1. Chemistry Comes Alive Part B2

2. Organic compounds Inorganic compounds Biochemistry
Contain carbon, are covalently bonded, and are often large
Inorganic compounds
Do not contain carbon
Water, salts, and many acids and bases

3. Properties of Water
High heat capacity – absorbs and releases large amounts of heat before changing temperature
High heat of vaporization – changing from a liquid to a gas requires large amounts of heat
Polar solvent properties – dissolves ionic substances, forms hydration layers around large charged molecules, and serves as the body’s major transport medium

4. Cushioning – resilient cushion around certain body organs
Properties of Water
Reactivity – is an important part of hydrolysis and dehydration synthesis reactions
Cushioning – resilient cushion around certain body organs
InterActive Physiology®: Fluid, Electrolyte, and Acid/Base Balance: Introduction to Body Fluids
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5. Contain cations other than H+ and anions other than OH–
Salts
Inorganic compounds
Contain cations other than H+ and anions other than OH–
Are electrolytes; they conduct electrical currents

6. Acids release H+ and are therefore proton donors
Acids and Bases
Acids release H+ and are therefore proton donors
HCl  H+ + Cl –
Bases release OH– and are proton acceptors
NaOH  Na+ + OH–

7. Acid-Base Concentration (pH)
Acidic solutions have higher H+ concentration and therefore a lower pH
Alkaline solutions have lower H+ concentration and therefore a higher pH
Neutral solutions have equal H+ and OH– concentrations

8. Acid-Base Concentration (pH)
Acidic: pH 0–6.99
Basic: pH 7.01–14
Neutral: pH 7.00
Figure 2.12

9. Systems that resist abrupt and large swings in the pH of body fluids
Buffers
Systems that resist abrupt and large swings in the pH of body fluids
Carbonic acid-bicarbonate system
Carbonic acid dissociates, reversibly releasing bicarbonate ions and protons
The chemical equilibrium between carbonic acid and bicarbonate resists pH changes in the blood
InterActive Physiology®: Fluid, Electrolyte, and Acid/Base Balance: Acid/Base Homeostasis
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10. Organic Compounds
Molecules unique to living systems contain carbon and hence are organic compounds
They include:
Carbohydrates
Lipids
Proteins
Nucleic Acids

11. Contain carbon, hydrogen, and oxygen
Carbohydrates
Contain carbon, hydrogen, and oxygen
Their major function is to supply a source of cellular food
Examples:
Monosaccharides or simple sugars
Figure 2.13a

12. Disaccharides or double sugars
Carbohydrates
Disaccharides or double sugars
Figure 2.13b

13. Polysaccharides or polymers of simple sugars
Carbohydrates
Polysaccharides or polymers of simple sugars
Figure 2.13c

14. Lipids
Contain C, H, and O, but the proportion of oxygen in lipids is less than in carbohydrates
Examples:
Neutral fats or triglycerides
Phospholipids
Steroids
Eicosanoids

15. Neutral Fats (Triglycerides)
Composed of three fatty acids bonded to a glycerol molecule
Figure 2.14a

16. Other Lipids
Phospholipids – modified triglycerides with two fatty acid groups and a phosphorus group
Figure 2.14b

17. Other Lipids
Steroids – flat molecules with four interlocking hydrocarbon rings
Eicosanoids – 20-carbon fatty acids found in cell membranes
Figure 2.14c

18. Representative Lipids Found in the Body
Neutral fats – found in subcutaneous tissue and around organs
Phospholipids – chief component of cell membranes
Steroids – cholesterol, bile salts, vitamin D, sex hormones, and adrenal cortical hormones
Fat-soluble vitamins – vitamins A, E, and K
Eicosanoids – prostaglandins, leukotriens, and thromboxanes
Lipoproteins – transport fatty acids and cholesterol in the bloodstream

19. Amino Acids
Building blocks of protein, containing an amino group and a carboxyl group
Amino acid structure
InterActive Physiology®: Fluid, Electrolyte, and Acid/Base Balance: Introduction to Body Fluids
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20. Amino Acids
Figure 2.15a-c

21. Amino Acids
Figure 2.15d, e

22. Protein
Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds
Figure 2.16

23. Structural Levels of Proteins
Primary – amino acid sequence
Secondary – alpha helices or beta pleated sheets
Chemistry of Life: Proteins: Secondary Structure
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24. Structural Levels of Proteins
Tertiary – superimposed folding of secondary structures
Quaternary – polypeptide chains linked together in a specific manner
Chemistry of Life: Proteins: Tertiary Structure
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Chemistry of Life: Proteins: Quaternary Structure
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25. Structural Levels of Proteins
Figure 2.17a-c

26. Structural Levels of Proteins
Figure 2.17d, e

27. Fibrous and Globular Proteins
Fibrous proteins
Extended and strandlike proteins
Examples: keratin, elastin, collagen, and certain contractile fibers
Globular proteins
Compact, spherical proteins with tertiary and quaternary structures
Examples: antibodies, hormones, and enzymes

28. Protein Denuaturation
Reversible unfolding of proteins due to drops in pH and/or increased temperature
Figure 2.18a

29. Protein Denuaturation
Irreversibly denatured proteins cannot refold and are formed by extreme pH or temperature changes
Figure 2.18b

30. Molecular Chaperones (Chaperonins)
Help other proteins to achieve their functional three-dimensional shape
Maintain folding integrity
Assist in translocation of proteins across membranes
Promote the breakdown of damaged or denatured proteins

31. Characteristics of Enzymes
Most are globular proteins that act as biological catalysts
Holoenzymes consist of an apoenzyme (protein) and a cofactor (usually an ion)
Enzymes are chemically specific
Frequently named for the type of reaction they catalyze
Enzyme names usually end in -ase
Lower activation energy

32. Characteristics of Enzymes
Figure 2.19

33. Mechanism of Enzyme Action
Enzyme binds with substrate
Product is formed at a lower activation energy
Product is released
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How Enzymes Work

34. Mechanism of Enzyme Action
Active site
Amino acids 1
Enzyme (E)
Substrates (s)
Enzyme-substrate complex (E–S)
H20
Free enzyme (E) 2 3
Peptide bond
Internal rearrangements leading to catalysis
Dipeptide product (P)
Figure 2.20

35. Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus
Nucleic Acids
Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus
Their structural unit, the nucleotide, is composed of N-containing base, a pentose sugar, and a phosphate group
Five nitrogen bases contribute to nucleotide structure – adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U)
Two major classes – DNA and RNA

36. Deoxyribonucleic Acid (DNA)
Double-stranded helical molecule found in the nucleus of the cell
Replicates itself before the cell divides, ensuring genetic continuity
Provides instructions for protein synthesis

37. Structure of DNA
Figure 2.21a

38. Structure of DNA
Figure 2.21b

39. Ribonucleic Acid (RNA)
Single-stranded molecule found in both the nucleus and the cytoplasm of a cell
Uses the nitrogenous base uracil instead of thymine
Three varieties of RNA: messenger RNA, transfer RNA, and ribosomal RNA

40. Adenosine Triphosphate (ATP)
Source of immediately usable energy for the cell
Adenine-containing RNA nucleotide with three phosphate groups

41. Adenosine Triphosphate (ATP)
Figure 2.22

42. How ATP Drives Cellular Work
Figure 2.23