General Biology Lab Study Guide: Metric System, Microscopy, Biomolecules, Diffusion & Osmosis, and Human Bones

Lab 1A: The Metric System and the Scientific Method

Metric System

The metric system is a decimal-based system of measurement used in science worldwide. Understanding metric units and their conversions is essential for laboratory work.

• Basic Units: Meter (length), Gram (mass), Liter (volume)

• Prefixes: Kilo (k), Centi (c), Milli (m), Micro (μ)

• Common Conversions:

Metric	Equivalent
1 km	0.62 miles
1 m	39.36 inches
1 pound	454 g
1 inch	2.54 cm
1 L	1.06 quarts
1 kg	2.2 pounds (lbs)

• Application: Use a graduated cylinder to measure volume; use a metric ruler to measure length.

The Scientific Method

The scientific method is a systematic approach to investigation in science.

• Steps of the Scientific Method:

  1. Observation

  2. Question

  3. Hypothesis

  4. Experiment

  5. Data Collection

  6. Conclusion

• Variables:

  • Independent Variable: The factor that is changed or controlled in an experiment.

  • Dependent Variable: The factor that is measured or observed.

Lab 2: Microscopy

Compound Microscope

A compound microscope is used to magnify small objects using multiple lenses. Understanding its parts and functions is crucial for biological studies.

• Parts of a Compound Microscope: Ocular lens (eyepiece), objective lenses, stage, light source, diaphragm, coarse and fine focus knobs.

• Key Terms:

  • Magnification: The process of enlarging the appearance of an object.

  • Diameter of Field: The width of the area visible through the microscope.

  • Total Magnification: Calculated as:

$\text{Total Magnification} = \text{Ocular Magnification} \times \text{Objective Magnification}$

• Application: Calculate the size of microscopic objects by relating their size to the diameter of the field of view.

Lab 3: Biologically Important Molecules

Chemical (Molecular) Formula

The chemical formula represents the types and numbers of atoms in a molecule. Recognizing and writing formulas is fundamental in biology.

• Key Terms: Atom, molecule, element, macromolecule.

• Major Classes of Biomolecules:

  • Carbohydrates: Sugars and starches; energy storage and structure.

  • Lipids: Fats and oils; energy storage, insulation, and cell membranes.

  • Proteins: Made of amino acids; structure, enzymes, and signaling.

  • Nucleic Acids: DNA and RNA; genetic information.

• Functional Groups: Recognize positive and negative tests for each class (e.g., Benedict's for sugars, Biuret for proteins).

• Structural Formulas to Know: H2O, CO2, CH4, CH3COOH, CH3NH2

Lab 4: Diffusion and Osmosis

Cell Membrane and Transport

Cells regulate the movement of substances through their membranes via diffusion and osmosis. Understanding these processes is key to cell biology.

• Major Organelles: Know the animal cell model and functions of organelles (e.g., nucleus, mitochondria, endoplasmic reticulum).

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

• Osmosis: The diffusion of water across a selectively permeable membrane.

• Selectively Permeable: Allows some substances to pass while blocking others.

• Solution Types:

  • Hypertonic: Solution with higher solute concentration than the cell; water moves out.

  • Hypotonic: Solution with lower solute concentration than the cell; water moves in.

  • Isotonic: Solution with equal solute concentration as the cell; no net water movement.

• Application: Be able to determine the tonicity of solutions using potato slices or dialysis experiments.

• Dialysis Experiment: Understand the movement of glucose, starch, and water molecules across a membrane.

Human Bones

Major Bones of the Human Skeleton

Identifying the major bones is essential for understanding human anatomy.

• Upper Limb: Humerus, radius, ulna

• Lower Limb: Femur, tibia, fibula

• Hand: Carpals (wrist), metacarpals (palm), phalanges (fingers)

• Foot: Tarsals (ankle), metatarsals (foot), phalanges (toes)

• Pelvis: Hip bones

Application: Be able to locate and identify these bones on a diagram or model.