BIOCHEM FINAL ALL (ONLINE EXAM VARIENTS 2020) MCQs !

1.Which of the following statements about phenylalanine degradation are TRUE?

1) phenylalanine hydroxylase uses ascorbic acid as a cofactor

2) phenylalanine hydroxylase uses tetrahydrobiopterin as a cofactor

3) phenylalanine hydroxylase uses NADPH as a cofactor

4) a deficiency of homogentisate oxidase causes tyrosinemia type II

5) a deficiency of phenylalanine hydroxylase results in higher concentration of phenylpyruvate, phenyllactate and phenylacetate

2+5

2.Which statements concerning the anabolic processes are CORRECT?

1) they are processes of synthesis of cell-specific proteins and nucleic acids

2) they are processes of energy accumulation in microergic compounds

3) they are processes of oxidation of substrate molecules

4) they are processes of synthesis of ATP

5) they are reductive processes that "store" energy in the bonds of organic molecules

1+5

3.Which of the following hormones have a membrane receptor?

1) retinoic acid

2) ACTH

3) triiodothyronine

4) glucagon

5) calcitriol

2+4

4.Glycogen synthase is:

active in its dephosphorylated form

5.Which processes do NOT take place in the liver?

1) synthesis of chylomicrons

2) urea synthesis

3) synthesis of direct bilirubin

4) synthesis of bile acids

5) ammoniagenesis

1+5

6.What type of bond connects the nucleotides in DNA?

3', 5'-phosphodiester

7.Which of the following statements about Krebs cycle is TRUE?

1) the regulatory enzymes are more active when the levels of ATP are high

2) the regulatory enzymes are less active when the levels of NADH are high

3) the cycle represents the final steps of oxidation of C-atoms that come from different substrates of biological oxidation

4) some of the intermediates of the cycle could be used for the synthesis of carbohydrates, lipids and proteins

5) the enzyme activities of the cycle are also found in the cytoplasm and various cell organelles

2+3+4

8."Jaundice" is a condition of hyperbilirubinemia, the reasons for which could be:

1) intensive degradation of N-containing substrates in the cells

2) increased intake of N-containing molecules with food

3) abnormal breakdown of red blood cells (accelerated hemolysis)

4) obstruction of the biliary paths

5) defects in the enzyme UDP-glucuronyl transferase in the liver or other liver diseases

3+4+5

9.In тhе red blood cells (RBCs):

1) glycolysis can be performed either in aerobic or anaerobic conditions

2) the end product of glycolysis is always lactate

3) RBCs contain smaller amounts of 2,3-bisphosphoglycerate compared to the rest of the cells

4) the pentose phosphate pathway is of crucial importance for RBCs

5) reduced glutathione is of great importance for RBCs

2+4+5

10.The irreversible kinase reactions in glycolysis are catalyzed by:

1) hexokinase (glucokinase)

2) phosphoglycerate kinase

3) phosphofructokinase

4) phosphoenolpyruvate carboxykinase

5) pyruvate kinase

1+3+5

11.Which of the lipoprotein complexes transports exogenous (dietary) lipids, mainly TAG?

chylomicrons

Which of the following compounds does NOT derive from arginine:

polyamines

nitric oxide (NO)

ornithine

ethanolamine

creatine phosphate

ethanolamine

13.The N-atom in carbamoyl phosphate, used for the pyrimidine ring synthesis, derives from:

glutamine

14.Which of the following statements about glycogen degradation in the liver is TRUE?

it is the first mechanism for maintenance of the blood glucose level during fasting periods

15.Cholesterol:

1) is synthesized from Acetyl-CoA

2) is synthesized in the cytoplasm and the endoplasmic reticulum

3) the main regulatory enzyme of the synthesis is HMG-CoA synthase

4) is completely degraded in the liver

5) its synthesis is activated by insulin

1+2+5

16.Indicate the protein involved in the storage of iron in cells?

ferritin

17.Which of the following phospholipids contain sphingosine, one fatty acid, a phosphate group and choline?

sphingomyelins

phosphatidylcholines

phosphatidyl inositols

ceramides

glucocerebrosides

sphingomyelins

18.Which of the following mechanisms play role in ammonia

detoxification?

1) glutamine biosynthesis in the brain

2) alanine biosynthesis in muscles

3) urea biosynthesis in muscles

4) urea biosynthesis in the kidneys

5) reductive amination of alpha-ketoglutarate

1+2+5

19.Which of the following shuttles is used in the synthesis of fatty acids?

citrate shuttle

glycerol-3-phosphate shuttle

malate shuttle

carnitine shuttle

shuttle of gluconeogenesis

citrate shuttle

20.Which of the following statements regarding the oxidation of fatty acids are CORRECT?

