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1

What does it mean for genetic code to be commaless?

Read from a fixed starting point as a continuous sequence of bases

2

What does it mean for genetic code to be non-overlapping?

Read from a fixed starting point

3

What does it mean for genetic code to be universal?

Genetic code is conserved throughout evolution

4

What are the properties of the genetic code?

1. Unambiguous.
2. Degenerate/redundant.
3. Commaless/nonoverlapping
4. Universal

5

When is genetic code not commaless/nonoverlapping?

In some viruses

6

What are exceptions to universality of genetic code?

1. Mitochondria
2. Archaebacteria
3. Mycoplasma
4. Some yeasts

7

Name that mutation: Same amino acid, often with a base change in 3rd position of codon

Silent mutation

8

What kind of mutation is called: silent

Same amino acid, often with a base change in 3rd position of codon

9

What mutation is masked by tRNA wobble?

Silent mutations

10

Name that mutation: Changed amino acid whose structure is dissimilar to proper amino acid

Missense mutation (not conservative)

11

Name that mutation: Changed amino acid whose structure is similar to proper amino acid

Conservative missense mutation

12

What kind of mutation is called: missense

Amino acid is changed. If the structure of the new amino acid is similar to the original, it is called conservative.

13

Name that mutation: Change resulting in early stop codon

Nonsense mutation

(Mnemonic: Stop the nonsense!)

14

What kind of mutation is called: nonsense

Change resulting in early stop codon

(Mnemonic: Stop the nonsense!)

15

Name that mutation: change resulting in misreading of all nucleotides downstream, usually resulting in a truncated protein

Frame shift mutation

16

What kind of mutation is called: frameshift

change resulting in misreading of all nucleotides downstream, usually resulting in a truncated protein

17

Mutations ordered by decreasing severity of damage

1. Nonsense
2. Missense
3. Silent

18

Eukaryotic genome: single/multiple origins of replication

multiple

19

Prokaryotic genome: single/multiple origins of replication

single

20

Eukaryotic genome: Trigger for replication

Consensus sequence of AT-rich base pairs

21

Prokaryotic genome: Describe DNA replication

Continuous bidirectional DNA synthesis on leading strand and discontinuous (Okazaki fragments) on lagging strand

22

Enzyme function: DNA topoisomerases

Create a nick in the helix to relieve supercoils

23

DNA Topoisomerase I: Mechanism

cuts one strand, passes the other through it then reanneals the cut strand

24

DNA Topoisomerase II: Mechanism

cuts both strands, and passes an unbroken double strand through it then reanneals the cut strand

25

Enzyme function: Primase

Makes an RNA primer on which DNA polymerase III can initiate replication

26

DNA polymerase III: Mechanism

1. Adds deoxynucleotides to the 3' end until it reaches primer of preceding fragment

2. 3' to 5' exonuclease activity proofreads" each added nucleotide"

27

DNA polymerase III: Which direction does it read?

3' to 5'

28

DNA polymerase III: Which direction does it write?

5' to 3'

29

DNA polymerase III: Which direction does it proofread?

3' to 5'

30

Enzyme function: DNA polymerase III

Elongates the chain

31

Enzyme function: DNA polymerase I

Degrades RNA primer and fills in the gap with DNA

32

DNA polymerase I: Which direction does it read?

3' to 5'

33

DNA polymerase I: Which direction does it write?

5' to 3'

34

DNA polymerase I: Which direction does it proofread?

5' to 3'

35

Enzyme function: DNA helicase

Separates the two strands of DNA into single strands allowing for replication to occur. The position of these separated strands is called the replication fork.

36

Types of DNA repair

Single stranded:
1. Nucleotide excision repair
2. Base excision repair
3. Mismatch repair

Double stranded:
1. Nonhomologous end joining

37

Nucleotide excision repair: Mechanism

1. Specific endonucleases release the oligonucleotide containing damaged bases
2. DNA polymerase and ligase fill and reseal the gap, respectively

38

In what condition is nucleotide excision repair mutated?

Xeroderma pigmentosa (dry skin with melanoma and other cancers)

39

Base excision repair: Mechanism

1. Specific glycosylases recognize and remove damaged bases
2. AP endonuclease cuts DNA at apyrimidinic site
3. Empty sugar is removed
4. Gap is refilled and resealed

40

Mismatch repair: Mechanism

1. Unmethylated, newly synthesized string is recognized
2. Mismatched nucleotides are removed
3. Gap is refilled and resealed

41

In what condition is mismatch excision repair mutated?

Hereditary Nonpolyposis Colon Cancer

42

Nonhomologous end joining: Mechanism

Brings together two ends of DNA fragments (no requirement for homology)

43

What is on the 5' end of a nucleotide

Triphosphate

44

What is on the 3' end of a nucleotide

Hydroxyl group

45

True/False: DNA is synthesized 5' to 3'

TRUE

46

True/False: DNA is synthesized 3' to 5'

FALSE

47

True/False: RNA is synthesized 5' to 3'

TRUE

48

True/False: RNA is synthesized 3' to 5'

FALSE

49

True/False: Protein synthesis proceeds 5' to 3'

TRUE

50

True/False: Protein synthesis proceeds 3' to 5'

FALSE

51

Types of RNA and their important qualities

Massive, Rampant, Tiny

mRNA is the largest type
rRNA is the most abundant type
tRNA is the smallest type

52

What does eukaryotic RNA polymerase I make?

rRNA

53

What does eukaryotic RNA polymerase II make?

mRNA

54

What does eukaryotic RNA polymerase III make?

tRNA

55

Which RNA polymerase makes rRNA?

eukaryotic RNA polymerase I and prokaryotic RNA polymerase

56

Which RNA polymerase makes mRNA?

eukaryotic RNA polymerase II and prokaryotic RNA polymerase

57

Which RNA polymerase makes tRNA?

eukaryotic RNA polymerase III and prokaryotic RNA polymerase

58

True/False: RNA polymerase proofreads.

FALSE

59

True/False: RNA polymerase does not proofread.

TRUE

60

Special points about RNA polymerase II

1. Opens DNA at promoter site
2. Inhibited by alpha-amanitin

61

What does alpha-amanitin do?

Inhibits RNA polymerase II leading to hepatic necrosis

62

mRNA initiation codons

1. AUG (inAUGurates protein synthesis)
2. GUG (rarely)

63

What does the mRNA initiation codon code for?

Methionine in eukaryotes. formyl-methionine in prokaryotes.

