Biochem Final
Identify the rate limiting enzyme in heme biosynthesis
&-aminolevulinic acid synthase (&-ALA synthase)
Which of the following enzyme is the rate-limiting enzyme for cholesterol biosynthesis
Catalyzed by acetyl CoA carboxchylomicrons
Which pair of vitamins participates in oxidation-reduction type of biochemical reactions?
Niacin and Riboflavin
Amino acid catabolism involves the breakdown of 20 amino acids all of which contain nitrogen but have different carbon skeletons. What overall strategy is used to deal with this problem
Nitrogen is removed by transamination to glutamate
What is the function of hormones in a lipoprotein lipase enzyme
Hydrolysis of triacylglycerols of plasma lipoprotein to supply free fatty acid to various tissue
Which of the following form of cobalamin is used to store it within the cytosol?
Hydroxycobalamin
which is the storage of vitamin B12 within the cytosol before it is converted to its active cofactor form?
Hydroxycobalamin
Used to esterify fatty acid to form triacyl
Hydroxyl group
Which of the following compounds is the first nucleotide produced during purine biosynthesis?
IMP
Which of the following statements is NOT TRUE
In skeletal muscle and heart, glucose cannot be completely oxidized nor it can be stores as glycogen.
What inhibits fatty acid biosynthesis
Increase in the cytosolic palmitic acid concentration
What is the function of glucagon during fasting condition?
Increases blood glucose level
What effects the statins on cholesterol biosynthesis pathway?
Inhibits HMG-CoA reductase
Which is one of the crucial function of prostacyclin
Inhibits platelet aggregation
Cellular uptake of glucose can be enhanced by
Insulin
What are the effects of a conjugation of bile salts with glycine
It decrease the pKa values of the bile salts, and make them more soluble and better detergent
What is the function of ferrochelatase?
It incorporates Fe2+
What is the effect of citrate on fatty acid biosynthesis?
It is an allosteric activator in fatty acid biosynthesis pathway
What is/are TRUE of vitamin E?
It prevents lipid peroxidation It protects tissues from oxidative damage it is an antioxidant ALL OF THE ABOVE ARE TRUE
What is the metabolic benefit of methionine synthase catalyzed conversion of homocysteine to methionine?
It regenerates methylcobalamin and maintains a store of tetrahydrofolate
What is the metabolic significance of the conversion of homocysteine to methionine
It regenerates methylcobalamin and maintains a store of tetrahydrofolate
What would be the impact of the presence of high levels of arginine above normal conditions on urea synthesis?
It will increase the synthesis of N-acetyl glutamate
What would be the effect of aspirin during an active inflammatory cascade in human systems
It would inhibit prostaglandin biosynthesis
Catabolism of which of the following types of amino acid produces acetyoacetyl-CoA
Ketogenic
Which of the following conditions can produce a negative nitrogen balance in humans
Kwashiorkor
Which of the following lipoproteins function as a carrier or act as a repository of apoprotein CII and apoprotein E for other nascent lipoprotein
LDL
Which of the pathways is involved in the synthesis of leukotrienes
Lipoxygenase pathway
Which of the following tissue can only supply glucose to the blood?
Liver
Which tissue contributes glucose to the blood?
Liver
what tissue can use lactate for gluconeogenesis?
Liver
Which condition activates the release of SREBP from SREBP SCAP and enhances cholesterol biosynthesis
Low Level cholesterol
Pantothetic acid or vitamin B5 is an integral component of?
Acyl carrier protein (ACP)
What is used to activate phosphatic acid conversion in two various phospholipids
CTP
A defect in which of the following enzymes can result in alcaptouria
Homogentisate oxidase
Dietary tryptophan deficiency could be one of the cause of ____
Niacin Deficiency
Which of the following pairs is NOT a correct match?
***Menaquinone-7 and Vitamin E Lipid peroxidation and Vitamin E Retinolic Acid and Viamin A A a Hydroxylase and Vitamin D Vitamin K and prothrombin
Which condition/vitamin deficiency is a correct match?
***Xeropthalmia/Vitamin A Hemorrhage/vitamin D Night blindness/vitamin E Hemolysis of red blood cells/VitaminA
Dietary tryptophan deficiency could be one of the cause of?
Niacin Deficiency
Which could be one of the major causes of thiamin deficiency?
