Lecture 01 BSC2010 Sci & Chem

Scientific Method

• Steps of the Scientific Method:

  1. Make Observations:

     • Begin by observing phenomena needing explanation.

  2. Ask a Question:

     • Formulate a question based on observations.

  3. Formulate Hypotheses:

     • Propose possible explanations (hypotheses) to answer the question.

  4. Make Predictions:

     • Determine what must be true if the hypothesis is correct.

  5. Conduct an Experiment:

     • Design an experiment to test the hypothesis, controlling for variables.

  6. Analyze Results:

     • Test results support or reject the hypothesis; repeat experiments as necessary.

Learning Objectives

• End of Lecture Goals:

  • List and relate the organizing principles of life to the domains of life.

  • Evaluate scientific data to support or refute hypotheses.

  • Compare and contrast discovery-based vs hypothesis-driven scientific inquiry.

  • Explain the differences between atoms and molecules and the forces acting upon them (van der Waals, hydrophobic, ionic, covalent, hydrogen bonds).

Fundamental Principles of Life

• Common Traits of Living Organisms:

  • Composed of cells.

  • Depend on interactions among complex parts for maintaining life.

  • Possess genetic information in a universal code.

  • Convert environmental molecules into biological molecules.

  • Extract energy from the environment for life processes.

  • Replicate genetic information for reproduction.

  • Share a fundamental set of similar genes.

  • Evolve through gradual genetic changes.

Characteristics of Living Organisms

• Characteristics to Consider:

  • Regulation of internal environment.

  • Cell composition.

  • Trait plasticity in response to need.

  • Energy extraction capabilities.

  • Ability to produce biological molecules.

Scientific Investigation Principles

• Basis of Science:

  • Science relies on quantifiable observations, experimentation, and reasoning.

  • Understanding natural history: obtaining food, reproduction, behavior.

  • Enhancing Observations:

    • Utilization of technology (microscopes, imaging).

  • Importance of quantifying observations through measurement and calculations.

  • Observations lead to further inquiries.

Types of Scientific Inquiry

• Broad Methodologies:

  • Discovery-Based Research:

    • Analyzes existing data for new patterns, forming hypotheses.

    • Examples: particle colliders, genome sequencing.

  • Hypothesis-Driven Research:

    • Formulates and tests hypotheses based on observations.

Experimental Design Steps

• Steps in an Experiment:

  1. Make observations.

  2. Ask a question.

  3. Construct a hypothesis for a possible answer.

  4. Make predictions based on the hypothesis (use if-then statements).

  5. Design and conduct the experiment (e.g., cell culture experiments).

  6. Analyze results and revise hypotheses as needed.

Atomic Structure and Elements

• Atomic Composition:

  • Atoms consist of protons (positive), electrons (negative), and neutrons (neutral).

  • Elements are categorized based on atomic structures (92 naturally occurring elements).

  • Major biological elements: Hydrogen (H), Carbon (C), Oxygen (O), Nitrogen (N).

Properties of Electrons and Bonds

• Atomic Structure Influence:

  • Electrons determine chemical bonding and molecular shape.

  • Shell and orbital structure dictate energy levels.

  • Atoms form stable molecules by filling outer electron shells following the octet rule.

Chemical Bonds Overview

• Types of Chemical Bonds:

  • Ionic Bonds:

    • Formed between atoms with significant electronegativity differences, resulting in charged ions.

  • Covalent Bonds:

    • Formed by the sharing of electron pairs between atoms, can be polar or nonpolar depending on electronegativity.

Additional Interactions

• Weak Interactions:

  • Hydrogen Bonds:

    • Occur between slightly charged atoms (e.g., between water molecules).

  • van der Waals Interactions:

    • Temporary dipoles due to electron movement, resulting in weak attractions among molecules.