64

mRNA stop codons

1. UGA (U Go Away)
2. UAA (U Are Away)
3. UAG (U Are Gone)

65

Define promoter of gene expression.

Site where RNA polymerase and multiple other transcription factors bind to DNA upstream from gene locus

66

What characterizes a promoter of gene expression?

AT-rich upstream sequence with TATA and CAAT boxes

67

What is the result of promoter mutation?

Dramatic decrease in amount of gene transcribed

68

Define enhancer of gene expression.

Stretch of DNA that alters gene expression by binding transcription factors. May be located close to, far from, or even within the gene whose expression it regulates.

69

Define operator of gene expression

Site where repressors bind

70

What is alternative splicing?

Rearrangement of exons to make unique proteins

71

What is the sequence of mRNA splicing?

1. Primary transcript combines with snRNP (snerp") to form spliceosome 2. Lariat-shaped intermediate is generated 3. Lariat is released to remove intron precisely and join two exons"

72

Where and when does eukaryotic RNA processing happen?

In the nucleus after transcription

73

What is the initial RNA transcript called?

heterogeneous nuclear RNA (hnRNA)

74

What are the steps in processing hnRNA to make mRNA? (Note: This is more than splicing.)

1. Capping on 5' end with 7-methyl-G
2. Polyadenylation on 3' end (approximately 200 As)
3. Splicing out of introns

75

How many nucleotides does tRNA contain?

75 to 90 nucleotides

76

What sequence does every tRNA share at the 3' end?

CCA along with a high percentage of chemically modified bases

77

Amino acid binding to tRNA: Where (on the tRNA) and how?

Where: 3' end
How: Covalently

78

What is the enzyme involved in processing tRNA

Aminoacyl tRNA synthetase (uses 1 ATP)

79

Aminoacyl tRNA synthetase: Mechanism

1. Scrutinizes amino acid before it binds to tRNA
2. Binds AMP-amino group to 3' end of tRNA
3. Scrutinizes amino acid again. If incorrect, bond is hydrolyzed.

80

What is wrong with a mischarged tRNA

Reads the regular bond but inserts wrong amino acid.

81

Which position on the codon is the wobble position?

3rd position

82

Names of the steps in protein synthesis

1. Initiation
2. Elongation
3. Termination

83

Sequence of events in the initiation step of protein synthesis.

1. Initiation factors assemble the 40S ribosomal subunit with the initiator tRNA
2. mRNA and (60S?) ribosomal subunit combine with the 40S subunit.
3. Initiation factors are released.

84

Sequence of events in the elongation step of protein synthesis.

1. Aminoacyl tRNA binds to the A site
2. Peptidyltransferase catalyzes peptide bond formation.
3. Peptidyltransferase transfers growing polypeptide to amino acid in A site.
4. Ribosome advances three nucleotides toward 3' end of RNA moving peptidyl RNA to P site.

85

Sequence of events in the termination step of protein synthesis.

1. Completed protein is released from ribosome.
2. Ribosome dissociates.

86

Role of ATP in protein synthesis

ATP does tRNA Activation (charging)

87

Role of GTP in protein synthesis

GTP does tRNA Going places (aka translocation) and Gripping

88

Role of A site in protein synthesis

A site holds incoming Aminoacyl tRNA.

89

Role of P site in protein synthesis

P site accomodates growing Peptide.

90

Role of E site in protein synthesis

E site holds Empty tRNA as it Exits

91

Which post-translational modification involves removal of N or C terminal pro-peptides from zymogens to generate mature proteins?

Trimming

92

What happens in post-translational trimming?

removal of N or C terminal pro-peptides from zymogens to generate mature proteins

93

Which post-translational modification involves phosphorylation?

post-translational covalent alteration

94

What happens during post-translational covalent alterations?

Either:
1. Phosphorylation
2. Glycosylation
3. Hydroxylation

95

Which post-translational modification involves glycosylation?

post-translational covalent alteration

96

Which post-translational modification involves hydroxylation?

post-translational covalent alteration

97

What happens during proteasomal degradation?

Attachment of ubiquitin to defective proteins to tag them for breakdown.

98

Ubiquitin or Ubiquinone: Proteosomal degradation

Ubiquitin

99

Ubiquitin or Ubiquinone: Coenzyme Q in oxidative phosphorylation

Ubiquinone

100

Where in the cell does the following occur: Fatty acid oxidation (beta-oxidation)

Mitochondria

101

Where in the cell does the following occur: acetyl-CoA production

Mitochondria

102

Where in the cell does the following occur: Krebs cycle

Mitochondria

103

Where in the cell does the following occur: Glycolysis

Cytoplasm

104

Where in the cell does the following occur: Fatty acid synthesis

Cytoplasm

105

Where in the cell does the following occur: Hexose Monophosphate Shunt

Cytoplasm

106

Where in the cell does the following occur: Protein Synthesis

Rough endoplasmic reticulum in the cytoplasm

107

Where in the cell does the following occur: Steroid synthesis

Smooth endoplasmic reticulum in the cytoplasm

108

Where in the cell does the following occur: Gluconeogenesis

Pathway has steps in the mitochondria and in the cytoplasm

109

Where in the cell does the following occur: Urea cycle

Pathway has steps in the mitochondria and in the cytoplasm

110

Where in the cell does the following occur: Heme synthesis

Pathway has steps in the mitochondria and in the cytoplasm

111

What type of bonds hold the phosphoryls together in ATP, and how much energy are the bonds worth?

Phosphoanhydride bonds are worth 7 kilocalories per mole (but only between the alpha and beta and the beta and the gamma, thus AMP's phosphoryl is not cleaved off for energy)

112

How many ATP molecules are produced by aerobic metabolism of glucose?

38 via the Malate shuttle, and 36 via the G3P shuttle.

113

In aerobic metabolism of glucose, which pathway produces 38 ATP?

Malate shuttle

114

In aerobic metabolism of glucose, which pathway produces 36 ATP?

G3P shuttle

115

How much ATP is produced by anaerobic glycolysis?

