BIOL 1406 Lecture Exam 1 Vocabulary

Vocabulary practice flashcards generated from BIOL 1406 Lecture Exam 1 review notes covering Chapters 1–4 and Section 19.1.

Cell

Smallest structural and physiological unit considered alive.

Homeostasis

Maintaining a relatively stable internal environment through change, response, and adjustment toward stability.

Population

A group of individuals of the same species living in an area.

Community

Multiple species or populations residing in an area.

Membrane

A phospholipid bilayer with a hydrophobic interior that creates a boundary and helps maintain an internal environment.

Prokaryote

An organism lacking a membrane-bound nucleus, encompassing the domains Bacteria and Archaea.

Eukaryote

An organism characterized by having a membrane-bound nucleus and multiple membrane-bound compartments.

Phylogenetic Tree

A diagram where nodes represent common ancestors, and a more recent common ancestor indicates a closer evolutionary relationship.

Evolution

Genetic change within a population across generations.

Natural Selection

An evolutionary mechanism requiring population variation, heritability, and differences in reproductive success.

Independent Variable

The variable that is manipulated in an experiment, plotted on the x-axis.

Dependent Variable

The variable that is measured in an experiment, plotted on the y-axis.

Inductive Reasoning

Reasoning that moves from specific observations to a broader pattern.

Deductive Reasoning

Reasoning that applies a general rule to make a specific prediction.

Element

A pure substance defined by its specific proton number.

Atomic Number

The number of protons in an atom, which identifies the element.

Mass Number

The total count of protons plus neutrons for a specific isotope.

Isotope

Forms of the same element containing the same proton number but a different neutron number.

Ion

An atom with a different number of electrons than protons.

Valence Shell / Electrons

The outermost occupied electron shell and the electrons residing in that shell.

CHONPS

Acronym for Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, and Sulfur—the biologically prominent elements.

Nonpolar Covalent Bond

A covalent bond formed between atoms with an electronegativity difference of $0-0.4$.

Polar Covalent Bond

A covalent bond formed between atoms with an electronegativity difference $>0.4-1.8$.

Ionic Bond

An attraction between oppositely charged ions characterized by an electronegativity difference $>1.8$.

Hydrogen Bond

An interaction usually formed between a partially positive hydrogen covalently bonded to a strongly electronegative atom and a filled valence orbital on another strongly electronegative atom.

Hydrophobic Interaction

The water-driven clustering of very nonpolar regions; not a new electron-sharing bond.

van der Waals Interactions

Weak electrostatic attractions between nearby nonpolar molecules or regions.

Cohesion

The property of water molecules being attracted to other water molecules.

Adhesion

The property of water molecules being attracted to another polar surface.

Hydrophilic

Describing charged or polar regions that interact favorably with water.

Hydrophobic

Describing nonpolar regions that do not interact favorably with water.

Amphipathic

A molecule possessing both hydrophilic and hydrophobic regions.

Acid

A substance that acts as a proton ($H^+$) donor.

Base

A substance that acts as a proton ($H^+$) acceptor.

pH

The negative logarithm of hydrogen ion concentration, calculated as $-\log_{10}[H^+]$.

Buffer

A weak acid/base pair that accepts added $H^+$ or replaces $H^+$ removed from solution to maintain stable pH.

Hydroxyl Group

A functional group written as $-\text{OH}$; polar and commonly involved in hydrogen bonding.

Carboxyl Group

A functional group written as $-\text{COOH}$; acts as an acid.

Amino Group

A functional group written as $-\text{NH}_2$; basic under typical biological conditions.

Sulfhydryl Group

A functional group written as $-\text{SH}$.

Phosphate Group

A functional group written as $-\text{PO}_4$; commonly charged and polar.

Methyl Group

A functional group written as $-\text{CH}_3$; hydrophobic and nonpolar.

Structural Isomers

Molecules with the same molecular formula but different covalent connectivity.

Cis-Trans Isomers

Molecules with the same connectivity but different spatial arrangement around restricted rotation bonds.

Optical Isomers

Molecules with identical formulas that exist as nonsuperimposable mirror images.

Dehydration Synthesis

A reaction that covalently joins monomers together while releasing a water molecule ($H_2O$).

Hydrolysis

A reaction that breaks a covalent bond between monomers using a water molecule ($H_2O$).

Starch

A glucose-based storage polysaccharide found in plants.

Glycogen

A glucose-based storage polysaccharide found in animals.

Cellulose

A glucose-based structural polysaccharide found in plant cell walls.

Chitin

A non-glucose structural polysaccharide found in animals.

Primary Structure

The specific linear amino-acid sequence of a protein linked by peptide bonds.

Secondary Structure

Local protein folding into alpha helices and beta sheets maintained by backbone hydrogen bonding.

Tertiary Structure

The overall 3D shape of a single polypeptide, driven largely by side-chain (R-group) interactions.

Quaternary Structure

The functional structural unit formed by the association of multiple polypeptide subunits.

Denaturation

The loss or disruption of a protein's normal folding and biological function.

Triglyceride

A lipid composed of one glycerol bonded to three fatty acids via ester bonds; serves as major long-term energy storage.

Saturated Fatty Acid

A fatty acid with no carbon-carbon double bonds ($C=C$), resulting in straight chains that pack tightly.

Unsaturated Fatty Acid

A fatty acid containing one or more double bonds ($C=C$); cis double bonds introduce kinks in the hydrocarbon chain.

Phospholipid

An amphipathic lipid with hydrophilic heads and hydrophobic tails that form membrane bilayers.

Steroid

A class of lipids characterized by a carbon skeleton consisting of four fused carbon rings.

Carotenoid

A type of lipid featuring extended conjugated double bonds that function in light absorption.

Nucleotide

The monomer of nucleic acids, composed of a phosphate group, a pentose sugar, and a nitrogenous base.

Purines

Nitrogenous bases containing two fused rings, comprising adenine (A) and guanine (G).

Pyrimidines

Nitrogenous bases containing a single ring, comprising cytosine (C), thymine (T), and uracil (U).

DNA

A usually double-stranded nucleic acid containing deoxyribose and thymine that stores primary hereditary information.

RNA

A usually single-stranded nucleic acid containing ribose and uracil that directly participates in gene expression.

Transcription

The biological process of synthesizing RNA from a DNA template ($\text{DNA} \rightarrow \text{RNA}$).

Translation

The biological process of synthesizing a protein from an RNA message ($\text{RNA} \rightarrow \text{protein}$).