1) β-oxidation of fatty acids with an even number of carbon atoms,

below 18 occurs in the mitochondria of the cells

2) all end products of the oxidation of fatty acids with an odd number of carbon atoms is Acetyl-CoA

3) oxidation of short-chain fatty acids occurs in peroxisomes

4) very long-chain fatty acids are oxidized in the cytoplasm

5) FADH2 and NADH are obtained in each of the cycles of β-oxidation in the mitochondria

5

21.Which of the following statements about the „de novo" synthesis of purines are TRUE?

1) the purine ring is built by adding atoms onto the basis of PRPP

2) phosphoribosyl is added to the already formed purine ring

3) a common metabolite of AMP and GMP synthesis is IMP

4) the synthesis begins with carbamoyl phosphate and aspartate

5) glycine and glutamine are involved in the synthesis

1+3+5

22.Which of the following statements about the regulation of the synthesis of fatty acids is TRUE?

the end product is an allosteric activator

the main regulatory enzyme is the acyl synthase complex

the synthesis is inhibited by insulin

citrate activates the main regulatory enzyme

the main regulatory enzyme is active in its phosphorylated form

citrate activates the main regulatory enzyme

23.How many ATP molecules are synthesized in the microsomal electron-transport chains?

three ATP molecules

24.Indicate the correct statement about receptors located on the cell membrane.

after activation, the receptor is transformed into a secondary messenger and transmits the information to a downstream component of the signaling pathway

25.Which of the listed statements about osteoblasts are CORRECT?

1) their activation leads to bone resorption

2) their activation leads to bone formation

3) they activate osteoclasts

4) they suppress osteoclasts

5) they express RANK (the receptor activator of NF-kB)

2+3

26.The mitochondrial electron-transport chains:

1) exist as multienzyme complexes that create electro-chemical

gradient, whose energy is used in ATP synthesis

2) are controlled by the ratio ubiquinone/ubiquinone.H2

3) consist of five (5) multienzyme complexes + an ATP-ase

4) are located in the inner mitochondrial membrane

5) require constant oxygen supply

1+4+5

27.Which of the statements concerning covalent modification of enzymes by phosphorylation /dephosphorylation are WRONG?

1) reversible phosphorylation/dephosphorylation is one of the ways to

regulate enzyme activity

2) dephosphorylation is catalyzed by enzymes called serine/threonine

protein kinases

3) phosphorylation is catalyzed by enzymes called protein phosphatases

4) the regulation by phosphorylation/dephosphorylation is under

nervous and hormonal control 5) regulation is achieved by causing a

slight conformational change affecting the active site of the enzyme

2+3

28.Which of the following statements regarding the synthesis and metabolism of lipoprotein complexes are TRUE?

1) pre-HDLs are synthesized only in the liver

2) VLDLs are metabolized by lipoprotein lipase

3) HDLs are produced as derivatives in VLDL metabolism

4) a high serum level of LDL increases the risk of myocardial infarction

5) HDLs carry cholesterol esters and clear up the excess of cholesterol

from extrahepatic tissues

2+4+5

29.Which of the following molecules is the product of the reaction, catalyzed by the pyruvate dehydrogenase complex?

acetyl-CoA

phosphoenolpyruvate

1,3-bisphosphoglycerate

succinyl-CoA

acyl-CoA

acetyl-CoA

30.The synthesis of conjugated bile acids requires:

1) 7-α-hydroxylase

2) 25-hydroxylase

3) NADPH

4) glycine and taurine

5) citrate and malate

1+3+4

31.Heme synthesis occurs with high rate in:

erythrocytes

kidneys

pancreas

liver

brain

liver

32.Which of the listed organs possess GLUT2 (glucose transporter 2) ?

1) liver

2) brain

3) muscles

4) pancreatic beta-cells

5) adipose tissue

1+4

33.Which of the following processes occur during long-term starvation?

1) glycogenolysis

2) ketogenesis

3) lipolysis

4) glycogenogenesis

5) gluconeogenesis

1+2+3+5

34.Vitamin D3:

1) is a cholesterol derivative

2) its active form is 1,25-dihydroxycholecalciferol (calcitriol)

3) is synthesized in the small intestine

4) its synthesis is activated by calcitonin

5) it inhibits the absorption of calcium in the small intestine

1+2

35.Which of the following compounds derive from tryptophan?

1) NAD+

2) melanin

3) dopamine

4) serotonin

1+4

36.Which is the end product of purine nucleotide catabolism in humans?

uric acid

37.Which are the regulatory enzymes of pyrimidine biosynthesis?

1) carbamoyl phosphate synthetase II

2) ornithine transcarbamoylase

3) dihydroorotate dehydrogenase

4) aspartate transcarbamoylase

5) carbamoyl phosphate synthetase I

1+4

38.Which of the following enzymes release arachidonic acid from the

membrane glycerophospholipids?

phospholipase D

all phospholipases

phospholipase A2

phospholipase A1

phospholipase C

phospholipase A2

39.Which of the following reactions require S-adenosyl methionine

(SAM) as a donor of methyl groups?

1) dopamine to norepinephrine

2) norepinephrine to epinephrine

3) ethanolamine to choline

4) dUMP to dTMP

5) synthesis of purines

2+3

40.Which of the following statements about insulin and glucagon are

TRUE?

1) insulin stimulates glucagon secretion

2) insulin is secreted in response to hyperglycemia

3) insulin is secreted in response to hypoglycemia

4) glucagon is an activator of gluconeogenesis and glycogen

degradation in liver

5) insulin inhibits the pentose phosphate pathway

3+4

41.Complex I of the mitochondrial respiratory chains:

1) receives electrons from the reduced cofactors of the oxidative

processes in the mitochondrial matrix

2) gives electrons to complex II of the respiratory chain

3) transports electrons towards ubiquinone

4) works as a proton pump in the outer mitochondrial membrane

5) co-works with cytochromes as its cofactors

1+3

42.Which of the following compounds are considered as "the key

molecules" for the cell metabolism?

1) glyceraldehyde-3-phosphate

2) glucose-6-phosphate

3) acetyl-CoA

4) pyruvate

5) phosphoenolpyruvate

2+3+4

43.Porphyrias belong to a heterogenic group of diseases where:

1) the regulatory enzymes of heme synthesis "escape" their allosteric

regulation

2) the reactions for detoxification of ammonia in the liver are impaired

3) there are deficiencies of enzymes included in heme synthesis pathway

4) there is a lack of heme and development of anemia

5) heme is overproduced

1+3

44.Which of the following redox-systems (redox pairs) belongs to the

heme-containing compounds?

NAD+/HADH

ubiquinone/ubiquinol

FAD/FADH2

oxidized glutathione/reduced glutathione

oxidized Cytochrome c / reduced Cytochrome c

oxidized Cytochrome c / reduced Cytochrome c

45.Glutamate dehydrogenase:

1) catalyzes the oxidative deamination of glutamate to alphaketoglutarate using NAD+ as a cofactor

2) catalyzes the oxidative amination of glutamate using NAD+ as a

cofactor

3) catalyzes the reductive amination of α-ketoglutarate to glutamate

using NADPН as a cofactor

4) takes part in transdeamination (predeamination)

5) is allosterically activated by ATP and GTP

1+3+4

46.Galactose is:

1) metabolized mainly in the liver

2) metabolized mainly in the muscles

3) metabolized mainly in the small intestine

4) activated by phosphorylation mainly by galactokinase

5) activated by phosphorylation mainly by hexokinase

1+4

47.Indicate the correct answers about the structure of elastin.

1) it forms a triple helix

2) it is synthesized as a soluble monomer (tropoelastin) and some

proline residues are hydroxylated

3) it is a glycoprotein as there is glycosylation of some of the

hydroxyproline residues

4) tropoelastin contains hydroxylated lysine residues (OH-Lys)

5) it does not contain regularly the Gly-X-Y sequences in its chain

2+4

48.Ketogenesis is active during:

1) starvation

2) well-fed state

3) diabetes mellitus type I

4) normal insulin secretion

5) inhibited β-oxidation

1+3

49.Which of the following metabolites ARE NOT substrates or

metabolites of the synthesis of cholesterol?

1) аcetyl-CoA

2) mevalonate

3) 3-hydroxy-3-methyl-glutaryl-CoA

4) malonyl-CoA

5) cholyl-CoA

4+5

50.Which of the following statements about iron metabolism is TRUE?

hepcidin decreases serum iron by blocking ferroportin (IREG1)

51.Which is the correct statement?

unlike glycoproteins, proteoglycans contain carbohydrates in big proportion (up to

95%)

proteoglycans are low molecular weight polycationic substances

all types of glycosaminoglycans contain building blocks that are highly sulfated

the carbohydrate part of glycoproteins is called "glycosaminoglycan"

proteoglycans have important biological functions in the blood

unlike glycoproteins, proteoglycans contain carbohydrates in big proportion (up to 95%)

52.Which of the following reactions from the urea cycle demand ATP?