2 ATP per glucose

116

What is this molecule an activated carrier of?: ATP

Phosphoryls

117

What is this molecule an activated carrier of?: NADH

Electrons

118

What is this molecule an activated carrier of?: NADPH

Electrons

119

What is this molecule an activated carrier of?: FADH2

Electrons

120

What is this molecule an activated carrier of?: Coenzyme A

Acyl

121

What is this molecule an activated carrier of?: Lipoamide

Acyl

122

What is this molecule an activated carrier of?: Biotin

CO2

123

What is this molecule an activated carrier of?: Tetrahydrofolate

1-carbon units

124

What is this molecule an activated carrier of?: S-adenosyl-methionine

Methyl groups

125

What is this molecule an activated carrier of?: Thiamine Pyrophosphate

Aldehydes

126

What activated carriers carry: Phosphoryl

ATP and GTP

127

What activated carriers carry: Electrons

1. NADH
2. NADPH
3. FADH2

128

What activated carriers carry: Acyl

1. Coenzyme A
2. Lipoamide

129

What activated carriers carry: CO2

Biotin

130

What activated carriers carry: 1-carbon units

1. Tetrahydrofolates (originally as formyl then methyl)
2. Biotin (as CO2)
3. S-adenosyl-methionine (as CH3)

131

What activated carriers carry: CH3 groups

1. S-adenosyl-methionine
2. N5-methyl-THF

132

What activated carriers carry: Formyl groups

N10-formyl-THF

133

What activated carriers carry: Aldehydes

Thiamine Pyrophosphate

134

ATP and methionine react to form what?

S-adenosyl-methionine

135

What reacts to yield S-adenosyl-methionine?

ATP and methionine

136

What vitamin is necessary for regeneration of S-adenosyl-methionine?

Vitamin B12

137

When is NAD used?

Catabolic processes to carry reducing equivalents away as NADH

138

When is NADPH used?

1. Anabolic process (steroid and fatty acid synthesis)
2. Respiratory burst
3. P-450

139

Where does NADPH come from?

HMP shunt

140

What disease results from NADPH oxidase deficiency?

Chronic Granulomatous Disease

141

This enzyme phosphorylates glucose with high affinity.

Hexokinase (as opposed to glucokinase)

142

This enzyme phosphorylates glucose with low affinity.

Glucokinase (as opposed to hexokinase)

143

This enzyme phosphorylates glucose with a low capacity.

Hexokinase (as opposed to glucokinase)

144

This enzyme phosphorylates glucose and is feedback inhibited by Glucose-6-Phosphate.

Hexokinase (as opposed to glucokinase)

145

This enzyme phosphorylates glucose with a high capacity.

Glucokinase (as opposed to hexokinase)

146

This enzyme phosphorylates glucose and is not feedback inhibited.

Glucokinase (as opposed to hexokinase)

147

Glucokinase: Where is it found and why does it do what it does?

Found in the liver and pancreatic beta cells. Phosphorylates glucose to sequester it after a big meal.

148

Hexokinase: Where is it found and why does it do what it does?

Found in every cell's cytoplasm. Phosphorylates glucose to proceed with glycolysis.

149

What are the net reactants and products in glycolysis.

Reactants
1. Glucose
2. 2 Phosphates
3. 2 ADP
4. 2 NAD

Products
1. 2 Pyruvate
2. 2 ATP
3. 2 NADH
4. 2 H+
5. 2 H20

150

What are the rate limiting steps of glycolysis?

1. Hexokinase (Glucose to Glucose-6-P)
2. *Phosphofructokinase-1 (Fructose-6-P to Fructose-1,6-BP)
3. Pyruvate kinase (Phosphoenolpyruvate to Pyruvate)

151

Phosphofructokinase-1: What does it do, and what stimulates and inhibits it?

PFK-1 1-phosphorylates fructose-6-phosphate to produce Fructose-1,6-Bisphosphate.

Inhibited by:
1. ATP (don't need more of me)
2. Citrate (my cycle is going well)

Stimulated by:
1. AMP (Hey, we need more ATP)
2. Fructose-2,6-BP (The fact that I'm being made means there's tons of glucose.)

152

Pyruvate kinase: What does it do, and what stimulates and inhibits it?

Pyruvate kinase converts phosphoenolpyruvate to pyruvate, thereby producing two ATP.

Inhibited by:
1. ATP (don't need more of me)
2. Alanine (I came from pyruvate, so we don't need any more.)

Stimulated by:
1. Fructose-1,6-BP (I was told we needed more ATP, so here I am, so you better move the line along.)

153

Pyruvate dehydrogenase: What does it do, and what stimulates and inhibits it?

Pyruvate dehydrogenase converts pyruvate to acetyl-coA, and produces NADH and CO2.

Stimulated by: excess pyruvate?
Inhibited by:
1. NADH (Listen, seriously, we don't need anymore of me.)
2. NADH (You produce NADH, soon there'll be more of me.)
3. Acetyl-CoA (Enough of me, save your pyrvuate.)

154

What disease state is glycolytic enzyme deficiency generally associated with?

Hemolytic anemia

155

What is the mechanism of hemolytic anemia in someone with glycolytic enzyme deficiency?

1. Lack of glycolysis leads to lack of ATP in RBCs
2. Lack of ATP leads to inactivity of Na, K-ATPase pump.
3. Lack of the pump leads to sodium influx.
4. Water follows sodium into the cell.
5. The cell swells and bursts.

156

What are the two most common glycolytic enzyme deficiencies?

Pyruvate kinase (95% of cases) followed by glucose phosphate isomerase (4% of cases)

157

What are the 5 cofactors necessary for pyrvuate dehydrogenase?

Lipoic acid plus the first four B vitamins in their active forms:
1. B1: TPP
2. B2: FAD
3. B3: NAD
4. B5: CoA

158

What are the 5 cofactors necessary for alpha-ketoglutarate dehydrogenase?

Lipoic acid plus the first four B vitamins in their active forms:
1. B1: TPP
2. B2: FAD
3. B3: NAD
4. B5: CoA

159

What are the net reactants and products in the reaction that Pyruvate Dehydrogenase catalyzes?

Reactants:
1. Pyruvate
2. CoA
3. NAD

Products
1. Acetyl CoA
2. CO2
3. NADH

160

What activates and what inhibits pyruvate dehydrogenase?

Activated by exercise, which stimulates:
1. Increased NAD/NADH ratio (We need more NADH.)
2. Increased ADP (We need more ATP.)
3. Ca2+ (More of me leads muscles to contract, and I'm taken up by mitochondria where I tell PDH that we need more ATP.)

Inhibited by:
1. NADH (No more of me please)
2. ATP (likewise)
3. Acetyl CoA (ditto)

161

Lipoamide or lipoate: Which carries aldehydes?

Lipoamide

162

Lipoamide or lipoate: Which is a cofactor for pyruvate dehydrogenase?

Lipoate (Lipoic acid)

163

What toxin inhibits lipoic acid?

Arsenic

164

What is the presentation of arsenic toxicity?

