Lab Quiz 1 – Complete Study Guide (Scientific Method, Plants, Transport, Enzymes)

Blind Study

A study in which participants do not know whether they are receiving the real treatment or the placebo.

Double-Blind Study

A study in which neither the participants nor the researchers know who receives the treatment versus placebo, preventing both subject and researcher bias.

Cross-Over Study

A study design where each participant receives both the treatment and placebo at different times, acting as their own control.

Placebo

A substance with no active therapeutic effect, used to measure psychological or expectation-based responses.

Meta-Analysis

A study method that combines data from multiple independent studies to create a stronger, more reliable conclusion.

Hypothesis

A falsifiable, testable prediction about the relationship between variables.

Scientific Theory

A well-supported explanation of natural phenomena, backed by repeated experimentation and large amounts of evidence.

Ethnobotany

The study of the relationship between plants and human culture, including traditional medicinal uses.

Infusion

A method of extracting medicinal properties by steeping delicate plant parts (leaves/flowers) in hot water.

Decoction

A method of extraction using tougher plant materials (roots/bark) simmered in water to release compounds.

Tincture

Medicinal preparation made by soaking herbs in alcohol or glycerin to extract active ingredients; long shelf life.

Capsules/Powders

Finely ground dried herbs taken orally or sprinkled onto food; externally can be mixed with oils.

Tonic Wine

Herbal preparation made by steeping herbs in wine to strengthen or tone the body.

Syrups/Cordials

Honey- or sugar-based preparations used to soothe throat, cough, or respiratory irritation.

Infused Oils

Herb-infused oils extracted by hot or cold infusion and used for massage, ointments, or topical healing.

Essential Oils

Concentrated plant extracts used topically for aches/pain but must be diluted because they irritate skin.

Ointments

Semi-solid preparations without water; combine oils/fats and protect/deliver medicinal compounds to skin.

Creams

Water + oil emulsions used to apply herbs externally; lighter than ointments and absorb more easily.

Poultice

Moist mass of herb applied to skin to relieve inflammation, swelling, or pain.

Compress

Cloth soaked in herbal infusion/decoction and applied to skin to reduce swelling or pain.

Steam Inhalation

Herbal steam used to open airways, ease congestion, and disinfect mucosa.

Gargles/Mouthwashes

Herbal liquids used for sore throats or oral infections; may be swallowed if dosage is safe.

Topical Agent

A medicine applied to skin or mucous membranes rather than taken internally.

Alcohol Contraindication

Alcohol interacts with enzymes and medications (e.g., Tylenol, Flagyl) and may increase toxicity or reduce drug efficacy.

Toxic Plant: Castor Bean

Contains ricin, one of the strongest poisons; lethal if ingested.

Toxic Plant: Poison Oak

Contains urushiol; causes allergic dermatitis with blistering and oozing.

Toxic Plant: Deadly Nightshade

Contains atropine-like alkaloids; highly poisonous; historically used as poison.

Toxic Plant: Tree Tobacco

Can cause toxicity if smoked or ingested; animals have died from eating it.

Cell Membrane Structure

Phospholipid bilayer with hydrophilic heads and hydrophobic tails; selectively permeable barrier.

Hydrophobic Tails

Nonpolar region of membrane that repels water; faces inward.

Hydrophilic Heads

Polar region of membrane that interacts with water; faces outward.

Selective Permeability

Only certain molecules (small, nonpolar) can cross the membrane easily.

Diffusion

Passive movement of molecules from high to low concentration.

Factors Affecting Diffusion

Temperature, molecule size, concentration gradient, membrane permeability.

Dynamic Equilibrium

State in which molecules move in and out at the same rate.

Small Nonpolar Molecule Passage

Nonpolar molecules like O₂ and CO₂ easily diffuse across the membrane.

Solutions

Homogeneous mixtures where solutes fully dissolve in solvents.

Colloids

Heterogeneous mixtures with large particles (1-100 µm) that remain suspended.

Suspensions

Mixtures with large particles (>100 µm) that settle unless agitated.

Brownian Motion

Random molecular movement caused by kinetic energy; greater in smaller particles and higher temperature.

Osmosis

Movement of water across a semipermeable membrane from low solute to high solute concentration.

Filtration

Movement of water/solutes across a membrane using hydrostatic pressure; passive mechanism.

Crystalloid Solution

Solution with small solutes (<1µm) like salts or sugars; transparent.

Osmotic Gradient

Difference in solute concentration that drives osmosis.

Hypertonic Solution

Higher solute concentration outside the cell; cell shrinks (crenation).

Hypotonic Solution

Lower solute concentration outside the cell; cell swells (lysis).

Isotonic Solution

Equal solute concentration; no net water movement.

Enzyme

A biological catalyst that speeds up chemical reactions by lowering activation energy.

Active Site

The region on the enzyme where the substrate binds.

Substrate

The molecule the enzyme acts upon.

Enzyme-Substrate Complex

Temporary binding between enzyme and substrate during reaction.

Allosteric Site

A regulatory site where molecules bind to change enzyme activity (activate or inhibit).

Competitive Inhibition

Inhibitor competes with substrate for active site; slows reaction.

Noncompetitive Inhibition

Inhibitor binds allosteric site, distorting active site; substrate cannot bind properly.

Hydrolysis

Enzymatic breakdown of molecules using water.

Protein Digestion

Begins in stomach with pepsin; continues in small intestine with trypsin and other proteases.

Carbohydrate Digestion

Begins in mouth with salivary amylase; completed by pancreatic amylase in small intestine.

Lipid Digestion

Requires bile for emulsification; lipase breaks down fats into glycerol and fatty acids.

Succinic Acid Dehydrogenase

Enzyme in Krebs cycle converting succinate → fumarate; reduces FAD to FADH₂.

Oxidation

Loss of electrons or hydrogen atoms.

Reduction

Gain of electrons or hydrogen atoms.

Methylene Blue Indicator

Turns colorless when reduced; blue when oxidized; used to track SDH activity.

Malonic Acid

Competitive inhibitor of succinate dehydrogenase; structurally similar to succinate.

Emulsification

Process in which bile salts break large fat droplets into smaller droplets, increasing surface area for lipase.