Biochem Fall 08 Ch. 17-27 (Excluding 20,21)

Front 1

All of the following are precursors for biosynthesis of BOTH purine and pyrimidine nucleotides EXCEPT
a. glutamine
b. aspartate
c. CO2
d. PRPP
e. glycine

Back 1

e. glycine

Front 2

The hyperuricemia associated with disorders such as Lesch-Nyhan syndrome and gout may result from a deficiency of the enzyme
a. glutamine synthetase
b. hypoxanthine-guanine phosphoribosyl transferase
c. PRPP synthetase
d. glutamine:PRPP amidotransferase
e. carbamoyl phosphate synthetase II

Back 2

b. hypoxanthine-guanine phosphoribosyl transferase

Front 3

Exercise helps control the symptoms and consequences of Type II diabetes because its effect on muscle is to stimulate the uptake of
a. glucose.
b. ketone bodies.
c. lactic acid.
d. VLDL.
e. calcium.

Back 3

a) glucose

Front 4

After 1 day of fasting, the major process providing fuel for the brain is
a. gluconeogenesis.
b. glycogenolysis.
c. ketone body synthesis.
d. the hexose monophosphate pathway.
e. anaerobic glycolysis.

Back 4

a) gluconeogenesis

Front 5

Hypoglycemia and lactic acidosis in the fasting state are characteristic of a deficiency of
a. glucose 6-phosphatase
b. glucokinase.
c. hexokinase.
d. muscle glycogen phosphorylase.
e. liver glycogen phosphorylase.

Back 5

a. glucose 6-phosphatase

Front 6

Which is true of the Pentose Phosphate Pathway?
a) requires an input of 1 ATP
b) requires an input of 2 ATP
c) produces 1 ATP
d) produces 2 ATP
e) produces 0 ATP

Back 6

e) produces 0 ATP. ATP isn't consumed nor produced in this pathway!

Front 7

Which of the following does not have high NADPH requirements? [NOTE: more than one answer may apply]
a) liver
b) mammary gland
c) spleen
d) adrenal cortex
e) kidney
f) adipose tissue
g) Red blood cells

Back 7

c) spleen

High NADPH requirements are going to utilize the Pentose Phosphate pathway.

*In the RBC, NADPH is required to keep glutathione in its reduced form. Glutathione is important in protecting against hemolytic anemia*

Front 8

A patient complained of painful cramps in her legs during exercise. Her patient history also revealed that she experienced easy fatigability. Which of the following are consistent with these observations?
A. The patient is diabetic
B. The patient is missing the enzyme glucose-6-phosphatase
C. The patient may have a defective debranching enzyme
D. The patient may have a defective muscle phosphorylase
E. The patient had no liver glycogen

Back 8

D. The patient may have a defective muscle phosphorylase

GLYCOGEN PHOSPHORYLASE!

Front 9

In the biosynthesis of purines the first purine derivative formed is:
A. inosine
B. inosine monophosphate
C. guanosine monophosphate
D. adenosine monophosphate
E. xanthosine monophosphate

Back 9

B. inosine monophosphate

Front 10

Enzyme distribution among tissues varies according to the function of the tissue. Which of the following is absent in muscle, but is present the liver?
A. hexokinase
B. glucose 6-phosphatase
C. lactate dehydrogenase
D. pyruvate dehydrogenase
E. glycogen phosphorylase

Back 10

B. glucose 6-phosphatase

Front 11

Which of the following statements about the pentose phosphate pathway is INCORRECT?
A. Pentoses can be formed both oxidatively and non-oxidatively.
B. This pathway is important to fatty acid synthesis because it produces reducing equivalents.
C. Fructose 6-phosphate can be used to make ribose 5-phosphate.
D. Glyceraldehyde 3-phosphate can be used to make ribose 5-phosphate.
E. NADH is formed by the action of glucose 6-phosphate dehydrogenase.

