Biochemistry: A Molecular View of Life

1. Biochemistry: A Molecular View of Life

2. Overview • Take a look at the cell • Discuss Metabolism • Cover the are 4 major groups of macromolecules • Carbohydrates • Lipids • Proteins • Nucleic acids

3. The Living Cell Biochemistry is the chemistry of living things and life processes.

4. The Living Cell The basic structural unit of all living organisms is the cell. All cells are enclosed in a cell membrane, which regulates the passage of nutrients and wastes.

5. The Living Cell In addition to a cellmembrane, plant cells are surrounded by a cell wallcomposed of cellulose.

6. The Living Cell Nucleus: The largest structure within the cell. The nucleus contains the genetic material that controls heredity. Ribosomes: The structure where proteinsynthesis occurs. Mitochrondria: The cell structure where energyproduction occurs.

7. The Living Cell Plant Cell Chloroplasts: Found only in plant cells. In the chloroplasts, photosynthesis occurs.

8. Energy in Biological Systems Green plants contain chloroplasts, which are capable of taking the radiant energy of the sunand storing it as chemical energy in glucosemolecules. ENERGY + 6 CO2 + 6 H2O → C6H12O6 + 6 O2 Plant cells can also convert carbohydrate molecules to fat molecules, and some are even capable of converting them to proteins. Animalscannot produce their own energy. They must obtain such energy by eating plants or other animals that eat plants.

9. Energy in Biological Systems Metabolism is defined as the series of chemical reactions that keep a cell alive. Metabolicreactions are divided into two categories: • Catabolism: The process of breaking down molecules to produce energy. • Anabolism: The process of synthesizing molecules (consumes energy).

10. Condensation Polymers In condensation polymerization, small molecules such as water, alcohols, ammonia, or HCl are released as by-products. 1 2 + + H2O Amide bond

11. Macromolecules: Introduction There are 4 large molecules (macromolecules) in the cell that that perform many important operations in the cell • Carbohydrates • Lipids • Proteins • Nucleic Acids Many are condensation polymers.

12. Carbohydrates Carbohydrates are polyhydroxyaldehydes or ketones or compounds that can be hydrolyzed to form such compounds. Monosaccharides: Carbohydrates that cannot be hydrolyzed into simpler compounds.

13. Carbohydrates Disaccharidesconsist of molecules that can be hydrolyzed into two monosaccharide units. Polysaccharidesare composed of large molecules that can be hydrolyzed into many monosaccharide units. Examples include starch, cellulose, and glycogen.

14. Carbohydrates Starchis composed of two polymers, amyloseand amylopectin. • In amylose, the glucose molecules are connected in long parallel chains. • In amylopectin, the chains are branched.

15. Fats and Other Lipids Lipids are biological molecules that are insoluble in water, but are soluble in nonpolarorganic solvents. Fatsare esters of long-chain fatty acids and glycerol. Fats are often called triglycerides or triacylglycerols.

16. Fats and Other Lipids Fatty Acids

17. Proteins are a vital component of all living things. Proteins

18. Proteins are polymers of amino acids. Amino acidscontain both an amineand carboxylate group attached to the same carbon called the alpha carbon. Proteins Peptide Bond 1 2 + + H2O amide Polypeptides if ten or more amino acid units. Proteins may contain 1000’s of amino acid units.

19. Proteins Amino Acids: There are 20 types

20. 4 Levels of Proteins Structure Primary structure: The primary structure of a protein is simply the sequence of amino acids from N-terminalto C-terminal. Asp-Arg-Val-Tyr-Ile-His-Pro-Phe Secondary structure: How the polypeptide chain folds and coils due to hydrogen bonding of the backbone amide groups. Examples include the alpha helix and beta-pleated sheet.

21. Tertiary structure: The three-dimensional shape of a protein due to the spatial relationships of groupsthat are far apart on the protein chain. One example is the protein chain in globular proteins. Structure of Proteins Quaternary structure: Involves the interaction of more than one peptide chain.

22. Structure of Proteins Four Ways to Link Protein Chains • Hydrogen bond: Hydrogen bonds are formed between amide nitrogen (N-H) and carboxyl oxygen (C=O). • Ionic bonds: Sometimes called salt bridges. These occur between oppositely charged side chains. • Disulfide linkages: When two cysteine side chains are oxidized, a (-S-S-) disulfide linkage can form. • Dispersion forces: These are attractive forces between two nonpolar side chains.

23. Nucleic Acids Nucleic acids serve as the information and control centers of the cell. They are in two major forms. Both consist of long chains (polymers) called nucleotides • deoxyribonucleic acid (DNA) • ribonucleic acid (RNA).

24. Nucleic Acids Monomer: Each nucleotideis composed of a; sugar unit phosphate unit heterocyclic aminebase.

25. Nucleotides are composed of a sugar, phosphate, and an amine base. Nucleic Acids DNA consists of a double helix.

26. Nucleic Acids The Information is obtained from a nucleic acid through base-pairing. Complimentary bases are thymine (T) and adenine (A), and cytosine (C) and guanine (G). These complimentary bases are held together by hydrogen bonding. T-A (DNA) U-A (RNA) C-G

27. DNA: Self-Replication

28. Nucleic Acids Structure of RNA RNA consists of single strands of nucleic acid.

29. Summary The cell is the basic unit of life Metabolism is as the series of chemical reactions that keep a cell alive There are 4 major macromolecules: they are mostly polymers 4. Carbohydratesare polyalcohols (with carbonylgroups) that are used for energy storage (starch) and structure (celullose) 5. Lipidsare biological molecules that are insoluble in water. Triacylgyceridesare three fatty acids 6. Proteins are polymers of amino acids. 7. Nucleic acids are polymers of nucleic acid and serve as the information and control centersof the cell