1) arginine -> ornithine + urea

2) ornithine + carbamoyl phosphate -> citrulline

3) NH3 + CO2 -> carbamoyl phosphate

4) citrulline + aspartate -> argininosuccinate

5) argininosuccinate -> arginine + fumarate

3+4

53.Aldolase B is an enzyme in the catabolic pathway of:

fructose

54.The absorption of vitamin B12 in the gastrointestinal tract (GIT) requires:

intrinsic factor

55.Which is the main product of the digestion of the triacylglycerols (TAG) in the small intestine?

2-monoacylglycerol

56.Which of the following molecules is a high-energy (macroergic)

phosphate derivative?

(1 βαθμός)

dihydroxyacetone phosphate

fructose-6-phosphate

glycerol-3-phosphate

1,3-bisphosphoglycerate

glucose-6-phosphate

1,3-bisphosphoglycerate

57.Which of the following enzymes digests carbohydrates?

alpha-amylase

58.The pentose phosphate pathway is:

1) localized in the mitochondria

2) localized in the cytosol

3) a source of NADPH for fatty acids biosynthesis

4) a source of NADPH for the respiratory chain

5) an alternative catabolic pathway for the degradation of glucose in

muscles

2+3

59.Which of the following statements are TRUE?

1) the higher Km is, the lower the affinity of an enzyme to the substrate

is

2) the higher Km is, the higher the affinity of an enzyme to the substrate

is

3) the lower Vmax is, the higher the stability of enzyme-substrate

complex is

4) the higher Vmax is, the higher the stability of enzyme-substrate

complex is

5) Km is that concentration of the substrate, at which the initial velocity

of the reaction is half of the Vmax (Vmax/2)

1+3+5

60.Which of the following statements about folic acid are TRUE?

1) its cofactor form is tetrahydrofolate

2) its cofactor form is dihydrofolate

3) it binds and carries C1-unit for synthesis of creatine phosphate

4) it binds and carries C1-units for the "de novo" synthesis of the purine

ring

5) its deficiency causes hemolytic anaemia

1+4

61.The glycerol produced in lipolysis in adipose tissue:

1) is activated by glycerol kinase in the adipose tissue

2) is released into the bloodstream and then enters the muscles

3) is converted to glycerol-3-phosphate in the liver

4) is converted to glyceraldehyde-3-phosphate in the liver

5) is used for gluconeogenesis in the liver

2+5

61.The glycerol produced in lipolysis in adipose tissue:

1) is activated by glycerol kinase in the adipose tissue

2) is released into the bloodstream and then enters the muscles

3) is converted to glycerol-3-phosphate in the liver

4) is converted to glyceraldehyde-3-phosphate in the liver

5) is used for gluconeogenesis in the liver

2+3

63.Which vitamin is involved in the structure of Coenzyme A?

vitamin B5 (pantothenic acid)

64.Which of the following statements regarding vitamin K are

CORRECT?

1) vitamin K is a water-soluble vitamin

2) vitamin K is required for prolyl and lysyl hydroxylation of collagen

3) vitamin K is required for prolyl hydroxylation of some of the blood

clotting factors

4) vitamin K is required for gamma-glutamyl carboxylation of some of

the blood clotting factors

5) deficiency of vitamin K results in bleeding

4+5

65.Which of the following statements about anaerobic glycolysis in

humans are TRUE?

1) occurs only in the cytosol

2) occurs in both cytosol and mitochondria

3) the final product of glucose oxidation is ethanol

4) the final product of glucose oxidation is lactate

5) produces only 2 moles ATP per 1 mole glucose

1+3+4

66.Which of the following statements about the synthesis of TAG are

CORRECT?

1) the synthesis occurs only in the adipose tissue

2) in the adipose tissue glycerol-3-phosphate is obtained from

dihydroxyacetone phosphate from glycolysis

3) in the small intestine there is a monoacylglycerol pathway

4) the enzyme glycerol-3-phosphate acyltransferase is active in its

phosphorylated form

5) the synthesis is inhibited by insulin

2+3

67.Which properties are characteristic of the enzymes?

