General Biology Lab Study Guide: Key Concepts and Skills

Lab 1 – Lab Safety

Lab Safety Rules and MSDS

Understanding laboratory safety is essential for preventing accidents and ensuring a safe working environment. The Material Safety Data Sheet (MSDS) provides critical information about chemicals used in the lab.

• Lab Safety Rules: Guidelines designed to protect students and staff from hazards in the laboratory.

• MSDS: A document that contains information on the properties of a particular substance, including hazards, handling, storage, and emergency measures.

• Key Information in MSDS: Chemical identity, hazard identification, first-aid measures, fire-fighting measures, accidental release measures, handling and storage, exposure controls, and personal protection.

Lab 2 – The Scientific Method

Steps and Reasoning in Scientific Investigation

The scientific method is a systematic approach to inquiry that helps scientists answer questions and solve problems.

• Steps of the Scientific Method:

  1. Observation

  2. Question

  3. Hypothesis

  4. Experiment

  5. Data Collection

  6. Analysis

  7. Conclusion

• Inductive Reasoning: Making generalizations based on specific observations.

• Deductive Reasoning: Making predictions based on general principles or theories.

• Application: Inductive reasoning is used to form hypotheses; deductive reasoning is used to test them.

Lab 3 & 4 – Scientific Notation and Metric System

Measurement, Calculation, and Scientific Notation

Accurate measurement and data representation are fundamental in biology. The metric system and scientific notation are standard tools for this purpose.

• Metric System: A decimal-based system of measurement (meter, liter, gram).

• Volume Calculation: Volume of a solid object (rectangular) is calculated as: $V = l \times w \times h$

• Density: The mass per unit volume of a substance. $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$

• Scientific Notation: A way to express very large or very small numbers using powers of ten (e.g., $3.2 \times 10^3$).

• Conversions: Ability to convert between units and express values in scientific notation.

• Mathematical Operations: Add, subtract, multiply, and divide using scientific notation.

Lab 5 – Microscopy

Types and Functions of Microscopes

Microscopes are essential tools in biology for observing structures too small to be seen with the naked eye.

• Types of Microscopes: Light microscopes, electron microscopes (transmission and scanning).

• Parts of the Microscope: Eyepiece, objective lenses, stage, light source, focus knobs, etc.

• Field of View: The visible area seen through the microscope; decreases as magnification increases.

• Working Distance: The distance between the objective lens and the specimen; decreases as magnification increases.

• Clarity: The sharpness of the image; affected by focus and lens quality.

• Electron vs. Light Microscopes: Electron microscopes provide higher magnification and resolution than light microscopes.

Lab 6 – Cellular Structure

Prokaryotic vs. Eukaryotic Cells and Organelles

Cells are the basic units of life, and understanding their structure is fundamental in biology.

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

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

• Cellular Organelles: Structures within cells that perform specific functions (e.g., mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus).

• Cell Models: Ability to identify organelles on diagrams or models.

• Plant vs. Animal Cells: Plant cells have cell walls, chloroplasts, and large central vacuoles; animal cells do not.

• Microscopy Application: Observing onion and cheek cells to identify cellular structures.

Lab 7 – Basic Chemistry Pt. 1

Atomic Structure and Chemical Reactions

Understanding atomic structure and chemical reactions is crucial for studying biological processes.

• Periodic Table: Tool for identifying atomic symbol, atomic mass, atomic number, number of protons, neutrons, and electrons.

• Atomic Number: Number of protons in an atom.

• Atomic Mass: Sum of protons and neutrons.

• Chemical Reactions: Indicators include formation of a solid (precipitate), gas, temperature change, or color change.

Lab 8 – Basic Chemistry Pt. 2

Acids, Bases, and Chemical Classification

Acids and bases are important in biological systems, and understanding their properties is essential.

• Acids: Substances that release hydrogen ions ($H^+$) in solution.

• Bases: Substances that release hydroxide ions ($OH^-$) in solution.

• Neutralization Reaction: When an acid reacts with a base to form water and a salt. Example: $\text{HCl} + \text{NaOH} \rightarrow \text{H}_2\text{O} + \text{NaCl}$

• pH Scale: Measures acidity or basicity; acids have pH < 7, bases have pH > 7.

• Elements, Compounds, Mixtures: Elements are pure substances; compounds are chemically combined elements; mixtures are physically combined substances.

Lab 9 – Organic Molecules

Macromolecules and Testing for Biomolecules

Organic molecules are the building blocks of life. Testing for their presence is a key laboratory skill.

• Monomers and Polymers: Monomers are small units that join to form polymers (e.g., amino acids form proteins).

• Controls in Experiments: Positive and negative controls ensure validity of experimental results.

• Testing for Proteins: Biuret reagent turns purple if protein is present.

• Testing for Starch: Iodine turns blue-black if starch is present.

• Testing for Simple Sugars: Benedict's reagent turns green, yellow, orange, or red when heated with reducing sugars.

• Testing for Fats and Oils: Sudan IV stains fats red; positive result is separation of red-stained layers.

Test	Reagent	Positive Result
Protein	Biuret	Purple color
Starch	Iodine	Blue-black color
Simple Sugars	Benedict's	Green/yellow/orange/red (after heating)
Fats/Oils	Sudan IV	Red-stained layer

Lab 10 – Diffusion and Osmosis

Movement of Molecules Across Membranes

Diffusion and osmosis are passive transport processes essential for cellular function.

• Diffusion: Movement of molecules from an area of higher concentration to lower concentration.

• Osmosis: Diffusion of water across a selectively permeable membrane.

• Brownian Movement: Random movement of particles suspended in a fluid due to collisions with molecules.

• Tonicity: Describes the relative concentration of solutes in solutions separated by a membrane.

  • Isotonic: Equal solute concentration; no net water movement.

  • Hypotonic: Lower solute concentration outside; water enters the cell.

  • Hypertonic: Higher solute concentration outside; water leaves the cell.

• Cell Behavior: In isotonic solutions, cells remain unchanged; in hypotonic, they swell; in hypertonic, they shrink.