BIOL 152 Midterm Review: Scientific Method, Macromolecules, Microscopy, Cells, Tissues, and Transport

Comprehensive vocabulary flashcards covering the BIOL 152 / GBIO_152 midterm review content, including scientific methodology, biochemical testing, microscopy, cell theory, tissue identification, and transport mechanisms.

Independent Variable

The variable that is manipulated or deliberately changed by the researcher in an experiment (e.g., testing different types of energy drinks such as Red Bull, Bang Energy, and coffee).

Dependent Variable

The outcome factor being observed and measured to assess the effect of changes made to the independent variable (e.g., productivity measured as the number of tasks completed).

Control (Experimental)

A standard of comparison in an experiment where the experimental condition or treatment is withheld (e.g., measuring the number of tasks completed without the consumption of energy drinks).

Null Hypothesis

A statement predicting that there is no relationship, difference, or effect caused by the independent variable on the dependent variable (e.g., "The type of energy drinks does not affect the number of tasks completed").

Qualitative Observation

Descriptive, non-numerical observations gathered through sensory perception (such as color, odor, or texture).

Quantitative Observation

Objective data obtained by measurement or counting, represented by numerical values.

Replication

Repeating an experimental trial under the same conditions to confirm findings, reduce variability, and ensure reliability of results.

Monomer

A small, basic molecular building block that covalently bonds with other similar molecules to assemble a large macromolecule.

Polymer

A large chain molecule composed of numerous repeated monomer subunits joined together by covalent bonds.

Carbohydrates

Organic macromolecules divided into monosaccharides (glucose, fructose), disaccharides (sucrose, maltose), and polysaccharides (starch, glycogen).

Proteins

Polymers constructed from amino acid monomers linked together by covalent peptide bonds.

Lipids

Hydrophobic macromolecules characterized by glycerol structures, fatty acid tails, and saturated or unsaturated configurations.

Nucleic Acids

Macromolecules responsible for storing and transferring genetic information, categorized primarily into DNA and RNA.

Benedict's Test

A biochemical test for reducing sugars that changes from a blue solution (none) to a green/yellow precipitate (traces), orange-red precipitate (moderate), or brick-red precipitate (large amount of reducing sugar).

Iodine Test

A biochemical test used to detect the presence of starch; a negative result remains orange/brown (no change), whereas a positive result produces a black or blue-black solution.

Biuret's Test

A biochemical test that identifies proteins by reacting with peptide bonds; remains light blue with water (negative) and turns violet or purple in the presence of protein (positive).

Total Magnification Formula

The formula used to find specimen magnification: $\text{Total Magnification} = \text{ocular lens} \times \text{objective lens}$.

A $10\times$ ocular with scanning ($4\times$, red), low ($10\times$, yellow), and high ($40\times$, blue) objectives yields $40\times$, $100\times$, and $400\times$, respectively.

Microscopy Golden Rules

1. Obtain sharp focus on the scanning objective lens before moving to the next lens.

2. NEVER use the coarse adjustment knob when using the high-power objective lens.

Field of Vision (FOV)

The total circular area visible through the microscope eyepiece; as total magnification increases ($\uparrow$), the field of vision decreases ($\downarrow$).

as total magnification increases

the field of vision decreases.

Resolving Power

The ability of a microscope lens system to distinguish two separate points as distinct entities, determining clarity and fine detail.

Depth of Field

The vertical thickness or depth of a specimen plane that remains in sharp focus simultaneously under a microscope objective.

Cell Theory

1. All living things are composed of one or more cells.

2. Cells are the basic structural and functional unit of life.

3. All cells arise from pre-existing cells.

Prokaryotic Cells

Small, less complex cells that lack a membrane-bound nucleus and membrane-bound organelles.

Eukaryotic Cells

Relatively large, structurally complex cells containing a true membrane-bound nucleus, membrane-bound organelles, and a cytoskeleton.

Universal Cell Characteristics

plasma membrane,

genetic material (DNA),

chemical reactions (metabolism),

cytosol.

Plant Cell Specific Structures

a rigid cell wall,

chloroplasts for photosynthesis,

and a large central vacuole.

Histology

The microscopic study of the anatomy, organization, and specialized functions of biological tissues and cells.

Simple Columnar Epithelial Tissue

A tissue type located in the intestine lining

composed of tall, column-like cells

whose functions are absorption, protection, and secretion.

Smooth Muscle Tissue

Non-striated,

involuntary muscle tissue

located wrapped around the digestive tract

facilitates involuntary contractions.

Striated Skeletal Muscle Tissue

Muscle tissue featuring visible alternating light and dark bands

located along the skeleton and biceps;

responsible for voluntary contractions.

Adipose Fat Tissue

Connective tissue consisting of lipid-storing cells

located around muscle tissue;

functions in energy storage, cushioning, and insulation.

Blood Connective Tissue

A specialized fluid connective tissue

found everywhere in the body comprising plasma, red blood cells, white blood cells, and platelets;

functions to transport oxygen and nutrients throughout the body.

Simple Diffusion

The passive net movement of solute molecules from an area of high concentration to an area of low concentration driven by intrinsic kinetic energy.

Concentration Gradient

A gradual difference in the concentration of a chemical substance across a distance or between two distinct regions.

Brownian Motion

The erratic, continuous random motion of microscopic particles resulting from constant collisions with surrounding molecules powered by thermal energy.

Factors Affecting Diffusion Rate

1. Temperature: higher thermal energy increases molecular velocity and rate.

2. Steepness of concentration gradient: a greater difference causes faster diffusion.

3. Molecular size: smaller molecules diffuse more rapidly than larger ones.

Osmosis

The net diffusion of water molecules through a selectively permeable membrane from an area of high water concentration to an area of low water concentration until equilibrium is reached.

Selectively Permeable Membrane

A biological or artificial barrier that permits the transit of specific substances (such as water or small solvents)

while preventing the passage of other molecules (such as large proteins or solutes).

Isotonic Environment

A solution where the solute concentration outside the cell equals the solute concentration inside the cell (e.g., $70\%$ water and $30\%$ solute on both sides), resulting in no net movement of water.

Hypertonic Environment

A solution where the solute concentration outside the cell is higher than inside the cell (e.g., $50\%$ solute outside vs. $30\%$ solute inside),

causing water to flow out of the cell. (shrink)

Hypotonic Environment

A solution where the solute concentration outside the cell is lower than inside the cell (e.g., $10\%$ solute outside vs. $30\%$ solute inside),

causing water to flow into the cell. (swell