1. Vomiting
2. Rice water stools
3. Garlic breath

165

Pyruvate dehydrogenase deficiency: Mechanism

Backup of pyruvate and alanine leads to lactic acidosis.

166

Pyruvate dehydrogenase deficiency: Congenital or Acquired

Both. Acquired cases happen in cases of B1 deficiency (such as in alcoholics.)

167

Pyruvate dehydrogenase deficiency: Presentation

Lactic acidosis and neurologic defects

168

Pyruvate dehydrogenase deficiency: Treatment

Increased intake of ketogenic nutrients (such as high fat content or increased lysine and leucine)

169

What are the miscellaneous fates of pyruvate, and what are the end products used for?

1. Alanine: Carries amino groups to the liver from muscle
2. Oxaloacetate: Replenishes TCA cycle or is used gluconeogenesis
3. Acetyl-CoA: Used in TCA cycle
4. Lactate: No good use

170

Which tissues and organs primarily convert pyruvate into lactate?

1. RBCs and WBCs
2. Lens and cornea
3. Renal medulla
4. Testes

171

What enzymes and cofactors are used in conversion of pyruvate to alanine?

Enzyme: Alanine Transaminase (ALT)

Cofactors: None

172

What enzymes and cofactors are used in conversion of pyruvate to oxaloacetate?

Enzyme: Pyruvate Carboxylase (contains biotin and magnesium)

Cofactors: CO2 and ATP

173

What are the reactants and products in the reaction catalyzed by pyruvate carboxylase?

Reactant:
Pyruvate (with CO2 and ATP)

Product:
Oxaloacetate

174

What are the reactants and products in the reaction catalyzed by lactate dehydrogenase?

This reaction is reversible, so the products can switch with the reactants.

Reactants:
1. Pyruvate
2. NADH (rehydrogenates in this direction)
3. H+

Products:
1. Lactate
2. NAD

175

Where do the various pyruvate transformation reactions happen?

Cytosol:
1. ALT (Alanine to/from pyruvate)
2. LDH (Lactate to/from pyruvate)

Mitochondria
1. Pyruvate carboxylase (pyruvate to oxaloacetate)
2. Pyruvate dehydrogenase (pyruvate to acetyl-coa)

176

Where does the Cori Cycle happen?

In the liver and muscle/RBCs

Liver: Pyruvate converts to glucose
Muscle/RBCs: Glucose converts to Pyruvate

177

What is the purpose of the Cori cycle?

Transfers excess reducing equivalents from RBCs and the muscle to liver so they can function anaerobically

178

What reaction does citrate synthase catalyze?

Oxaloacetate and acetyl coA combine to yield citrate.

179

What is the order of the citric acid cycle beginning at citrate?

CAn I Keep Selling Sex For Money, Officer?

1. Citrate
2. cis-Aconitate
3. Isocitrate
4. alpha-Ketoglutarate
5. Succinyl CoA
6. Succinate
7. Fumarate
8. Malate
9. Oxaloacetate

180

What is the order of the citric acid cycle beginning at cis-aconitate?

1. cis-Aconitate
2. Isocitrate
3. alpha-ketoglutarate
4. succinyl coA
5. succinate
6. fumarate
7. money
8. oxaloacetate
9. citrate

181

What is the order of the citric acid cycle beginning at isocitrate?

1. isocitrate
2. alpha-ketoglutarate
3. succinyl coa
4. succinate
5. fumarate
6. malate
7. oxaloacetate
8. citrate
9. cis-aconitate

182

What is the order of the citric acid cycle beginning at alpha-ketoglutarate?

1. alpha-ketoglutarate
2. succinyl coA
3. succinate
4. fumarate
5. malate
6. oxaloacetate
7. citrate
8. cis-aconitate
9. isocitrate

183

What is the order of the citric acid cycle beginning at succinyl coA?

1. succinyl coA
2. succinate
3. fumarate
4. malate
5. oxaloacetate
6. citrate
7. cis-aconitate
8. isocitrate
9. alpha-ketoglutarate

184

What is the order of the citric acid cycle beginning at succinate?

Sex Feels Marvelous Over Cordelia And If Kruti Sucks-a-Neil.

1. Succinate
2. Fumarate
3. Malate
4. Oxaloacetate
5. Citrate
6. cis-aconitate
7. Isocitrate
8. alpha-ketoglutarate
9. succinyl coA

185

What is the order of the citric acid cycle beginning at fumarate?

1. fumarate
2. malate
3. oxaloacetate
4. citrate
5. cis-aconitate
6. isocitrate
7. alpha-ketoglutarate
8. succinyl coA
9. succinate

186

What is the order of the citric acid cycle beginning at malate?

1. malate
2. oxaloacetate
3. citrate
4. cis-aconitate
5. isocitrate
6. alpha-ketoglutarate
7. succinyl coA
8. succinate
9. fumarate

187

What is the order of the citric acid cycle beginning at oxaloacetate?

1. oxaloacetate
2. citrate
3. cis-aconitate
4. isocitrate
5. alpha-ketoglutarate
6. succinyl coA
7. succinate
8. fumarate
9. malate

188

What stimulates and inhibits citrate synthase?

Stimulate: Nothing
Inhibit: ATP

189

What stimulates and inhibits isocitrate dehydrogenase?

Stimulate: ADP

Inhibit:
1. ATP
2. NADH

190

What stimulates and inhibits alpha-ketoglutarate dehydrogenase?

Stimulate: Nothing
Inhibit:
1. ATP
2. NADH
3. Succinyl CoA

191

Which steps in the citric acid cycle produce CO2?

The steps where carbons are lost, the two structures after isocitrate each have one less carbon than the last.

1. Isocitrate to alpha-ketoglutarate
2. alpha-ketoglutarate to succinyl coA

192

Which steps in the citric acid cycle produce reducing equivalents?

The only step that produces FADH2 is the only one that also yields an F product.

1. Isocitrate to alpha ketoglutarate (1 NADH)
2. alpha-ketoglutarate to succinyl coA (1 NADH)
3. Succinate to Fumarate (1 FADH2)
4. Malate to Oxaloacetate (1 NADH)

193

Which steps in the citric acid cycle produce ATP?

None, however 1 GTP is produced from the conversion of Succinyl CoA to Succinate.

194

How much ATP is produced by the citric acid cycle per molecule of acetyl coA?