1) they have extremely high efficiency

2) they increase the activating energy of the reaction by formation of an

enzyme-substrate complex

3) they have low substrate specificity

4) they act in large quantities

5) the activity and the synthesis of enzymes in the cells are regulated

1+5

68.Ketolysis occurs in:

the mitochondria of extrahepatic tissues

69.Indicate the CORRECT statements about digestion and the secretory

activity of the stomach.

1) the secretion of hydrochloric acid by the parietal cells of gastric

glands requires the enzyme carbonic anhydrase

2) the cells of gastric glands secrete digestive enzymes that break down

the glycosidic bonds of starch

3) the "intrinsic factor" activates the formation of pepsin by pepsinogen

4) the chief cells of gastric glands synthesize and secrete pepsinogen

5) the chief cells of gastric glands synthesize and secrete pepsin

1+4

70.Which of the following statements about the biochemical

characteristics of blood clotting are TRUE?

1) zymogens of serine proteases are involved

2) the extrinsic and the intrinsic pathway of blood clotting are not linked

3) transglutaminase (factor XIII) destroys fibrin molecules

4) several of the blood clotting factors undergo maturation via Vitamin

K-dependent carboxylation

5) thrombin is a tyrosine protein kinase

1+4

Acetyl-CoA is NOT a metabolite of:

ketogenesis

glycolysis

β-oxidation

citric acid cycle

synthesis of cholesterol

glycolysis

72.Which of the following statements about ATP are TRUE?

1) ATP is a macroergic compound with two pyrophosphate bonds

2) ATP gives away its energy only by hydrolysis of its second

pyrophosphate bond

3) ATP synthesis is coupled with endergonic processes

4) ATP synthesis is coupled with exergonic processes

5) ATP is a cofactor of the enzymes catalyzing kinase reactions

1+4+5

73.Which of the following statements about hormones are TRUE?

1) hydrophobic hormones are transported across cell membranes and

are recognized and bound by intracellular receptors

2) hydrophilic hormones do not enter the cells and are recognized and

bound by cell membrane receptors

3) hydrophilic hormones are transported across the cell membrane and

are recognized and bound by intracellular receptors

4) hydrophobic hormones do not enter cells and are recognized and

bound by receptors on the cell membrane

5) are effective only at very high concentrations

1+2

74. Which of the following processes are free oxidation processes?

1) heat production

2) beta-oxidation of fatty acids

3) oxidation of xenobiotics with cytochrome P450

4) hydroxylation of tryptophan to 5-hydroxytryptophan

5) oxidation of alpha-keto acids

1+3+4

75.Please, indicate the CORRECT features of insulin signaling pathways.

1) insulin has a membrane receptor that does not have intrinsic tyrosine

kinase activity and activates intracellular tyrosine kinases

2) insulin has a membrane receptor with intrinsic tyrosine kinase activity

3) insulin activates the phosphatidyl inositol-3-kinase (PI3K) pathway

4) a MAP kinase cascade is activated

5) JAK-STAT signaling pathway is activated

2+3+4

76.Which is the rate limiting step in the pentose phosphate pathway?

glucose-6-phosphate dehydrogenase reaction

77.Which of the following statements about eicosanoids are TRUE?

1) they are synthesized in glands

2) they have a very long half-life

3) they are signal molecules and trigger signal pathways

4) they are synthesized in many tissues and work as local hormones

5) they are synthesized in small concentrations

3+4+5

78.Which of the statements about the parathyroid hormone (PTH) are

TRUE?

1) the low plasma Ca2+ level decreases PTH secretion

2) the low plasma Ca2+ level increases PTH secretion

3) it stimulates bone resorption and the release of Ca2+ in the

extracellular space

4) binds to a serpentine receptor associated with G protein and activates

the adenylyl cyclase pathway

5) inhibits the transcription of the enzyme 1-α-hydroxylase in the

kidneys, necessary for the activation of vitamin D3

2+3+4

79.Which of the listed statements about calcitonin is WRONG?

it is secreted by the C-cells of the thyroid gland

it is secreted when the Ca2+ level in blood is low

the triggered signaling pathway in target cells is cAMP-dependent

promotes renal excretion of Ca2+

the receptors of calcitonin are G-protein associated membrane receptors

it is secreted by the C-cells of the thyroid gland

80.Which vitamins are needed as cofactors of the enzymes catalyzing the transformation of propionyl-CoA (one of the products of the

oxidation of fatty acids with an odd number of carbon atoms)?

