Inorganic compounds in cells. Vladimíra Kvasnicová

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1 Inorganic compounds in cells Vladimíra Kvasnicová

2 water ions buffers crystals in bones blood gases reactive oxygen and nitrogen species toxic heavy metals

3 Chemical composition of human body (mass %) 60% water (2/3 intracellular, 1/3 extracellular) 18% proteins, peptides, amino acids 15% lipids (mainly triacylglycerols of fatty tissue) 1% saccharides (poly- and monosaccharides) 1% nucleic acids, nucleotides 5% mineral substances

4 Chemical composition of cells mass% - water polar solvent, most of chemical reactions in a human body take place in aqueous solutions mass% - organic compounds a) high molecular weight (proteins, nucleic acids, glycogen) b) low molecular weight (glucose, lipids, amino acids, metabolic intermediates e.g. organic acids derivatives) 3. 5 mass% - inorganic compounds

5 Minerals in human body (adult man, 70 kg) Ca g 99% in bones and teeth: Ca 10 (PO 4 ) 6 (OH) 2 ; cell signalling, muscle contraction, blood clotting P 840 g 85% in bones; energy metabol.; structures of nucleic acids, phospholipids, macroergic comp. K 180 g most: intracellularly, maintenance of osmotic pressure, membrane potential, heart activity S 140 g in proteins (Cys, Met), component of biocatalysts Cl 110 g most: extracellularly, maint.of osmotic pressure Na 100 g most: extracellularly, maintenance of osmotic pressure, membrane potential Mg 40 g 60% in bones, intracellul.: stabilisation of ATP Fe 5g most in hemoglobin (O 2 transport), component of enzymes (electron transport - redox reactions)

6 PERIODIC TABLE of elements The figure is found at (September 2007)

7 Biogenic elements = elements essential for structure and function of organisms macrobiogenic elements: C O H N Ca P S Na Cl K Mg over 0,005 % of body mass recommended daily intake over 100 mg blood concentration more than micromolar microbiogenic (trace) elements Fe Cu Zn Se F I Co Cr Mn Mo Si V less than 0,005 % of body mass recommended daily intake less than 100 mg blood concentration: micromolar or lower

8 Required knowledge: 1) classification of elements 2) symbols and English names of elements 3) Latin names of elements 4) names of common cations and anions 5) common names of selected compounds

9 The figure is found at (September 2007)

10 Memorize: 1) classification of elements see Periodic table alkali metals: Li, Na, K, Rb, Cs, Fr (IA) alkali earth metals: (Be, Mg), Ca, Sr, Ba (IIA) halogens: F, Cl, Br, I (VIIA) inert gases: He, Ne, Ar, Kr, Xe, Rn (VIIIA)

11 Memorize: 1) classification of elements see Periodic table nonmetals: H (IA) B (IIIA) C, Si (IVA) N, P, As (VA) O, S, Se (VIA) halogens (VIIA) central atoms of acids

12 Memorize: 1) classification of elements see Periodic table transition metals: Cu, Ag, Au (IB) Zn, Cd, Hg (IIB) Cr, Mn, Fe, Co, Ni, Mo, Pt other metals: Al, Sn, Sb, Pb, Bi

13 Memorize: 1) classification of elements 2) symbols and English names of elements symbols are derived from Latin names of elements H = Hydrogenium = hydrogen Na = Natrium = sodium Ag = Argentum = silver (Ar = Argon)

14 Memorize: 1) classification of elements 2) symbols and English names of elements 3) Latin names of elements symbols of elements used in naming of some compounds used in medicine

15 Symbol Na K Sn Pb Sb W Fe Cu Ag Au Hg Latin name Natrium Kalium Stannum Plumbum Stibium Wolframium Ferrum Cuprum Argentum Aurum Hydrargyrum English name sodium potassium tin lead antimony tungsten iron copper silver gold mercury

16 Compounds called by their common names H 2 O water H 3 O + hydronium NH 3 ammonia NH 4 + ammonium NO NaCl HCO 3 - nitric oxide salt bicarbonate

17 Name these compounds: Na 2 SO 3 K 3 PO 4 (NH 4 ) 2 HPO 4 LiH 2 PO 4 Ca(HCO 3 ) 2 Ag 2 S ZnSO 4 KMnO 4 NaBrO Ba(NO 3 ) 2 HgCl 2 Na 2 B 4 O H 2 O KAl(SO 4 ) 2 NaAl(SO 4 ) H 2 O (NH 4 ) 2 CO 3 CaSO 4. ½ H 2 O ZnSO 4. 7 H 2 O K 2 Cr 2 O 7 KMgF 3 NH 4 MgPO 4 PbClF Cu 3 (CO 3 ) 2 F 2