A decreased in thiamin phosphate kinase catalyzed reaction
How many Isoprene units are required to produce one molecule of cholesterol
6
Which is the precursor for the biosythesis of the active vitamin D3 in humans?
7-Dehydrocholesterol
A defect in which of the following enzymes would lead to an inability to produce primary bile salts
7-alpha-hydroxylase
How many cycle of Beta-oxidation are required for complete oxidation of activated steatic acid
8 Cycle
How many total molecules of acetyl-CoA can be generated through one complete cycle of Beta-oxidation of one molecule of palmitic acid
8 Molecule
LCAT major component of which of the following lipoprotein
ADL
Which of the following provides energy formation of carboxybiotin in fatty acid biosynthesis
ATP
Which of the following is (are) required to synthesize carbamoyl phosphate in the urea cycle
ATP Bicarbonate Ammonium ion ALL OF THE ABOVE
Which of the following could be the precursors for the biosynthesis of PRPP?
ATP and Ribose 5-phosphate
The common compound generated during the oxidation degradation of fatty acids and glucose is?
Acetly CoA
"Ketone Bodies"
Acetoacetate
Which of the following functional group is transferred during esterification of cholesterol?
Acyl
Beta oxidation fatty acid enzyme in correct order
Acyl CoA dy, Enoy CoA hy, Beta-hydro, thiolase
A free form of a large chain of fatty acid 16C is activated for its catabolism. Which of the following enzymes is required for its activation before the fatty acid is ready to enter its catabolic pathway
Acyl CoA synthetase
Which of the following moiety in fatty acid synthase complex directly associated with vitamin B5 contains a sulfhydryl group
Acyl carrier protein
Panthothenic Acid or vitamin B5 is an integral component of?
Acyl carrier protein (ACP)
Which isoform of vitamin A is produced when rhodopsin is bleached?
All trans-retinal
Which of the following compounds is required to synthesize citrulline from omithine
Carbamoyl phosphate
Chain larger than 14-carbon atom
Carnitine
Which of the following apoprotein guides the chylomicron remnants and acts as ligand for LDL-receptors leading to receptors-mediated endocytosis
ApoE
Which of the following enzymes of the urea cycle finally catalyzes the release of urea
Arginase
Mary's diet is very high in protein and fats, but very low in carbohydrates. Mary was on this diet for about three weeks. In which form the excess amino acids being consumed by Mary can be stored within the body? Consider in this case the amino acids obtained from the protein degradation are utilized to synthesize new molecules.
As liver glyccogen
Which of the following vitamins has the ability to decrease lipid peroxidation?
Ascorbic Acid
Which water soluble vitamin can produce toxicity if taken in excessive quantities that is more than 1 gram per day for several weeks?
Ascorbic Acid
Which vitamin B is used for carboxylation of pyruvate to form acetyl coA?
Ascorbic acid
Which of the following compounds incorporates second nitrogen atom of urea in urea cycle
Aspartate
Which of the following drugs is an irreversible inhibitor of the enzyme cyclooxygenase
Aspirin
What is the major function of ApoB 100 and ApoB 48
Assembly and secretion of triacylglycerols and cholesterols
Presence of which of the following prevents biotin absorption through the interstinal epithelial cells?
Avidin
Presence of which of the following prevents biotin absorption through the intestinal epithelial cells?
Avidin
Which of the following forms of Vitamin A is available in certain vegetables and orange fruits, like spinach, carrots, ripe papaya, and ripe mangoes?
B-Carotene
Thiamin deficiency can cause?
Beriberi
which of the following compounds is a degraded product of heme metabolism following oxidation of heme molecule?
Billirubin
Biosynthesis of fatty acid is formed from malonyl CoA. Which of the following pair of compound are used as substrate for this enzyme biosynthesis of malonyl-CoA
Biocarbonate and acetyl CoA
Which of the following does NOT release glucose into the blood?
Brain Skeletal Muscle Red Blood Cells All Of the Above
Defective activity of which of the following enzymes is responsible for maple syrup urine disease
Branched chain alpha-keto acid dehydrogenase
How aspirin modulates the activity of the cyclo-oxygenase enzyme
By acetylation of the seryl hyrdroxyl group of the enzyme
In diabetic patient
CBS Decrease
A 7-year-old boy is referred to a specialty clinic because of digestive problems. He often experiences severe abdominal cramps after eating high fat meal. He is worked up and diagnosed with a genetic defect resulting in a deficiency of lipoprotein lipase. Which of the following substances would most likely be elevated in this patient's plasma following a fatty meal?