Back 11

E. NADH is formed by the action of glucose 6-phosphate dehydrogenase.

Front 12

In transamination, which amino acid is converted into oxaloacetic acid?
A. Lysine
B. Aspartic
C. Glutamic
D. Threonine
E. Methionine

Back 12

B. Aspartic

Front 13

Fructose 2,6-bisphosphate:
A. is required for gluconeogenesis.
B. synthesis is stimulated by insulin.
C. is increased by cyclic AMP.
D. inhibits phosphofructokinase.
E. stimulates fructose 1,6-bisphosphatase

Back 13

B. synthesis is stimulated by insulin.

Front 14

The rate of glycolysis is increased by:
A. insulin.
B. ATP.
C. citrate.
D. NADH.
E. glucose 6-phosphate.

Back 14

A. insulin

Front 15

An appropriate balance between AMP and GMP levels is achieved at least partly because

A. AMP, GMP and IMP inhibit the rate-limiting step of de novo synthesis.
B. the reactions after the branch point in AMP and GMP synthesis are not subject to allosteric inhibition.
C. ATP provides energy for GMP production and GTP provides energy for AMP production.
D. GMP is produced from AMP in a sequential process.
E. AMP and GMP converge to a common intermediate in their degradative pathways.

Back 15

C. ATP provides energy for GMP production and GTP provides energy for AMP production.

Front 16

Allopurinol is

A. a metabolic intermediate in the breakdown of purine nucleotides.
B. a metabolic precursor to uric acid.
C. a metabolic intermediate in the breakdown of pyrimidine nucleotides.
D. an inhibitor of xanthine oxidase.
E. a specific drug used to inhibit acetaldehyde dehydrogenase in acute alcoholism.

Back 16

D. an inhibitor of xanthine oxidase.

*Xanthine oxidase catalyzes the final step to the uric acid formation. Allopurinol is kind of like a suicide inhibitor of xanthine oxidase. It is a treatment for GOUT

Front 17

All of the molecules below are nucleosides EXCEPT which one?

A. adenosine
B. uridine
C. inosine
D. guanosine
E. thymidine

Back 17

C. inosine

Front 18

Glycogen synthase is only capable of forming _____ bonds. The glucose residue is added to the _____ end of the growing glycogen monomer.
a) 1,4 glycosidic; reducing
b) 1,4 glycosidic; non-reducing
c) 1,6 glycosidic; reducing
d) 1,6 glycosidic; non-reducing

Back 18

b) 1,4 glycosidic; non-reducing

Front 19

Jason is a 4-yeard old boy who is brought to the pediatric clinic by his father Won after an entire night of performing Dutch Rudders on each other. Jason is tired, eating poorly ("failure to thrive").

Upon examination Jason has severe hypotonia, ataxia, and choreoathetosis. His pupillary responses are poor and he has poor visual tracking with disconjugate eye movements.

His lab tests reveals the presence of a lactic acidosis. What is wrong with poor Jason?

a) Antimycin A defiency
b) Carbamoyl phophate sythetase II deficiency
c) Pyruvate Dehydrogenase deficiency
d) Glucose 6-phosphate deficiency
e) Alpha 1,4 glycosidase deficiency
f) Branching enzyme deficiency

Back 19

c) Pyruvate Dehydrogenase deficiency

Front 20

T/F
Glycogen degradation requires a primer?

Back 20

False, glycogen synthesis requires a primer (Glycogenin--has a tyrosine residue)

Front 21

Which of the following are bifunctional enzymes? (more than one answer may apply)
a) Phosphoglucomutase
b) Hexokinase
c) PDH
d) PFK-II
e) Pyruvate Kinase
f) Glucose 6 phosphatase

Back 21

'a' and 'd'
-these can work as a kinase or a phosphatase.

Front 22

1) Glycogen mobilization is [favored or unfavored] during post absorbative phase (some time after eating or if we skip a meal).

2) The insulin/glucagon ratio is going to be [high or low] if you skip a meal?

3) Is glucagon going to be high or low if you don't eat?

3) You decide to eat and your blood sugar is now high, is glycogen synthase or glycogen phosphorylase going to be high?

Back 22

1) favored
2) low
3) high
4) Glycogen synthase will be high

Front 23

What type of tree does Shaw keep using as an analogy for the high branching in glycogen?
a) Maple
b) Pine
c) Palm
d) Oak

Back 23

d) Oak

Front 24

*[think these through carefully they are important]

1) Is glycogen synthase turned on or off when phosphorylated?

