Biochem 2 Exam 1

Bile salts are critical to the initial stages of digestion of triacylglerols in the duodenum because they:

a. form ester bonds between fatty acids and glycerol

b. emulsify the triacylglycerol globules to have a greater surface area, which increases lipase activity

c. activate cleavage at the C-2 position

d. act as coenzymes in catalysis

e. are enyzmes that break down triacylglycerols into fatty acids

Bile salts are critical to the initial stages of digestion of triacylglerols in the duodenum because they:

a. form ester bonds between fatty acids and glycerol

b. emulsify the triacylglycerol globules to have a greater surface area, which increases lipase activity

c. activate cleavage at the C-2 position

d. act as coenzymes in catalysis

e. are enyzmes that break down triacylglycerols into fatty acids

b. emulsify the triacylglycerol globules to have a greater surface area, which increases lipase activity

Fatty acids (FAs) have advantages over saccharides as energy storage structures. FAs are not generally hydrated as are monosaccharides and polysaccharides. What is an important advantage of this feature?

a. all FAs can be reduced but saccharides can never be reduced

b. FAs are typically unsaturated

c. FAs can pack more closely in adipose tissue

d. FAs are always shorter in length

e. none of the above

c. FAs can pack more closely in adipose tissue

Where does digestion of lipids begin?

a. small intestine

b. stomach

c. pancrease

d. gall bladder

e. esophagus

b. stomach

What type of reaction takes place when NADPH is used in a metabolic pathway?

a. hydration

b. none of these

c. reduction

d. dehydration

e. esterification

c. reduction

What is the primary product of the action of pancreatic lipase on triacylglycerols?

a. an amino acid

b. glycerolphosphorylcholine

c. 2-monoacylglycerol

d. a phospholipid

e. cholesterol

c. 2-monoacylglycerol

What is the function of cholecystokin (CCK)?

a. it's a hormone that regulates blood pressure

b. it's an enzyme that catalyzes lipid degradation

c. it's a hormone that regulates cholesterol formation

d. acts on the gallbladder to release bile

e. acts on the pancrease to release chymotrypsin

d. acts on the gallbladder to release bile

What are the primary three most common ketone bodies?

a. acetoacetate, hydroxyacetone phosphate, α-butyrate

b. acetone, α-hydroxybutyrate, acetoacetate

c. acetone, β-hydroxybutyrate, acetoacetate

d. acetone, acetyl-CoA, acetoacetate

e. acetone, butyrate, acetyl-CoA

c. acetone, β-hydroxybutyrate, acetoacetate

What makes a fatty acid unsaturated?

a. presence of ester bonds

b. presence of a hydrophobic "tail"

c. none of the above

d. presence of one or more double bonds

e. presence of a carboxyl group

d. presence of one or more double bonds

What is the primary product of the fatty acid synthase pathway?

a. NADPH

b. linoleic acid

c. citrate

d. malonyl-CoA

e. palmitate

e. palmitate

Where does fatty acid (β-oxidation) take place?

a. mitochondria

b. peptidoglycan layer

c. adipose tissue

d. lymph nodes

e. lipid bilayer

a. mitochondria

When beta-oxidation (FA degradation) takes place, a fragment is removed from the carboxyl end of the fatty acyl-CoA. How many carbons are removed in the fragment?

a. five

b. two

c. one

d. four

e. three

b. two

In uncontrolled diabetes mellitus I, the formation of what type of compound is formed?

a. ketone body

b. phytanic acid

c. fatty acids

d. glycerol

e. acetate

a. ketone body

Which of the following has the highest concentration of triacylglerol?

a. HDL

b. LDL

c. lipases

d. VLDL

e. chylomicrons

e. chylomicrons

What enzyme functions as a major control point for cholesterol synthesis?

a. HMG-CoA reductase

b. acyl-CoA dehydrogenase

c. acetyl-CoA carboxylase

d. SREBP-2

e. pancreatic lipase

a. HMG-CoA reductase

Why is the carnitine shuttle important for fatty acid degradation?

a. it's not important for fatty acid degradation

b. it's required for transport of long chain fatty acids from the cytosol to the mitochondrial matrix

c. it's requred for transport of short chain fatty acids from the mitochondrial matrix to the cytosol

d. it's required for transport of short chain fatty acids from the cytosol to the mitochondrial matrix

e. carnitine is a substance found in meat

b. it's required for transport of long chain fatty acids from the cytosol to the mitochondrial matrix

