oxidation of which substance results in ketone bodies?
a. maltose
b. fatty acids
c. glucose
d. aldehyde
b. fatty acids
Synthesis of 1 molecule of glucose from lactate requires ____ ATP.
a. 2
b. 3
c. 5
d. 6
a. 2
anaerobic glycolysis- lactic acid cycle
lactate back into glucose by the liver= Cori cycle
glucose precursors are primarily derived from ____.
a. fatty acids
b. sterols
c. amino acids
d. ketone bodies
c. amino acids
Which of these is a disaccharide with B 1->4 bond?
a. lactose
b. maltose
c. sucrose
d. cellulose
a. lactose
which of these is a C-4 epimer of glucose?
a. galactose
b. mannose
c. fructose
d. ribose
a. galactose
which of these is a C-2 epimer of glucose?
a. galactose
b. mannose
c. fructose
d. ribose
b. mannose
which of these compounds is a simple sugar?
a. maltose
b. glycogen
c. dihydroxyacetone
d. cellulose
c. dihydroxyacetone
dihydroxyacetone is a triose which is a simple sugar or monosaccharide
the other trioses are L and D glyceraldehyde
trioses are important in cellular respiration
What is the principal carbohydrate produced by the action of alpha-amylase on dietary starch?
a. alpha-amylose
b. glucose
c. amylopectin
d. maltose
d. maltose
The hydrolysis of amylopectin by amylase results in what end product?
a. amylose
b. cellulose
c. sucrose
d. limit dextrin
d. limit dextrin
hydrolysis of amylose by amylase results in dextrins
The enzymes that catalyze the breakdown of maltose are secreted by the mucosal cells of the _____.
a. mouth
b. stomach
c. small intestine
d. pancreas
c. small intestine
maltase, lactase and sucrase are brush border enzymes of the small intestine
Carbon atoms for fatty acid synthesis are transported to the cytoplasm in the form of ____.
a. succinyl-CoA
b. citrate
c. acetyl-CoA
d. pyruvate
c. acetyl-CoA
fatty acid synthesis is the creation of fatty acids from acetyl-CoA and NADPH through the action of enzymes called fatty acid synthases
succinyl-CoA, citrate and pyruvate are involved in citric acid cycle
The malic enzyme catalyzes the conversion of malate to pyruvate and provides which substance used in fatty acid biosynthesis?
a. oxaloacetate
b. NADPH
c. acetyl-CoA
d. NADH
c. acetyl-CoA
Cholesterol is NOT a precursor of _____.
a. aldosterone
b. estrogen
c. Vitamin D
d. lecithin
d. lecithin
Triacylglycerols are transported from intestinal cells to adipose cells within _____.
a. chylomicrons
b. VLDLs
c. LDLs
d. HDLs
a. chylomicrons
The bonding between the fatty acid and the glycerol in a 2-monoacylglycerol is best described as which of these?
a. glycosidic bond
b. ester linkage
c. peptide linkage
d. anhydride bond
b. ester linkage
A lack of lipoprotein lipase results in ____.
a. a decrease in free fatty acids released by adipocytes
b. an elevated level of chylomicrons following a high fat meal
c. overproduction of LDLs
d. overproduction of HDLs
b. an elevated level of chylomicrons following a high fat meal
known as familial chylomicronemia syndrome- autosomal recessive
Which of these is a good source of omega-3 fatty acids?
a. shrimp
b. butter
c. salmon
d. chicken
c. salmon
Which type of fatty acid is abundant in olive oil?
a. saturated
b. monounsaturated
c. short-chain
d. polyunsaturated
b. monounsaturated
Dietary lipids are converted into _____ by pancreatic lipase
a. lipoproteins
b. 2-monoacylglyercols
c. bile salts
d. cholesterol
b. 2-monoacylglycerols
Which of these actions occurs during the alanine cycle?
a. Pyruvate converted to glucose in the liver
b. Pyruvate transaminated to glutamate in liver
c. Pyruvate transported from skeletal muscle to liver
d. Gluconeogenesis occurs in the skeletal muscle
c. Pyruvate transported from skeletal muscle to liver
called the Cahill cycle; pyruvate is transaminated to form alanine not glutamate
similar to Cori cycle, but Cori cycle uses lactate
Arginase catalyzes the enzymatic conversion of arginine into ____ and urea
a. ornithine
b. alanine
c. lysine
d. citrulline
a. ornithine
arginase is a manganese containing enzyme which is the final enzyme in the urea cycle
arginine + H2O -> ornithine + urea
Acetyl-CoA derived from the oxidative breakdown of amino acids is completely oxidized to CO2 through a series of reactions known as the _____.
a. pentose-phosphate pathway
b. electron transport chain
c. glycolytic pathway
d. TCA
d. TCA
Bile acids contain a carboxyl group in their side chain that is often bound in amide linkage with _____.
a. phenylalanine
b. tryptophan
c. histidine
d. taurine
d. taurine
or glycine
Which of these is characteristic of myoglobin?
a. it is a tetramer
b. it is present in erythrocytes
c. it has a fibrous quality
d. it is a single polypeptide
d. it is a single polypeptide
which of these is not an essential amino acid?