Chylomicrons
Mitochondria acetyl CoA must be converted 1st to which of the following compound during fatty acid biosynthesis
Citrate
What type of reaction combines malonyl-CoA and acetyl CoA to produce Beta-Ketoacyl ACP on fatty acid synthase multi enzyme complex?
Condensation
You want to use one specific enzyme catalyzed reaction to convert a specific amino acid to its corresponding biogenic amine neurotransmitter in one step. What kind of biochemical reaction would you select?
Decarboxylation
Which of the following condition can decrease the biosynthesis of 1,25 dihydroxycholcalciferol?
Decreases in parathyroid hormone secretion
Hypercholesterolemia can be caused by
Defective level of functional LDL receptors
Pellegra is caused by?
Deficiency of Niacin
Which of the following statements is TRUE
Eicosanoids can be derived from certain fatty acids
How many molecules of acetyl CoA and NADPH are required to synthesize one molecule of palmitic acid
Eight molecules of acetyl CoA and 14 molecules of NADPH
Which of the following is an oxidation function of fatty acid?
Exergonic
The fatty acid acyl-CoA dehydrogenase reaction is analogous to the succinate dehydrogenase reaction. Identify the active form of vitamin that is used as a coenzyme in both reaction
FAD
Which of the following is the correct sequence of event in the cycle of Betaoxidation beginning with saturated fatty acyl CoA
FAD-hydeation, NAD+, tylolytic clevage
In the mitochondrial, as a ______ makes from the intermembrane space to the matrix, _______ is transported in opposite direction.
Fatty acyl-carnitine; carnitine
Deficiency of what vitamin interrupts DNA methylation?
Folic Acid
Deficiency of which of the following vitamins interrupts DNA methylation?
Folic Acid
Which of the following intermediates of the tricarboxylic acid cycle is generated during urea biosynthesis that also produce malate
Fumarate
Which of the following types of glucose transporters (GLUT) protein is present in skeletal muscle tissue?
GLUT 4
Which amino acid is the immediate precursor of methionine
Homocysteine
Which of the following sentences is true for glucocorticoids
Glucocorticoids can enhance inducible cyclooxygenase 2 (COX2) activity
Which of the following biochemical pathways is the best major pathway that can produce glucose molecules during severe starvation
Gluconeogenesis
Which of the following is the primary metabolic fuel in humans?
Glucose
Which amino acid is produced in a transamination reaction when alpha-ketoglutarate reacts with another amino acid, such as glutamine
Glutamate
Which of the following is true for glutamate dehydrogenase catalyzed reaction when glutamate is the substrate
Glutamate is oxidatively deaminated
Which of the following amino acids is glucogenic
Glutamic Acid
Lack of which enzyme can prevent vitamin C biosynthesis?
Gulonolactone Oxidase
Recognize the compound produced commonly during the biosynthesis of both cholesterol and ketone bodies
HMG-CoA
Place the following intermediates of cholesterol biosynthesis in correct order starting from the beginning
HMG-CoA, mevalonate, isoprene unit, geranyl pyrophosphate, farnesyl pyrophosphate, squalene, lanosterol, cholesterol
which condition/vitamin deficiency is NOT a correct match?
Hemolysis of red blood cells/vitamin D
Which of the following compounds could be an activator of phospholipase A2 during eicosanoid biosynthesis
Histamine
Which of the following amino acids is strictly ketogenic
Lysine
Which of the following is NOT intermediate in the synthesis of lanosterol from acetyl CoA
Malonyl CoA
Which product of reaction catalyzed by acetyl CoA carboxylase is a carbon source for biosynthesis of palmitic acid?
Malonyl CoA
Inability to synthesize or obtain tetrahydrofolic acid (THF) can also lead to deficiency of....
Methionine
Which of the following compounds inhibits dihydrofolate reductase activity
Methotrexate
Which of the following one-carbon functional groups can be transferred by SAM?
Methyl
Which of the functional group is transferred to guanidinoacetate to synthesize creatine?
Methyl
Which of the following compounds transfer methyl group to synthesize methionine from homocysteine in the methionine synthase catalyzed reaction?
