Essential Biology Vocabulary Review (Chapters 1 - 4)

Vocabulary flashcards covering chapters 1 through 4 of Essential Biology, including scientific methodology, chemistry fundamentals, biological macromolecules, and cell structure.

Biology

The scientific study of life.

Data

Recorded observations upon which scientific inquiry is based.

Hypothesis

A proposed, testable, and falsifiable explanation for a set of observations.

Theory

A comprehensive and well-substantiated explanation of natural phenomena, broader in scope than a hypothesis.

Controlled Experiment

An experiment that compares two or more groups that differ only in one specific variable being tested.

Independent Variable

The factor in an experiment that is manipulated by researchers as a potential cause.

Dependent Variable

The factor in an experiment that is measured to judge the outcome and changes in response to the manipulated factor.

Placebo

A medically ineffective treatment used as a control in medical drug trials.

Double-Blind Experiment

An experimental setup in which neither the participant nor the experimenter knows which group is the control group or experimental group.

Pseudoscience

Any field of study that is falsely presented as having a scientific basis.

Anecdotal Evidence

An assertion based on a single or a few unverified examples that do not support a generalized conclusion.

Metabolism

The vast network of interconnected chemical reactions within living cells that continually converts energy and recycles matter.

Natural Selection

The driving process of evolution in which the environment selects existing heritable traits, leading to unequal reproductive success.

Evolutionary Adaptations

Inherited traits that enhance survival and reproductive success in an organism's specific environment.

Matter

Anything that occupies space and has mass.

Element

A substance that cannot be broken down into other substances by chemical reactions.

Trace Elements

Elements required by organisms in only very small amounts that are essential for life.

Atom

The smallest unit of matter that still retains the properties of an element.

Atomic Number

The unique number of protons found in all atoms of a particular element.

Mass Number

The sum of the number of protons and neutrons in an atom's nucleus.

Isotopes

Alternate forms of an element that have the same number of protons but different numbers of neutrons.

Radioactive Isotope

An isotope whose nucleus decays spontaneously, releasing high-energy particles.

Ionic Bond

A chemical bond formed between oppositely charged ions following the gain or loss of electrons.

Covalent Bond

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

Polar Molecule

A molecule containing an uneven distribution of electrical charge.

Hydrogen Bond

A weak electrical attraction formed between neighboring polar molecules.

Cohesion

The tendency of molecules of the same kind to stick together.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid.

Solvent

The dissolving agent in a liquid solution.

Solute

The substance that is dissolved in a liquid solution.

Acid

A chemical compound that releases $H^+$ ions to a solution.

Base

A chemical compound that accepts $H^+$ ions and removes them from a solution.

pH Scale

A numerical scale describing the acidity or basicity of a solution based on its $H^+$ concentration.

Buffers

Substances that minimize changes in pH by accepting or donating $H^+$ ions.

Organic Compounds

Carbon-based molecules essential to life's functions.

Functional Groups

Groups of atoms in organic molecules directly involved in chemical reactions.

Macromolecules

Gigantic biological molecules, including carbohydrates, proteins, and nucleic acids.

Polymers

Large molecules made by stringing together many smaller monomer units.

Monomers

Small building-block molecules used to construct polymers.

Dehydration Reaction

A chemical reaction that links two monomers together by removing a molecule of water.

Hydrolysis

A chemical process that breaks down polymers into monomers by adding water.

Monosaccharides

The monomers of carbohydrates that cannot be broken down into smaller sugars.

Isomers

Molecules that have the same molecular formula but different structural arrangements.

Disaccharide

A double sugar constructed from two monosaccharides joined by a dehydration reaction.

Polysaccharides

Complex carbohydrates made of long chains of monosaccharide monomers.

Starch

A storage polysaccharide in plant cells consisting of long chains of glucose monomers.

Glycogen

An energy-storage polysaccharide composed of glucose monomers found in animal cells.

Cellulose

An indigestible structural polysaccharide that forms cable-like fibrils in plant cell walls.

Lipids

Hydrophobic biological molecules, such as fats and steroids, that do not mix with water.

Triglyceride

A fat molecule consisting of a glycerol molecule joined with three fatty acid molecules.

Saturated Fat

A fat whose fatty acid chains contain the maximum number of hydrogen atoms and no double bonds.

Unsaturated Fat

A fat whose fatty acid chains contain fewer than the maximum number of hydrogen atoms due to double bonds.

Trans Fats

A type of unsaturated fat created through artificial hydrogenation that is particularly harmful to health.

Steroids

Lipids characterized by a carbon skeleton consisting of four fused rings.

Peptide Bond

The covalent bond linking adjacent amino acid monomers formed via a dehydration reaction.

Prions

Misfolded versions of normal brain proteins that cause severe nervous system disorders.

Nucleotides

The monomer building blocks of nucleic acids, consisting of a five-carbon sugar, a phosphate group, and a nitrogenous base.

Cell Theory

The fundamental biological principle stating that all living things are composed of cells and all cells come from earlier cells.

Prokaryotic Cells

Smaller, simpler cells lacking a nucleus and membrane-bound organelles, found in domains Bacteria and Archaea.

Eukaryotic Cells

Larger, complex cells containing a nucleus and membrane-bound organelles, found in protists, plants, fungi, and animals.

Nucleoid

A non-membrane-enclosed region in a prokaryotic cell containing its single circular bacterial chromosome.

Plasma Membrane

A fluid mosaic phospholipid bilayer that separates a living cell from its nonliving surroundings.

Extracellular Matrix

A sticky coat secreted by most animal cells that protects and holds them together in tissues.

Chromatin

Fibers in the nucleus composed of long DNA molecules and associated proteins.

Nucleolus

A prominent structure within the nucleus where the components of ribosomes are produced.

Ribosomes

Cellular structures responsible for protein synthesis.

Endomembrane System

A membranous network in eukaryotic cells including the nuclear envelope, ER, Golgi apparatus, lysosomes, and vacuoles.

Rough ER

A region of the endoplasmic reticulum studded with ribosomes that manufactures membrane and secretory proteins.

Smooth ER

A region of the endoplasmic reticulum lacking ribosomes that synthesizes lipids and detoxifies circulating drugs.

Golgi Apparatus

An organelle that receives, refines, stores, and distributes chemical products manufactured in the cell.

Lysosome

A membrane-enclosed sac of digestive enzymes found in animal cells.

Central Vacuole

A versatile plant cell organelle that stores nutrients, absorbs water, and holds pigments or toxins.

Chloroplasts

Photosynthetic organelles found in plants and algae that convert solar light energy into chemical energy.

Mitochondria

Organelles in eukaryotic cells where cellular respiration occurs to harvest energy from food molecules and produce ATP.

Cytoskeleton

A network of protein fibers extending throughout the cytoplasm that provides structural support and cellular movement.

Cilia

Short, numerous extensions from a cell made of microtubules that move in a coordinated back-and-forth rowing motion.