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Chemistry Question Correction

1. The most abundant amino acid in collagen is: ● glycine ● lysine/hydroxylysine ● alanine ● proline/hydroxyproline

2. Chondroitin sulfate is built of: GalNAc + GlcUA

Alternating N-acetylgalactosamine and glucuronic acid, with variable sulfation along the polysaccharide. D-glucuronic acid (GlcA) and N-acetyl-D-galactosamine (GalNAc).

3. Mark chemical functional groups that may be present in natural sugar derivatives ● sulfhydryl ● amine ● sulfate ● nitric ● acetylamine ● carboxyl ● acetyl

4. What is the impact of unsaturated fatty acids on the properties of cell membrane: Unsaturated fatty acid in their tails push adjacent phospholipid molecule away which help maintain fluidity in the membrane

5. Porins: ● are classified as peripheric membrane proteins ● serve as channels that enable transport of proteins inside the cell ● are present in outer membrane of bacteria, but also in mitochondrial and chloroplast

membranes ● are transmembrane proteins with B-barrel structure

6. List three groups of products derived from arachidonic acid through its cyclic oxidation Prostaglandins, leukotrienes, thromboxanes

7. Mark the true sentences ● Glutathione acts as a scavenger of free radicals through the formation of disulfide

bonds between the two molecules. ● Vasopressin is nonapeptide hormone involved in maintaining blood pressure ● Glutathione is an important tripeptide involved in maintaining redox balance inside

the cell.



8. Mark true sentences ● Polypeptide chain fragments of regular secondary structure are connected with tight B

turns and irregular omega loops. ● In the hydrogen bond stabilizing secondary protein structure carbonyl group is

hydrogen donor while amine group is hydrogen acceptor. ● Mesomeric transfer of electrons makes peptide bond rigid and lacking free rotationπ ● Secondary protein structure is maintained by hydrogen bonds located in amino acids

side chains ● Desmosine is a product of a cross-link of four valine side chains and maintains the

structure of keratins.

9. Mark the amino acids which are susceptible to nitration ● Phe ● Val ● Tyr ● His ● Asp ● Arg

10. Biogenic amines derived from tryptophan include: ● DOPA ● melatonine ● adrenaline ● serotonine ● putrescine

11. Biogenic amines derived from tyrosine include: ● DOPA ● serotonine ● histamine ● cadaverine ● adrenaline

12. 45 mg of glucose (MW = 180 g/mol) was dissolved in water to prepare 100 mL of the solution. Its molar concentration is:

● 4 mM ● 0,04 M ● 2,5 mM



13. The percentage of 2M solution of NaCl (MW = 58,5 g/mol, density of the solution: 1 g/mL) is:

● 29 % ● 11,7 % ● 5,85 %

14. In mammal biological membranes, the following lipid compounds may be present: ● cholesteryl esters ● glycerophospholipids ● cerebrosides and gangliosides ● lipopolysaccarides ● triacylglycerides ● phosphoceramides

15. Mark sentences that characterize a-helical transmembrane proteins ● transmembrane fragments contain mostly serine, aspargine and cysteine to anchor in

the membrane ● may serve as signal transduction molecules exploiting extracellular domain to catch

the signal and intracellular one to start metabolic pathways ● make the membrane porous and more fluid ● are permanently bound to the membrane

16. List the most typical compounds that may estrify phosphatidic acid to extend its polar head: Stearic acid and other fatty acids

17. Mark the sentences that characterize collagen: ● In collagen cross links Shiff base is formed between hydroxyproline and lysine ● Hydroxyapatite may be deposited in the gaps between tropocollagen units to harden

the structure ● Proline residue protruding outside the helix helps in maintaining the appropriate shape

of collagen molecule ● Network forming collagen is present in tendons, collagen, skin and blood vessels,

while the fibril-forming one builds mainly the basement membrane

18. Mark the features that characterize fibrous proteins ● form long filaments shaped like rods or wires ● often play roles of hormones and transporters ● often contain repeating amino acid sequences ● present in blood and the other body fluids ● may be present both inside the cell and in extracellular matrix ● need low concentration of salt to be dissolved in water environment



19. 10 mg of liophylized (dried) protein was dissolved in 20 mL of a buffer. Protein molar mass is 100 000 Da. Molarity of the solution is:

