Lecture Notes - The Cell PDF

LECTURE NOTES IN BIOCHEMISTRY Lecture 1 - The Cell Learning Objectives: By the end of this lesson, you should be able to: 1. Discuss the three major parts of a eukaryotic cell: nucleus, cytoplasm, and cell membrane. 2. E...

LECTURE NOTES IN BIOCHEMISTRY Lecture 1 - The Cell Learning Objectives: By the end of this lesson, you should be able to: 1. Discuss the three major parts of a eukaryotic cell: nucleus, cytoplasm, and cell membrane. 2. Explain the role of water, buffer, and mineral ions in living cells. 3. Identify organelles and classify their functions (regulatory, defense, synthesis, or transport). 4. State the biochemical substances present in organelles of the cell. Biochemistry The study of chemical substances in living organisms and how they interact. Inorganic substances in cells: ○ Water ○ Buffer ○ Mineral ions Biochemical Substances in Cells 1. Bioinorganic substances: ○ Water, buffer, minerals. 2. Bioorganic substances: ○ Proteins (15%) ○ Lipids (8%) ○ Carbohydrates (2%) ○ Nucleic acids (2%) ○ Enzymes, coenzymes, and energy-rich systems 1 Prepared by: CCepeda Water (60-80% of body weight): Essential properties: ○ High heat of vaporization: helps cool the body. ○ High heat capacity: prevents abrupt temperature changes. ○ Polar solvent properties: dissolves and dissociates ionic substances. ○ Reactivity: vital for hydrolysis and dehydration synthesis. ○ Cushioning: protects organs from physical trauma. Buffers: Resist changes in pH when small amounts of acid or base are added. Maintain pH balance in biological systems, crucial for survival. The Cell: Eukaryotic Structure Fundamental unit of life. Composed of organelles, each performing specific functions: ○ Regulatory ○ Transport ○ Synthesis ○ Defense Three Major Parts: 1. Nucleus 2. Cytoplasm 3. Cell Membrane I. Nucleus: The "brain" of the cell, controlling all cellular activities. Contains DNA, the main site for nucleic acid biosynthesis. Nucleolus: Site for RNA and protein biosynthesis. Chromosomes are located here, conjugated with histone proteins. 2 Prepared by: CCepeda II. Cytoplasm: A living material surrounding the nucleus, where metabolic processes occur. The cytoplasm contains organelles and a liquid portion called cytosol. Organelles include: ○ Ribosomes: Sites for protein synthesis. ○ Smooth ER: Lipid synthesis and detoxification. ○ Lysosomes: Defense organelles containing hydrolytic enzymes for intracellular digestion. ○ Mitochondria: The powerhouse of the cell, generating ATP through cellular respiration. III. Cell Membrane: Outer boundary of the cell, enclosing the cytoplasm. Composed of a phospholipid bilayer with embedded proteins and cholesterol for fluidity. Functions: ○ Selectively allows substances in and out of the cell. ○ Supports communication between cells. Key Cellular Organelles: 1. Nucleus: Site of nucleic acid (DNA/RNA) synthesis. 2. Nucleolus: Produces RNA and proteins. 3. Ribosomes: Protein synthesis. 4. Lysosomes: Contain hydrolytic enzymes for digestion. 5. Mitochondria: Generate ATP via the electron transport chain (ETC). 6. Golgi Apparatus: Packages cellular secretions, modifies proteins, synthesizes carbohydrates. 7. Peroxisomes: Break down fatty acids and neutralize free radicals. Important Concepts: Electron Transport Chain (ETC): Takes place in mitochondria, producing ATP by transferring electrons through enzyme complexes. Buffers in Cells: Help maintain pH levels critical for cell function. Cell Membrane: Maintains the fine balance of salts, water, and organic matter essential for life. 3 Prepared by: CCepeda Summary of Biochemical Systems in Organelles: Nucleus: Nucleic acids, proteins, lipids. Nucleolus: RNA, proteins. Ribosomes: RNA, proteins. Lysosomes: Proteins (hydrolytic enzymes). Mitochondria: CHONs (proteins), CHOs (carbohydrates), NAs (nucleic acids), ATP. Golgi Apparatus: Proteins, carbohydrates, lipids. Cell Membrane: Proteins, lipids, carbohydrates. 4 Prepared by: CCepeda