1. Chemistry Comes Alive Part B2
Chemistry Comes Alive
Part B

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

3. Organic Compounds
Molecules unique to living systems contain carbon and hence are organic compounds
They include:
Carbohydrates
Lipids
Proteins
Nucleic Acids

4. 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

5. Carbohydrates
Disaccharides or double sugars
Figure 2.13b

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

7. 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

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

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

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

11. 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

12. 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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13. Amino Acids
Figure 2.15a-c

14. Amino Acids
Figure 2.15d, e

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

16. 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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17. 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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18. Primary and Secondary Structural Levels of Proteins
Figure 2.17a-c

19. Structural Levels of Proteins
Figure 2.17d, e

20. 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

21. Molecular Chaperones (Chaperonins)
Chaperones are globular proteins that help other proteins. They help by:
Helping other proteins to achieve their three-dimensional shape
Maintaining folding integrity
Assisting in translocation of proteins across membranes
Promoting the breakdown of damaged or denatured proteins

22. Enzymes
Enzymes are also globular proteins that act as biological catalysts.
A catalyst is a chemical that speeds up or regulates the rate of reactions.
Enzymes are chemically specific and Frequently named for the type of reaction they catalyze
Enzyme names usually end in -ase

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

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

25. Characteristics of Enzymes
Figure 2.19

26. Enzymes
Enzymes can be either purely protein or can have a protein and another attached element.
Enzymes that have two parts are called holoenzymes.
The protein part of a holoenzyme is called an apoenzyme.
The other element part is called the cofactor.
Most cofactors come from vitamins.

27. Enzymes
The main purpose of an enzyme is to lower the energy need to make a reaction start called Activation Energy.
How enzymes do this is not entirely understood, but the following steps are known.

28. Mechanism of Enzyme Action
Enzyme binds with a substrate (substrate is the substance needing to react)
The substrate rearranges its shape to better bond. Energy is absorbed and water is released.
Product is released and Enzyme goes off to find another substrate.
The rearranging of the substrate allows it to bond more easily and therefore lowers the energy needed to make it work.

29. 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

30. 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

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

32. Adenosine Triphosphate (ATP)
Figure 2.22