Methylcobalamin
The enzyme for oxidative degradation of fatty acid are localized in?
Mitochondrial Matrix
________is an allosteric activator of carbamoyl phosphate synthetase-1 (CPS-1) in urea cycle
N-acetyl glutamate (NAG)
Which is the most stable and most reduced form of tetrahydrofolate (THF) carrying a one-carbon group
N5- methyl- THF
Which of the following is not required in the synthesis of fatty acids
NAD+ NADPH
Which of the following activated form of the vitamins is required by the enzyme dihydrofolate reductase to convert folic acid to its active coenzyme form?
NADPH
Which of the following active form of vitamins converts folate to dihydrofolate to tetrahydrofolate?
NADPH
Which of the following nutrient would yield maximum amount of energy upon completed oxidation in human
One mole of palmitic acid
Which of the following intermediates of the citric acid cycle is used to directly synthesize aspartic acid
Oxaloacetate
Which type of reaction is the vitamin riboflavin?
Oxidation-reduction
Lack of intrinsic factor can cause?
Pernioius Anemia
Which of the following essential amino acids is required to synthesize the amino acid tyrosine
Phenylalanine
In the visual cycle transduction activates
Phosphodiesterase
which compound would activate carbamoyl phosphate synthase II by a postive feedback mechanism?
Phosphoribosyl Pyrophosphate PRPP
Which type of reaction initiates vitamin D biosynthesis in humans?
Photolysis
Which type or reaction initiates Vitamin D biosynthesis in humans?
Photolysis
Which of the following statements is TRUE
Plasma membrane is impermeable to glutamate
What is one of the specific structural characteristics of thromaboxane A2 which retains its full functional activities
Presence of a hydroxyl group attached to the carbon 15
What are the functions of transcarboxylase moiety present in acetyl CoA carboxylase enzyme complex fatty acid biosynthesis
Produce malonyl CoA
Which of the following dietary requirements is involved in nitrogen balance
Proteins
Which of the following vitamins is used to produce L-Dopamine?
Pyridoxine
Which of the following compounds is used in a direct transamination reaction to synthesize alanine
Pyruvate
What is one of the biochemical function of vitamin B12?
Rearrangement of the methy group (-CH3) of L-methyl malonyl-CoA to form succinyl-CoA
________ completely depend on glucose for their energy requirements
Red blood cells
Which of the following forms of Vitamin A can support reproduction??
Retinol
Which of the following statements is NOT TRUE for fat solube vitamins?
Retinol cannot be synthesized from isoprene units .... (in other words, via fat soluble vitamins, Retinol can be synthesized from isoprene units)
Which of the following chemical forms of vitamin A can be stored in animal tissue
Retinyl ester
Formation of which of the following compound is required for vision in poor light and dark adaptation?
Rhodopsin
What is the visual pigment?
Rhodopsin
Does aspirin have anti-platelet effects
Yes
___________, one of the intermediates obtained from the __________pathway can synthesize histidine.
Ribose 5-phosphate, pentose phosphate
What may happen if the LDL receptor biosynthesis is severely decreased?
Rise in LDL level
Which amino acid is NOT used in the biosynthesis of purine and pyrimidine bases?
Serine
Which of the following amino acids is used to synthesize cysteine
Serine
Which of the following amino acids is used to synthesize glycine
Serine
Brain tissue utilizes ketone bodies as its another source of energy during _____
Severly starved conditions
Which of the following is a phospholipid
Sphingomyelin
CDP-diglyceride, not involved in biosynthesis
Sphyngomyelin
Which of the following undergo cyclization process in order to form cholesterol in CBS
Squalene
Which of the following conditions stimulates the highest rate of biosynthesis of ketone bodies in humans?
Starvation
Which of the following intermediates of the citric acid cycle is directly used for the biosynthesis of pyrrole ring during heme biosynthesis?
Succinyl-CoA
A person does not like to do exercise and eats high fat diet. What would happen to this person with high triacylglycerol (TG) storage in his adipose tissue if blood glucose levels rise after a meal?
TG storage will increase
Which of the following coenzyme is used for aromatic amino acid ring hydroxylation
Tetrahydrobiopterin BH4
Deficiency of which of the following compounds can interrupt dTMP biosynthesis
Tetrahydrofolate
Which vitamin is required for the biosynthesis of glycine from serine?
