Each new DNA formed consists of one old

strand and one new strand. Because of complementary base pairing, each DNA 192. strand encodes the information for building its own complement. If the sequence

of nucleotides in one strand of DNA is ATG-GCT, the sequence of its complement would be (6 answers):

193. 194. 195. 196. 197. The nucleotide sequence in the RNA molecule is complementary to the

nucleotide sequence in the corresponding chain of DNA. If the sequence of nucleotides on the corresponding strand of DNA is ATG-GCT, the sequence

198. on the transcribed RNA molecule would be (6 answers): 199. 201. 200. 202. 203. Three types of RNA play a role in protein synthesis. One type, , codes for the

sequence of amino acids in a polypeptide. A second type, , is a structural 204. component of the ribosomes. The third type, , picks up amino acids in the

cytoplasm and carries them to a ribosome to be linked to a growing polypeptide 205. chain. 206. When the sequence of nucleotides on mRNA codes for the sequence of amino

acids in a polypeptide, the process is called:

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Questions 165-209 (continued): Match the correct terms in the key (or write in a number, when appropriate) to the questions below regarding protein synthesis.

a. adenine m. pentose b. codon n. purines c. cytosine o. pyrimidines d. deoxyribonucleic acid (DNA) p. ribonucleic acid (RNA) e. deoxyribose q. ribose f. double helix r. ribosomal RNA (rRNA) g. guanine s. thymine h. messenger RNA (mRNA) t. transcription i. mutagen u. transfer RNA (tRNA) j. mutation v. translation k. nitrogenous base w. uracil l. nucleotide 207. The three nucleotide sequence on mRNA that codes for one amino acid in a

polypeptide is called a: 208. An inheritable change in the genetic material is called a: 209. Any agent in the environment that can cause a mutation is called a: 210. If a DNA triplet is AAT, the complementary mRNA codon would be:

a. UUG b. TTA c. UUA d. AAT e. GGA

211. Which of the following are found in equal proportions in DNA:

a. adenine and cytosine b. cytosine and thymine c. thymine and guanine d. adenine and thymine

212. The number of bases that code for a single amino acid in a protein is:

a. 1 b. 2 c. 3 d. 4

213. Thymine in one strand of a DNA double helix always pairs up with this nitrogen

base in the complementary DNA strand: a. adenine b. guanine c. cytosine d. uracil

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214. If the sequence of nitrogen bases in one strand of DNA is GTA-GCA, what would be the sequence of bases on its complementary DNA strand:

a. CAU-CGU b. CAT-CGT c. GAU-GCU d. GAT-GCT

215. If the nitrogen base sequence in a strand of mRNA is UCG-CCG-CGA, what is

the nitrogen base sequence in the DNA strand that coded for it: a. ACG-GGC-GCU b. AGC-GGC-GCT c. TGC-GGC-GCT d. TGC-GGC-GCU

216. How does DNA differ from RNA:

a. it contains uracil b. it is double stranded c. it contains deoxyribose d. both a and b e. both b and c

217. Which of the following nitrogenous bases is absent in RNA:

a. adenine b. guanine c. cytosine d. thymine e. uracil

218. A long sequence of mRNA that contains only two of the four possible nitrogenous

bases in an alternating sequence (i.e. AUAU...) will translate a polypeptide composed of a maximum of different amino acids: a. 2 b. 4 c. 6 d. 8

219. When DNA replicates, the two DNA molecules that result are correctly described

by which of the following statements: a. each molecule is composed entirely composed of new strands of DNA b. each strand of each DNA molecule contains some old DNA and some new

DNA c. both molecules contain one old strand and one new strand d. one DNA molecule contains two old strands and the other contains two

new strands

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220. The process of DNA coding for the sequence of nucleotides in an RNA molecule is called: a. conjugation b. transduction c. translation d. transcription

221. If a mutation results in the substitution of C for T in the DNA triplet ATG, then the

amino acid ________ would be built into the polypeptide chain during translation instead of the amino acid ________ (see page 4-30 to answer this question): a. serine, tyrosine b. phenylalanine, tyrosine c. cysteine, tyrosine d. leucine, tyrosine

222. If a strand of a DNA molecule contained the base sequence C, T, A, G, C, the

complementary strand would contain the base sequence: a. A, G, C, T, A b. G, A, T, C, G c. C, T, A, G, C d. T, G, C, A, T

