BIOL 115 Module 4 Review: Cellular Membranes and Experimental Design

Vocabulary flashcards covering experimental design variables, osmosis, solute concentrations, and membrane lipid permeability based on BIOL 115 Module 4.

Hypothesis

A proposed testable explanation for an observation, such as: if increasing environmental temperature speeds up biochemical reactions inside amoebas, and biologists count how many bacteria amoebas at different temperatures eat, then the amoebas at the highest temperature will eat the most bacteria.

Independent Variable

The condition manipulated by an experimenter to test its effect, such as the temperature set in environmental growth chambers during the amoeba study.

Dependent Variable

The variable measured to observe the outcome of an experiment, such as the number of bacteria ingested by amoebas in $24\text{ hours}$.

Hypotonic

Describing a cell or solution with a lower solute concentration relative to another solution, such as a red blood cell placed in a beaker containing a higher solute concentration than the inside of the cell.

Hypertonic

Describing a solution that has a higher concentration of dissolved solutes than the intracellular fluid of a cell placed within it.

Red Blood Cell Osmotic Response

The behavior of a red blood cell dropped into a hypertonic solution with higher solute concentration than the cell, causing it to lose water and shrivel up.

Potassium Ion ($K^+$) Osmotic Flow

The movement of water across a membrane impermable to $K^+$ ions, resulting in a net movement of water into an artificial cell when the internal $K^+$ concentration exceeds the external concentration.

Cholesterol-Mediated Membrane Permeability

The stabilization of membrane permeability by cholesterol; for an organism with 50\text{\null}\% of its membrane lipids as cholesterol, moving it from $10\text{ }^\text{o}\text{C}$ to a colder $0\text{ }^\text{o}\text{C}$ environment results in no change in membrane permeability to glycerol.