Biochemistry

OBJECTIVE: Investigate and understand the chemical and biochemical principles essential for life. Key concepts include- b) the structure and function of macromolecules c) the nature of enzymes.

Most life processes are a series of chemical reactions influenced by environmental and genetic factors.

Metabolism the sum of all biochemical processes

2 Metabolic Processes Anabolism- the building up of complex molecules Catabolism- the breaking down of complex molecules

The main components of a living cell are: Carbon Hydrogen Nitrogen Oxygen -Phosphorus -Sulfur

Inside every cell is a concentrated mixture of thousands of different macromolecules forming a variety of specialized structures that carry out cell functions, such as: energy production transport waste disposal synthesis (creation) of new molecules storage of genetic material.

Organic Compounds Compounds that contain CARBON are called organic. Macromolecules are large organic molecules.

Carbon (C) Carbon has 4 electrons in outer shell Carbon can form covalent bonds with as many as 4 other atoms (elements) Usually with H, O, N, or C Example: C6H12O6 (sugar)

Macromolecules Large organic molecules. Also called POLYMERS. Made up of smaller “building blocks” called MONOMERS. Examples: 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids (DNA and RNA)

1. Carbohydrates Small sugar molecules to large sugar molecules. Examples: A. monosaccharide B. disaccharide C. polysaccharide

1. Carbohydrates A. monosaccharide: one sugar unit Examples: glucose (C6H12O6 blood sugar) deoxyribose ribose galactose (milk sugar) fructose (honey) glucose

B. disaccharide: two sugar unit Example: sucrose = glucose + fructose

C. polysaccharide: many sugar units Examples: starch (bread, potatoes) glycogen (beef muscle) cellulose (lettuce, corn) chitin (exoskeletons) glucose cellulose

The primary functions of carbohydrate macromolecules are to: provide and store energy.

2. Lipids General term for compounds which are not soluble in water. Lipids are soluble in hydrophobic solvents. Remember: “stores the most energy”

2. Lipids Examples: 1. Fats 2. Phospholipids 3. Oils 4. Waxes 5. Steroid hormones 6. Triglycerides

5 functions of lipids: 1. Long term energy storage (fat) 2. Protection against heat loss (insulation) 3. Protection against water loss & germs (oils & waxes) 4. Chemical messengers (hormones & steroids) 5. Major component of membranes (phospholipids)

Triglycerides: composed of 1 glycerol and 3 fatty acids. H H-C----O glycerol O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = fatty acids O C-CH2-CH2-CH2-CH =CH-CH2-CH2-CH2-CH2-CH3 =

There are two kinds of fatty acids you may see on food labels: 1. Saturated fatty acids: no double bonds (bad) 2. Unsaturated fatty acids: double bonds (good) O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = saturated O C-CH2-CH2-CH2-CH =CH-CH2-CH2-CH2-CH2-CH3 = unsaturated

3. Proteins (Polypeptides) Amino acids (the building blocks of protein) 2 kinds of amino acids essential & non-essential amino acids Essential amino acids cannot be synthesized by our body & need to be obtained through our diet

7 functions of proteins: 1. Storage: albumin (egg white) 2. Transport: hemoglobin 3. Regulatory: hormones 4. Movement: muscles 5. Structural: membranes, hair, nails 6. Enzymes: cellular reactions 7. Defense: antibodies

A protein’s structure depends on its specific job The sequence of amino acids and the shape of the chain are a consequence of attractions between the chain’s parts.

Four levels of protein structure: A. Primary Structure (1°) B. Secondary Structure (2°) C. Tertiary Structure (3°) D. Quaternary Structure (4°)

A. Primary Structure (1°) Amino acids bonded together by peptide bonds. aa1 aa2 aa3 aa4 aa5 aa6 Peptide Bonds Amino Acids (aa)

B. Secondary Structure (2°) 3-dimensional folding arrangement of a primary structure into coils and pleats held together by hydrogen bonds.

B. Secondary Structure (2°) Two examples: Alpha Helix Beta Pleated Sheet Hydrogen Bonds

Alpha Helix Beta Pleated Sheets

C. Tertiary Structure (3°) Secondary structures bend and fold into a more complex 3-D arrangement. Called a “subunit”.

C. Tertiary Structure (3°) Alpha Helix Beta Pleated Sheet

Alpha Helix & Beta Pleated Sheets joined together Subunit: Alpha Helix & Beta Pleated Sheets joined together

D. Quaternary Structure (4°) Composed of 2 or more “subunits”. Example: enzymes (hemoglobin) 3° subunits

Subunits

Enzymes: Special Proteins

Enzymes Enzymes are proteins that help speed-up chemical reactions in the body. Enzymes are specific in their choosing Each enzyme has only one reaction it can help.

Enzymes are always recycled when they perform their function. The specific enzyme can be used over and over again. The structure is what determines its function. High temperatures or changes in pH can affect the structure of an enzyme and make it unusable. This is called denaturation.

The place where the substrate binds to an enzyme is called the active site. Enzymes and substrates fit together like a lock & key.

Most cells function best within a narrow range of temperature and pH. At very low temperatures, reaction rates are too slow. High temperatures or extremes of pH can irreversibly change the structure of proteins and alter their function.

4. Nucleic acids Nucleic acids (DNA and RNA) control cell activities by controlling protein synthesis

4. Nucleic acids Two types: 1. deoxyribonucleic acid (DNA-double helix) 2. ribonucleic acid (RNA-single strand) Nucleic acids are composed of long chains of nucleotides

4. Nucleic acids Nucleotides: phosphate group sugar (5-carbon) nitrogenous bases adenine (A) thymine (T) - uracil (U) RNA cytosine (C) guanine (G)

Nucleotide O O=P-O N CH2 O C1 C4 C3 C2 Phosphate Group Nitrogenous base (A, G, C, or T) CH2 O C1 C4 C3 C2 5 Sugar (deoxyribose)

DNA - double helix P O 1 2 3 4 5 P O 1 2 3 4 5 G C T A

Thank You