2) Protein kinase-a phosphorylates glycogen phosphorylate turning it on or off? Does this favor glycogen mobilization or glycogen synthesis?

3) High levels of insulin [increase or decrease?] phosphoprotein phosphatase I, which in turn converts glycogen synthase [b to a, or a to b?] which then in turn [increases or decreases?] glycogenesis.

Back 24

1) OFF!!!
2) ON, favors glycogen mobilization

3) High levels of insulin [INCREASE] phosphoprotein phosphatase I, which in turn converts glycogen synthase [B TO A] which then in turn [INCREASES] glycogenesis.

Front 25

[*think carefully about these two it's important)
1) If you are exercising are you going to be mobilizing or synthesizing glycogen?

2) When you are exercising you are hydrolyzing ATP and it's broken down to ADP and AMP. Does this AMP increase or decrease the activity of the less active B form of glycogen phosphorylase?

Back 25

1) mobilizing
2) It INCREASES it. This is a bit tricky because you have to keep in mind we are talking about MUSCLE tissue. When you are exercising the muscle cells want to get the maximal activity out of glycogen phophorylase A which is a given because it's the most active form, but you also want to get the maximal activty out of glycogen phosphorylase B. Under those times of exercise you want all the forms (A and B) to be working.
Compare this to the LIVER, where glycogen phosphorylase B is not activated by AMP like muscle enzymes are.

Front 26

*MAKE SURE YOU KNOW THESE*
[MATCH THE LETTER WITH CORRECT NUMBER]
a) Von Gierke's disease
b) Anderson's disease
c) Pompe's disease
d) Hers' disease
e) McArdles disease
f) Cori's disease


1) deficiency of glucose 6-phosphatase in liver
2) disease of liver--glycogen phosphorylase deficiency
3) disease of muscles--glycogen phosphorylase deficiency
4) all organs-- branching enzyme deficiency
5) disease of all organs-- debranching enzyme deficiency
6) Type II lysosomal deficiency of alpha-1,4-glucosidase

Back 26

a) 1
b) 4
c) 6
d) 2
e) 3
f) 5

Front 27

T/F
The innermitochondrial membrane is permeable to NADH.

Back 27

False, impermeable. Hence the shuttling system.

Front 28

The British Journal of Pharmacology (2007) mentioned in class talks about:

a) Aging mitochondrial becoming damaged and causing a wide variety of diseases.

b) The effectiveness of treating Gout long term with Allopurinol

c) The rate of PRPP synthesis and adenylosuccinate synthetase.

d) Chronic use of artificial thymidylate drugs

Back 28

a) Aging mitochondrial becoming damaged and causing a wide variety of diseases.

NOTE: Gerontologists are the doctors that study old/aging people. Mitochondrial oxidative metabolism is important in the aging process, diabetes, and a wide variety of diseases. There are a variety of drugs that can target mitochondrial metabolism (ex: Gauchers disease)

Front 29

A person has painful cramps and muscle damage during exercise as well as elevated muscle enzymes (CK and aldolase). What disease do they have?
a) Pompes
b) Von Gierkes
c) Cori's
d) McArdles
e) Hers'
f) Andersons

Back 29

d) McArdles--they can't mobilize glycogen reserves.

Front 30

What are the cells responsible for acid secretion in the stomach?
a) Chief
b) Columnar
c) Acidotic
d) Parietal

Back 30

d) Parietal

Front 31

T/F
The Glycerol Phosphate shuttle is the simpler but less efficient shuttle only producing ~2 moleules of ATP. The malate-shuttle system is more complex and can generate ~3 molecules of ATP.

Back 31

True

Front 32

What is the first irreversible step in the Pentose Phosphate Pathway?
a) Glucose 6-phosphate dehydrogenase
b) Gluthathione reductase
c) Robonuclotide reductase
d) Glyceraldehyde 3-phosphate dehydrogenase
e) Phosphofructokinase I

Back 32

a) Glucose 6-phosphate dehydrogenase

Front 33

Which shuttle system requires the activity of FAD linked glycerol 3-phosphate dehydrogenase to donate electrons to COMPLEX II to ETC (ubiquinone)?

a) Malate
b) Glycerol Phosphate
c) Aspartame
d) Ibiquinone system

Back 33

b) Glycerol Phosphate

Front 34

A person has problems with their blood sugar and must constantly be fed even overnight including the use of a nasogastric tube to maintain blood sugar. What disease does this person have?

a) Pompes
b) Von Gierkes
c) Cori's
d) McArdles
e) Hers'
f) Andersons

Back 34

b) Von Gierkes (sometimes referred to as Nibblers disease I believe?)-this is the most common of all at 1:200,000 where glucose 6-phosphatase in the liver is defected.