a. alanine
b. serine
c. lysine
d. asparagine
c. lysine
Which enzyme is controlled by product inhibition allowing skeletal muscle cells to accumulate glucose?
a. hexokinase
b. glucokinase
c. pyruvate kinase
d. phosphofructokinase
a. hexokinase
high affinity for glucose (low Km)
The toxicity of many pesticides results from ___ enzyme inhibition
a. irreversible
b. competitive
c. synergistic
d. allosteric
b. competitive
When the equilibrium constant for a reaction is equal to 1, then the standard free-energy charge for the reaction is ______.
a. -1.36
b. 0.00
c. 1.36
d. 2.73
b. 0.00
Saturation levels of substrate concentration in an enzyme-catalyzed reaction cause the progress curve to display ______.
a. zero-order kinetics
b. first-order kinetics
c. negative cooperativity
d. feedback inhibition
b. zero-order kinetics
The anabolism and catabolism phases of protein metabolism are both affected by which of these?
a. estrogen
b. glucagon
c. testosterone
d. glucocorticoids
b. glucagon
Which of these hormones enhances the activity of glycogen phosphorylase in skeletal muscle?
a. epinephrine
b. testosterone
c. estrogen
d. aldosterone
a. epinephrine
also glucagon
Which of these hormones activates glycogenolysis while inhibiting glycogenesis and glycolysis to maximize the release of glucose?
a. insulin
b. glucagon
c. cortisol
d. aldosterone
b. glucagon
Glucagon activates which enzyme in the plasma membrane of hepatocytes?
a. phosphoprotein phosphatase
b. glycogen synthase
c. protein kinase
d. adenylate cyclase
d. adenylate cyclase
adenylate cyclase makes cAMP which activates protein kinase A
Which of these factors characterizes gout?
a. overproduction of purine nucleotides
b. tyronase deficiency
c. adenine and guanine biosynthesis deficiency
d. urea cycle hyperactivity
c. adenine and guanine biosynthesis deficiency
also underproduction of purine nucleotides and decrease in urea cycle
One-carbon transfers during the production of purines and pyrimidines are dependent on_____.
a. biotin
b. thiamine
c. folic acid
d. tocopherols
c. folic acid
Which enzyme catalyzes peptide bond formation during protein synthesis at the ribosome?
a. RNA polyamerase
b. DNA ligase
c. peptidyl transferase
d. peptidyl dehydratase
c. peptidyl transferase
Which amino acid initiates protein synthesis in humans?
a. serine
b. methionine
c. leucine
d. isoleucine
b. methionine
The primary function of vitamin D is to regulate the absorption and metabolism of which minerals?
a. sodium and potassium
b. calcium and phosphorus
c. iron and phosphorus
d. sodium and calcium
b. calcium and phosphorus
Which mineral is required for activity of most glycolytic enzymes?
a. copper
b. magnesium
c. cobalt
d. sulfur
b. magnesium
Which coenzyme is required for oxidative decarboxylation processes?
a. biotin
b. cobalamin
c. thiamine pyrophosphate
d. pyridoxal phosphate
c. thiamine pyrophosphate
Vitamin K is essential for the synthesis of ____.
a. fibrinogen
b. hemoglobin
c. rhodopsin
d. prothrombin
d. prothrombin
Dietary supplementation of therapeutic amounts of folic acid may be detrimental because it can ___.
a. cause kidney stones
b. mask a B12 deficiency
c. damage the liver
d. inhibit absorption of other vitamins
b. mask a B12 deficiency
can also promote tumor growth and cause zinc deficiency
Which of these foods are the richest sources of vitamin E?
a. root vegetables
b. vegetable oils
c. fruits
d. fish
b. vegetable oils
What vitamin is synthesized by intestinal flora?
a. A
b. D
c. E
d. K
d. K
It is possible for which vitamin to be synthesized from tryptophan?
a. thiamine
b. cyanocobalamin
c. niacin
d. pyroxidine
c. niacin
which of these is characteristic of a spontaneous reaction?
a. standard free energy is positive
b. an enzyme has catalyzed the reaction
c. Gibbs’s free energy is negative
d. Keq is greater than 1
c. Gibbs’s free energy is negative
-delta G is favorable with a large K
+delta G is not favorable with low K
delta G 0= equilibrium
The phosphate groups of ATP are linked by ___ bonds.
a. phosphoanhydride
b. phosphate amide
c. phosphodiester
d. hydrogen
a. phosphoanhydride
Which compound catalyzes the formation of GTP in the tricarboxylic acid cycle?
a. succinate dehydrogenase
b. alpha-ketoglutarate dehydrogenase
c. malate dehydrogenase
d. succinate thiokinase
d. succinate thiokinase
In the tricarboxylic acid cycle, isocitrate dehydrogenase converts isocitrate to ____.
a. fumarate
b. a-ketoglutarate
c. succinyl-CoA
d. citrate
b. a-ketoglutarate
Which complex of the electron transport system contains copper?
a. NADH dehydrogenase
b. succinate dehydrogenase
c. ubiquinol-cytochrome c oxidoreductase
d. cytochrome c oxidase
d. cytochrome c oxidase
held by copper
NADH dehydrogenase- FMN