General Biology: Foundational Concepts and Processes (Chapters 1–5, 7)

Chapter 1: Biology – The Study of Scientific Life

Properties and Organization of Life

• Properties of Life: Living organisms exhibit order, regulation, growth and development, energy processing, response to the environment, reproduction, and evolutionary adaptation.

• Hierarchy of Biological Organization: Life is organized from the smallest to largest as: molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere.

• Emergent Properties: New properties arise at each level of organization that are not present at the preceding level.

Scientific Method and Hypotheses

• Hypothesis: A testable and falsifiable explanation for an observation.

• Control Group: Provides a basis for comparison in experiments.

• Scientific Theory: Broader than a hypothesis, supported by a large body of evidence.

Energy Flow and Ecosystems

• Energy Flow: Energy enters ecosystems as sunlight and exits as heat; matter cycles within the ecosystem.

• Producers, Consumers, Decomposers: Producers (plants) convert energy, consumers eat other organisms, decomposers recycle nutrients.

Evolution and Unity of Life

• Evolution: The process by which species change over time through natural selection and adaptation.

• Genetic Code: All living things share a common genetic code, reflecting evolutionary unity.

Chapter 2: The Chemical Basis of Life

Elements and Compounds

• Major Elements: The four most common elements in living organisms are C, H, O, N (carbon, hydrogen, oxygen, nitrogen).

• Trace Elements: Required in small amounts (e.g., iron, zinc).

Atoms and Chemical Bonds

• Atomic Structure: Atoms consist of protons, neutrons, and electrons. Atomic number = number of protons.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Covalent Bonds: Atoms share electrons; can be polar (unequal sharing) or nonpolar (equal sharing).

• Ionic Bonds: Transfer of electrons from one atom to another.

• Hydrogen Bonds: Weak bonds important in water and biological molecules.

Water and Its Properties

• Cohesion and Adhesion: Water molecules stick to each other and to other substances.

• Ice Floats: Ice is less dense than liquid water due to hydrogen bonding.

• Solvent of Life: Water dissolves many substances, facilitating chemical reactions.

pH and Buffers

• pH Scale: Measures hydrogen ion concentration; lower pH = more acidic.

• Buffers: Substances that minimize changes in pH.

Chapter 3: The Molecules of Cells

Organic Molecules and Functional Groups

• Carbon: Forms four covalent bonds, allowing for diverse organic molecules.

• Functional Groups: Specific groups of atoms (e.g., hydroxyl, carboxyl, amino, phosphate) that determine molecule properties.

Macromolecules

• Carbohydrates: Sugars and polymers of sugars; main energy source. Example: glycogen in animals, starch in plants.

• Lipids: Fats, phospholipids, steroids; hydrophobic molecules used for energy storage and cell membranes.

• Proteins: Polymers of amino acids; structure determined by sequence and folding. Functions include enzymes, transport, structure.

• Nucleic Acids: DNA and RNA; store and transmit genetic information.

Enzymes

• Enzymes: Biological catalysts that speed up reactions by lowering activation energy.

• Denaturation: Loss of protein structure and function due to environmental changes (e.g., temperature, pH).

Chapter 4: A Tour of the Cell

Microscopy and Cell Structure

• Light Microscopes: Use light and glass lenses to magnify images.

• Electron Microscopes: Use electron beams for higher resolution; can view cell ultrastructure.

Prokaryotic vs. Eukaryotic Cells

• Prokaryotic Cells: Lack a nucleus and membrane-bound organelles (e.g., bacteria).

• Eukaryotic Cells: Have a nucleus and organelles (e.g., plants, animals, fungi, protists).

Cell Organelles and Functions

• Nucleus: Contains DNA and controls cell activities.

• Ribosomes: Synthesize proteins.

• Endoplasmic Reticulum (ER): Rough ER synthesizes proteins; smooth ER synthesizes lipids.

• Golgi Apparatus: Modifies, sorts, and ships proteins and lipids.

• Lysosomes: Digest cellular waste and macromolecules.

• Vacuoles: Storage and structural support in plant cells.

• Mitochondria: Site of cellular respiration and ATP production.

• Chloroplasts: Site of photosynthesis in plant cells.

Chapter 5: The Working Cell

Membrane Structure and Function

• Fluid Mosaic Model: Describes the plasma membrane as a flexible layer with proteins embedded in or attached to a phospholipid bilayer.

• Selective Permeability: The membrane allows some substances to cross more easily than others.

Transport Across Membranes

• Passive Transport: Diffusion of substances across a membrane without energy input (includes simple diffusion, facilitated diffusion, osmosis).

• Active Transport: Movement of substances against their concentration gradient, requiring energy (ATP).

• Endocytosis and Exocytosis: Bulk transport of materials into (endocytosis) or out of (exocytosis) the cell.

Enzymes and Metabolism

• Metabolism: All chemical reactions in a cell.

• Exergonic vs. Endergonic Reactions: Exergonic reactions release energy; endergonic reactions absorb energy.

• ATP: Main energy currency of the cell.

• Enzyme Inhibition: Competitive and noncompetitive inhibitors regulate enzyme activity.

Chapter 7: Photosynthesis – Using Light to Make Food

Overview of Photosynthesis

• Photosynthesis: The process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose.

• Location: Occurs in the chloroplasts of plant cells.

Light Reactions

• Light Reactions: Capture solar energy and convert it to chemical energy (ATP and NADPH), releasing oxygen as a byproduct.

• Photosystems: Protein complexes in the thylakoid membrane that absorb light and transfer electrons.

Calvin Cycle

• Calvin Cycle: Uses ATP and NADPH from the light reactions to convert CO2 into glucose.

• Key Steps: Carbon fixation, reduction, release of G3P, regeneration of RuBP.

Summary Equation

• Overall Equation for Photosynthesis:

$6CO_2 + 6H_2O + light\ energy \rightarrow C_6H_{12}O_6 + 6O_2$

Diagrammatic Representation

• See provided diagrams for the flow of electrons in the light reactions and the steps of the Calvin cycle.

Additional info: Diagrams referenced in the materials illustrate the electron transport chain in the thylakoid membrane and the cyclic nature of the Calvin cycle, showing the transformation of energy and carbon compounds.