EXAM 1 RECAP

Scientific Method

  • Steps in the Scientific Method:

    1. Observation

    2. Question

    3. Hypothesis/Prediction: Educated guess that is evidence-based, falsifiable, and testable.

    4. Data/Evaluate

    5. Conclusion

    6. Share data

Testing Hypotheses

  • Control Experiment:

    • Composed of two groups: Experimental and Control.

    • Manipulate the independent variable in the experimental group.

    • The experimental variable receives treatment to establish causation.

  • Correlation vs. Causation:

    • Causation can only be established through experiments.

  • Sample Size:

    • Minimum of 30 people in experimental groups (n > 30).

  • Alternative Experimental Designs:

    • Use of three or more groups and levels of treatment.

  • Natural Experiment:

    • No manipulation by scientists; nature performs the manipulation.

Properties of Life

  • Reproduction

  • Order

  • Growth and Development

  • Response to Environment

  • Energy Processing

  • Regulation/Homeostasis

  • Evolutionary Adaptation

Biological Hierarchy

  • Atom

  • Molecules

  • Cells (important for exam)

  • Tissues

  • Organs

  • Organ Systems

  • Organisms

Taxonomy

  • Three Domains:

    1. Bacteria

    2. Archaea

    3. Eukarya

  • Four Kingdoms of Eukarya:

    • Plants

    • Animals

    • Fungi

    • Protists

  • Hierarchical Levels:

    • Kingdom

    • Phylum

    • Class

    • Order

    • Family

    • Genus

    • Species

Electronegativity

  • Definition: Ability of an element to attract electrons.

  • Octet Rule: Elements tend to fill their outer shell with 8 electrons (exception: hydrogen).

Types of Chemical Bonds

Ionic Bond

  • Electrons are gained or lost, forming ions.

  • Attraction occurs between positively and negatively charged ions.

Covalent Bond

  • Atoms share electrons.

  • Polar Covalent Bond: Unequal sharing of electrons, leading to Hydrogen Bonds (weak bonds).

Properties of Water

  • Solvent: The substance that dissolves; Solute: The substance being dissolved.

  • Ice floats on water due to being less dense because of maximum hydrogen bonding.

  • Cohesion: Water molecules stick together, leading to surface tension.

  • Adhesion: Water molecules stick to other substances.

Chemical Properties

Heat Capacity

  • Water requires a significant amount of heat to increase its temperature.

Hydrophilic vs. Hydrophobic

  • Hydrophilic: Compounds that love water (ionic or polar).

  • Hydrophobic: Compounds that fear water (lipids or nonpolar).

Acids and Bases

  • Acid: Substance that donates hydrogen ions in solution.

  • Base: Substance that removes hydrogen ions from solution.

  • pH Scale: Measures concentration of hydrogen ions; ranges from 0 (acidic) to 14 (basic).

Biological Importance of pH

  • Specific pH is essential for enzyme activity and function.

Biomolecules

  • All biomolecules are built on a carbon framework; can form four stable covalent bonds leading to various structures.

  • Functional Groups: Specific groups of atoms that change the function of molecules.

Reactions Involving Biomolecules

  • Monomers → Polymers (dehydration reaction).

  • Polymers → Monomers (hydrolysis reaction).

Types of Biomolecules

Carbohydrates

  • Elements: C, H, O (ratio 1:2:1).

  • Monosaccharides: Glucose.

  • Polysaccharides:

    • Starch (plant storage),

    • Glycogen (animal nutrient storage),

    • Cellulose (structural in cell walls),

    • Chitin (insect exoskeleton).

Lipids

  • Types: Steroids, Phospholipids, and Triglycerides.

  • Saturated (no double bonds, solid) vs. Unsaturated (double bonds, liquid).

Proteins

  • Elements: C, H, O, N (and sometimes S for sulfur).

  • Comprised of amino acids and form polypeptides.

  • Four Levels of Protein Structure:

    1. Primary Structure: Amino acid sequence.

    2. Secondary Structure: α-helix and β-sheet.

    3. Tertiary Structure: 3D structure.

    4. Quaternary Structure: Interaction of multiple folded proteins (e.g., hemoglobin).

Nucleic Acids

  • Elements: C, H, O, N, P.

  • Comprised of nucleotides; examples include DNA and RNA.

RNA vs. DNA

  • DNA: Double-stranded; stores genetic information; nitrogenous bases A, T, C, G; contains deoxyribose.

  • RNA: Single-stranded; used in protein production and stores genetic info for viruses; nitrogenous bases A, U, C, G; contains ribose.

Cell Types

Eukaryotic Cells

  • Include plants, animals, fungi, and protists; possess a nucleus.

Prokaryotic Cells

  • Include bacteria and archaea; lack a nucleus.

Organelles

  • Mitochondria: Energy production.

  • Rough Endoplasmic Reticulum (RER): Protein synthesis.

  • Smooth Endoplasmic Reticulum (SER): Lipid synthesis and detoxification.

  • Lysosomes: Recycling of materials.

  • Golgi Apparatus: Protein processing and shipping.

  • Ribosomes: Protein factory.

Plasma Membrane Structure

  • Composed of:

    1. Phospholipid bilayer.

    2. Cholesterol (for patching and lubrication).

    3. Proteins:

      • Integral: Imbedded in the membrane.

      • Peripheral: Stuck to one side.

    4. Glycocalyx: Carbohydrate chains for cell adhesion and binding.

Membrane Permeability

  • Semi-permeable Membrane: Allows specific compounds to pass.

  • Water moves toward higher solute concentration.

Transport Mechanisms

Active Transport

  • Requires energy to move substances against the concentration gradient.

Passive Transport

  • No energy required; substances move down the concentration gradient.

    • Diffusion: Movement from high to low concentration.

    • Facilitated Diffusion: Requires protein channels for transport.

    • Osmosis: Movement of water from low to high solute concentration.

Bulk Transport Processes

  • Exocytosis: Cell expelling materials via vesicles.

  • Endocytosis: Cell engulfing materials, forming vesicles.

    • Pinocytosis: "Cell Drinking" (fluids).

    • Phagocytosis: "Cell Eating" (larger particles, e.g., bacteria).