12 ATP.

3 NADH x 3 ATP/NADH= 9 ATP
1 FADH2 x 2 ATP/FADH2 = 2 ATP
1 GTP x 1 ATP/GTP = 1 ATP

The total is 12 ATP

195

How much ATP is produced by the citric acid cycle per molecule of glucose?

24

1 cycle:
3 ATP/NADH= 9 ATP
1 FADH2 x 2 ATP/FADH2 = 2 ATP
1 GTP x 1 ATP/GTP = 1 ATP

The total is 12 ATP per acetyl coA. However, there are 2 acetyl coA molecules produced per glucose molecule. Thus the total is 24.

196

Name the complexes and important coenzymes and cytochromes in the electron transport chain.

1. Complex I
2. Coenzyme Q
3. Complex III
4. Cytochrome C
5. Complex IV
6. Complex V

197

Where in the electron transport chain do NADH and FADH2 release their electrons?

Complex I

198

Where in the electron transport chain is O2 reduced to 2H2O?

Complex IV

199

Where in the electron transport chain is ADP converted to ATP?

Complex V aka ATP synthase aka mitochondrial ATPase

200

Name three classes of oxidative phosphorylation poisons.

1. Electron transport inhibitors
2. ATPase inhibitors
3. Uncoupling agents

201

What is the mechanism of electron transport inhibitors?

1. Directly inhibit electron transport causing:
2. Decreased protein gradient and decrease in O2 consumption, thereby:
3. Blocking ATP synthesis

202

What is the mechanism of ATPase inhibitors?

1. Directly inhibit mitochondrial ATPase causing:
2. Increased protein gradient and increased oxygen consumption, but no ATP is produced because electron transport stops.

203

What is the mechanism of uncoupling agents?

Uncouples" ATP synthesis from gradient production

204

What is rotenone?

An electron transport inhibitor.

205

What is the mechanism of CN?

Electron transport inhibition

206

What is the mechanism of CO?

Electron transport inhibition

207

What is antimycin A?

An electron transport inhibitor.

208

What is the mechanism of oligomycin?

ATPase inhibition

209

What is the mechanism of thermogenin?

Uncoupling protein OR UCP which is an uncoupling agent

210

Where is thermogenin found?

Brown adipose tissue

211

What is the mechanism of 2,4-dinitrophenol?

Uncoupling agent

212

Name three uncoupling agents

1. UCPs (such as Thermogenin)
2. 2,4-dinitrophenol
3. aspirin

213

Name the irreversible enzymes in gluconeogenesis, and where they are found.

Pathway Produces Fresh Glucose

All the enzymes are found only in the liver, kidney, and intestinal epithelium
1. Pyruvate carboxylase in the mitochondria
2. PEP carboxykinase in the cytosol
3. Fructose-1,6-bisphosphatase in the cytosol
4. Glucose-6-Phosphatase in the endoplasmic reticulum

214

Name the irreversible enzymes in glycolysis.

1. Hexokinase
2. Phosphofructokinase-1
3. Pyruvate kinase
4. Pyruvate dehydrogenase

215

What are the requirements of PEP carboxykinase?

GTP

216

Where does the pentose phosphate pathway happen?

Cytoplasm of Red Blood Cells, and in lactating mammary glands, liver, and adrenal cortex (all sites of fatty acid or steroid synthesis except RBCs)

217

How much ATP is used in the pentose phosphate shunt?

None

218

What are the main products of the pentose phosphate shunt and their uses?

1. NADPH (for fatty acid and steroid synthesis, glutathione reduction, and cytochrome P-450)
2. Ribose-5-phosphate (for nucleotide synthesis)
3. G3P and F6P (glycolytic intermediates)

219

What are the key enzymes of the pentose phosphate shunt and are the reactions reversible or irreversible?

1. Glucose-6-phosphate dehydrogenase (irreversible)
2. Transketolase (reversible)

220

What does transketolase require?

Thiamine (Vitamin B1)

221

What is the rate-limiting enzyme in the Pentose phosphate pathway?

Glucose-6-Phosphate Dehydrogenase

222

What is glutathione used for?

Detoxification of free radicals and peroxides.

223

What does NADPH deficiency in RBCs result in?

Hemolytic anemia

224

Name some oxidizing agents that someone with a G6PD deficiency is vulnerable to.

1. Fava beans
2. Sulfonamides
3. Primaquine
4. Antituberculosis drugs

225

What protection does G6PD deficiency provide?

Protection against malaria

226

Which group is more likely to have G6PD deficiency?

Blacks

227

What are Heinz bodies?

altered Hemoglobin precipitates within RBCs, found in G6PD deficiency

228

What histologic change is seen in G6PD deficiency

Heinz bodies within red blood cells

229

What is the etiology of fructose intolerance?

1. Lack of aldolase B
2. Build up of Fructose-1-Phosphate
3. Decrease in available phosphate
4. Inhibition of glycogenolysis and gluconeogenesis

230

What is the clinical presentation of fructose intolerance?

hypoglycemia, jaundice, cirrhosis, and vomiting

231

What is the difference in presentation between von Gierke's disease and fructose intolerance?

Both have hypoglycemia, jaundice, cirrhosis and vomiting.

von Gierke's disease also has lactic acidosis whereas fructose intolerance does not.

232

What is the treatment for fructose intolerance?

Decreased intake of both fructose and sucrose.

233

What is the etiology of essential fructosuria?

Defect in fructokinase leading to lack of metabolism of fructose. Benign and asymptomatic

234

What is the clinical presentation of essential fructosuria?

Fructose appears in the blood and urine

235

Which is more serious, essential fructosuria or fructose intolerance?

Fructose intolerance, because it depletes the cells of phosphate.

236

What is the etiology of classic galactosemia?

1. Absence of galactose-1-phosphate uridyl transferase
2. Build up of toxic substances including galactitol

237

What is the presentation of classic galactosemia?

Early:
1. Galactosemia
2. Galactosuria
3. Vomiting
4. Diarrhea
5. Jaundice

Late:
1. Cataracts
2. Hepatosplenomegaly
3. Mental retardation

238

How does galactokinase deficiency present?

1. Galactosemia
2. Galactosuria

More severe symptoms such as cataracts, hepatosplenomegaly and mental retardation can follow.

239

What is the treatment for classic galactosemia?

Exclude galactose and lactose from the diet.

240

What enzyme converts galactose to galactitol?

Aldose reductase

241

What does aldose reductase do?

Converts galactose to galactitol

242

What enzyme converts Galactose to galactose-1-phosphate?

Galactokinase

243

What enzyme converts Galactose-1-Phosphate to Glucose-1-Phosphate?