The reaction of aminotransferase is reversible between α-ketoglutarate and glutamate

a. True

b. False

a. True

In the Urea Cycle, Carbamoyl Phosphate Synthetase I has which of the following as an absolute requirement for activation?

a. N-acetylglutamate

b. N-acetylglutamine

c. Glutamate

d. Fumarate

e. It does not need to be activated

a. N-acetylglutamate

Which of the following pairs of amino acids are considered "purely" ketogenic?

a. Lysine and Asparagine

b. Leucine and Isoleucine

c. Valine and Leucine

d. Tryptophan and Alanine

e. Lysine and Leucine

e. Lysine and Leucine

What vitamin B6 coenzyme is required in the conversion of α-ketoglutarate to glutamate?

a. Pyrodoxal phosphate

b. Coenzyme Q

c. Vitamin B12

d. Biotin

e. Pyrodoxine

a. Pyrodoxal phosphate

Which compound crosses the mitochondrial membrane and enters the cytosol in the urea cycle?

a. Citrulline

b. Ornithine

c. Carbamoyl phosphate

d. Arginine

e. Fumurate

a. Citrulline

Which amino acid is a precursor for the synthesis of dopamine?

a. Proline

b. Histidine

c. Tryptophan

d. Arginine

e. Tyrosine

e. Tyrosine

Glutamine Synthetase catalyzes what reaction?

a. It utilizes ADP to convert glutamate to glutamine

b. It combines ammonia with glutamate to form glutamine

c. It catylizes the reaction between glutamate and a-ketoglutarate

d. It removes ammonia from glutamine to form glutamate

e. It combines ammonia with ATP

b. It combines ammonia with glutamate to form glutamine

Which of the following is NOT an enzyme involved in peptide cleavage?

a. Carboxypeptidase B

b. Chymotrypsin

c. Elastase

d. Trypsin

e. Trypsinogen

e. Trypsinogen

Which amino acid is a precursor for the synthesis of serotonin?

a. Tyrosine

b. Serine

c. Phenylalanine

d. Tryptophan

e. Histidine

d. Tryptophan

Which amino acid is a precursor for the synthesis of epinephrine?

a. Tyrosine

b. Serine

c. Tryptophan

d. Proline

e. Histidine

a. Tyrosine

Glutamate Dehydrogenase uses what coenzyme for the oxidative deamination of glutamate?

a. It utilizes only NADP+

b. It utilizes only NAD+

c. It utilizes ether NAD+ or NADP+ as an electron acceptor

d. It does not require any cofactors

e. It is an amine acceptor

c. It utilizes ether NAD+ or NADP+ as an electron acceptor

At which point does Tyrosine enter the TCA cycle?

a. Pyruvate

b. Acetoacetate

c. Oxaloacetate

d. Succinate

e. Fumarate

e. Fumarate

In the urea cycle what is arginine cleaved into?

a. Ammonia and Carbon Dioxide

b. Citrulline and Ornithine

c. Urea and Glutamate

d. Urea and Carbon Dioxide

e. Urea and Ornithine

e. Urea and Ornithine

Ammonia is produced by all tissues. All of the following are sources of ammonia EXCEPT:

a. Gluconeogenesis

b. Amines

c. Bacteria in the intestine

d. Glutamine

e. Purines

a. Gluconeogenesis

Serotonin is derived from which amino acid?

a. Tryptophan

b. Tyrosine

c. Phenylalanine

d. Isoluecine

e. Histadine

a. Tryptophan

Which is not a common lipid?

a. Phospholipid

b. Cholesterol

c. Steroid

d. Gastric lipase

d. Gastric lipase

The pentose pathway is the primary source of NADPH for fatty acid synthesis. What other reaction supplies NADPH?

a. Conversion of ribulose-5-phosphate to 6-phosphate

b. Conversion of lactate to pyruvate

c. Conversion of malate to pyruvate

d. Conversion of malate to oxaloacetate

c. Conversion of malate to pyruvate

Which of the following does NOT contain a fatty acid component?