Tetrahydrofolate
Hyperhomocysteinemia has been linked to cardiovascular and neurologic diseases. Deficiency of which of the following compounds increases the levels of homocysteine in the blood circulation?
Tetrahydrofolate (THF)
Which one of the following statements is true?
The brain perfers glucose as an energy source, but can use ketone bodies
Which of the following statements is NOT TRUE in reference to the mammalian synthesis of urea
The carbon atom of urea is derived from mitochondrial HCO3-
Vitamin E is also known as
a-Tochopherol
What is the mechanism of action of the NSAIDs, ibuprofen and acetaminophen
They target cyclo-oxygenase and inhibits the enzyme activity by binding irreversibly at the active site of the enzyme so that substrate binding site is blocked.
Which of the following vitamin participates in oxidative carboxylation type of biochemical reaction.
Thiamin
Which vitamin B used for carboxylation type of biochemical reaction?
Thiamin
Which vitamin is used for oxidative decarboxylation of pyruvate to form acetyl-CoA?
Thiamin
What is the active coenzyme form of thiamin or vitamin B1
Thiamin pyrophosphate
Which protein present within the intestinal epithelial cells delivers vitamin B12 into the blood circulation?
Transcobalmin II
Which is the required guanine-nucleotide binding protein in visual signal transduction?
Transduction
Which of the following compounds are carried mostly by chylomicrons
Triacylglycerols
The largest energy store in a well nourished individual is
Triacylglycerols in adipose tissues
The largest energy store in a well nourished individual is?
Triacylglycerols in adipose tissues
Deficiency of which amino acid can block biosynthessis of melatonin?
Tryptophan
Which of the following amino acid is nutritionally essential in humans
Tryptophan
Which of the following amino acids is the precursor of melatonin
Tryptophan
which amino acid is the precursor of the neurotransmitter serotonin?
Tryptophan
Which amino acid is precursor for the synthesis of thyroid hormones?
Tyrosine
Which of the following amino acids is the precursor to dopamine
Tyrosine
Which of the following is the first nucleotide produced during pyrimidine biosynthesis?
UMP
Which of the following compounds can inhibit the rate-limiting step in pyrimidine biosynthetic pathway?
UTP
If a person's urine contains unusually high concentrations of urea, which one of the following diets has he or she probably been eating recently
Very low carbohydrate, very high protein
Which vitamin helps transportation of oligosaccharides across the lipid bilayer?
Vitamin A
A patient is undergoing long term dialysis dificiency of the following vitamins is a possibility?
Vitamin B complex
Deficiency of which of the following pair of vitamins can cause megablastic anemia?
Vitamin B12 and folic acid
A person was clinically diagnosed to have megaloblastic anemia. Deficienncy of which of the following pair of vitamins can cause this anemia?
Vitamin B12, and Folic acid
Deficiency of which of the following vitamin can impair release of stored iron?
Vitamin C
Deficiency of which one of the following vitamins can interrupt the biosynthesis of norepinephrine when the starting compound in this biosynthesis pathway is dopamine?
Vitamin C
Deficiency of which vitamin can cause a disease showing symptoms of bleeding gum?
Vitamin C
Lack of gulonolactone oxidase would prevent biosynthesis of which vitamin?
Vitamin C
Which vitamins can increase absorption of iron from small intestines?
Vitamin C
Biosynthesis of which of the following vitamins is initiated by photochemical reaction in human skin?
Vitamin D
Deficiency of which vitamin can cause rickets?
Vitamin D
Which vitamin shows antioxidant properties at highest oxygen concentration?
Vitamin E
Deficiency of which vitamin can interfere with the blood clotting?
Vitamin K
Menaquinone-7 is the precursor of which of the following vitamins?
Vitamin K
What is the primary mechanism of action of vitamin K?
Vitamin K acts as cofactor of the enzyme y-carboxylase that produces gamma-carboxyglutamate.
Ingested food is broken down to their corresponding monomeric units and water as a result of his breakdown the reactions produce energy?
Vitamins
Which cyclic nucleotide is generated and used to activate protein phosphorylation/dephosphorylation--mediated signal transduction in visual mechanism?
cGMP
Tetrahydrofolate (THF) and its derivatives shuttle _________ between different substrates.
one carbon unit
Which of the following is produced if palmintoyl CoA is elongated by 2C
palmitic acid