Zoology Cheatsheet

Cheatsheet Content

### Zoology in Science - **One-World View:** Interconnectedness of all life forms. - **Genetic Unity:** All life shares a common genetic code (DNA/RNA) and fundamental cellular units. - **Evolutionary Oneness:** Diversity of life arises from common ancestry through evolution. - **Environment & Resources:** Zoology studies interactions between animals and their environment, vital for resource management. - **What is Zoology?** The scientific study of animals, including their structure, function, behavior, and evolution. - **Classification:** Hierarchical system (taxonomy) used to group and name animals based on shared characteristics. - **Scientific Method:** A systematic approach to inquiry: observation, hypothesis, experiment, analysis, conclusion. ### The Chemical Basis of Animal Life #### Atoms and Elements: Building Blocks of All Matter - **Atoms:** The smallest unit of an element that retains the chemical identity of that element. Composed of protons, neutrons, and electrons. - **Elements:** Pure substances consisting only of atoms that all have the same number of protons (atomic number). Key elements in animal life include Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), and Sulfur (S). #### Compounds and Molecules: Aggregates of Atoms - **Molecules:** Two or more atoms held together by chemical bonds. Can be composed of atoms of the same element (e.g., O₂) or different elements (e.g., H₂O). - **Compounds:** Molecules that contain at least two different elements bonded together in a fixed ratio (e.g., H₂O, CO₂, Glucose C₆H₁₂O₆). - **Chemical Bonds:** Forces that hold atoms together in molecules and compounds. - **Covalent Bonds:** Formed when atoms share electrons (e.g., C-H bonds in organic molecules). Can be polar or nonpolar. - **Ionic Bonds:** Formed by the electrostatic attraction between oppositely charged ions, which result from the transfer of electrons between atoms (e.g., NaCl). - **Hydrogen Bonds:** Weak attractions between a partially positive hydrogen atom in one molecule and a partially negative atom (like oxygen or nitrogen) in another molecule. Crucial for water properties and protein/DNA structure. #### Acids, Bases, and Buffers - **Acids:** Substances that release hydrogen ions (H⁺) when dissolved in water, increasing the H⁺ concentration (pH 7). - **Buffers:** Solutions that resist changes in pH when small amounts of acid or base are added. They typically consist of a weak acid and its conjugate base, or a weak base and its conjugate acid. Essential for maintaining stable internal environments (homeostasis) in living organisms. #### Molecules of Animals (Macromolecules) - **Carbohydrates:** - **Structure:** Organic compounds made of carbon, hydrogen, and oxygen, typically with a (CH₂O)n ratio. - **Function:** Primary source of quick energy (e.g., glucose, fructose), and structural components (e.g., cellulose in plants, chitin in arthropods). - **Types:** Monosaccharides (simple sugars), Disaccharides (two monosaccharides), Polysaccharides (long chains of monosaccharides like starch, glycogen). - **Lipids:** - **Structure:** Diverse group of hydrophobic (water-fearing) molecules, primarily composed of carbon and hydrogen. - **Function:** Long-term energy storage, insulation, structural components of cell membranes (phospholipids), and hormones (steroids). - **Types:** Fats (triglycerides), phospholipids, steroids. - **Proteins:** - **Structure:** Complex macromolecules made of long chains of amino acids linked by peptide bonds. They fold into specific 3D structures crucial for their function. - **Function:** Extremely diverse roles including acting as enzymes (biological catalysts), structural support (collagen, keratin), transport (hemoglobin), defense (antibodies), and communication (hormones). - **Nucleotides:** - **Structure:** Composed of a five-carbon sugar (ribose or deoxyribose), a nitrogenous base (adenine, guanine, cytosine, thymine, or uracil), and one or more phosphate groups. - **Function:** Building blocks of nucleic acids, and also function as energy carriers (e.g., ATP - adenosine triphosphate), coenzymes, and signaling molecules. - **Nucleic Acids:** - **Structure:** Polymers of nucleotides. - **Function:** Store and transmit genetic information. - **Types:** - **DNA (Deoxyribonucleic Acid):** Double helix structure, stores hereditary information. - **RNA (Ribonucleic Acid):** Single-stranded, involved in gene expression and protein synthesis (mRNA, tRNA, rRNA). ### Cells, Tissues, Organs, & Organ Systems - **Cell Membranes:** Phospholipid bilayer with embedded proteins; selectively permeable. - **Movement Across Membranes:** - **Passive:** Diffusion, osmosis, facilitated diffusion (no energy). - **Active:** Requires energy (ATP) to move against concentration gradient. - **Cytoplasm, Organelles & Cellular Components:** - **Ribosomes:** Protein synthesis. - **Endoplasmic Reticulum (ER):** - **Rough ER:** Protein synthesis and modification (with ribosomes). - **Smooth ER:** Lipid synthesis, detoxification. - **Golgi