a. Pancreatic lipase

b. Sodium palmitate

c. Phosphatidylcholine

d. Cholesterol ester

a. Pancreatic lipase

CAT-I is inhibited by:

a. Malonyl-CoA

b. Succinyl-CoA

c. Glucagon

d. Palmitoyl-CoA

a. Malonyl-CoA

HMG-CoA reductase is indirectly activated by:

a. Sterols

b Epinephrine

c. Glucagon

d. Insulin

d. Insulin

Enzyme that cleaves the peptide bond before lysine:

a. trypsin

b. elastase

c. chymotrypsin

d. carboxypeptidase B

d. carboxypeptidase B

Which of the following is an amino acid in the urea cycle?

a. fumarate

b. arginase

c. ornithine

d. lysine

c. ornithine

A side effect of PKU, hence the name, is the presence of ___________ in urine.

a. phenylpyruvate

b. phenylalanine hydroxylase (PAH)

c. tyrosine

d. acetoacetate

a. phenylpyruvate

Progesterone is synthesized from:

a. cholesterylesters

b. cortisol

c. pregnenolone

d. testosterone

c. pregnenolone

Which of the following is NOT used in beta oxidation?

a. NADPH

b. FAD

c. H2O

d. NAD+

a. NADPH

Type I diabetes can result in ketoacidosis. All of the following can be an explanation for a high level of ketone bodies EXCEPT:

a. high levels of free fatty acids in blood

b. over production of HMG-CoA

c. carnitine deficiency

d. too much acetyl-CoA produced by liver

c. carnitine deficiency

Process by which an amine is removed as free ammonia while producing an alpha-keto acid:

a. peptidase cleavage

b. transamination

c. reductive amination

d. oxidative deamination

d. oxidative deamination

Why is lactic acidosis expected in individuals with dihydrolipoyl dehydrogenase (E3)-deficient maple syrup urine disease?

a. BCAAs are catabolized primarily by peripheral tissues where lactate increases

b. BCKD causes an accumulation of ketogenic BCAAs

c. oxidative decarboxylation of leucine leads to alpha-ketoisocaproic acid

d. lactate increases because of reduced activity of PDH complex

d. lactate increases because of reduced activity of PDH complex

N-acetylglutamate (NAG) serves what function in the urea cycle?

a. it is a coenzyme for glutamate dehydrogenase

b. it degrades into acetyl-CoA and glutamate

c. it is an allosteric activator of carbamoyl phosphate synthetase I (CPS I)

d. it is an allosteric activator of glutamine synthetase

c. it is an allosteric activator of carbamoyl phosphate synthetase I (CPS I)

What is the preferred substrate for hormone-sensitive lipase?

a. glycerol-3-phosphate

b. triacylglycerol

c. acetyl-CoA

d. diacylglycerol

d. diacylglycerol

What are the primary products of the action of pancreatic lipase on phosphatidylcholine?

a. glycerol and 3 fatty acids

b. 2-monoacyl glcycerol and 2 fatty acids

c. glycerylphosphoryl-choline and 2 fatty acids

d. glycerylphosphoryl-choline and 1 fatty acid

c. glycerylphosphoryl-choline and 2 fatty acids

Synthesis of heme begins with:

a. poryphobilinogen

b. glycine and succinyl-CoA

c. histidine and acetyl-CoA

d. histidine and succinyl-CoA

b. glycine and succinyl-CoA

What are the steps in beta oxidation?

a. oxidation hydration oxidation transferase

b. oxidation dehydration reduction transferase

c. reduction hydration reduction lyase

d. oxidation lyase oxidation ligase

a. oxidation hydration oxidation transferase

Enzyme that cleaves before arginine:

a. trypsin

b. carboxypeptidase B

b. carboxypeptidase B

The term ketogenic amino acids implies:

a. will not be converted either to fatty acids or ketone bodies

b. can yield acetoacetate or acetyl-CoA after degradation

c. can yield pyruvate, alpha-ketoglutarate, and oxaloacetate

d. are precursors for the synthesis of glucose

b. can yield acetoacetate or acetyl-CoA after degradation

Pyruvate can be formed by the removal of an amino group from which of the following amino acids?

a. alanine

b. glycine

c. aspartate

d. glutamate

a. alanine

Deficiency of tyrosine hydroxylase could result in _____ deficiency:

a. serotonin

b. tyrosine

c. dopamine

d. fumarate

c. dopamine

Lipoprotein with the highest level of triacylglycerol:

a. VLDL

b. HDL

c. LDL

d. chylomicrons

d. chylomicrons

This is NOT a ketone body produced from beta oxidation of fatty acids:

a. acetone

b. acetoacetate

c. beta-hydroxybutyrate

d. acetate

d. acetate

In the following reaction, which component is the reducing agent?

