Biology Lecture Flashcards

These flashcards cover key vocabulary and definitions based on the biology lecture notes. They encompass fundamental concepts related to atoms, molecules, biochemistry, and cellular structure.

Electrons

Negatively charged subatomic particle.

Neutrons

Uncharged subatomic particle that occurs in the atomic nucleus.

Protons

Positively charged subatomic particle that occurs in the nucleus of all atoms.

Nucleus

Of an atom; core area occupied by protons and (in most atoms) neutrons.

Atomic Number

Number of protons in the atomic nucleus; defines the element.

Isotopes

Forms of an element that differ in the number of neutrons.

Radioactive Decay

Process in which atoms of a radioisotope emit energy and subatomic particles when their nucleus spontaneously breaks up.

Elements

A pure substance that consists only of atoms with the same number of protons.

Mass Number

Of an isotope, the total number of protons and neutrons in the atomic nucleus.

Radioisotope

An isotope with an unstable nucleus.

Tracer

A substance that can be traced via its detectable component.

Compound

Molecule that has atoms of more than one element.

Shell Model

Conceptual diagram of electron distribution in an atom.

Free Radicals

Atom with an unpaired electron. Most are highly reactive and can damage biological molecules.

Chemical Bond

A strong attractive force between two atoms; links atoms in molecules.

Ions

An atom or molecule that carries a net charge.

Ionic Bond

Type of chemical bond in which a strong mutual attraction links ions of opposite charge.

Solvent

Liquid in which other substances dissolve.

Covalent Bond

Type of chemical bond in which two atoms share electrons.

Hydrogen Bond

Attraction between a covalently bonded hydrogen atom and another atom taking part in a separate covalent bond.

Polarity

Separation of charge into positive and negative regions.

Hydrophilic

Describes a substance that dissolves easily in water.

Salt

Ionic compound that releases ions other than H+ and OH- when it dissolves in water.

Solute

A dissolved substance.

Solution

Uniform mixture of solute completely dissolved in a solvent.

Hydrophobic

Describes a substance that resists dissolving in water.

Concentration

Amount of solute per unit volume of solution.

Cohesion

Property in which the molecules of a substance resist separating from one another.

Evaporation

Transition of a liquid to a vapor.

Temperature

Measure of molecular motion.

pH

Measure of the amount of hydrogen ions in a fluid.

Acid

Substance that releases hydrogen ions in water.

Base

Substance that accepts hydrogen ions in water.

Organic

Describes a compound that consists mainly of carbon and hydrogen atoms.

Monomers

Molecule that is a subunit of polymers.

Buffer

Set of chemicals that can keep the pH of a solution stable by alternately donating and accepting ions that contribute to pH.

Polymer

Molecule that consists of multiple monomers.

Reactions

Process of molecular change.

Metabolism

Collective term for all of the enzyme-mediated chemical reactions in a cell.

Enzymes

Organic molecule (protein or RNA) that speeds up a reaction without being changed by it.

Cellulose

Tough, insoluble polysaccharide that is the major structural material in plants.

Carbohydrates

Saccharide. Molecule that consists primarily of carbon, hydrogen, and oxygen atoms in a ratio of approximately 1:2:1.

Lipids

Fatty, oily, or waxy organic compound; e.g., a triglyceride, steroid, or wax.

Saturated Fat

Triglyceride with three saturated fatty acid tails.

Saturated Fatty Acids

Fatty acid with only single bonds linking the carbons in its tail.

Fatty Acid

Lipid that consists of a (hydrophilic) carboxyl group 'head' and a (hydrophobic) 'tail'.

Triglyceride

A lipid with three fatty acid tails bonded to a glycerol; a fat.

Unsaturated Fatty Acid

Fatty acid that has at least one double bond between carbons making up its tail.

Fat

A triglyceride.

Lipid Bilayer

Double layer of phospholipids arranged tail-to-tail; structural foundation of all cell membranes.

Phospholipid

Lipid with two (hydrophobic) fatty acid tails and a (hydrophilic) head that contains a phosphate group.

Unsaturated Fats

Triglyceride molecule with one or more unsaturated fatty acid tails.

Steroids

A type of lipid with four carbon rings and no fatty acid tails.

Protein

Organic molecule that consists of one or more amino acid chains folded into a specific shape.

Wax

Firm, water-repellent substance that is a complex, varying mixture of lipids.

Amino Acid

Small organic compound that is a monomer of proteins.

Denaturation

Loss of a protein’s three-dimensional shape.

Peptide Bond

A covalent bond between the amine group of one amino acid and the carboxyl group of another.

Prion

Infectious protein.

ATP

Adenosine triphosphate. Nucleotide that serves as an important energy carrier in cells.

Nucleic Acids

Molecule that consists of one or more strands of nucleotides; DNA or RNA.

Nucleotides

Small organic molecule with a deoxyribose or ribose sugar, a nitrogen-containing base, and one, two, or three phosphate groups.

RNA

Ribonucleic acid. Nucleic acid that consists of ribose-containing nucleotides; most types are single-stranded.