Front 35

T/F
One reason we have two shuttle systems is because the Malate-Aspartate shuttle system can work even when NADH/NAD levels in the cytoplasm are low.

Back 35

False, the glycerol phosphate shuttle system can work when it's low, not the malate shuttle system.

Front 36

(referring to the Pentose Phosphate Pathway)
When cells are rapidly dividing is there going to be more of a need for Ribose 5-phosphate or NADPH? [choose one]

Back 36

Ribose 5-phosphate

Front 37

(referring to the Pentose Phosphate Pathway)
When we're making fatty acids and steroids is there going to be more of a need for Ribose 5-phosphate or NADPH? [choose one]

Back 37

NADPH

Front 38

Which of the following is not a stage in the Pentose Phosphate Pathway?
a) an irreversible oxidative phase
b) Isomerization/Epimerzation phase
c) Rearrangment Phase
d) Reducing phase

Back 38

d) reducing phase

Front 39

Which of the following is/are NOT a function of the Pentose Phosphate Pathway? [more than one answer could apply]

a) Synthesis of ATP via NADPH
b) Production of NADPH for reductive biosynthesis of fatty acids and cholesterol
c) Reduction of oxidized glutathione via NADPH
d) Nucleic acid synthesis via ribose 5-phosphate
e) Enables degradation of pentoses to glycolytic intermediates
f) Increases PDH via glutathione oxidation and NADPH

Back 39

'a' and 'f' are both false.

Front 40

T/F
A nucleoside consists of a sugar, nitrogenous base, and one or more phosphate groups.

Back 40

False, nucleotide.

A funny way to remember this difference is something I got from Examkrackers Audio Osmosis:
"Did you say nucleoside, or nucleotide? Because I thought 'nucleoside' was when you committed suicide with a nuclear weapon. Which reminds me of a story..."

[cheesy music plays]

"I knew a nitrogenous base, he took a wife named ribose, and together they had three little phosphates. Now the winter was long that year, and they lost those three little phosphates. And you know, they took that loss real hard. They committed nucleoside."

Front 41

The increased ability of DNA to absorb UV light following denaturation is known as:
a) Hyperchromic shift
b) UV spectroscopy absorption
c) UV shifting
d) Polychromatic absorption
e) Apoptosis

Back 41

a) Hyperchromic shift

-As you heat up DNA it denatures it and you expose the nitrogenous bases and they will absorb the UV light.

Front 42

Which is totally not involved in the Pentose Phosphate Pathway?
a) Glucose 6-phosphate dehydrogenase
b) 6-phosphogluconolactonase (lactonase)
c) 6-phosphogluconate dehydrogenase
d) 5-phosphogluconase

Back 42

d) 5-phosphogluconase

Front 43

T/F
Pertaining to the Pentose Phosphate Pathway, an epimerase enzyme converts Ribulose 5-phosphate to Xylulose 5-phosphate, and an isomerase enzyme converts Ribulose 5-phosphate to Ribose 5-Phosphate.

Back 43

True

Front 44

Which is/are false concerning the Pentose Phosphate Pathway? [more than one answer could apply]

a) Transketolase transfers a 2 carbon unit from of a ketose to an aldose
b) Transaldolases move 3 carbon units from a aldose to a ketose
c) Production of NADPH and reduced glutathione may provide protection from cancer and maintain RBC membrane.
d) Defects in glucose 6-phosphate dehydrogenase could cause hemolytic anemia.
e) The Pentose Phosphate Pathway was first identified in Bacteria

Back 44

b) Transaldolases move 3 carbon unit from a aldose to a ketose

This is wrong in two ways because transaldolases are going to move 3 carbon FRAGMENTS from a KETOSE TO ALDOSE. Aldoses are always acceptors, while ketoses are always donors.

