AP Biology Unit 1: Chemistry of Life, Macromolecules, and Data Analysis Flashcards

Vocabulary flashcards covering foundational chemistry of life, water properties, functional groups, macromolecule structures, protein folding levels, and experimental data analysis principles from AP Biology Unit 1.

Matter

Anything that has mass and takes up space.

Element

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

Compound

A substance containing two or more different elements chemically bonded together.

Essential elements

Elements that organisms need to survive and reproduce, specifically C, H, O, N, P, and S.

Trace elements

Elements required by organisms in very small amounts, such as iron (Fe), zinc (Zn), copper (Cu), and iodine (I).

Atom

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

Atomic number

The number of protons in an atom's nucleus, which identifies the specific element.

Mass number

The total number of protons plus neutrons in an atom's nucleus.

Isotope

An atom of the same element that has a different number of neutrons, resulting in a different mass number.

Radioactive isotope

An isotope with an unstable nucleus that naturally breaks down over time, releasing radiation.

Half-life

The amount of time it takes for half of a radioactive isotope sample to decay.

Valence electrons

The electrons located in the outermost shell of an atom that determine its chemical behavior and bonding.

Electronegativity

An atom's ability to attract shared electrons toward itself in a chemical bond.

Nonpolar covalent bond

A covalent bond in which atoms share electrons approximately equally.

Polar covalent bond

A covalent bond in which atoms share electrons unequally because one atom pulls the electrons more strongly.

Ionic bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions following an electron transfer.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Hydrogen bond

A relatively weak attraction involving a partially positive hydrogen atom and an electronegative atom with a partial negative charge.

Reactants

The starting materials in a chemical reaction.

Products

The materials produced by a chemical reaction.

Polar molecule

A molecule that features an uneven distribution of electrical charge across its structure.

Cohesion

The phenomenon of water molecules sticking to other water molecules via hydrogen bonding.

Surface tension

A measure of the strength of a liquid's surface layer caused by strong attractions between surface water molecules.

Adhesion

The phenomenon of water molecules sticking to other polar or charged surfaces.

Specific heat

The amount of energy needed to change the temperature of a substance.

Evaporative cooling

The process in which the surface of an object cools during evaporation due to the absorption and removal of heat energy by evaporating water.

Solvent

The substance in a solution that does the dissolving.

Solute

The substance in a solution that is being dissolved.

Aqueous solution

A solution in which water is the dissolving solvent.

Hydrophilic

Describes polar, charged, or ionic substances that interact well with water.

Hydrophobic

Describes nonpolar, hydrocarbon-rich substances that do not interact well with water.

Molarity

A measure of solution concentration defined conceptually as the amount of solute per volume of solution.

Acid

A substance that increases the concentration of $H^+$ ions in a solution.

Base

A substance that decreases the concentration of $H^+$ ions in a solution, often by accepting $H^+$.

pH scale

A logarithmic measurement of hydrogen ion concentration where every 1-unit change corresponds to a 10-fold change in $H^+$.

Buffer

A substance that helps resist sudden changes in pH by accepting or donating hydrogen ions when acid or base is added.

Hydrocarbon

An organic molecule composed exclusively of carbon and hydrogen atoms.

Isomer

Molecules that have the same molecular formula but a different structural arrangement of atoms.

Hydroxyl group

A polar functional group with the chemical formula $-OH$ that can form hydrogen bonds and is common in sugars and alcohols.

Carbonyl group

A functional group characterized by a carbon double-bonded to an oxygen ($C=O$), common in aldehydes and ketones in sugars.

Carboxyl group

An acidic functional group with the formula $-COOH$ that can donate an $H^+$ ion.

Amino group

A basic functional group with the formula $-NH_2$ that can accept an $H^+$ ion and is found in amino acids.

Sulfhydryl group

A functional group with the formula $-SH$ that contains sulfur and can form disulfide bridges to stabilize protein tertiary structure.

Phosphate group

A negatively charged functional group containing phosphorus ($-PO_4$) essential to DNA, RNA, ATP, and phospholipids.

Methyl group

A nonpolar functional group with the formula $-CH_3$ that can affect gene expression, molecular shape, and interactions.

Monomer

A smaller building-block subunit used to synthesize polymers.

Polymer

A large molecule composed of many repeating monomer units bound together.

Dehydration synthesis

A reaction that links two smaller monomer molecules to build a larger molecule with the loss of a water molecule.

Hydrolysis

A reaction that breaks polymers into smaller molecules through the addition and consumption of a water molecule.

Monosaccharide

A single sugar molecule, such as glucose, fructose, or galactose, serving as the building block for carbohydrates.

Disaccharide

A double sugar molecule composed of two monosaccharides linked together by a glycosidic linkage.

Polysaccharide

A large carbohydrate polymer composed of many monosaccharide units connected by glycosidic linkages.

Glycosidic linkage

A covalent bond formed between two sugar molecules via a dehydration synthesis reaction.

Starch

A storage polysaccharide in plants consisting entirely of glucose monomers.

Glycogen

A highly branched storage polysaccharide made of glucose found in animal tissues.

Cellulose

A structural polysaccharide of plant cell walls consisting of glucose monomers in a specific linkage orientation that humans cannot digest.

Chitin

A structural polysaccharide found in fungal cell walls and arthropod exoskeletons.

Triglyceride

A lipid molecule composed of one glycerol molecule joined to three fatty acid chains by ester linkages.

Saturated fatty acid

A fatty acid chain with no carbon-carbon double bonds ($C=C$), resulting in a straight structure that packs tightly and is solid at room temperature.

Unsaturated fatty acid

A fatty acid chain containing one or more carbon-carbon double bonds ($C=C$) that cause kinks, preventing tight packing and making it liquid at room temperature.

Phospholipid

An amphipathic molecule composed of a hydrophilic polar head and two hydrophobic nonpolar tails that forms the cell membrane bilayer.

Amphipathic

Having both a hydrophilic (water-attracting) region and a hydrophobic (water-repelling) region.

Peptide bond

The covalent bond formed between amino acids during dehydration synthesis to construct polypeptides.

Primary structure

The unique, linear sequence of amino acids in a polypeptide chain held together by peptide bonds.

Secondary structure

Local folding pattern of the polypeptide backbone into alpha helices or beta pleated sheets stabilized by backbone hydrogen bonds.

Tertiary structure

The overall 3-D folding shape of a single polypeptide chain stabilized by interactions among amino acid R groups.

Quaternary structure

The structural level of a protein resulting from the aggregation of two or more distinct polypeptide subunits.

Denaturation

A process in which a protein loses its functional 3-D shape due to the disruption of weak interactions without necessarily breaking peptide bonds.

Nucleotide

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

Central dogma of molecular biology

The directional pathway describing the biological flow of genetic information: DNA to RNA to Protein.

Independent variable

The specific variable in an experiment that is intentionally changed or manipulated by the researcher.

Dependent variable

The variable measured or recorded in an experiment to observe the effect of changing the independent variable.

Control group

A baseline comparison group in an experiment that receives standard conditions or does not receive the experimental treatment.