● 0,5 mM ● 5 Mµ ● 0,5 Mµ

20. Lipid fragments that serve as anchors that bind a protein to cell membrane include ● acetyl residue ● glycosylated sfingolipid ● glycosyl-phosphatidyl-inositol ● fatty acids ● isoprenyl oligomers

21. Phosphate buffer is involved in: ● calcification of bones ● excretion of the excess of hydrogen ions with urea ● resorption of bicarbonate in kidneys ● maintaining partial pressure of CO2 in lungs

22. Respiratory acidosis means that: ● Co2 concentration in blood is too low ● bicarbonate ions are lost because of kidney impairment ● bicarbonate concentration in blood is too low ● Co2 cannot be exhaled properly

23. Respiratory alkalosis means that: ● Co2 concentration in blood is increased ● bicarbonate is lost because of kidney impairment ● bicarbonate ion concentration in blood is increased ● Co2 exhale is too fast and intensive

24. Chemical compounds classified as carbohydrates must contain: ● carbonyl group ● more than one hydroxyl group ● carboxyl group ● amine group ● hydroxyl group



25. Mark the amino acids that tend to gather inside the molecule of globular proteins to avoid contact with water

● Asp ● Val ● Ser ● Ala ● Ile ● His ● Gln ● Phe

26. Product of chemical reduction of mannose is called: ● mannitol ● mannose-phosphate ● mannic acid ● sorbitol

27. Select the appropriate secondary/tertiary structure for the following fibrous proteins: A: collagen , B: keratin , C: elastin structure descriptions: 1: polymerisation of short unfolded fragments via inter-chain crosslinks 2: bundle of a-helices 3: triple helix of polypeptide chains, products of three different genes 4: anti-parallel B-structured fibrils A-3 B- 2 C- 1

28. The child who weighs 10 kg should be given the medicine. The recommended medicine amount is 2 mg per 1 kg of body weight per day, and this total amount should be divided into 2 doses. Commercial drug preparation contains 0,2% of the active compound. The volume of a single dose that should be administered is:

● 2 mL ● 5 mL ● 0,5 mL



29. The child who weighs 15 kg should be given the medicine. The recommended medicine amount is 1 mg per 1 kg of body weight per day, and this total amount should be divided into 3 doses. Commercial drug preparation contains 0,1% of the active compound. The volume of a single dose is:

● 2,5 mL ● 5 mL ● 1 mL

30. Lysine charge in the physiological pH (7,4) is: ● positive ● negative ● almost neutral

31. Proteins work as buffers thanks to their: ● ionization ability of functional a-amino and carboxyl groups of amino acids ● ability to form anions and cations depending on the acidity of the environment ● content of acidic and basic amino acids with side chains able to attract and release

protons ● tendency to aggregation in low ionic strength

32. Enolization means: ● change of a monosaccharide to its epimer (for example glucuronic to iduronic acid) ● change of aldose to ketose via re-arrangement of chemical bonds in high temperature

and alkaline solution ● change of a to B sugar ring anomer through the chain form

33. In B-turn the following amino acids are the most common: ● Val Asp Lys ● Ile Trp Pro ● Gly Asp Asn ● Pro Lys Hyp

34. Four miligrams of a lyophilized (dried) protein was dissolved in 10 mL of a buffer (final volume). Protein molecular mass is 80 000 Da. Molar concentration of the solution is:

● 0,2 mM ● 5 Mµ ● 2 Mµ



35. The risk of cardiovascular disease is suggested by ● the ratio of LDL/HDL fractions ● high level of HDL fraction in blood ● the ratio of ILD/LDL fractions ● too low level of chylomicrons

36. As a result of proper folding the protein molecule can reach the structure of maximal internal energy

● true ● false

37. The percentage of 1 M glucose solution (MW = 180 g/mol, density 1 g/mL) is: ● 1,8 % ● 18 % ● 9 %

38. Post-translational modification of glutamic acid side chain important for blood clotting cascade is called:

● carboxylation ● phosphorylation ● methylation ● acetylation

39. The patient suffers from respiratory tract problems (asthma). As a result CO2 is not exhaled properly and its blood concentration increases. What happens to the blood pH? Explain. How is this rate called? Acidosis. The pH of the blood is lower than 7,35.

