bio

Element

Substances that cannot be broken down into simpler substances by chemical means.

Oxygen (O)

An essential element used to build biological molecules.

Carbon (C)

An essential element used to build biological molecules.

Hydrogen (H)

An essential element used to build biological molecules.

Nitrogen (N)

An essential element used to build biological molecules.

Trace Elements

Elements required by an organism only in very small quantities.

Subatomic Particles

Particles smaller than an atom, including protons, neutrons, and electrons.

Atom

The unit of life and building block of the physical world.

Proton

Positively charged particle found in the nucleus of an atom.

Neutron

Uncharged particle found in the nucleus of an atom.

Electron

Negatively charged particle that orbits the nucleus of an atom.

Isotope

Atoms with the same number of protons but a different number of neutrons.

Compound

A substance made up of two or more elements.

Chemical bond

Forces that hold atoms together in a compound.

Ionic bond

A bond formed when one or more electrons are transferred from one atom to another.

Ion

Charged forms of atoms after ionic bonding.

Covalent bond

A bond formed when electrons are shared between atoms.

Non-polar covalent bond

A covalent bond where electrons are shared equally.

Polar covalent bond

A covalent bond where electrons are shared unequally.

Hydrogen bond

Weak chemical bonds that form between molecules.

Cohesive forces

The strong tendency of water molecules to stick together.

Adhesive forces

The tendency of water molecules to stick to other substances.

Capillary action

The ability of water to rise up through roots and plant structures due to cohesion and adhesion.

Surface tension

The tension at the surface of water caused by cohesion.

Acidic solution

A solution that contains a lot of hydrogen ions (H+).

Basic solution

A solution that contains a lot of hydroxide ions (OH–).

pH scale

A scale that measures the acidity or alkalinity of a solution.

Organic molecules

Molecules that contain carbon.

Inorganic compounds

Molecules that do not contain carbon.

Macromolecules

Polymers formed from monomers, essential for life.

Polymers

Chains of building blocks (monomers).

Monomers

Individual building blocks of a polymer.

Dehydration synthesis

A process that occurs when monomers join together and release water.

Hydrolysis

The breakdown of polymers into monomers using water.

Carbohydrates

Organic compounds made of carbon, hydrogen, and oxygen, usually in a 1:2:1 ratio.

Monosaccharides

The simplest form of carbohydrates, serving as an energy source.

Disaccharides

Sugars formed by the joining of two monosaccharides.

Polysaccharides

Complex carbohydrates made up of long chains of monosaccharides.

Glycosidic linkage

The bond formed between two monosaccharides.

Glycogen

A polysaccharide that stores sugar in animals.

Starch

A polysaccharide that stores sugar in plants.

Cellulose

A polysaccharide that makes up cell walls in plants.

Chitin

A polymer of β-glucose molecules that serves as a structural molecule in fungi.

Proteins

Essential molecules for structure, function, and regulation in tissues and organs.

Amino acids

Building blocks of proteins containing carbon, hydrogen, oxygen, and nitrogen.

Peptide bond

A bond formed between two amino acids.

Polypeptide

A chain of amino acids that forms proteins.

Primary structure

The linear sequence of amino acids in a protein.

Secondary structure

The folding or twisting of amino acids into coils or sheets.

Tertiary structure

The overall three-dimensional shape of a protein.

Quaternary structure

The interaction of multiple polypeptide chains in a protein.

Lipids

Biomolecules made mainly of carbon, hydrogen, and oxygen, also important for energy storage.

Triglycerides

A type of lipid made from glycerol and fatty acids.

Phospholipids

Lipids that contain two fatty acids and a phosphate group, important for cell membranes.

Cholesterol

A four-ringed molecule that regulates membrane fluidity.

Nucleic Acids

Biomolecules that store and transmit genetic information.

DNA

The nucleic acid that carries hereditary information.

RNA

The nucleic acid that aids in protein synthesis.

Cell

The basic unit of structure and function in living organisms.

Cell structure

The organization and arrangement of different components in a cell.

Plasma membrane

The semipermeable membrane surrounding the cell.

Cytoplasm

The fluid inside a cell that contains organelles.

Organelles

Small structures within a cell that perform specific functions.

Ribosomes

The sites of protein synthesis in a cell.

Endoplasmic reticulum (ER)

A network of membranes involved in protein and lipid synthesis.

Golgi apparatus

An organelle that modifies, sorts, and packages proteins for secretion.

Mitochondria

Organelles that convert energy from organic compounds into ATP.

Lysosome

An organelle that contains digestive enzymes to break down waste.

Vacuole

A fluid-filled sac that stores nutrients, wastes, and other substances.

Cytoskeleton

A network of fibers that provides structure and shape to a cell.

Microtubules

Protein filaments that maintain cell shape and support cell division.

Microfilaments

Thin protein filaments involved in movement and shape.

Cilia

Hair-like structures that aid in movement of single-celled organisms.

Flagella

Whip-like structures used for locomotion.

Chloroplasts

Organelles that contain chlorophyll and are involved in photosynthesis.

Photosynthesis

The process of converting light energy into chemical energy.

Cellular respiration

The process by which cells convert glucose into ATP.

Aerobic respiration

A type of respiration that requires oxygen.

Anaerobic respiration

A type of respiration that occurs without oxygen.

Glycolysis

The first stage of cellular respiration, breaking down glucose.

Krebs cycle

A series of reactions that produce ATP and electron carriers.

Electron transport chain

A series of proteins that transfer electrons and generate ATP.

Photosystem

A cluster of pigments involved in the light reactions of photosynthesis.

Calvin Cycle

The cycle that uses ATP and NADPH to fix carbon dioxide into sugar.

Homeostasis

The maintenance of stable internal conditions in an organism.

Taxis

Movement toward or away from a stimulus.

Signal transduction pathway

A series of events that convert a signal into a cellular response.

Ligands

Signaling molecules that bind to receptors to trigger a response.

Feedback inhibition

A regulatory mechanism in which the end product inhibits its own production.

Mitosis

The process of cellular division that results in two identical daughter cells.

Intercepting Phase

The longest phase of the cell cycle, where the cell grows and duplicates its DNA.

Checkpoints

Control mechanisms that ensure proper cell division.

Apoptosis

Programmed cell death.

Cyclins

Proteins that regulate the cell cycle.

Aneuploidy

Having an abnormal number of chromosomes due to nondisjunction.

Genotype

The genetic makeup of an organism.

Phenotype

The physical appearance of an organism based on its genotype.

Homozygous

An organism with two identical alleles for a trait.

Heterozygous

An organism with two different alleles for a trait.

Punnett square

A tool used to predict the genotype and phenotype ratios of offspring.