Front 45

T/F
When the nitrogenous base is Adenine, the nucleoside is Adenylic Acid.

Back 45

False
-When the nitrogenous base is Adenine, the nucleoside is Adenosine. When the nitrogenous base is Adenine, the nucleotide is Adenylic Acid.

Front 46

Purines have __ atoms in their double unsaturated ring structure and the numbering system goes ____.
a) 6, clockwise
b) 6, counterclockwise
c) 9, clockwise
d) 9, counter clockwise
e) 11, clockwise
f) 11, counter clockwise

Back 46

d) 9, counter clockwise

Front 47

T/F
Purine bases are metabolized to Uric Acid.

Back 47

True, if this accumulates you get Gout!

(in other words, Uric acid is the final product of purine degradation, and is excreted into the urine)

Front 48

Which is/are not an example of a Cyclic AMP phosphodiesterase inhibitor?
a) Caffeine
b) Choline
c) Pseudofed
d) Theophylline
e) a and b
f) c and d
g) b and c

Back 48

g) b and c

-Caffeine and Theophylline inhibit the enzyme that breaks down cyclic AMP, causing an increase in cyclic AMP levels.

Front 49

Which is a drug that is isolated from sponges on the bottom of the ocean and can be incorporated and phosphorylated inside cells and can be used to inhibit cell replication?
a) Tyrosine
b) Adenine Nulonside
c) Cytosine Arabinoside
d) Flourouracil
f) 6-mercaptopurine

Back 49

c) Cytosine Arabinoside

Front 50

What is the enzyme that joins nucleotides together?
a) RNA monomerase
b) DNA polymerase
c) DNA monomerase
d) DNA helidesmosomes

Back 50

b) DNA polymerase

Front 51

T/F
The classic secondary messenger is produced slowly, active in large amounts, and is a specific pathway for the removal of the secondary messenger.

Back 51

False- The classic secondary messenger is produced RAPIDLY, active in SMALL amounts, and is a specific pathway for the removal of the secondary messenger.

Front 52

T/F
Nucleotides have many roles, one such role is the involvement in signal transduction and chemical messenging.

Back 52

True

Front 53

Back in the day scientists fed radiolabeled isotopes to rats and pigeons and examined radiolabeled uric acid and this allowed us to know the origins of various things. Back in the day, who were responsible for the sequence of enzyme formation of IMP?
a) Wallace and Sheers
b) Smith and Black
c) Buchanan and Greenberg
d) Morey and Klein

Back 53

c) Buchanan and Greenberg

Front 54

Which is always required for both purine and pyrimindine biosynthesis?
a) PRPP
b) AMP
c) GTP
d) PPT
e) G6P

Back 54

a) PRPP
*for the exam you don't have to know the really, really long words.

Front 55

What is the committed ('rate-limiting') step in purine nucleotide biosynthesis?
a) Adenylsuccinate synthetase
b) IMP dehydrogenase
c) PRPP glutamyl amidotransferase
d) Adenine phosphoribosyltransferase
e) HGPRT

Back 55

*c) PRPP glutamyl amidotransferase

Front 56

Which of the following catalyzes salvage reactions in purine synthesis but if absent can lead to Lesch-Nyhan syndrome?
a) Adenylsuccinate synthetase
b) IMP dehydrogenase
c) PRPP glutamyl amidotransferase
d) Adenine phosphoribosyltransferase
e) HGPRT

Back 56

e) HGPRT (hypoxanthine-guanine phosphoribosyltransferase)

*OTHER IMPT INFO
-Symptoms: self mutilating behavior, bites lips and nails (sometimes fingers need amputated from biting nails so low)
-POOR prognosis
-Rarely reach 30 or 40 yrs of age (kidney problems)
-X linked and more common in MEN

Front 57

Purine biosynthesis is a 10 step energy intensive process ongoing in the CYTOPLASM using __ ATP to synthesize ___.
a) 3, GTP
b) 3, IMP
c) 6, GTP
d) 6, IMP
e) 3, AMP
f) 6, AMP

Back 57

d) 6, IMP

Front 58

In purine biosynthesis, which steps are catalyzed by multifunctional proteins (a single polypeptide chain with more than one catalytic activity)?
a) 1, 2, 4
b) 3, 5, 9
c) 2,3, 5
d) 3, 4, 7

Back 58

d) 3, 4, 7

-It is not uncommon in biochemistry for multifunctional proteins to work together to increase catalytic efficiency.

