Biochemistry SOL BIO 3 b,c
BIO 3 b, c OBJECTIVE: • TSW 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
At very low temperatures, reaction rates are too slow. • Most cells function best within a narrow range of temperature and pH. • High temperatures or extremes of pH can irreversibly change the structure of proteins and alter their function.
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. Nucleic acids (DNA and RNA) 4. Proteins
1. Carbohydrates • Small sugar molecules to large sugar molecules. • Examples: A. monosaccharide B. disaccharide C. polysaccharide
glucose 1. Carbohydrates A. monosaccharide: one sugar unit • Examples: glucose (C6H12O6 blood sugar) deoxyribose ribose galactose (milk sugar) fructose (honey)
fructose glucose B. disaccharide: two sugar unit • Example: sucrose = glucose + fructose
glucose glucose glucose glucose cellulose glucose glucose glucose glucose C. polysaccharide: many sugar units • Examples: starch (bread, potatoes) glycogen (beef muscle) cellulose (lettuce, corn) chitin (exoskeletons)
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)
O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = H H-C----O H-C----O H-C----O H O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = O C-CH2-CH2-CH2-CH fatty acids = =CH-CH2-CH2-CH2-CH2-CH3 glycerol • Triglycerides: composed of 1 glycerol and 3 fatty acids.
O C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 = saturated O C-CH2-CH2-CH2-CH = unsaturated =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)
3. Nucleic acids • Nucleic acids (DNA and RNA) control cell activities by controlling protein synthesis
3. 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
3. Nucleic acids • Nucleotides: Backbone: phosphate group sugar (5-carbon) nitrogenous bases: adenine (A) thymine (T) - uracil (U) RNA cytosine (C) guanine (G)
Nitrogenous Base pairs: • DNA: A-T RNA: A-U G-C G-C
Phosphate Group O O=P-O O 5 CH2 O N Nitrogenous base (A, G, C, or T) C1 C4 Sugar (deoxyribose) C3 C2 Nucleotide
5 O 3 3 O P P 5 5 C O G 1 3 2 4 4 1 2 3 5 O P P T A 3 5 O O 5 P P 3 DNA - double helix
4. 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°)
Amino Acids (aa) aa1 aa2 aa3 aa4 aa5 aa6 Peptide Bonds A. Primary Structure (1°) • Amino acids bonded together by peptide bonds.
B. Secondary Structure (2°) • 3-dimensional folding arrangement of a primary structure into coils and pleats held together by hydrogen bonds.
Alpha Helix Beta Pleated Sheet Hydrogen Bonds B. Secondary Structure (2°) Two examples:
Alpha Helix Beta Pleated Sheets
C. Tertiary Structure (3°) • Secondary structuresbend and fold into a more complex 3-D arrangement. • Called a “subunit”.
Alpha Helix Beta Pleated Sheet C. Tertiary Structure (3°)
3° subunits D. Quaternary Structure (4°) • Composed of 2 or more “subunits”. • Example: enzymes (hemoglobin)