40. In a-helix, hydrogen bonds are aligned along the helix axes and amino acid side chain are hidden insight the helix:

● false ● true

41. Glucose is the metabolic precursor of: ● vitamin K ● vitamin C ● vitamin B12 ● vitamin D



42. For each monosaccharide select information that describes its structure (possible more than one feature) A) erythrose B) fructose C) xylulose features to be chosen: 1: hexose 2: aldose 3: tetrose 4: ketose 5: pentose

erythrose- tetrose + aldose fructose- ketose + hexose xylose- pentose + ketose

43. Which chemical compounds are gathered inside lipoproteins: Inside: triacylglycerides and cholesteryl esters

external: phospholipids, free cholesterol, apoproteins

44. Mark all the components that built GPI anchor ● ethanolamine ● 2 fatty acids ● glycerol ● phosphate ● serine ● mannitol ● oligosaccharide (GlcNAcMan3) ● ceramide

45. Mark all the sets of amino acids with an isoelectric point close to six in all of them: ● Ala, Thr, Gly ● His, Arg, Gly ● Asn, Gln, Ser ● Lys, Ile, Trp ● Val, Glu, Ser ● Leu, Ile, Thr



46. Complete the sentence: Heparan sulfate is built of…. linear chains of repeating disaccharide units consisting of a glucosamine and uronic acid

47. Mark true sentences ● Hemoglobin and myoglobin belong to all a-protein structural class ● Rodopsin in anchored in the membrane eye retina with the bundle of seven a-helices ● Chaperone proteins are involved in degradation of incorrectly folded proteins ● In immunoglobulins the same active domain is responsible for antigen binding and

interaction with the cells of immune system ● Blood plasma albumin is responsible for water balance between blood and tissues

48. Guanidine functional group that provides positive charge is present in: ● arginine ● methionine ● tryptophan ● lysine ● histidine ● valine

49. List the components of the external layer of lipoproteins: phospholipids, cholesterol, apolipoproteins

50. In all a-protein’s the helical fragments may be arranged in a globin fold or a bundle of parallel sections

● False ● True

51. Mark all sentences that are true for eikosanoids ● their excess increases a risk of heart attach and stroke ● in blood they are transported inside lipoproteins ● prostaglandins belong to this group of compounds ● they are important mediators of immune reactions ● this group comprise plasmalogens, cerebrosides and tromboxanes ● they are derivatives of fatty acid containing 20 C atoms and 4 double bonds



52. Functional groups present in non-polar amino acids include: ● guanidine group ● amide group ● isopropyl and other branched hydrocarbons ● hydroxyl group ● phenyl group ● thioether group

53. Complete the sentence: Dermatan sulfate is built of…. GalNAc+ IdUA/GlcUA

linear polysaccahrides assembled as disaccaride units containing a hexosamine, N-acetyl galactosamine or glucuronic acid joined by B 1,4 or 1,3 linkages respectively

Complete the sentence: Heparan sulfate is built of…. GlcNAc+ IUA/GlcUA

54. Mannose and galactose are: ● none of above ● anomers ● epimers ● diastereoizomers

55. The change of a to B anomer via open ring (chain form) is called: ● mutarotation ● obtaining mirror reflection structure ● oxidation ● reduction

56. The fibrous protein that builds hair, nails, animal fur and horns is called: ● kreatinine ● fibroine ● keratine ● troponine

57. Posttranslational modifications necessary to maintain collagen structure are: ● hydroxylation of lysine and proline ● fosforylation of tyrosine ● methylation of lysine ● lysine/allysine cross links ● glycation



58. Globular proteins: ● are soluble in water or low concentration salt solution thanks to hydration envelope

surrounding the molecule ● help in maintaining acid-base balance thanks to their buffering properties ● serve as structural support in tissue or cell ● present non-polar amino acids on their surface ● differ in water solubility depending on their size, shape and charge distribution. ● often contain repeating amino acid sequences

59. Free aspartic acid in physiological pH (7,4) forms: ● cations ● anions ● zwitterions (bipolar ions)

60. 11,7 g of NaCl (MW = 58,5 g/mol) was dissolved in water to prepare 200 mL of the solution. Molarity of the solution (density; 1 g/mL) is:

● 0,5 M ● 0,2 M ● 1 M

61. List the monosaccharides that build glycosaminoglycans. What is their common chemical modification. Uronic acid and amino sugars. Chemical modifications of GAGs, which are commonly performed to engineer molecular delivery systems, affect protein binding and are highly dependent on the site of modification on the GAG molecules.