Uridyl transferase

244

What enzyme converts UDP-galactose to UDP-glucose?

4-epimerase

245

What does galactokinase do?

converts Galactose to galactose-1-phosphate

246

What does 4-epimerase do?

converts between UDP-galactose and UDP-glucose

247

What does Uridyl transferase do?

1. converts UDP-glucose to UDP-galactose
2. converts Galactose-1-Phosphate to Glucose-1-Phosphate

248

What enzyme converts UDP-glucose to UDP-galactose?

Uridyl transferase

249

Which groups are more likely to be lactose intolerant?

1. Blacks
2. Asians

250

What is the etiology of lactose intolerance?

Loss of brush-border lactase

251

How does lactose intolerance present?

1. Bloating
2. Cramps
3. Osmotic diarrhea

252

What is the treatment for lactose intolerance?

Avoid milk or add lactase pills to the diet

253

What are the essential amino acids?

PVT TIM HALL

1. Phenylalanine
2. Valine
3. Threonine
4. Tryptophan
5. Isoleucine
6. Methionine
7. Histidine
8. Alanine
9. Leucine
10. Lysine

254

What are the conditionally essential amino acids, and why are they conditionally essential?

The condition is age. They are necessary early in life during growth.

Mnemonic: Babies CRY for Help

1. Cysteine
2. aRginine
3. tYrosine
4. Histidine

255

Cysteine or Cystine: The amino acid

Cysteine

256

Cysteine or Cystine: Two copies of the amino acid joined by a disulfide bond

Cystine

257

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Phenylalanine

Essential
Both glucogenic and ketogenic

258

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Valine

Essential
Glucogenic

259

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Tryptophan

Essential
Both glucogenic and ketogenic

260

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Threonine

Essential
Both glucogenic and ketogenic

261

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Isoleucine

Essential
Both glucogenic and ketogenic

262

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Methionine

Essential
Glucogenic

263

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Histidine

Essential
Glucogenic

264

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Arginine

Essential
Glucogenic

265

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Leucine

Essential
Ketogenic

266

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Lysine

Essential
Ketogenic

267

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Tyrosine

Conditionally essential (during life and early growth)

(Phenylalanine and Tetrahydrobiopterin produce tyrosine and dihydrobiopterin)

Both glucogenic and ketogenic

268

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Glutamate

Inessential (made from alpha-ketoglutarate)
Glucogenic

269

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Aspartate

Inessential (made from asparagine or oxaloacetate by aspartate aminotransferase)
Glucogenic

270

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Proline

Inessential (Glutamate makes proline and ornithine)
Glucogenic

271

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Glycine

Inessential (synthesized during reactions involving tetrahydrofolate)
Glucogenic

272

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Cysteine

Conditionally essential (during life and early growth)

(Methionine begets S-adenosyl methionine which begets intermediates which beget cysteine)

Glucogenic

273

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Alanine

Inessential (made from pyruvate by alanine aminotransferase in the Cori cycle)
Glucogenic

274

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Serine

Inessential (made from a descendant of 3PG and with an amine group from glutamate)
Glucogenic

275

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Glutamine

Inessential (made from glutamate)
Glucogenic

276

Is the following amino acid essential or inessential, and is it glucogenic, ketogenic, or both?: Asparagine

Inessential (made from aspartate)
Glucogenic

277

Which amino acids are acidic?

Aspartate and glutamate are negatively charged at body pH

278

Which amino acids are basic?

Arginine, Lysine and Histidine

Arginine and Lysine are increased in histones which bind negatively charged DNA.

Histidine has no charge at body pH.

279

Zinc deficiency: Presentation

Delayed wound healing, hypogonadism, and decreased adult hair (axillary, facial, pubic)""

280

Zinc deficiency: Predisposes to what?

Alcoholic cirrhosis

281

Ethanol metabolism: All steps with enzymes and cofactors

Step 1: Ethanol is oxidized by NAD (forming NADH) to acetaldehyde using alcohol dehydrogenase. Step 2: Acetaldehyde is oxidized by NAD (forming NADH) to acetate using acetaldehyde dehydrogenase.""

282

Ethanol metabolism: Limiting reagent

NAD+

283

Ethanol metabolism: Order of kinetics of alcohol dehydrogenase

Zero-order kinetics

284

Disulfiram: Mechanism

Disulfiram inhibits acetaldehyde dehydrogenase, leading to an accumulation of acetaldehyde, leading to increased hangover symptoms.""

285

Which drug inhibits acetaldehyde dehydrogenase?

Disulfiram

286

Ethanol hypoglycemia: mechanism

1. Ethanol metabolism increases NADH/NAD ratio in the liver. 2. Pyruvate and oxaloacetate are reduced by NADH respectively to lactate and malate. 3. Decreased pyruvate and oxaloacetate leads to decreased gluconeogenesis. 4. Decreased gluconeogenesis leads to hypoglycemia.""

287

What are the consequences of the altered NADH/NAD ratio seen in alcoholics?

Short-term: Hypoglycemia, Long-term: Hepatic fatty change""

288

What is the mechanism behind chronic fatty change in alcoholics?

1. Ethanol metabolism leads to an increased NADH/NAD ratio in the liver. 2. This ratio prefers fatty acid synthesis over glycolysis.""

289

Kwashiorkor: Clinical picture

Small child with a swollen belly and depigmented hair.

290

Kwashiorkor: Clinical presentation

Kwashiorkor results from protein-deficient MEALS. Malabsorbtion, Edema, Anemia, Liver (fatty change), Skin lesions""

291

Protein malnutrition leads to what disease?

Kwashiorkor (as opposed to Marasmus from energy malnutrition)

292

Energy malnutrition leads to what disease?

Marasmus (as opposed to Kwashiorkor from protein malnutrition)

293

Marasmus: Clinical presentation

Tissue and muscle wasting, loss of subcutaneous fat, and variable edema""

294

Chromatin structure: In the beads on a string analogy, what are the beads?""

Start with a nucleosome core made up of an 8 histone cube (two each of positively-charged histones H2A, H2B, H3, and H4). Negatively charged DNA loops twice around nucleosome core.""

295

Chromatin structure: In the beads on a string analogy, what is the string and how long is it?""

Histone H1 ties the nucleosomes together in a 30-nm fiber string

296

Chromatin structure: What histones are included and which of these are not in the nucleosome core?

H1 (only one not in the core), H2A, H2B, H3, and H4""

297

Heterochromatin or Euchromatin: Which is more condensed?

