Molecules and Biology_ Key Concepts.pdf

🧬 Molecules and Fundamentals of Biology 9/9/24, 4:25 PM Molecules and Biology: Key Concepts Basic Terminology Matter: Anything that takes up space and has mass. Element: A pure substance that has specific chemical...

🧬 Molecules and Fundamentals of Biology 9/9/24, 4:25 PM Molecules and Biology: Key Concepts Basic Terminology Matter: Anything that takes up space and has mass. Element: A pure substance that has specific chemical and physical properties and can't be broken down into a simpler substance. Atom: The smallest unit of matter that still retains the chemical properties of the element. "Atoms are the building blocks of matter, and they are the smallest units of a chemical element." Biological Chemistry Molecule: Two or more atoms joined together. Intramolecular forces: Attractive forces that act on atoms within a molecule. Intermolecular forces: Attractive forces that exist between molecules and affect the physical properties of the resulting substance. Monomers and Polymers Monomers: Single molecules with the capability of polymerizing. Polymers: Substances made of many monomers linked together. Polymerization: The continuous bonding of one monomer to another, forming a polymer. "Polymerization is a process in which monomers are linked together to form a larger molecule." Dehydration and Hydrolysis Reactions Dehydration (condensation) reaction: A polymerization reaction that results in the release of water. Hydrolysis: A depolymerization reaction that utilizes water to break bonds. 🍞 Carbohydrates Definition and Composition Carbohydrates: Molecules used for both fuel and structural support. Composition: Carbon, hydrogen, and oxygen. Types of Carbohydrates Type Monosaccharides Carbohydrate m Disaccharides Composed of two monosaccha Polysaccharides Contain multiple monosaccharides held togethe Examples of Polysaccharides Starch: Energy storage polysaccharide of glucose monomers used by plants. Glycogen: Energy storage polysaccharide of glucose monomers held together and used by animals. Cellulose: Structural support polysaccharides made of many glucose monomers, an important component of plant cell walls. https://www.turbolearn.ai/content/b0256e95-8912-4b40-8a03-b9b659d1a313 1/6  🧬 Protein Structure 9/9/24, 4:25 PM Molecules and Biology: Key Concepts Amino Acids Amino acids: Protein monomers composed of carbon, hydrogen, nitrogen, and oxygen. 20 different amino acids, each with a unique R (functional) group. Polypeptides Polypeptides (proteins): Strands of many amino acids held together by peptide bonds. Peptide bonds: Between the carboxyl group of one amino acid and the amino group of another, created by dehydration (condensation) reactions and broken by hydrolysis reactions. Protein Structural Levels Level Primary structure The simp Secondary structure Folding patterns of the Tertiary structure Three-dimen Quaternary structure Multip Conjugated Proteins Conjugated proteins: Composed of amino acids and non-protein components (e.g., metalloproteins, glycoproteins). Protein Denaturation Protein denaturation: The loss of protein function and higher-order structures. Factors that can cause denaturation: extreme temperatures, pH changes, salt concentrations. 🧬 Enzymes Definition and Function Enzymes: Biological catalysts, most are proteins. Active sites: Receptor regions on an enzyme that are specific for a substrate. Mechanisms of Enzyme Catalysis Common ways in which enzymes can catalyze reactions: Conformational changes to bring substrates closer together with correct orientation Stabilization of the transition state Having basic groups that can accept protons from a substrate Having acidic groups that can donate protons to a substrate Electrostatic interactions between the enzyme and the substrate Types of Enzymes https://www.turbolearn.ai/content/b0256e95-8912-4b40-8a03-b9b659d1a313 2/6 9/9/24, 4:25 PM Molecules and Biology: Key Concepts Type Phosphatase Cleavage of a pho Phosphorylase Directly adds a p Kinase Indirectly adds a phosphate group to a substrat 📊 Enzyme Inhibition and Kinetics Factors Influencing Enzyme Activity Temperature pH Substrate concentration Inhibitors Feedback Regulation A mechanism by which the end product of a metabolic pathway inhibits an earlier step in the pathway. Competitive Inhibition A type of inhibition in which the inhibitor competes with the substrate for the active site of the enzyme. Noncompetitive Inhibition A type of inhibition in which the inhibitor binds to a site other than the active site and reduces the enzyme's activity. Enzyme Kinetics Vmax: The maximum rate of the reaction. Km: The Michaelis constant, a measure of the binding affinity of the enzyme for the substrate.## Enzyme Inhibition and Kinetics 🧬 Types of Enzyme Inhibition Competitive Inhibition: A type of inhibition where a molecule directly competes with the substrate for the enzyme's active site. "Competitive inhibition occurs when a molecule, other than the substrate, binds to the active site of an enzyme, thereby blocking the substrate from binding and reducing the enzyme's activity." Noncompetitive Inhibition: A type of inhibition where a molecule binds to the enzyme's allosteric site, changing the shape of the active site and reducing the enzyme's activity. "Noncompetitive inhibition occurs when a molecule binds to the allosteric site of an enzyme, causing a conformational change that reduces the enzyme's activity, regardless of the presence of the substrate." Enzyme Kinetics Enzyme Kinetic Plots: Graphs used to visualize the effects of inhibitors on enzyme activity. Vmax: The maximum velocity of an enzyme-catalyzed reaction. Km: The Michaelis constant, which represents the substrate concentration