General Biology 151 Vocab Exam 1

Life

The ability of an entity comprised of one or more cells to conduct metabolism, sense changes in the environment and respond, and reproduce, and for populations of those entities to evolve.

Metabolism

The chemical reactions and other processes that enable organisms to take in resources and process them in ways that make growth and reproduction possible.

Organism

A living thing—a being or individual.

Evolution

A change in the genetic characteristics of a population.

Fossil Record

Any trace of an organism that lived in the past.

Adaptation

 A heritable trait that increases the ability to survive and reproduce in a particular environment.

Element

A distinct type of substance or matter. Each element has atoms that contain a unique number of protons in the nucleus.

Atom

The fundamental unit of an element, made of protons, neutrons, and electrons.

Ion

An atom or molecule that carries a full charge—positive if it contains more protons than electrons, and negative if it contains more electrons than protons. 

Molecule

A structure made of two or more atoms held together by covalent bonds.

Covalent Bond

An attraction between two atoms based on shared electrons.

Electronegativity

The tendency for an atom's nucleus to attract the shared electrons in a covalent bond.

Polar Covalent Bond

An asymmetry in the position of shared electrons, due to differences in the electronegativities of the atoms involved, that creates a partial positive charge on one atom and a partial negative charge on the second atom.

Nonpolar Covalent Bond

Equal sharing of electrons, due to equal or roughly equal electronegativities of the atoms involved.

Hydrogen Bond

An attraction between a partial positive charge on a hydrogen atom and a partial negative charge on another atom.

Hydrophilic Molecule

a molecule that can readily interact with partial charges on water.

Hydrophobic Molecule

a molecule that contains mostly nonpolar covalent bonds and cannot readily interact with the partial charges on water.

Ion

an atom or molecule that carries a full charge.

Acid

an ion or molecule that releases a proton (H+)

Base

an ion or molecule that acquires a proton (H+)

pH Scale

a method for expressing the concentration of protons in a solution—specifically, the negative of the base 10 logarithm of the proton concentration. 

Cell

The smallest thing that can function as an independent organism; also the building block of larger organisms.

Chromosome

A DNA molecule — circular or linear, depending on the species — usually associated with specific proteins that bind to the DNA.

Ribosome

A molecular machine consisting of RNA and proteins that is the site of protein synthesis

Organelle

Any membrane-bound compartment inside a cell

Cytoskeleton

Rod-like proteins inside cells that function in structural support, transport of materials, and movement in some species.

Cell Wall

A stiff structure outside the cell membrane composed of carbohydrates and other molecules.

Flagellum

A long, flexible structure that extends from the cell and whips or rotates to propel the cell through water.

Nucleus

An organelle unique to eukaryotes enclosed by a double membrane and containing the cell’s chromosomes.

Mitrochondrion

An organelle found in all eukaryotes that functions in “burning” sugars to provide energy for the cell.

Eukaryote

A lineage of species with cells that contain a nucleus and mitochondria.

Prokaryote

A species in the lineages Archaea and Bacteria, with cells that lack a nucleus.

Vacuole

An organelle that stores key molecules; very prominent in most plant cells.

Chloroplast

An organelle that contains the molecular machinery required for photosynthesis.

Cell Wall

A stiff structure outside of many types of cells, usually made primarily of carbohydrates.

Endoplasmic Reticulum (ER)

A eukaryotic organelle that forms a branching network of narrow tubes and flattened sacs. The place where proteins, membrane lipids, and other molecules are synthesized and/or processed. Can have ribosomes associated with it (rough ER) or not (smooth ER).

Golgi

An organelle comprised of stacked, flattened sacs, where proteins and other molecules are processed and packaged for shipment to specific destinations.

Actin Filaments

Small-diameter cytoskeletal fibers made of subunits of the protein actin.

Intermediate Filaments

Cytoskeletal fibers whose size is intermediate between those of actin filaments and microtubules and can be made from a variety of protein subunits.

Microtubules

Large-diameter, hollow cytoskeletal elements made of pairs of the proteins α-tubulin and β-tubulin.

Monosaccharide

an organic molecule that includes a carbon chain, a C=O group, and C-OH groups. The carbon chain can be linear or form a ring structure. Also called a simple sugar.

Glycosidic linkage

a covalent bond that links monosaccharides together to form polymers

Glycan

a polymer made up of many monosaccharides joined by glycosidic linkages. (synonymous with ‘polysaccharide’)

Carbohydrates

a family of molecules that includes both monosaccharides and glycans