Apparatus:** Modifies, sorts, and packages proteins and lipids. - **Lysosomes:** Digest waste materials and cellular debris. - **Mitochondria:** "Powerhouses" of the cell; ATP production via cellular respiration. - **Cytoskeleton:** Structural support, cell movement (microtubules, microfilaments, intermediate filaments). - **Cilia & Flagella:** Hair-like structures for movement. - **Centrioles & Microtubules:** Involved in cell division and cytoskeleton organization. - **Vacuoles:** Storage and waste removal (more prominent in plants, but present in some animal cells). - **The Nucleus:** - **Nuclear Envelope:** Double membrane surrounding the nucleus. - **Chromosomes:** Condensed DNA carrying genetic information. - **Nucleolus:** Ribosome synthesis. - **Tissues:** Groups of similar cells performing a specific function. - **Epithelial:** Cover surfaces, line cavities, form glands. - **Connective:** Support, protect, bind together other tissues (e.g., bone, blood, fat). - **Muscle:** Contraction for movement (skeletal, smooth, cardiac). - **Nervous:** Transmit electrical signals (neurons, glial cells). - **Structural Integration:** Tissues form organs, organs form organ systems, working together to maintain homeostasis. ### Energy & Enzymes: Life's Driving Forces - **Energy & Laws of Transformation:** - **First Law (Conservation):** Energy cannot be created or destroyed, only transformed. - **Second Law (Entropy):** Transformations increase disorder (entropy) in the universe. - **Activation Energy:** Energy required to initiate a chemical reaction. - **Enzymes:** Biological catalysts (proteins) that speed up reactions by lowering activation energy. - **Structure:** Specific 3D shape with an active site. - **Function:** Bind to specific substrates. - **Factors Affecting Activity:** Temperature, pH, substrate concentration, inhibitors. - **Cofactors & Coenzymes:** Non-protein helpers required by some enzymes (e.g., metal ions, vitamins). - **ATP (Adenosine Triphosphate):** Primary energy currency of the cell, used for most cellular work. ### How Animals Harvest Energy from Nutrients - **Glycolysis:** - First stage of glucose breakdown. - Occurs in cytoplasm. - Glucose (6C) $\rightarrow$ 2 Pyruvate (3C). - Produces 2 ATP (net) and 2 NADH. - **Fermentation:** - Anaerobic process (without oxygen). - Regenerates NAD⁺ for glycolysis. - Produces lactic acid (animals) or alcohol (yeast). - Yields much less ATP than aerobic respiration. - **Aerobic Respiration:** - Major source of ATP in presence of oxygen. - Occurs in mitochondria. - **Stages:** Pyruvate oxidation, Krebs cycle, Electron Transport Chain (ETC). - Produces ~30-32 ATP per glucose molecule. - **Metabolism of Fats & Proteins:** - Fats broken down into fatty acids and glycerol, entering pathways at different points (e.g., fatty acids $\rightarrow$ acetyl-CoA). - Proteins broken down into amino acids, which can be converted to intermediates of glycolysis or the Krebs cycle. - **Control of Metabolism:** Regulated by enzymes, hormones, and feedback mechanisms to meet cellular needs. - **Metabolic Pool:** Interconnected network of metabolic pathways where intermediates can be interconverted. ### Ecology I: Individuals & Populations - **Animals & Abiotic Environment:** Interactions with non-living factors (temperature, water, light, soil). - **Populations:** Group of individuals of the same species in the same area. - **Characteristics:** Size, density, dispersion, birth/death rates, growth patterns. - **Population Growth:** Exponential vs. logistic models. - **Limiting Factors:** Resources, predation, disease. - **Interspecific Interactions:** Interactions between different species. - **Competition:** Negative for both. - **Predation:** Predator benefits, prey harmed. - **Herbivory:** Herbivore benefits, plant harmed. - **Parasitism:** Parasite benefits, host harmed. - **Mutualism:** Both benefit. - **Commensalism:** One benefits, other unaffected. ### Ecology II: Communities & Ecosystems - **Community Structure & Diversity:** - **Community:** All populations of different species living and interacting in an area. - **Species Diversity:** Number of different species (richness) and their relative abundances (evenness). - **Trophic Structure:** Feeding relationships (food chains, food webs). - **Ecological Succession:** Changes in community composition over time. - **Ecosystems:** Community of living organisms (biotic) interacting with their non-living environment (abiotic). - **Energy Flow:** Unidirectional, typically from sun $\rightarrow$ producers $\rightarrow$ consumers $\rightarrow$ decomposers. - **Nutrient Cycling:** Biogeochemical cycles (carbon, nitrogen, phosphorus, water). - **Ecosystems of the Earth:** Major biomes (e.g., forests, deserts, grasslands, aquatic biomes). - **Ecological Problems:** - **Human Population Growth:** Puts strain on resources. - **Pollution:** Contamination of air, water, soil. - **Resource Depletion:** Overuse of non-renewable and renewable resources. - **Biodiversity Loss:** Decline in species variety due to habitat destruction, climate change, etc.