BIG BIO TEST 1.pdf

Chapter 1: Introduction to Biology Criteria for Life: All living things share five criteria: cellular organization, metabolism, homeostasis, growth and reproduction, and heredity. Major Unifying Theories: ○ Cell Theory: All living organisms are composed of...

Chapter 1: Introduction to Biology Criteria for Life: All living things share five criteria: cellular organization, metabolism, homeostasis, growth and reproduction, and heredity. Major Unifying Theories: ○ Cell Theory: All living organisms are composed of cells, and all cells come from pre-existing cells. ○ Central Dogma: Describes the flow of genetic information within a biological system (DNA → RNA → Protein). A gene is a segment of DNA that encodes a functional product. ○ Theory of Evolution: Natural selection involves variation, inheritance, and differential fitness. Micron (µm): A micrometer is one-millionth of a meter. Base units for the metric system include meters (length), grams (mass), and liters (volume). Hypothesis: A testable statement. Null Hypothesis: A statement that there is no effect or difference. Scientific Theory: A well-substantiated explanation of some aspect of the natural world. Well-Designed Experiment: Includes controls, independent and dependent variables, and clear, interpretable results. Hierarchical Organization: Atoms → Molecules → Organelles → Cells → Tissues → Organs → Organ Systems → Organisms. Classification and Nomenclature: Use Linnaean binomial nomenclature (Genus species). Species Definition: A group of organisms that can interbreed and produce fertile offspring. Limitations include hybrid species and asexual organisms. Three-Domain System: Bacteria, Archaea, Eukarya. Four Eukaryotic Kingdoms: Protista, Fungi, Plantae, Animalia. Prokaryotic vs. Eukaryotic Cells: Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have both. Phylogenetic Trees: Show evolutionary relationships among species. Biodiversity: The variety of life and its importance for ecosystem stability and resilience. Chapter 2: Chemistry of Life Chemical Terms: Elements, atoms (protons, neutrons, electrons), bonds (hydrogen, ionic, covalent). Periodic Table: Determines the number of protons, neutrons, and electrons. Atomic Structure: Shell model configuration of electrons. Chemical Symbols: Common elements in living things include C, H, O, N, P, S. Water’s Role: Hydrogen bonding, evaporation, adhesion, cohesion, solvent properties, hydrolysis, and condensation. pH: Scale from 0 to 14, with acids 7. Buffers maintain stable pH in living organisms. Organic Compounds: Proteins, nucleic acids, carbohydrates, lipids contain carbon and are covalently bonded. Functional Groups: Specific groups of atoms within molecules that confer specific chemical properties. Hydrocarbons: Contain only carbon and hydrogen. Chapter 3: Proteins and Enzymes Building Blocks of Proteins: Amino acids, which have a core structure that varies by the side chain (R group). Hydrophilic vs. Hydrophobic: Hydrophilic substances interact with water, while hydrophobic substances repel water. Protein Diversity: Proteins vary in size, shape, and function. Levels of Protein Structure: ○ Primary: Sequence of amino acids. ○ Secondary: Alpha helices and beta sheets. ○ Tertiary: Three-dimensional folding. ○ Quaternary: Multiple polypeptide chains. Protein Folding: Proper folding is essential for function. Denaturation: Loss of structure and function, which can be reversible or irreversible. Examples of Proteins: Hemoglobin (oxygen transport), enzymes (catalysis). Enzymes: Good catalysts because they lower the activation energy of reactions. Proteins and Genes: Genes encode proteins, which perform various functions in the cell. Chapter 4: Nucleic Acids Building Blocks of Nucleic Acids: Nucleotides, which consist of a nitrogenous base, a five-carbon sugar (deoxyribose in DNA and ribose in RNA), and one or more phosphate groups. Sugar-Phosphate Backbone: The backbone of DNA and RNA is composed of alternating sugar and phosphate groups. It has chemical directionality, running from the 5’ end (phosphate group) to the 3’ end (hydroxyl group). Complementary Base Pairing: