Introduction to Cell Biology PDF - Kwame Nkrumah University

Introduction to Cell Biology Prince E. Adjei Kwame Nkrumah University of Science and Technology Topic: The Chemistry of the Cell Module 0: Introduction to Cell Biology Cell Biology (BME 161) © 2024 Prince E. Adjei  Chemistry of...

Introduction to Cell Biology Prince E. Adjei Kwame Nkrumah University of Science and Technology Topic: The Chemistry of the Cell Module 0: Introduction to Cell Biology Cell Biology (BME 161) © 2024 Prince E. Adjei  Chemistry of Cells Topics: (1). Water and Its Role in the Cell (2). Chemical Bonds in Biological Systems (3). Bonding in Biomolecules (4). Chemical Engineering Applications in Biological Systems  Learning Objectives Describe the importance of water in maintaining cellular structure and supporting biochemical reactions. Identify key ions and small molecules involved in cellular processes and explain their functions. Explain how different types of chemical bonds contribute to macromolecule structure and function. Understand the role of pH and buffers in regulating cellular environments and enzyme activity. Apply knowledge of chemistry to real-world applications, such as biomaterials and bioprocess engineering.  Review Cell is the basic structural and functional unit of cellular organisms, except viruses. Cell Theory states: 1. All organisms are composed of one or more cells. 2. Cells are the basic unit of structure and function in organisms. 3. All cells come only from other cells. WATER  Red represents Oxygen atom Grey represents 2 Hydrogen atom  Water Water: is considered a polar molecule has a positive and negative end  Water All living organisms are dependent on water. The structure of water is the basis for its properties. The most important property of water is the ability to form hydrogen bonds.  Importance of Water in the Cell Water is: a vital chemical of living cells makes up 60-90% of the fresh mass of an organism Fresh mass = solid components + water Dry mass= solid components Water as a Medium for Biochemical Reactions Breaking down lipids and carbohydrates Photosynthesis  Water for Transport Acts as a transport medium in blood, lymphatic, excretory, digestive systems, and vascular tissue of plants.  Water to Aid in Lubrication mucus and synovial fluid consist of water. mucus - assists in the movement of food substances. synovial fluid - eases the movement of the joint  Water For Support gives support in hydrostatic skeletons eg. in earthworms An earthworm moving  Water In Plant Cells is needed in plant cells for cell enlargement, cell turgidity, and support in plants.  Cooling Effect of Water has a cooling effect: transpiration in plants and sweating and panting in animals.  Water for Seed Germination needed for seed germination - testa swells and splits after being imbibed.  Water for Osmotic Balance Dissolved inorganic salts in water maintain the osmotic balance in animal blood and interstitial fluid.  Chemical Bonds There are several bonds in biological systems. They include: Covalent bonds, Ionic bonds, Hydrogen bonds, and Vander Waal forces  Covalent Bonds A covalent bond forms when two non-metal atoms share electrons to achieve a stable electron configuration (full outer shell).  Covalent Bonds Formation of these bonds : Electron Sharing: Atoms share electrons to become more stable Molecule Formation: Covalent bonds form molecules (e.g., H₂, O₂, H₂O). Bond Strength: Covalent bonds are strong due to shared electrons.  Ionic Bonds An ionic bond forms when one atom transfers electrons to another, creating oppositely charged ions that attract each other. Formation: Electron Transfer: One atom loses electrons (becomes positively charged), the other gains electrons (becomes negatively charged). Ion Attraction: The oppositely charged ions are held together by electrostatic attraction. Bond Strength: Ionic bonds are strong but can dissolve in water.  Hydrogen Bonds A hydrogen bond is a weak interaction between a hydrogen atom covalently bonded to an electronegative atom (oxygen in water) and another electronegative atom. In water (H₂O), the oxygen atom is highly electronegative, creating a partial negative charge (δ−) on oxygen and partial positive charges (δ+) on the hydrogens.  Van der waal Forces Van der Waals forces are weak, non-covalent interactions between molecules or atoms due to temporary shifts in electron distribution. Temporary Dipoles: Electrons in atoms or molecules move randomly, creating temporary positive and negative regions (dipoles). Attraction: These temporary dipoles cause weak attraction between neighboring molecules or atoms. Weak but Important: Though weak, these forces are crucial for the properties of gases, liquids, and solids.  Bonding in Biomolecules Proteins: Hydrogen bonds and disulfide bonds stabilize protein folding and function.  Bonding in Biomolecules DNA: Hydrogen bonds between complementary bases hold the double helix structure. These bases pair in a particular manner: Adenine (A) pairs with Thymine (T) Cytosine (C) pairs with Guanine (G)  Bonding in Biomolecules Lipids: Van der Waals forces contribute to the fluidity of the lipid bilayer in cell membranes Recommended Materials