18 Cytosol is an aqueous solution H 2 O 60 % of a cell by mass water is a polar solvent it dissolves other polar compounds

19 Properties of water polar covalent bond between oxygen and hydrogen partial charges in water molecule hydrogen bonds in aqueous solutions (weak attractions not covalent but important) water molecules tend to stick together resulting in high surface tension water makes hydration shell of dissolved solutes

20 protein in water oil in water

21 Autoprotolysis of water (dissociation of water) in aqueous solutions: K w = [H 3 O + ] x [OH - ] = [H 3 O + ] = 10-7 ph = 7 [OH - ] = 10-7 in pure water: [H 3 O + ] = [OH - ] in acidic solutions: [H 3 O + ] > [OH - ] ph < 7 in basic solutions: [H 3 O + ] < [OH - ] ph > 7

22 The figure was found at (April 2007)

23 ph in cells lower than in extracellular fluid because metabolic reactions produce acids (CO 2 H 2 CO 3, lactic acid) cytosol: ph = 6,8 7,0 in lyzosomes: ph = 4,5 5,0 in the blood: ph = 7,40 ± 0,04 in the urine: ph = 5,0 6,0

24 The metabolism produces acids: CARBON SKELETON CO 2 +H 2 O HCO 3- + H + (generally) saccharides glucose pyruvate, lactate + H + triacylglycerols fatty acids, ketone bodies + H + phospholipids phosphate + H + proteins amino acids sulfate, urea + H +

25 Intracellular buffers proteins (ampholytes): side chains of amino acids phosphates inorganic: HPO 4 2- / H 2 PO 4 - organic: phosphoric acid esters and anhydrides bicarbonate buffer is the principal buffer of extracellular fluid (blood) HCO 3- / H 2 CO 3 Henderson Hasselbalch equation ph = pk a + log (c b / c a )

26 Dissociation constant and buffer ph! the best buffering properties: ph = pk ± 1! a) ph = pk + log (1 / 1) ph = pk b) ph = pk + log (10 / 1) ph = pk + 1 c) ph = pk + log (1 / 10) ph = pk 1 ph = pk a + log (c b / c a )

27 Problems Calculate a ratio of phosphate buffer components (HPO 2-4 / H 2 PO 4- ) in blood, if ph = 7,40 pk(h 2 PO 4- ) = 7,0 (2,5 = 25/10 = 5/2, i.e. HPO 2-4 predominates) Calculate a ratio of phosphate buffer components (HPO 2-4 / H 2 PO 4- ) in urine, if ph = 6,0 pk(h 2 PO 4- ) = 7,0 (0,1 = 1/10, i.e. H 2 PO 4- predominates)

28 Use of the dissociation constant the ratio of phosphate buffer components (HPO 2-4 / H 2 PO 4- ) pk 2 = 7,0 if a) ph = 7,4 (blood) b) ph = 7,0 (cell) c) ph = 6,0 (urine) 2,5 = 25/10 = 5/2 1,0 = 1/1 0,1 = 1/10

29 Henderson-Hasselbalch equation for bicarbonate buffer at blood ph the buffer base (HCO 3- ) predominates because the value of blood ph is higher than the value of buffer pk (7,4 > 6,1) the bicarbonate buffer which ratio is 20/1 is still efficient because CO 2 formed by buffering is excreted by lungs (open buffer system) [CO 2 ] = α x pco 2 α = 0,226 for pco 2 expressed in kpa α = 0,03 for pco 2 expressed in mmhg

30 Conversion of units pressure = the force acting normally on unit area of a surface (in pascals, Pa) 1 kpa = 10 3 Pa Dalton s law = the total pressure of a mixture of gasses or vapours is equal to the sum of the partial pressures of its components partial pressure = pressure of one gas present in a mixture of gases

31 Air composition: Conversion of units 78% N 2 21% O 2 1% water, inert gases, CO 2 (0,04%) Air pressure: 1 atm = Pa (~ 101 kpa) = 760 Torr (= mmhg) 1 mmhg = 0,1333 kpa 1 kpa = 7,5 mmhg

