1. Organic compounds - Contain carbon & hydrogen, are covalently bonded
Biochemistry
Organic compounds - Contain carbon & hydrogen, are covalently bonded
Inorganic compounds
Water, salts, and many acids and bases
acid HCl --> H+ (proton donor) + Cl- pH below 7
base NaOH --> Na+ (cation) + OH- , proton acceptor, pH above 7
salt NaCl --> Na+ (cation) + Cl- (anion), pH 7

2. Figure 2.14

3. Organic Compounds
Carbohydrates
Lipids
Proteins
Nucleic Acids

4. Contain carbon, hydrogen, and oxygen Function: source of cellular food
Carbohydrates
Contain carbon, hydrogen, and oxygen
Function: source of cellular food
Examples: Monosaccharides or simple sugars
6-carbon structural isomers
Figure 2.14a

5. Figure 2.16

7. Figure 2.15a

8. Figure 2.17

9. Figure 2.15b

10. Disaccharides or double sugars
Carbohydrates
Disaccharides or double sugars
Figure 2.14b

11. Polysaccharides or polymers of simple sugars
Carbohydrates
Polysaccharides or polymers of simple sugars
Figure 2.14c

12. Starch vs. Cellulose (fiber)

13. 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

14. Neutral Fats (Triglycerides)
Composed of three fatty acids bonded to a glycerol molecule
Neutral fats – found in subcutaneous tissue and around organs
Figure 2.15a

15. Figure 2.19

16. Phospholipids – chief component of cell membranes
Other Lipids
Phospholipids – modified triglycerides with two fatty acid groups and a phosphorus group
Phospholipids – chief component of cell membranes
Figure 2.15b

17. Figure 2.20

18. Steroids – four interlocking hydrocarbon rings
Other Lipids
Steroids – four interlocking hydrocarbon rings
cholesterol, bile salts, vitamin D, sex hormones, and adrenal cortical hormones
Figure 2.15c

19. Amino Acids
Building blocks of protein, containing an amino group, NH2 and a carboxyl (acid) group COOH

20. Figure 2.23a

22. Protein
Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds
Amino acid
Dehydration
synthesis
Hydrolysis
Dipeptide
Peptide bond + N H C R O
H2O OH
Figure 2.17

23. Structural Levels of Proteins
Primary
Secondary
Tertiary
Quaternary

24. Structural Levels of Proteins
Figure 2.18a–c

25. Structural Levels of Proteins
Figure 2.18b,d,e

26. Protein Denaturation
Reversible unfolding of proteins due to drops in pH and/or increased temperature
Figure 2.19a

27. Protein Denaturation
Irreversibly denatured proteins cannot refold and are formed by extreme pH or temperature changes
Figure 2.19b

28. 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

30. Characteristics of Enzymes
Figure 2.20

31. Mechanism of Enzyme Action
Enzyme binds with substrate
Product is formed at a lower activation energy
Product is released
Active site
Amino acids
Enzyme (E)
Enzyme-substrate
complex (E-S)
Internal rearrangements
leading to catalysis
Dipeptide product (P)
Free enzyme (E)
Substrates (S)
Peptide bond
H2O +

32. Nucleic acids are polymers of monomers called nucleotides.
Each nucleotide consists of three parts: a nitrogen base, a pentose sugar, and a phosphate group

33. Nucleic Acids
Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus
Their structural unit, the nucleotide composed of
N-containing base
pentose sugar
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

34. 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

35. Structure of DNA
Figure 2.22b

36. 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

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

38. Figure 2.29

39. The capacity to do work (put matter into motion) Types of energy
Kinetic – energy in action
Potential – energy of position; stored (inactive) energy

40. Forms of Energy
Chemical – stored in the bonds of chemical substances
Electrical – results from the movement of charged particles
Mechanical – directly involved in moving matter
Radiant or electromagnetic – energy traveling in waves (i.e., visible light, ultraviolet light, and X-rays)
Energy is easily converted from one form to another (First Law of Thermodynamics)
During conversion, some energy is “lost” as heat ( Second Law of Thermodynamics - Entropy)

41. An exergonic reaction - release of free energy
Chemical reactions can be classified as either exergonic (exothermic) or endergonic (endothermic)
An exergonic reaction - release of free energy
lower potential energy in endproduct
Fig. 6.6a
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42. An endergonic reaction is one that absorbs free energy from its surroundings.
Endergonic reactions store energy greater potential energy in endproduct
Sunlight- source of energy for photosynthesis
Fig. 6.6b
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43. ATP couples exergonic reactions to endergonic reactions
ATP (adenosine triphosphate) is a type of nucleotide consisting of the nitrogenous base adenine, the sugar ribose, and a chain of three phosphate groups.
Fig. 6.8a
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44. The bonds between phosphate groups can be broken by hydrolysis.
ATP is regenerated by adding a phosphate group to ADP.

45. Enzymes speed up metabolic reactions by lowering energy barriers
A catalyst is a chemical agent that changes the rate of a reaction without being consumed by the reaction.
An enzyme is an organic catalyst.
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46. Exergonic reaction requiring Activation energy
Activation energy is the amount of energy necessary to push the reactants over an energy barrier.
Fig. 6.12
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47. Figure 2.26

48. Enzyme speed reactions by lowering EA.
The transition state can then be reached even at moderate temperatures (body temperature).
Enzymes hasten reactions that would occur eventually.
enzymes are selective they determine which chemical processes will occur at any time.
Fig. 6.13
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49. Enzymes are substrate specific
A substrate is a reactant which binds to an enzyme at its active site.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings