Chemistry of Living Things Lecture Review

Flashcards covering key vocabulary from the lecture on the Chemistry of Living Things, including definitions of chemical components, bonds, macromolecules, and their functions.

Chemistry

The study of matter and energy.

Matter

Anything that has mass and occupies space, composed of elements.

Energy

The power to do work.

Elements

Pure forms of matter that cannot be broken down, listed on the periodic table.

Atoms

Composed of subatomic particles (protons, neutrons, electrons).

Atomic number

The number of protons in an atom's nucleus.

Mass number

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

Isotopes

Atoms of the same element with a different number of neutrons, resulting in different atomic mass.

Radioisotopes

Unstable isotopes that give off radiation, used in dating fossils, diagnostic imaging, and cancer treatment.

Free radicals

Atoms with unpaired electrons that are highly reactive and can damage proteins/DNA, speeding up cellular aging.

Molecule

A stable association between two or more atoms.

Potential energy

Stored energy.

Kinetic energy

Energy in motion, doing work.

Chemical bonds

Attractive forces holding atoms together (covalent, ionic, hydrogen bonds).

Covalent bonds

Bonds formed by the sharing of a pair of valence electrons by two atoms.

Single covalent bond

Sharing of one pair of valence electrons.

Double covalent bond

Sharing of two pairs of valence electrons.

Non-polar covalent bonds

Atoms share electrons equally due to identical electronegativity.

Polar covalent bonds

Unequal sharing of electrons, causing partial positive or negative charges for each atom or molecule.

Ion

An electrically charged atom or molecule.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Ionic bond

An attraction between an anion and a cation, often forming ionic compounds or salts.

Hydrogen bonds

Form when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom.

Solution

A liquid that is a homogeneous mixture of substances.

Solvent

The dissolving agent of a solution.

Solute

The substance that is dissolved in a solution.

Aqueous solution

A solution in which water is the solvent.

Hydration shell

A sphere of water molecules surrounding an ion when dissolved in water.

Hydrophilic

A substance that has an affinity for water.

Hydrophobic

A substance that does not have an affinity for water.

Acid

Any substance that increases the H+ concentration of a solution; a molecule that can donate hydrogen ions.

Base

Any substance that reduces the H+ concentration of a solution; a molecule that can accept hydrogen ions.

pH scale

A measure used to express hydrogen ion concentration, indicating if a solution is acidic (less than 7), neutral (7), or basic (greater than 7).

Buffers

Substances that minimize changes in concentrations of H+ and OH– in a solution, helping maintain stable pH in body fluids.

Organic molecules

Molecules made of carbon and hydrogen, often with other elements, held together by covalent bonds, forming carbohydrates, lipids, proteins, and nucleic acids.

Dehydration synthesis (condensation)

A reaction where biomolecules are synthesized, one subunit loses an —H, another loses an —OH, forming a new covalent bond and releasing water.

Hydrolysis

A reaction where biomolecules are broken down, water is used, and an —H is added to one subunit and an —OH to another.

Polymers

Large molecules made of repeating subunits called monomers.

Carbohydrates

Organic molecules with a backbone of carbons, hydrogen, and oxygen, used for energy and structural support (e.g., glucose, starch, cellulose).

Monosaccharides

Simple sugars, the basic building blocks of carbohydrates (e.g., glucose, fructose).

Disaccharides

Two monosaccharides linked together (e.g., sucrose, lactose).

Polysaccharides

Thousands of monosaccharides joined in chains, used for energy storage (starch, glycogen) and structural support (cellulose).

Lipids

Hydrophobic macromolecules that do not dissolve in water, including triglycerides, phospholipids, and steroids.

Triglycerides

Fats and oils composed of glycerol bonded to three fatty acids, serving as energy storage molecules.

Saturated fatty acids

Fatty acids with all single bonds between carbons.

Unsaturated fatty acids

Fatty acids that include some double bonds between carbons.

Phospholipids

Composed of glycerol, two fatty acids, and a phosphate group; primary component of cell membranes with hydrophilic heads and hydrophobic tails.

Steroids

Lipids composed of four carbon-based ring structures (e.g., cholesterol, hormones).

Proteins

Complex structures constructed of amino acids joined by peptide bonds, performing various functions in the body.

Amino acids

The monomer subunits of proteins, each with an amino end, carboxyl end, and an R group (20 different types).

Peptide bond

A bond that forms between the carboxyl end of one amino acid and the amino end of the next amino acid.

Polypeptide

A polymer of 3–100 amino acids.

Protein structure (Primary)

The unique sequence of amino acids in a polypeptide chain, stabilized by peptide bonds.

Protein structure (Secondary)

Local folding patterns like alpha helix or beta pleated sheets, stabilized by hydrogen bonds.

Protein structure (Tertiary)

The overall three-dimensional shape of a single polypeptide chain, stabilized by various bonds and interactions creating polar and nonpolar areas.

Protein structure (Quaternary)

The structure formed when two or more polypeptide chains are joined together.

Denaturation

Disruption of a protein's structure, often irreversible, caused by factors like high temperature or changes in pH.

Enzymes

Proteins that function as biological catalysts, speeding up chemical reactions without being altered or consumed, essential for sustaining life.

Nucleic acids

Long chains of nucleotide monomers, storing genetic information (DNA and RNA).

DNA (deoxyribonucleic acid)

A double-stranded nucleic acid containing deoxyribose sugar, phosphate, and nitrogenous bases (A, T, C, G), carrying instructions for producing RNA.

RNA (ribonucleic acid)

A single-stranded nucleic acid containing ribose sugar, phosphate, and nitrogenous bases (A, U, C, G), carrying instructions for producing proteins.

Nucleotides

The building blocks (monomers) of nucleic acids, each containing a five-carbon sugar, a nitrogenous base, and a phosphate group.

Nitrogenous bases

Components of nucleotides, including pyrimidines (Cytosine, Uracil, Thymine) and purines (Adenine, Guanine).

Adenosine triphosphate (ATP)

The universal energy source for cells, with potential energy stored in the bonds between phosphate groups that is released upon breaking.