Front 59

What is the starting material in Purine biosynthesis?
a) Ribulose 5-phosphate
b) Ribose 5 phosphate
c) PRPP
d) Glucose 6-phosphate
e) Glucose

Back 59

b) Ribose 5 phosphate

*This comes from the Pentose phosphate pathway

Front 60

In purine biosynthesis, after IMP formation the pathways split: one towards ___ and the other towards ___.
a) AMP, GMP
b) AMP, ADP
c) GMP, ATP
d) ADP, ATP
e) GDP, AMP

Back 60

a) AMP, GMP


*IF AMP and GMP levels are high, this will inhibit purine nucleotide synthesis (because they are the end products of the pathway)

Front 61

T/F
Uric acid is the end product of purine nucleotide metabolism, but ideally you don't want this to happen. To help avoid this you can salvage these purine nucleotides.

Back 61

True

-Salvage reactions are like recycling: you can take an existing base or whatever and you can add on a sugar or phosphate group etc without having to start from scratch (de novo).

Front 62

Pyrimidine nucleotide biosynthesis of UMP requires ___ steps and an input of energy in the form of ___ ATP.

a) 9, 3
b) 9, 6
c) 6, 6
d) 6, 3
e) 6, 1

Back 62

d) 6, 3

Front 63

Which of the following enzymes is involved in the committed step in mammals for pyrimidine biosynthesis?
a) Aspartate transcarbamoylase
b) Uridine monophosphase
c) Dihydroroorotase
d) Phosphoribosyl transferase
e) carbamoyl phosphate synthetase II

Back 63

e) carbamoyl phosphate synthetase II
^CYTOSOLIC

Front 64

T/F
In pyrimidine biosynthesis, the methylation of dUMP to dTMP is catalyzed by thymidylate synthase

Back 64

True

-This is done using N^5,N^10-methylene-tetrahydrofolate as the methyl group donor and a source of reducing equivalents.

Front 65

All of the following statements are true except:

a) In purine biosynthesis, you start with Ribose first and then the base is constructed around a N coming from glutamine.
b) Anticancer drugs target pyrimidine biosynthesis notably thymidylate synthetase
c) Methotrexate inhibits dihydrofolate reductase
d) In pyrimidine synthesis you start with Ribose 5-phosphate then the ring is added.
e) Uracil is the precursor of both cytosine and thymine.

Back 65

d) In pyrimidine synthesis you start with Ribose 5-phosphate then the ring is added.

-This is false because in pyrimidine synthesis the ring is synthesized first and then the sugar ribose 5-phosphate is added.

Front 66

Regarding Gout, which of the following is/are NOT true: [NOTE: more than one answer may apply]

a) 70-80% of gout deals with the joint of the big toe
b) ~10% of people with hyperuricemia are asymptomatic
c) The diagnostic gold standard of diagnosing gout is enlarged joints seen via x-ray
d) gout can be caused from purines in our diet such as liver, fish, and red wine
e) uric acid levels of 7-8 mg/dL can preciptiate out
f) Syndrome X is a term used to describe individuals suffering with an unknown form of arthritis
g) The number one goal of the clinician is to reduce the pain of the gout sufferer.

Back 66

b,c, and f are all false.

- ~95% are asymptomatic

-the diagnostic gold standare of diagnosing gout is the aspiration of the fluid from the painful joint.

-Syndrome X (metabolic syndrome)-individuals suffering from this are overweight, hyperuricemic, hypertension, diabetes, and elevated levels for LDL

Front 67

When Thymine is the nitrogenous base, the nucleotide is called:
a) Thymidine
b) Thymidylic acid
c) deoxythymidine
d) deoxythymidylic acid

Back 67

d) deoxythymidylic acid

(this is the tricky one to remember of the nitrogenous bases)