Oxaloacetate + NADH --> Malate + NAD+

a. oxaloacetate

b. NADH

c. NAD+

d. malate

b. NADH

An essential amino acid:

a. valine

b. proline

c. glutamate

d. glutamine

a. valine

Which of the following pancreatic enzymes cleaves a peptide after serine?

a. carboxypeptidase A

b. trypsin

c. elastase

d. chymotrypsin

c. elastase

Which of the following is NOT a common transamination pair?

a. aspartate/oxaloacetate

b. alanine/pyruvate

c. tyrosine/fumarate

d. glutamate/alpha-ketoglutarate

c. tyrosine/fumarate

Creatine is synthesized from:

a. creatinine and ATP

b. succinyl-CoA and glycine

c. arginine and glycine

d. guanidnoacetate and ATP

c. arginine and glycine

Heme is synthesized from what two precursors?

a. histidine and iron

b. conjugated bile and iron

c. glycine and succinyl-CoA

d. porphobilinogen and iron

c. glycine and succinyl-CoA

Branched-chain amino acid that is strictly ketogenic:

a. lysine

b. valine

c. isoleucine

d. leucine

d. leucine

Which of the following is FALSE regarding ketone bodies?

a. during prolonged starvation, the brain adapts to using ketone bodies as fuel

b. excess acetone during ketoacidosis is exhaled

c. ketone bodies can be used as a carbon source for fatty acid synthesis

d. ketone bodies can be converted into glucose during ketosis for energy

d. ketone bodies can be converted into glucose during ketosis for energy

Which is NOT required for fatty acid synthesis?

a. HCO3- (CO2)

b. NADH

c. malanyl-CoA

d. biotin

b. NADH

Bile acids are derived from:

a. cholesterol

b. sphingomyelin

c. phosphatidyl-choline

d. biliverdin

a. cholesterol

In the reaction: lactate + NAD+ --> pyruvate + NADH, which compound is being reduced?

a. lactate

b NAD+

c. pyruvate

d. NADH

b NAD+

Which compound is NOT transported across the inner mitochondrial membrane in neither urea cycle nor aspartate-arginosuccinate shunt?

a. fumarate

b. aspartate

c. ornithine

d. citrulline

a. fumarate

Which of the following is NOT true regarding pepsin?

a. it is a hydrolase

b. it is highly active at neutral pH

c. it is a lyase

d. it is secreted in response to protein ingestion

b. it is highly active at neutral pH

Amino acid involved in the synthesis of dopamine:

a. phenylalanine

b. tyrosine

c. histidine

d. tryptophan

b. tyrosine

Lipid commonly present in lung surfactant of healthy individuals:

a. ceramides

b. leukotrienes

c. dipalmitoyl-phosphatidyl-choline

d. phosphatidyl-inositol

c. dipalmitoyl-phosphatidyl-choline

Synthesis of malonyl-CoA from acetyl-CoA is MOST similar to what other reaction?

a. conversion of malate to fumarate

b. conversion of pyruvate to acetyl-CoA

c. conversion of phosphoenolpyruvate to 2-phosphoglycerate

d. conversion of pyruvate to oxaloacetate

d. conversion of pyruvate to oxaloacetate

Which statement is FALSE regarding the regulation of HMG-CoA reductase?

a. inhibited by phosphorylation

b. inhibited by elevated levels of ATP

c. competitively inhibited by statin-based drugs such as pravastatin

d. indirectly inhibited by elevated blood glucose

b. inhibited by elevated levels of ATP

Which amino acid is essential?

a. alanine

b. asparagine

c. serine

d. lysine

d. lysine

Methyl donor necessary to convert norepinephrine to epinephrine:

a. tyrosine hydroxylase

b. tetrahydrobiopterin (BH4)

c. S-adenosylmethionine (SAM)

d. tetrahydrofolate (THF)

c. S-adenosylmethionine (SAM)

