Biology: Biomolecules and Proteins

Organization of Life

• Levels of organization: molecules, organelles, cells, tissues, organs, organ systems, organisms

Importance of Water

• Water is essential for life, making up approximately 60-70% of an organism's body weight
• Water's unique chemical and physical properties allow it to play a crucial role in biological processes

Biomolecules

Amino Acids

• Building blocks of proteins
• 20 standard amino acids, classified as essential or non-essential
• Amino acids linked by peptide bonds form a polypeptide chain

Carbohydrates

• Provide energy and structural support
• Classified as monosaccharides, disaccharides, and polysaccharides
• Examples: glucose, fructose, sucrose, lactose, glycogen, starch, cellulose

Lipids

• Energy storage and structural components of cells
• Include triglycerides (fats and oils), phospholipids, and steroids
• Examples: cholesterol, phosphatidylcholine, triolein

Proteins

• Perform a wide range of functions: structural, enzymatic, transport, and storage
• Primary structure: sequence of amino acids
• Secondary structure: α-helices and β-pleated sheets

Protein Structure, Folding, and Function

Myoglobin

• Oxygen storage protein in muscles
• Has a hydrophobic pocket that binds oxygen

Hemoglobin

• Oxygen transport protein in red blood cells
• Tetrameric structure with each subunit containing a heme group

Lysozyme

• Enzyme that breaks down bacterial cell walls
• Hydrolyzes peptidoglycan, a component of bacterial cell walls

Ribonuclease A

• Enzyme that breaks down RNA
• Hydrolyzes the phosphodiester bond between nucleotides

Carboxypeptidase and Chymotrypsin

• Digestive enzymes that break down proteins
• Carboxypeptidase cleaves peptide bonds at the C-terminus, while chymotrypsin cleaves at specific internal sites

Enzyme Kinetics

• Enzyme regulation involves controlling enzyme activity to achieve desired outcomes
• Enzyme inhibition can be competitive, non-competitive, or uncompetitive, affecting substrate binding and enzyme activity

Vitamins and Coenzymes

• Vitamins are essential nutrients that cannot be synthesized by the body
• Coenzymes are molecules that assist enzymes in catalyzing reactions

Metabolism and Bioenergetics

• ATP (adenosine triphosphate) is the primary energy currency of the cell
• Generation of ATP involves cellular respiration and photosynthesis
• Utilization of ATP involves energy-requiring processes like muscle contraction and transport

Metabolic Pathways

• Glycolysis: converts glucose into pyruvate, generating ATP and NADH
• TCA (tricarboxylic acid) cycle: converts pyruvate into acetyl-CoA, generating ATP, NADH, and FADH2
• Pentose phosphate pathway: generates NADPH and pentoses from glucose
• Oxidative phosphorylation: generates ATP from electron transport chain
• Gluconeogenesis: generates glucose from non-carbohydrate sources
• Glycogen metabolism: stores and breaks down glycogen, a complex carbohydrate
• Fatty acid metabolism: breaks down fatty acids to generate ATP and NADH

Nitrogen Metabolism

• Nitrogen fixation: converts atmospheric nitrogen into ammonia
• Amino acid metabolism: involves synthesis and breakdown of amino acids
• Nucleotide metabolism: involves synthesis and breakdown of nucleotides

Photosynthesis

• Calvin cycle: converts CO2 into glucose using ATP and NADPH from light-dependent reactions