223. The transfer of genetic information from the nucleus into the cytoplasm is a

function of: a. DNA molecules b. ribosomal RNA c. messenger RNA d. transfer RNA

224. If a DNA strand has the organic base sequence T, T, A, C, G, A, the

corresponding base sequence of a messenger RNA molecule would be: a. A, A, U, G, C, U b. A, A, T, G, C, T c. T, T, A, C, G, A d. U, U, T, G, C, T

225. During the process of protein synthesis, amino acids are positioned in the proper

sequence by molecules of: a. ribosomal RNA

b. transfer RNA c. messenger RNA d. nuclear RNA

226. A mutation is:

a. a change in the rate of protein synthesis from mRNA b. a change in the DNA molecule, which changes the protein that will be

formed c. a problem with the way mRNA molecules leave the nucleus d. a lack of replication of DNA before cell division

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227. Which of the following is a difference between RNA and DNA molecules: a. RNA contains uracil instead of thymine b. RNA contains ribose instead of glucose c. RNA is usually composed of a double strand instead of a single strand like

DNA d. none of the above; RNA and DNA are essentially the same

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FIRST BASE IN SECOND BASE IN THE CODON THIRD BASE IN THE CODON U C A G THE CODON U Phenylaline Serine Tyrosine Cysteine U Phenylaline Serine Tyrosine Cysteine C Leucine Serine Terminator Terminator A Leucine Serine Terminator Tryptophan G

C Leucine Proline Histidine Arginine U Leucine Proline Histidine Arginine C Leucine Proline Glutamine Arginine A

Leucine Proline Glutamine Arginine G A Isoleucine Threonine Asparagine Serine U Isoleucine Threonine Asparagine Serine C Isoleucine Threonine Lysine Arginine A

Start Methionine Threonine Lysine Arginine G G Valine Alanine Aspartic acid Glycine U Valine Alanine Aspartic acid Glycine C Valine Alanine Glutamic acid Glycine A Valine Alanine Glutamic acid Glycine G

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Answers to Drill for Chapter 4 – Cellular Metabolism (up to Nucleic Acids and Protein Synthesis)

1. d 2. m 3. j 4. h 5. m 6. g 7. i 8. c 9. m 10. a 11. h 12. k 13. m 14. g 15. i 16. l 17. m 18. e 19. f 20. h 21. m 22. g 23. i 24. j 25. d 26. m 27. b 28. j 29. g 30. j 31. i 32. m 33. a 34. c 35. m 36. b 37. a 38. i 39. a 40. g 41. m 42. e 43. f 44. m 45. l 46. b

47. i 48. e 49. g 50. f 51. m 52. b 53. c 54. d 55. j 56. a 57. e 58. g 59. i 60. b 61. h 62. e 63. f 64. c 65. c 66. k 67. q 68. c 69. n 70. q 71. a 72. n 73. c 74. d 75. a 76. i 77. n 78. c 79. c 80. b 81. m 82. a 83. o 84. e 85. c 86. e 87. i 88. n 89. i 90. n 91. c 92. f

93. k 94. p 95. e 96. h 97. r 98. a 99. a 100. e 101. h 102. r 103. b 104. c 105. b 106. m 107. j 108. c 109. m 110. j 111. m 112. l 113. q 114. f 115. k 116. e 117. o 118. a 119. e 120. e 121. b 122. d 123. b 124. b 125. b 126. c 127. d 128. d 129. b 130. c 131. d 132. c 133. d 134. g 135. b 136. a 137. b 138. c

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139. c 140. a 141. b 142. b 143. c 144. b 145. b 146. a 147. b 148. b 149. b 150. c 151. c 152. a 153. d 154. b 155. c 156. a 157. d 158. c 159. b 160. a 161. e 162. c 163. b 164. a 165. d 166. p 167. l 168. m

169. k 170. e 171. q 172. a 173. c 174. g 175. s 176. 4 177. n 178. o 179. a 180. c 181. g 182. w 183. 4 184. f 185. s 186. c 187. l 188. q 189. w 190. t 191. s 192. a 193. c 194. c 195. g 196. a 197. w 198. a

199. c 200. c 201. g 202. a 203. h 204. r 205. u 206. v 207. b 208. j 209. i 210. c 211. d 212. c 213. a 214. b 215. b 216. e 217. d 218. a 219. c 220. d 221. c 222. b 223. c 224. a 225. b 226. b 227. a