In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). In RNA, adenine pairs with uracil (U) instead of thymine. Storage and Transmission of Genetic Information: DNA stores genetic information in the sequence of its bases, which is transcribed into RNA. RNA then translates this information into proteins. RNA’s Versatility: RNA can fold into various shapes, allowing it to perform multiple functions, such as catalysis, gene regulation, and serving as a template for protein synthesis. RNA and Evolution of Life: RNA is hypothesized to have been the first genetic material, capable of both storing genetic information and catalyzing chemical reactions, which may have sparked the evolution of life. DNA vs. RNA: DNA is double-stranded, stable, and stores genetic information long-term. RNA is single-stranded, more versatile, and involved in protein synthesis and regulation. Chapter 5: Carbohydrates Building Blocks and Functions: ○ Monosaccharides: Simple sugars like glucose and fructose. ○ Disaccharides: Two monosaccharides linked together, such as sucrose and lactose. ○ Polysaccharides: Long chains of monosaccharides, such as starch (plants), glycogen (animals), and cellulose (plants). Structure and Functions: Carbohydrates provide energy, store energy, and serve as structural components in cells. Potential Energy in Bonds: Energy is stored in the chemical bonds of molecules, particularly in the bonds of carbohydrates, which can be broken down to release energy. Chapter 6: Lipids Structure and Functions: Lipids include fats, oils, phospholipids, and steroids. They store energy, provide insulation, and make up cell membranes. Fluid Mosaic Model: Describes the structure of the plasma membrane as a mosaic of components, including phospholipids, cholesterol, and proteins, that move fluidly. Selective Permeability: Membranes allow some substances to pass while blocking others, maintaining homeostasis. Osmosis: Water moves through a semi-permeable membrane from a hypotonic (low solute) to a hypertonic (high solute) solution. Isotonic solutions have equal solute concentrations. Transport Mechanisms: ○ Simple Diffusion: Movement of molecules from high to low concentration without energy. ○ Facilitated Diffusion: Movement through a membrane protein from high to low concentration without energy. ○ Active Transport: Movement against the concentration gradient using energy (ATP). Chapter 7: Cell Structure and Function Cell Size: Small size allows for efficient nutrient uptake and waste removal. Compartmentalization in Eukarya: Organelles allow for specialized functions. Bacteria lack this level of compartmentalization due to their simpler structure. Eukaryotic vs. Prokaryotic Cells: Eukaryotic cells have a nucleus and membrane-bound organelles, while prokaryotic cells do not. Organelles and Their Functions: ○ Ribosomes: Protein synthesis. ○ Nucleus: Contains DNA; nuclear membrane has pores for transport. ○ Chromosomes/Chromatin: DNA and protein complex within the nucleus. ○ Plasma Membrane: Phospholipid bilayer with embedded proteins; fluidity affected by temperature and lipid composition. ○ Cell Wall: Found in plants, fungi, and bacteria; provides structure and protection. ○ Endomembrane System: Includes the ER, Golgi apparatus, lysosomes, and vesicles; involved in protein and lipid synthesis and transport. ○ Endoplasmic Reticulum (ER): Rough ER has ribosomes for protein synthesis; smooth ER synthesizes lipids. ○ Golgi Apparatus: Modifies, sorts, and packages proteins and lipids. ○ Lysosomes: Contain enzymes for digestion; involved in autophagy, receptor-mediated endocytosis, and phagocytosis. ○ Peroxisomes: Break down fatty acids and detoxify harmful substances. ○ Mitochondria: Powerhouse of the cell; site of ATP production. ○ Chloroplasts: Site of photosynthesis in plant cells. ○ Nucleolus: Produces ribosomal RNA. ○ Central Vacuole: Found in plant cells; stores nutrients and waste products. ○ Cytoskeleton: Provides structural support and aids in cell movement. Microtubules: Maintain cell shape and facilitate cell division. Microfilaments: Involved in muscle contraction and cell movement. Intermediate Filaments: Provide mechanical support.