1) Vit. B9

2) Vit. PP (B3)

3) Vit. B6

4) Vit. B12

5) Vit. H (biotin)

4+5

81.Which of the following molecules DOES NOT serve as a precursor for

gluconeogenesis?

lactate

alanine

methionine

acetoacetate

glycerol

acetoacetate

82.Heme degradation is initiated by a substrate-inducible enzyme called:

heme oxygenase

83.Which of the following statements are CORRECT?

1) fibrous proteins have polypeptide chains arranged in long strands

2) globular proteins have polypeptide chains folded into a spherical shape

3) most enzymes and regulatory proteins are fibrous

4) globular proteins are insoluble in water

5) fibrous proteins are keratin, collagen and elastin

1+2+5

84.Which of the following biologically active compounds DO NOT derive

from tyrosine?

1) thyroxine

2) melanin

3) melatonin

4) GABA

5) epinephrine

3+4

85.Which of the listed properties are valid for serum albumin?

1) it transports bile acids

2) it transports free fatty acids

3) its synthesis increases in liver diseases

4) it does not participate in the maintenance of the osmotic pressure of the plasma

5) it transports mainly peptide hormones

1+2

86.Gluconeogenesis occurs mainly in:

1) liver

2) brain

3) renal cortex

4) muscles

5) lungs

1+3

87.Which of the following statements about aminotransferases are TRUE?

1) they have NAD+ as a coenzyme

2) they have pyridoxal phosphate as a coenzyme

3) the serum ASAT concentration increases in myocardial infarction

4) the serum ASAT and ALAT concentrations decrease when a patient suffers from a liver disease (e.g. hepatitis)

5) they play an important role in the terminal detoxification of

xenobiotics

2+3

88.The organic component of bone consists mainly of:

type 1 collagen

89.Which is the correct and complete sequence of the reactions in the

Krebs cycle?

citrate synthase, aconitase, isocitrate dehydrogenase, α-ketoglutarate

dehydrogenase, succinyl-CoA synthetase, succinate dehydrogenase, fumarase, malate

dehydrogenase

The concentration (activity) of which of the listed enzymes is increased in the serum of patients with viral hepatitis?

alanine aminotransferase (ALAT)

Which of the following statements about aminotransferases are TRUE?

1) they have NAD+ as a coenzyme

2) they have pyridoxal phosphate as a coenzyme

3) the serum ASAT concentration increases in myocardial infarction

4) the serum ASAT and ALAT concentrations decrease when a patient suffers

from a liver disease (e.g. hepatitis)

5) they play an important role in the terminal detoxification of xenobiotics

2+3

Which of the following molecules is the product of the reaction, catalyzed by the pyruvate dehydrogenase complex?

acetyl-CoA

Which of the following processes are free oxidation processes?

1) heat production

2) beta-oxidation of fatty acids

3) oxidation of xenobiotics with cytochrome P450

4) hydroxylation of tryptophan to 5-hydroxytryptophan

5) oxidation of alpha-keto acids

1+3+4

Complex I of the mitochondrial respiratory chains:

1) receives electrons from the reduced cofactors of the oxidative processes in

the mitochondrial matrix

2) gives electrons to complex II of the respiratory chain

3) transports electrons towards ubiquinone

4) works as a proton pump in the outer mitochondrial membrane

5) co-works with cytochromes as its cofactors

1+3

Which of the following statements about insulin and glucagon are TRUE?

1) insulin stimulates glucagon secretion

2) insulin is secreted in response to hyperglycemia

3) insulin is secreted in response to hypoglycemia

4) glucagon is an activator of gluconeogenesis and glycogen degradation in

liver

5) insulin inhibits the pentose phosphate pathway

2+4

Which is the rate limiting step in the pentose phosphate pathway?

glucose-6-phosphate dehydrogenase reaction

Which of the following phospholipids contain sphingosine, one fatty acid, a phosphate group and choline?

sphingomyelins

Porphyrias belong to a heterogenic group of diseases where:

1) the regulatory enzymes of heme synthesis "escape" their allosteric

regulation

2) the reactions for detoxification of ammonia in the liver are impaired

3) there are deficiencies of enzymes included in heme synthesis pathway

4) there is a lack of heme and development of anemia

5) heme is overproduced

1+3

Heme synthesis occurs with high rate in:

liver

Which of the following compounds derive from tryptophan?

1) NAD+

2) melanin

3) dopamine

4) serotonin

5) triiodothyronine (T3)

1+4