62. Antiparallel B-structure is more stable than a-helix ● False ● True

63. Product of glucose chemical oxidation in the mild conditions is called: ● gluconic acid ● glucaric acid ● glucuronic acid ● sorbitol

64. mark the sets of amino acids containing only those with four ionic forms: ● His, Arg, Glu ● Glu, Asn, Gln ● Asn, Val, Thr ● Trp, Arg, Lys ● Glu, Asp, Lys



65. Mark the sentences that describe proteoglycans: ● they act as important mediators of inflammation ● they are involved in transport of lipid compounds in blood ● they form an important storage material in the liver, because of their content of long

polysaccharide chain ● some of them take part in signal transduction from the external environment of the

cell ● they are components of connective tissue (skin, cartilage, synovial fluid and so on) ● they are responsible for mechanic strength of a tissue and act as dumpers

66. Cholesterol is transported in blood mainly in lipoprotein fraction: ● chylomicrons ● LDL ● VLDL ● HDL

67. List the buffers that maintain acid-base balance in the organism. Which one of the supports gas exchange in lungs and peripheral tissues. Bicarbonate buffer

68. Twenty microliters were taken from the patient’s serum and diluted to obtain a final volume of 1 mL. Next, glucose concentration was determined with the phenolic method and the absorbance of the sample was 0,2. Sugar concentration in patient blood is:

● 2 mg/ml ● 400 g/mlµ ● 0,2 mg/ml



69. The presented compound is:

● hydrophobic ● polar ● amphipatic

70. Which of the presented fractions is necessary for proper digestion of dietary lipids:

● A ● C ● B

71. Which of the presented structure belongs to sphingolipids?

● B ● A ● C



72. To determine protein concentration in patients serum 200 L of the sample was taken andµ diluted up to 1 mL. Protein was determined with biuret method and the absorbance was equal to 0,5. Protein concentration in the serum is:

● 0,2 mg/mL ● 10 mg/mL ● 0,05 g/mL

73. The compound shown below belongs to:

● Phosphoglycerides ● Phosphosfingosides ● triacylglycerides

74. Among the presented structures, mark nonpolar amino acids:

● A ● E ● C ● D ● F ● B



75. The compound presented here is:

● polar ● amphipatic ● hydrophobic

76. Among the amino acids presented below find a set of those that tend to gather at the surface of globular proteins

● A, C, D, G ● B, E, F, G ● C, D, E, F ● A, B, E, G

77. The structure below presents:

● Vitamin D ● Glycocholic acid ● Cholesterol ● Testosteron



78. The figure present:

● protein association with the membrane through the fragment built of hydrophobic amino acids

● GPI anchor ● anchoring of membrane protein through acylation

79. The correct name of the presented tripeptide is:

● Cys-Thr-Val ● IIE-Ser-Cys ● Val-Thr-Cys ● Val-Ser-Cys

80. Which of the presented structures is classified as triacylglycerol

● B ● A ● C



81. Which of the presented structure belongs to plasmalogens

● C ● A ● B

82. Among the shown monosaccharides mark all ketoses:

● F ● E ● B ● A ● D ● C

83. The structure shown below:

● builds biological membrane ● serves for energy storage in the body



84. One hundred microliters were taken from the patient’s serum and diluted to obtain a final volume of 1 mL. Next, glucose concentration was determined with the phenolic method and the absorbance of the sample was 0,30. Sugar concentration in patient blood is:

● 60 g/ mlµ ● 120 g/ mlµ ● 0,6 mg/ml

85. The compound shown in the figure is involved in:

● mediation of inflammatory reactions ● transport of aromatic compounds in blood ● excretion of hydrophobic metabolites and xenobiotics with urine

86. The formula presents:

● glucocorticoid ● vitamin D ● taurocholic acid ● cholesteryl ester



87. Among the structures below, mark arginine:

● D ● A ● C ● B

88. The compound presented below:

Cholesterol ● too high level in blood may result from an inappropriate diet ● too high level in blood may be associated with a risk of cardiovascular disease ● is highly hydrophobic ● is necessary for proper structure and function of biological membranes ● too low level in blood may be associated with a risk of osteoporosis ● works as a mediator of immune reactions

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