Heterochromatin. Euchromatin is less condensed.

298

Heterochromatin or Euchromatin: Which is less condensed?

Euchromatin. Heterochromatin is more condensed.

299

Heterochromatin or Euchromatin: Which is transcriptionally active?

Euchromatin (""eu"" means true, so think ""truly transcribed"")""

300

Heterochromatin or Euchromatin: Which is transcriptionally inactive?

Heterochromatin

301

Name the purines.

Adenine and Guanine

302

Name the pyrimidines.

Cytosine, Uracil, Thymine""

303

Which base pair bond has 3 Hydrogen bonds?

Guanine to Cytosine

304

Which base pair bond has 2 Hydrogen bonds?

Adenine to Thymine

305

How many Hydrogen bonds does the Guanine to Cytosine pairing have?

3

306

How many Hydrogen bonds does the Adenine to Thymine pairing have?

2

307

Which amino acids are necessary for purine synthesis?

Glycine, Aspartate, Glutamine""

308

In nucleic acids, what kind of substitution is a transition?""

TransItion = Identical type (Purine for purine or pyrimidine for pyrimidine")"

309

In nucleic acids, what kind of substitution is a transversion?""

TransVersion = conVersion between types (Purine for pyrimidine or vice versa")"

310

What does it mean for genetic code to be unambiguous?

Each codon specifies only one amino acid.

311

What does it mean for genetic code to be degenerate?

More than one codon may code for the same amino acid.

312

What does it mean for genetic code to be redundant?

More than one codon may code for the same amino acid.

313

Which amino acid is coded by only one codon?

Methionine

314

~ average pKa of carboxyl group on AA""

2.3

315

~ pKa of side chain of Glutamic Acid""

>4""

316

~ pKa of side chain of Histidine""

6

317

~ pKa of side chain of Cysteine""

8

318

~ average pKa of amino group on AA""

9.6

319

~ pKa of side chain of Tyrosine""

10

320

~ pKa of side chain of Lysine""

10.5

321

~ pKa of side chain of Arginine""

12.5

322

An acid with a pKa of x serves as a buffer best at x + what?""

positive or negative 1 (equal amounts of charged and uncharged acid)""

323

Trypsin cleaves peptides at which side of what residues?""

C-terminal of lysine or arginine (the most basic amino acids)""

324

Cyanogen bromide cleaves peptides at which side of what residues?""

C-terminal of methionine""

325

Pepsin cleaves peptides at which side of what residues?""

C-terminal side of tyrosine, phenylalanine, and tryptophan (all have phenyl groups, these are the same bonds as chymotrypsin. Pepsin's action ceases when the NaHCO3 raises the pH of the intestinal contents)""

326

Chymotrypsin cleaves peptides at which side of what residues?""

C-terminal side of tyrosine, phenylalanine, and tryptophan residues (all have phenyl groups, these are the same bonds as pepsin, whose action ceases when the NaHCO3 raises the pH of the intestinal contents).""

327

# of aas in one turn of alpha-helix""

3.6

328

Amino acids that disrupt alpha-helix""

proline, many charged aas, bulky side chains""

329

Which reagent sequentially removes N-terminal residues from a polypeptide?""

Phenylisothiocyanate (Edman degradation)""

330

Which reagent sequentially removes C-terminal residues from a polypeptide?""

Carboxypeptidase""

331

What kind of inheritance and mutation is the alpha-1-antitrypsin deficiency?""

Autosomal recessive, single purine substitution (GAG to AAG)""

332

Anode: What does it attract?""

Anions""

333

Anode: What does it contain?""

Cations""

334

Cathode: What does it attract?""

Cations""

335

Cathode: What does it contain?""

Anions""

336

Inhibitors of electron transport from FMNH2 to Coenzyme Q""

Amytal and Rotenone""

337

Inhibitors of electron transport from Cytochrome b to Cytochrome c""

Antimycin A""

338

Inhibitors of electron transport from Cytochrome a+a3 to Oxygen""

Cyanide, CO, and Sodium azide""

339

Where do GLUT1 receptors predominate over other GLUT receptors?""

RBCs""

340

Where do GLUT4 receptors predominate over other GLUT receptors?""

Adipose tissue and skeletal muscle""

341

Which tissues have cotransport of glucose?""

Epithelial cells of the intestine, renal tubular cells, and choroid plexus""

342

Which tissues (7) need glucose as fuel?""

Brain, RBCs, Renal medulla, lens, cornea, testes, exercising muscle""

343

Where is pyruvate carboxylase found and not found?""

Found in mitochondria of liver and kidney cells, not foudn in mitochondria of muscle""

344

Where is Fructose 1-6 bisphosphatase found?""

Liver and kidney""

345

What is the Cori cycle?""

Lactate in muscle is shuttled to liver where it is turned into glucose.""

346

How does glucagon stimulate gluconeogenesis?""

Regulation of F2,6-BP and inactivation of Pyruvate Kinase via elevation of cAMP-dependent protein kinase A.""

347

This oxidation accounts for about two thirds of the total oxygen consumption and ATP production in most animals, including humans.""

Oxidation of acetyl coA to CO2 and H2O.""

348

What inhibits pyruvate dehydrogenase?""

Acetyl CoA and NADH (no need for more of either). These activate PD kinase (Phosphorylates enzyme with ATP, which must be in abundance, so no more is needed)""

349

What stimulates pyruvate dehydrogenase?""

ADP (need more ATP. Inhibits PD kinase and stimulates PD phosphatase.)""

350

Which is active?: Phosphorylated or dephosphorylated pyruvate dehydrogenase""

Dephosphorylated.""

351

What inhibits citrate synthase?""

ATP and NADH (no need for more of either), Succinyl CoA (""Slow down partner, the guys ahead of you are trying to do their job!""), Acyl CoA fatty acid derivatives (Citrate provides acetyl CoA to synthesize fatty acids and activates acetyl CoA carboxylase, rate limiting enzyme of fatty acid synthesis).""

352

Where in glycolysis and TCA does CO2 come off?""

3 places: Pyruvate to Acetyl CoA, Isocitrate to alpha-ketoglutarate, and alpha-ketoglutarate to Succinyl CoA""

353

What is the rate-limiting step of the TCA?""

Isocitrate to alpha-ketoglutarate by isocitrate dehydrogenase""

354

What activates isocitrate dehydrogenase?""

ADP""

355

What inhibits isocitrate dehydrogenase?""

