Unit 1: Atomic Structure and Macromolecules of Life

Comprehensive review flashcards covering atomic structure, chemical bonding, solutions, macromolecules, and functional groups.

What is an atom?

The basic building block of matter and the smallest unit of a chemical element that keeps the element’s unique properties, having the same number of protons and electrons.

What is an element?

A pure substance made of only one type of atom that cannot be broken down into simpler substances by ordinary chemical reactions.

What is a proton and what role does it play?

A positively charged subatomic particle found in the nucleus of an atom whose movement and transfer drive vital cellular energy processes.

What is a neutron?

A subatomic particle with no electric charge that resides in the nucleus of most atoms alongside protons.

What is an electron?

A tiny, negatively charged subatomic particle that surrounds the nucleus of an atom and drives the energy and chemical bonding processes essential for life.

What is an ion?

An atom or molecule that has a net electrical charge because it has an unequal number of protons and electrons.

What are isotopes?

Forms of the same chemical element that have an identical number of protons but a different number of neutrons.

What is a covalent bond?

A strong chemical link where two atoms share pairs of valence electrons to fill their outer shells and achieve stability.

What is a hydrogen bond?

A weak electrostatic attraction between a partially positive hydrogen atom (covalently bound to an electronegative atom like oxygen or nitrogen) and another nearby electronegative atom.

What is a molecule?

A group of two or more atoms held together by chemical bonds, forming the smallest unit of a substance that keeps its physical and chemical properties.

What is a compound?

A substance made of two or more different elements that are chemically bonded together in fixed porportions.

What is a solution?

A uniform (homogeneous) mixture where one or more substances (solutes) are completely dissolved in another substance (solvent), usually water.

What is a solute?

A substance that dissolves in a liquid or gas to form a uniform mixture.

What is a solvent?

A liquid substance—usually present in the greatest amount in a solution—that dissolves other molecules known as solutes.

What is diffusion?

The net movement of particles from an area of higher concentration to an area of lower concentration down a concentration gradient.

What is osmosis?

The passive movement of water molecules through a semipermeable membrane from an area of higher water concentration (low solute) to an area of lower water concentration (high solute).

What does hydrophilic mean?

Something that loves water.

What does hydrophobic mean?

Something that fears water.

What is an acid?

A molecule that releases hydrogen ions or acts as a proton donor in cellular fluids, characterized by a low pH.

What is a base?

A chemical substance that accepts hydrogen ions to keep cellular fluids at the right pH level.

What happens during hydrolysis?

Water is consumed to break the bonds holding large biological molecules together (takes away water).

What happens during dehydration synthesis?

A chemical reaction joins smaller molecules (monomers) together to form a larger molecule (polymer) while releasing a water molecule as a byproduct (adds water).

What is a monomer?

A small, basic molecular unit that can bind chemically to other similar or identical molecules to form a larger structure called a polymer.

What is a polymer?

A large molecule made up of many smaller, repeating subunits called monomers joined together by covalent bonds.

What is a protein?

Large, complex biomolecules made of one or more long chains of amino acid subunits linked by peptide bonds.

What is an amino acid?

An organic molecule that serves as the fundamental building block of proteins.

What is an enzyme?

A biological catalyst—almost always a protein, though occasionally RNA—that speeds up specific chemical reactions in living cells without being consumed or altered in the process.

What is a catalyst?

A substance that speeds up a chemical reaction without being used up or changed permanately in the process.

What is an R-group?

The variable chemical group attached to the central carbon atom of an amino acid that gives each individual amino acid its unique properties.

What is a lipid?

A diverse group of organic, water fearing biochemicals that do not dissolve in water but dissolve in organic solvents.

What is a fatty acid?

A building block of lipids made of a long chain of carbon and hydrogen atoms with an acidic carboxyl group.

What is a phospholipid?

A type of lipid molecule that consists of a glycerol backbone, two hydrophobic fatty acid tails, and a hydrophilic phosphate group head.

What is a steroid?

A type of lipid molecule characterized by a core structure of four fused carbon rings.

What is a carbohydrate?

An organic biomolecule composed of carbon, hydrogen, and oxygen atoms.

What is a monosaccharide?

The simplest type of carbohydrate that acts as a basic building block, or monomer, for more complex sugars.

What is glucose?

A simple sugar.

What is a polysaccharide?

A large, complex carbohydrate made of many simpler sugar units joined together by chemical bonds.

What is starch?

A complex carbohydrate made of many glucose molecules linked together.

What is glycogen?

A branched polysaccharide that animals and fungi use to store extra glucose.

What are nucleic acids?

Large biological molecules made of nucleotide chains that store and pass on genetic information.

What are nucleotides?

The basic building block of nucleic acids like DNA and RNA.

What is DNA?

The hereditary molecule in cells that carries the genetic instructions for development, functioning, growth, and reproduction of all known living organisms.

What is RNA?

A single-stranded nucleic acid present in all living cells that carries out the instructions encoded in DNA to build and regulate proteins.

What is a hydroxyl functional group?

A functional group consisting of one oxygen atom covalently bonded to one hydrogen atom.

What is a carboxyl functional group?

A chemical functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group.

What is an amino functional group?

A basic nitrogen-containing group.

What is a phosphate group?

A chemical ion made of one phosphorus atom bound to four oxygen atoms.

What is a methyl group?

A small chemical tag made of one carbon atom bonded to three hydrogen atoms.