BIOL 160 – Exam 1 Review Guide

Vocabulary practice flashcards covering fundamental concepts in BIOL 160 Exam 1, including the characteristics of life, the scientific method, general chemistry, water properties, thermodynamics, and biological macromolecules.

Biology

The scientific study of life and living organisms.

Characteristics of Life

The fundamental set of biological properties shared by all living organisms, including cellular organization, energy processing, homeostasis, growth, reproduction, and evolutionary adaptation.

Homeostasis

The ability of an organism to maintain stable internal conditions necessary for survival despite fluctuating external environments.

Biological Hierarchy of Organization

The tiered sequence of biological complexity arranged in order from smallest to largest: atom, molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, and biosphere.

Emergent Property

A novel characteristic or function that arises at higher levels of organizational complexity and is not present in the individual component parts.

Hypothesis

A tentative, testable, and falsifiable proposed explanation for a specific scientific observation.

Scientific Theory

A broad, comprehensive, and well-substantiated explanation of natural phenomena supported by a vast body of empirical evidence.

Inductive Reasoning

A form of logical thinking that uses related specific field observations to arrive at a general conclusion or formulate a hypothesis.

Deductive Reasoning

A form of logical thinking that uses a general principle or law to forecast specific results, such as designing an experimental test of a hypothesis.

Independent Variable

The single factor that is intentionally manipulated or changed by the experimenter to test its effect on a system.

Dependent Variable

The measurable response or outcome in an experiment that changes in response to manipulations of the independent variable.

Standardized Variable

Any experimental factor intentionally kept constant across all test groups to ensure that only the independent variable influences the results.

Control Group

The baseline group in a controlled experiment that does not receive the experimental treatment, serving as a standard of comparison.

Experimental Group

The group in a scientific experiment that receives the specific treatment or independent variable being tested.

Peer Review

The rigorous formal evaluation process in which independent experts in the same field assess scientific research for validity, methodology, and originality prior to publication.

Pseudoscience

Claims, beliefs, or practices presented as scientific that lack supporting empirical evidence, testability, falsifiability, or adherence to the scientific method.

Basic Science

Scientific inquiry aimed purely at expanding the fundamental body of knowledge and understanding natural processes, regardless of immediate practical application.

Applied Science

Scientific research focused on utilizing existing scientific knowledge to develop practical solutions, technologies, or interventions for real-world problems.

Atom

The fundamental unit of matter that retains all chemical properties of an element, composed of a central nucleus containing protons and neutrons surrounded by orbiting electrons.

Atomic Number

The specific number of protons found in the nucleus of an atom, defining the identity of that chemical element.

Mass Number

The total sum of protons and neutrons located within the nucleus of an atom.

Ionic Bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions following the complete transfer of one or more valence electrons.

Covalent Bond

A strong chemical bond formed when two nonmetal atoms share one or more pairs of valence electrons.

Nonpolar Covalent Bond

A covalent bond formed between atoms of similar electronegativity, resulting in an equal sharing of electrons and no partial electrical charges.

Polar Covalent Bond

A covalent bond formed between atoms with significantly different electronegativities, causing unequal electron sharing and resulting in partial positive and partial negative charges.

Hydrogen Bond

A weak electrostatic attraction between a partially positive hydrogen atom in a polar covalent bond and an electronegative atom (such as oxygen or nitrogen) of another molecule.

Hydrophilic

A property describing polar or ionic substances that interact favorably with and dissolve readily in water ("water loving").

Hydrophobic

A property describing nonpolar substances that do not interact favorably with water and tend to aggregate together in aqueous solutions ("water fearing").

Equilibrium Reaction

A reversible chemical reaction in which the rate of the forward reaction equals the rate of the reverse reaction, keeping reactant and product concentrations constant.

Exergonic Reaction

A spontaneous chemical reaction that releases free energy, in which the reactants have higher free energy than the products.

Endergonic Reaction

A non-spontaneous chemical reaction that absorbs free energy, such as photosynthesis converting $\text{CO}_2$ into $\text{C}_6\text{H}_{12}\text{O}_6$ using $\text{H}_2\text{O}$ and photon energy.

Enzyme

A biological catalyst (usually a protein) that accelerates chemical reactions by lowering the required activation energy without being consumed in the process.

Central Dogma of Molecular Biology

The foundational principle describing the two-step directional flow of genetic information within a biological system: $\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$.

Monomer

A small molecular subunit that can covalently bind with other identical or similar subunits to form a larger biological macromolecule.

Polymer

A large complex molecule composed of repeating structural units called monomers linked together by covalent bonds.

Dehydration Synthesis

A condensation reaction that joins monomers into a polymer by removing a hydrogen atom from one monomer and a hydroxyl group from another, releasing $\text{H}_2\text{O}$ as a byproduct.

Hydrolysis Reaction

A chemical cleavage reaction that breaks down polymers into smaller monomers through the addition of a water molecule ($\text{H}_2\text{O}$).

Glycosidic Bond

The specific covalent linkage formed by a dehydration synthesis reaction between monosaccharide units in carbohydrates such as starch and cellulose.

Saturated Fatty Acid

A fatty acid hydrocarbon chain containing no carbon-carbon double bonds, maximizing the number of attached hydrogen atoms and forming straight chains that pack densely at room temperature.

Unsaturated Fatty Acid

A fatty acid chain that contains one or more double bonds ($\text{C}=\text{C}$), resulting in fewer attached hydrogen atoms and reduced packing density.

Cis-unsaturated Fatty Acid

An unsaturated fatty acid in which hydrogen atoms attached to the double-bonded carbons are on the same side, creating a physical kink that increases membrane fluidity.

Trans-unsaturated Fatty Acid

An unsaturated fatty acid in which hydrogen atoms attached to the double-bonded carbons are on opposite sides, yielding a straight chain configuration that packs tightly.

Phospholipid Bilayer

A double-layered biological membrane structure formed spontaneously in water, composed of amphipathic molecules with hydrophilic phosphate heads facing the aqueous exterior and hydrophobic fatty acid tails sequestered inside.

Amino Acid

The monomer building block of proteins, consisting of a central alpha carbon bonded to a hydrogen atom ($-\text{H}$), an amino group ($-\text{NH}_2$), a carboxyl group ($-\text{COOH}$), and a variable side chain ($-\text{R}$ group).

Polypeptide

A polymer of amino acid monomers linked in series by covalent peptide bonds ($-\text{C}(=\text{O})-\text{NH}-$), featuring an amino terminus ($\text{H}_2\text{N}-$), a carboxyl terminus ($-\text{COOH}$), and alternating side chains.

Protein Denaturation

The loss of a protein's biological shape and native secondary, tertiary, and quaternary conformations caused by environmental stress (such as heat or extreme pH), while the primary structure remains intact.

Nucleotide

The monomer unit of nucleic acids, structurally composed of three components: a five-carbon pentose sugar, a nitrogenous base, and one or more phosphate groups.

Buffer System

A chemical solution (such as the carbonic acid-bicarbonate system) that resists abrupt fluctuations in physiological pH by absorbing excess $\text{H}^+$ ions when conditions become acidic or donating $\text{H}^+$ when conditions become basic.