required to reach half of the maximum velocity. Competitive Inhibition Effect on Km Increased https://www.turbolearn.ai/content/b0256e95-8912-4b40-8a03-b9b659d1a313 3/6 9/9/24, 4:25 PM Molecules and Biology: Key Concepts Competitive Inhibition Effect on Vmax No change Product Feedback Regulation Feedback Loops: Mechanisms by which the product of a reaction affects the rate of the reaction itself. Negative Feedback Loop: A type of feedback loop where the product of a reaction inhibits the reaction. Positive Feedback Loop: A type of feedback loop where the product of a reaction activates the reaction. Lipids 🥖 Fatty Acids Saturated Fatty Acids: Fatty acids with no double bonds in their hydrocarbon chain. Unsaturated Fatty Acids: Fatty acids with one or more double bonds in their hydrocarbon chain. Triglycerides Triglyceride: A type of lipid composed of a glycerol backbone and three fatty acid chains. "Triglycerides are the main component of animal fats and vegetable oils." Phospholipids Phospholipid: A type of lipid composed of a glycerol backbone, a phosphate group, and two fatty acid chains. "Phospholipids are amphipathic molecules, meaning they have both hydrophilic and hydrophobic regions." Factors Affecting Membrane Fluidity 🌡️ Temperature: Membrane fluidity increases with higher temperatures and decreases with lower temperatures. Cholesterol: Membrane fluidity increases with higher cholesterol concentrations and decreases with lower cholesterol concentrations. Fatty Acid Unsaturation: Membrane fluidity increases with higher levels of unsaturated fatty acids and decreases with higher levels of saturated fatty acids. Nucleic Acids 🧬 Nucleosides vs Nucleotides Nucleoside: A molecule composed of a sugar and a nitrogenous base. Nucleotide: A molecule composed of a sugar, a nitrogenous base, and one or more phosphate groups. RNA vs DNA RNA (Ribonucleic Acid): A single-stranded molecule containing ribose sugar nucleotides. DNA (Deoxyribonucleic Acid): A double-stranded molecule containing deoxyribose sugar nucleotides. Sugar-Phosphate Backbone Sugar-Phosphate Backbone: The structural chain of alternating sugars and phosphates that makes up the backbone of nucleic acids. "The sugar-phosphate backbone is held together by phosphodiester bonds between the 5' phosphate group of one nucleotide and the 3' hydroxyl group of another nucleotide." https://www.turbolearn.ai/content/b0256e95-8912-4b40-8a03-b9b659d1a313 4/6 9/9/24, 4:25 PM Molecules and Biology: Key Concepts Types of RNA mRNA (Messenger RNA): A single-stranded molecule that carries genetic information from DNA to the ribosome for protein synthesis. tRNA (Transfer RNA): A molecule that carries amino acids to the ribosome for protein synthesis. rRNA (Ribosomal RNA): A molecule that makes up a large part of the ribosome and plays a crucial role in protein synthesis. miRNA (MicroRNA): A small molecule that regulates gene expression by binding to mRNA and preventing its translation. dsRNA (Double-Stranded RNA): A molecule that contains complementary base pairing and is used by some viruses as a genetic material.## Nucleic Acids 🧬 Nucleic acids are a class of molecules that are all composed of either deoxyribose or ribose nucleic acids. Nucleosides and Nucleotides Nucleosides: made of 1 sugar and 1 nitrogenous base Nucleotides: nucleosides with the addition of phosphate(s) Types of Nucleic Acids Type DNA (Deoxyribonucleic acid) RNA (Ribonucleic acid) Structure of Nucleic Acids Sugar-phosphate backbone: formed by sugars and phosphates bonded together Phosphodiester bonds: hold nucleotides together via a condensation reaction Nitrogenous bases: paired in a specific manner to form the rungs of the DNA ladder Functions of RNA mRNA (Messenger RNA): encodes the information for protein production tRNA (Transfer RNA): transfers amino acids to ribosome enzymes rRNA (Ribosomal RNA): helps to form the ribosome enzymes miRNA (MicroRNA): can silence gene expression by binding to mRNA dsRNA (Double-stranded RNA): used by viruses to store genetic information Biological Hypotheses and Theories 🧬 Hypothesis vs. Theory A hypothesis is a proposed explanation of a scientific phenomenon that is based on prior knowledge but requires further testing and scrutiny. A theory is an explanation of a scientific phenomenon that has been accepted due to extensive testing yielding repetitive results. Primordial Earth Theory 🌎 Primordial atmosphere: comprised of inorganic compounds creating a reducing environment (low O gas) Primordial sea: formed when Earth cooled and gases condensed Evolution of life: simple compounds evolved into more complex organic compounds, which eventually formed the first cells Modern Cell Theory 🧬 https://www.turbolearn.ai/content/b0256e95-8912-4b40-8a03-b9b659d1a313 5/6 9/9/24, 4:25 PM Molecules and Biology: Key Concepts Cells are the basic structural, functional, and organizational unit of life All lifeforms have one or more cells Cells come from other cells via cell division Genetic information is stored and passed down through DNA Central Dogma of Genetics 🧬 Information is passed from DNA to RNA to proteins Exceptions: reverse transcriptase and prions RNA World Hypothesis 🌐 RNA was the first nucleic acid to store genetic information and catalyze chemical reactions RNA was eventually replaced by DNA and proteins as the major facilitators of these functions Endosymbiotic Theory 🌿 Eukaryotes developed when aerobic bacteria were internalized as mitochondria, while photosynthetic bacteria became chloroplasts Evidence: similarities between mitochondria and chloroplasts, including size, circular DNA, and ribosomes with a large and small subunit. https://www.turbolearn.ai/content/b0256e95-8912-4b40-8a03-b9b659d1a313 6/6