32 Problems Partial pressures of blood gases were measured in a laboratory: po 2 = 71 mmhg pco 2 = 35 mmhg Convert the values to kpa. po 2 = 9,5 kpa pco 2 = 4,7 kpa

33 Inorganic ions in cells inorganic ions = minerals (0,5% of mass) intracellular fluid (ICF) K + > > Mg 2+ > Na + > > > > > (Ca 2+ ) phosphates > proteins > sulfates > HCO 3- > Cl - extracellular fluid (ECF) e.g. in blood plasma: Na + > > > K + > Ca 2+ > Mg 2+ Cl - > > HCO 3- > proteins > phosphates > sulfates membrane transport (channels, transporters)

34 Trace elements (0,005 % of body mass and less) often act as cofacors of enzymes 1) plasma concentration of µmol / L Fe, Zn, Cu / common oxidative statets! 2) low plasma concentrations (µmol/l, nmol/l) Se, Mn, Mo, Cr, Co, Si, F, I,...

35 cations of blood plasma Na + K + Ca 2+ Mg 2+ Fe 3+ H + mmol/l 142 4,2 2,5 0,9 0,02 0, nmol/l

36 Inorganic products of metabolism C, H, O CO 2, H 2 O H 2 CO 3 / HCO - 3 N NH 3 / NH + 4 P H 2 PO 4- / HPO 2-4 = phosphate S SO 2-4 = sulfate I - from degradation of thyroid hormones CO from degradation of heme H + from acids / H as a reducing equivalent

37 Sample test questions Course 1 Structure of cells course test: 7 th November 2016

38 Choose correct statement(s) a) the movement of water through a cellular membrane is called diffusion b) if potassium channel opens in the cellular membrane K + flows out of the cell c) Na + /K + -pump transports these ions along their concentration gradients d) when calcium channel opens in the cellular membrane Ca 2+ enters the cell

39 Choose correct statement(s) a) the movement of water through a cellular membrane is called diffusion b) if potassium channel opens in the cellular membrane K + flows out of the cell c) Na + /K + -pump transports these ions along their concentration gradients d) when calcium channel opens in the cellular membrane Ca 2+ enters the cell NO YES NO YES

40 In human cells a) magnesium is the most common cation b) chloride is the most common anion c) phosphate acts as a buffer d) CO is produced as the end product of oxidation of various organic compounds

41 In human cells a) magnesium is the most common cation b) chloride is the most common anion c) phosphate acts as a buffer d) CO is produced as the end product of oxidation of various organic compounds NO NO YES NO

42 Do you agree with the following statements? a) a chemical formula of ammonia is NH 4 + b) hydrogen phosphate is HPO 4-1 c) phosphate buffer in cells is composed of H 2 PO 4- and H 3 PO 4 d) bicarbonate is a base derived from carbonic acid

43 Do you agree with the following statements? a) a chemical formula of ammonia is NH 4 + b) hydrogen phosphate is HPO 4-1 c) phosphate buffer in cells is composed of H 2 PO 4- and H 3 PO 4 d) bicarbonate is a base derived from carbonic acid NO NO NO YES

44 Choose the correct statement(s) a) ferrous ion can be oxidized to ferric ion b) Cu +II is called cuprous ion c) when CO 2 dissolves in water carbonic acid is formed d) H 3 O + is called hydrogen cation

45 Choose the correct statement(s) a) ferrous ion can be oxidized to ferric ion b) Cu +II is called cuprous ion c) when CO 2 dissolves in water carbonic acid is formed d) H 3 O + is called hydrogen cation YES NO YES NO

46 Which statements are correct? a) as concentration of H 3 O + increases ph of the solution rises b) concentration of H 3 O + in a basic solution is the same as in pure water c) ph in cells is often higher than in an extracellular fluid d) proteins are important intracellular buffers

47 Which statements are correct? a) as concentration of H 3 O + increases ph of the solution rises b) concentration of H 3 O + in a basic solution is the same as in pure water c) ph in cells is often higher than in an extracellular fluid d) proteins are important intracellular buffers NO NO NO YES

48 Choose the correct statement(s) a) kalium is Latin name for calcium b) magnesium is alkali metal c) the only biologically important halogen is chlorine d) Cu, Zn and Se are trace elements from group of transition metals

49 Choose the correct statement(s) a) kalium is Latin name for calcium b) magnesium is alkali metal c) the only biologically important halogen is chlorine d) Cu, Zn and Se are trace elements from group of transition metals NO NO NO NO

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