01_Lecture_W16_BIO_1110_UPDATED_ONLINE

Cell Basics

• Cytoplasm: The gel-like substance within the cell membrane where organelles are suspended.

• Ribosomes: Protein synthesis sites; can be free-floating in the cytoplasm or attached to the endoplasmic reticulum.

• Mitochondria: Known as the powerhouses of the cell, they generate ATP through cellular respiration.

• Lysosomes: Organelles that contain digestive enzymes to break down waste and cellular debris.

• Nucleus: Contains the cell's genetic material and controls its activities.

• Endoplasmic Reticulum: Involved in protein and lipid synthesis; Rough ER has ribosomes, Smooth ER does not.

• Golgi Body: Modifies, sorts, and packages proteins and lipids for secretion or use within the cell.

• Vacuole: Storage organelle, larger in plant cells, helps maintain turgor pressure.

• Cell Membrane: A phospholipid bilayer that protects the cell, controlling the movement of substances in and out of the cell.

Chapter 1: Introduction to Biology Today

Understanding Science

• Definition: Derived from the Latin word meaning "to know"; encompasses a body of knowledge and a process for understanding the natural world.

• Features:

  • Involves asking questions and making observations.

  • Emphasizes inquiry and experimentation for knowledge acquisition.

The Capabilities of Science

• Explanations: Provide insights into the natural world; particularly observable and measurable phenomena.

• Limitations: Cannot study or explain supernatural occurrences.

• Testability: Explanations must be testable, allowing for evidence collection.

• Falsifiability: A core component; must be possible to disprove an explanation.

• Ongoing Process: Scientific conclusions are provisional and subject to change based on new evidence.

Biology: The Study of Life

• Definition: Biology is the scientific exploration of life.

• Characteristics of Living Things:

  • Properties are displayed through actions rather than simple definitions.

  • Key properties include ordered structure, homeostasis, growth, metabolism, responsiveness, reproduction, and evolution (adaptation).

Diversity of Life

• Species Estimates: At least 290,000 plant species, 52,000 vertebrates, and over 1 million insects identified; total species estimates range from 10 million to 100 million.

• Three Domains of Life:

  1. Bacteria

  2. Archaea

  3. Eukarya

     • Subdivisions: Protists, Fungi, Plants, Animals.

  • Humans belong to the Eukarya domain.

Hierarchical Organization of Life

• Levels of Biological Organization:

  1. Biosphere

  2. Ecosystems

  3. Communities

  4. Populations

  5. Organisms

  6. Organ Systems and Organs

  7. Tissues

  8. Cells

  9. Organelles

  10. Molecules and Atoms

• Properties of life emerge at various organizational levels.

Major Themes in Biology

• Structure and Function: Investigates how biological structures relate to their functions.

• Information Flow: How genetic information is transferred and expressed.

• Energy Transformations: The processes through which energy is transformed to support life.

• Interconnections within Systems: Understanding the complexity and interactions among biological systems.

The Process of Science

• Types of Science:

  • Discovery Science: Observational and descriptive.

  • Hypothesis-Driven Science: Experimental and explanatory.

The Scientific Method

• Process Overview: A formalized approach to conducting science involving:

  1. Observation: Noting phenomena.

  2. Question: Formulating a question based on observations.

  3. Hypothesis: Proposing a testable and falsifiable explanation.

  4. Experimentation: Conducting tests to support or refute the hypothesis.

  5. Analysis: Evaluating data to arrive at conclusions.

Hypothesis Formation

• Definition: A statement predicting a specific outcome of an experiment.

• Criteria: Must be specific, testable, and falsifiable and often framed as "If ___, then ___" statements.

Benefits and Outcomes of Scientific Inquiry

• Exploration and Discovery: Motivated by curiosity, technology, and practical problems.

• Testing Ideas: Involves peer review, replication, and theoretical development.

• Community Engagement: Sharing findings and acquiring feedback.

Proper Experimental Design

• Key Components:

  • Treatment: The condition applied to experimental groups.

  • Experimental Group: Receives treatment whereas the control group does not.

  • Variables: Elements that can change in an experiment, categorized as independent or dependent.

  • Replication: Repeating experiments to verify results.

Controlling Variables

• Significance: Ensures that only the independent variable affects the dependent variable—essential for valid results.

• Definitions:

  • Independent Variable: The factor manipulated by the researcher.

  • Dependent Variable: The factor being measured in response to changes in the independent variable.

Illustration of the Scientific Process

• Data Collection and Analysis:

  • Use graphs to represent the dependent (y-axis) and independent (x-axis) variables to examine trends and correlations.

Science Theories

• Definition: A comprehensive explanation supported by substantial evidence and repeatedly tested.

• Examples: Atomic theory, gravitational theory, cell theory, evolutionary theory.

• Purpose: Theories provide a framework for exploring and generating new hypotheses.