Nitrogenous waste in mammals is eliminated as:

a. ammonia

b. urea

c. purines

d. both ammonia and urea

d. both ammonia and urea

Carbamoyl phosphate synthetase I is allosterically acivated by:

a. glutamate

b. N-acetylglutamate

c. acetyl-CoA

d. ammonia

b. N-acetylglutamate

Cholesterol is synthesized from:

a. acetyl-CoA

b. LDLs

c. cholecalciferol

d. malonyl-CoA

a. acetyl-CoA

PKU, alkaptonuria, and Parkinson's are all connected by the metabolism of:

a. leucine

b. tryptophan

c. alanine

d. phenylalanine

d. phenylalanine

which is not a common lipid?

a. phospholipid

b. cholesterol

c. steroid

d. gastric lipase

d. gastric lipase

which of the following does not contain a fatty acid component?

a. pancreatic lipase

b. sodium palmitate

c. phosphatidylcholine

d. cholesteryl ester

a. pancreatic lipase

enzyme that cleaves the peptide bond before lysine:

a. trypsin

b. elastase

c. chymotrypsin

d. carboxypeptidase-b

d. carboxypeptidase-b

deficiency of tyrosine hydroxylase could result in _____________ deficiency:

a. serotonin

b. tyrosine

c. dopamine

d. fumarate

c. dopamine

a nonessential amino acid that is both ketogenic and glycogenic:

a. tyrosine

b. alanine

c. isoleucine

d. lysine

a. tyrosine

pancreatic enzyme that cleaves a peptide after glycine:

a. trypsin

b. elastase

c. carboxypeptidase b

d. carboxypeptidase a

b. elastase

an essential fatty acid:

a. oleic acid

b. TAG

c. linoleic acid

d. arachidonic acid

c. linoleic acid

beta oxidation of odd-numbered carbons results in production of acetyl-coa and ___________.

propionyl coa

pyrodroxal phosphate (PLP) is a coenzyme required for:

a. oxidative deamination

b. aminotransferase

c. succinylcholine

d. beta oxidation

b. aminotransferase

which of these is not a common nonessential amino acid synthesis combination?

a. pyruvate/alanine

b. oaa/aspartate

c. a-ketoglutarate/glutamate

d. malate/oaa

d. malate/oaa

what reactants are needed in the first step in the urea cycle?

a. alanine + pyruvate

b. bicarb + ammonia

c. bicarb + ammonium

d. succinyl coa + glycine

b. bicarb + ammonia

fatty acid synthase is stimulated by:

a. insulin

b. glucagon

c. catecholemines

d. PLP

a. insulin

enzyme that covers diacylglycerols to monoacylglycerols:

a. ATGL

b. CCK

c. HSL

d. HMG CoA reductase

c. HSL

aspartate is formed from the deamination of:

a. arginine

b. aspartic acid

c. alanine

d. succinate

a. arginine

The main storage of lipids is ______ in ________

a. chylomicrons; adipocytes

b. cholesterol; liver

c. tag; liver

d. steroid; adipose tissue

c. tag; liver

which of the following is not a product of beta oxidation?

a. nadph

b. nadh

c. acteyl coa

d. fadh

a. nadph

Ornithine is not found in proteins but has three important metabolic roles. What is one of the functions of ornithine?

a. leaves mitochondrial matrix in urea cycle

b. transanimates into arginine

c. enters mitochondrial matrix in urea cycle

d. coenzyme for CPS-I

c. enters mitochondrial matrix in urea cucle

a nonessential amino acid derived from phenylalanine:

a. alanine

b. serine

c. proline

d. tyrosine

d. tyrosine

compound that allows fatty acids to cross into the mitochondrial matrix:

a. cat-1

b. cat-2

c. protein channels

d. lipid channels

b. cat-2

acts on the pancreas to release bicarb:

a. albumin

b. secretin

c. bile salts

d. pancreatic lipase

b. secretin

lipoprotein with the highest level of triacylglycerol:

a. HDL

b. VLFA

c. LDL

d. chylomicrons

d. chylomicrons

rate-limiting enzyme in cholesterol synthesis:

a. HMG CoA reductase

b. HMG CoA synthetase

c. CCK

d. chylomicrons

a. HMG CoA reductase

process by which an amine is removed as free ammonia while producing an alpha keto acid:

a. transamination

b. urea cycle

c. oxidative deamination

d. beta oxidation

c. oxidative deamination

aka. aminooxidation