ATP and NADH""

356

Sources of Succinyl CoA""

TCA intermediate, and from odd chained fatty acids, and from propionyl coA from metabolism of branched-chain amino acids.""

357

Uses of Succinyl CoA""

TCA intermediate, and biosynthesis of heme""

358

Where in the TCA does NADH come from?""

Pyruvate to Acetyl CoA, Isocitrate to alpha-ketoglutarate, alpha-ketoglutarate to succinyl coA, Malate to Oxaloacetate""

359

Where in the TCA does FADH2 come from my dear?""

Succinate to fumarate my sweet.""

360

Why is FAD used to oxidize succinate?""

Succinate is not powerful enough to reduce NAD.""

361

What are the important products of the HMP pathway?""

2 NADPH, Ribose, and glyceraldehyde-3-Phosphate and Fructose-6-phosphate""

362

Which major metabolic reactions require Thiamine as a cofactor?""

TCA: Pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase, HMP shunt: Transketolase""

363

What is NADPH used for?""

1. Reductive biosynthesis (eg fatty acids and steroids) 2. Reduction of oxygen directly (myeloperoxidase system's famed respiratory burst) and hydrogen peroxide indirectly (through reduction of glutathione) 3. Cytochrome P-450 mono-oxygenase system""

364

What is the famed respiratory burst?""

The rapid conversion of O2 to superoxide using NADPH.""

365

What disease process is due to a missing respiratory burst?""

Chronic granulomatous disease""

366

Where is the mutation for G6PD?""

Point mutation in coding region of the G6PD gene (X-linked)""

367

What is the relation of polyols to sugars?""

Polyols are monosaccharides where the carbonyl group is reduced to an alcohol.""

368

What is a glycoside?""

Carbohydrate attached to non-carbohydrate structures.""

369

What is a reducing sugar?""

A monosaccharide where the anomeric carbon (Carbon 1) is free.""

370

What is the result of lack of disaccharidase activity of intestinal mucosa?""

Osmotically active disaccharides suck water out of mucosa causing osmotic diarrhea.""

371

Where is fructokinase found?""

Liver (processes most dietary fructose), kidney, small intestine""

372

Why is fructose metabolism faster than glucose metabolism?""

Bypasses PFK, major regulatory step of glycolysis.""

373

What enzyme is missing in hereditary fructose intolerance?""

Aldolase B""

374

What does aldose reductase do?""

Reduces glucose to sorbitol""

375

Where is aldose reductase found?""

Lens, retina, Schwann cells, kidney, placenta, RBCs, and gonads""

376

What does sorbitol dehydrogenase do?""

Oxidizes sorbitol to fructose.""

377

Where is sorbitol dehydrogenase found?""

Liver and gonads (ovaries, seminal vesicles, sperm)""

378

Mechanism of sorbitol toxicity""

Extra glucose freely enters cells containing aldose reductase which converts it to sorbitol. Sorbitol may not pass through, and low or absent sorbitol dehydrogenase prevents it from being changed to fructose. Strong osmotic effects lead to swelling and damage.""

379

Chondroitin Sulfate: Where found?/Distinguishing characteristic from other GAGs""

Cartilage, tendons, ligaments, aorta. Most abundant GAG in body.""

380

Chondroitin Sulfate: Use/Mechanism""

Form proteoglycan aggregates. Cartilage: Bind collagen and hold fibers in a tight, strong network""

381

Dermatan Sulfate: Where found?/Distinguishing characteristic from other GAGs""

Found in skin, blood vessels, and heart valves""

382

Keratan Sulfate: Where found?/Distinguishing characteristic from other GAGs""

Found in cartilage proteoglycan aggregates with chondroitin sulfate, and in cornea. Most heterogeneous GAG.""

383

Heparin: Where found?/Distinguishing characteristic from other GAGs""

Intracellular compound (unlike other GAGs). Found in mast cells of artery walls, especially in lungs, liver, and skin""

384

Heparin: Use/Mechanism""

Anticoagulant""

385

Heparan Sulfate: Where found?/Distinguishing characteristic from other GAGs""

Extracellular, unlike heparin. Found in basement membrane and as a ubiquitous component of cell surfaces.""

386

Hyaluronic Acid: Where found?/Distinguishing characteristic from other GAGs""

Found in synovial fluid of joints, vitreous humor f eye, umbilical cord, and loose connective tissue. Unlike other GAGs: Unsulfated, not covalently attached to protein, and only GAG not limited to animal tissue, but also found in bacteria.""

387

Hyaluronic Acid: Use/Mechanism""

Lubricant and shock absorber""

388

Hunter's Syndrome vs Hurler's Syndrome: Enzyme deficiency""

Hunter's: Iduronate sulfatase, Hurler's: alpha-L-iduronidase""

389

Hunter's Syndrome vs Hurler's Syndrome: Corneal clouding?""

Hunter's: No, Hurler's: Yes""

390

Hunter's Syndrome vs Hurler's Syndrome: Mental retardation?""

Both (Hunter's ranges from mild to severe)""

391

Hunter's Syndrome vs Hurler's Syndrome: Physical deformity?""

Hunter's: Mild to severe, Hurler's: Dwarfing, coarse facial features, (gargoylism)""

392

Hunter's Syndrome vs Hurler's Syndrome: Which GAGs' degradation is affected?""

Both: Dermatan sulfate and Heparan sulfate""

393

Hunter's Syndrome vs Hurler's Syndrome: Severity?""

Hunter's: Less Hurler's: More""

394

Hunter's Syndrome vs Hurler's Syndrome: Inheritance?""

Hunter's: X-linked Recessive, Hurler's (and all other mucopolysaccharidoses): Autosomal recessive""

395

Hunter's Syndrome vs Hurler's Syndrome: Aggressive behavior?""

Hunter's: Yes, Hurler's: No""

396

Mnemonic for Hurler's syndrome: HURLERS. What does it stand for?""

H: Hepatosplenomegaly/Heparan and Dermatan sulfate, U:Ugly facies, R: aRteries filled with GAGs, L: L-iduronidase, E: Eyes clouded, early death, R: Retardation/Respiratory obstruction, S: Short/stubby fingers""

397

I-Cell disease: Pathophysiology""

Inability of cell to phosphorylate mannose residues on glycoproteins indicating that they are lysosome bound.""

398

I-Cell disease: Presentation""

Skeletal abnormalities, restricted joint movement, coarse facial features, severe psychomotor impairment, death by 8 years""

399

Refsum Disease: Pathophysiology""

Inability to degrade phytanic acid, resulting in accumulation in plasma and tissues""