AP Biology Master

Elements

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

Trace elements

Elements required by an organism only in very small quantities, such as iron (Fe), iodine (I), and copper (Cu).

Atoms

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

Protons

Positively charged (+) particles found in an atom.

Neutrons

Uncharged particles found in an atom.

Electrons

Negatively charged (-) particles found in an atom.

Isotopes

Atoms that have the same number of protons but differ in the number of neutrons in the nucleus.

Compounds

Substances that consist of two or more elements held together by chemical bonds.

Ionic bond

A bond formed between two atoms when one or more electrons are transferred from one atom to the other.

Ions

Charged forms of atoms.

Covalent bond

A bond formed when electrons are shared between atoms.

Non-polar covalent bond

A covalent bond where electrons are shared equally between atoms.

Polar covalent bond

A covalent bond where electrons are shared unequally between atoms.

Hydrogen bonds

Weak chemical bonds that form when a hydrogen atom is covalently bonded to another atom.

Cohesive forces

The tendency of water molecules to stick together.

Adhesive

The tendency of water molecules to stick to other substances.

Capillary action

The ability of water to rise up the roots, trunks, and branches of trees due to cohesion and adhesion.

Surface tension

The tension at the surface of water caused by the cohesion of water molecules.

Acidic solution

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

Basic solution

A solution that releases a lot of hydroxide ions (OH-) when added to water.

pH scale

A scale numbered from 1 to 14 that measures the acidity or alkalinity of a solution.

Neutral pH

A pH of 7, considered neutral.

pH formula

pH = -log [H+], indicating the concentration of hydrogen ions in a solution.

Organic molecules

Molecules that contain carbon.

Inorganic compounds

Molecules that do not contain carbon atoms.

Versatile atom

An atom, like carbon, that can bind with other carbons and a number of other elements.

Polymers

Chains of building blocks in macromolecules.

Monomers

The individual building blocks of a polymer.

Dehydration synthesis

A reaction through which polymers are formed, also known as condensation reactions.

Hydrolysis

When polymers can also be broken down into monomers.

Glycosidic linkage

The bond formed when two monosaccharides are joined.

Disaccharide

A sugar formed from two monosaccharides.

Polysaccharides

Made up of many repeated units of monosaccharides.

Carbohydrates

Organic compounds that contain carbon, hydrogen, and oxygen in a ratio of approximately 1:2:1.

Monosaccharides

An energy source for cells, with glucose and fructose as the two most common examples.

Glucose

An important part of the food we eat and the product made by plants during photosynthesis, with the chemical formula C6H12O6.

Fructose

A common monosaccharide that, along with glucose, serves as an energy source.

Maltose

The disaccharide formed from two glucose molecules.

Starch

A sugar storage molecule that stores sugar in plants.

Glycogen

A sugar storage molecule that stores sugar in animals.

Cellulose

Made up of β-glucose and is a major part of the cell walls in plants, lending structural support.

Chitin

A polymer of β-glucose molecules that serves as a structural molecule in the walls of fungus and in the exoskeletons of arthropods.

Proteins

Important for structure, function, and regulation of tissues and organs.

Amino acids

Building blocks of proteins containing carbon, hydrogen, oxygen, and nitrogen atoms, with 20 different types.

Peptide bond

The bond between two amino acids.

Polypeptide

A group of amino acids joined together in a 'string'.

Primary structure

The linear sequence of the amino acids in a protein.

Secondary structure

When the polypeptide begins to twist, forming either an alpha helix or beta-pleated sheets.

Tertiary structure

When the secondary structure reshapes the polypeptide, allowing amino acids that were far apart in the primary structure to interact.

Quaternary structure

When different polypeptide chains interact with each other.

Haemoglobin

A molecule in the blood that helps distribute oxygen to the tissues in the body.

Lipids

This consists of carbon, hydrogen, and oxygen atoms.

Examples of Lipids

The most common examples of lipids are triglycerides, phospholipids, and steroids.

Functions of Lipids

Lipids are important due to their non-polar structures; they function as structural components of cell membranes, sources of insulation, signalling molecules, and a means of energy storage.

Adipose Tissue

Our bodies store fat in tissue called adipose, which is made of cells called adipocytes; these cells are filled with lipids called triglycerides.

Triglycerides

Each triglyceride is made of a glycerol molecule (also called the glycerol backbone) with three fatty acid chains attached to it.

Fatty Acid Chain

A fatty acid chain is covered in hydrogen. One end of the chain has a carboxyl group.

Saturated Fatty Acid

A fatty acid can be saturated with hydrogens along its long carbon chain.

Unsaturated Fatty Acid

If there is a double bond in the chain it is an unsaturated fatty acid.

Lipid Saturation

The extent of saturation in a lipid can affect its structure and function. The more double bonds that exist within a lipid, the more unsaturated it is.

Phospholipids

Phospholipids contain two fatty acid tails and one negatively charged phosphate head.

Hydrophobic Tails

The two fatty acid tails are hydrophobic because they are non-polar and don't mix well with polar substances like water.

Hydrophilic Head

The phosphate head of the lipid is hydrophilic, meaning that it does mix well with water since it carries a negative charge.

Amphipathic Molecule

A phospholipid has both a hydrophilic region and a hydrophobic region.

Cholesterol

Cholesterol is a four-ringed molecule that is found in membranes.

Cholesterol Functions

It generally increases membrane fluidity, except at very high temperatures, and is important for making certain types of hormones and for making vitamin D.

Nucleic Acids

They contain carbon, hydrogen, oxygen, nitrogen, and phosphorus and are made up of simple units called nucleotides.

DNA

DNA contains the hereditary blueprints of all life.

RNA

RNA is essential for protein synthesis.

Cell

Cell is life's basic unit of structure and function.

Surface Area-to-Volume Ratio

As cells increase in volume, the surface area-to-volume ratio decreases, affecting the efficiency of material exchange.

Light Microscopes

Light microscopes are used to study stained or living cells and can magnify the size of an organism up to 1,000 times.

Electron Microscopes

Electron microscopes are used to study detailed structures of a cell that cannot be easily seen or observed by light microscopy.

Prokaryotic Cells

Prokaryotic cells are smaller and simpler than eukaryotic cells; examples include bacteria and archaea.

Cytoplasm

The inside of the cell is filled with a substance called cytoplasm.

Prokaryotic Genetic Material

The genetic material in a prokaryote is one continuous, circular DNA molecule found free in the cell in the nucleoid.

Cell Wall

Most prokaryotes have a cell wall composed of peptidoglycans that surrounds a lipid layer called the plasma membrane.

Ribosomes

Prokaryotes have small ribosomes.

Flagella

Some bacteria may have one or more flagella, which are used for motility.

Capsule

Some bacteria might have a thick capsule outside their cell wall for extra protection.

Membrane-bound Organelles

Prokaryotes do not have any membrane-bound organelles.

Plasma membrane

It is the outer envelope of the cell, made up of mostly phospholipids and proteins.

Eukaryotic cell

Eukaryotic cells are more complex. Fungi, protists, plants, and animals are examples of eukaryotes.

Eukaryotes

Organisms whose cells have a nucleus enclosed within membranes.

Organelles

Eukaryotic cells have many smaller structures called organelles.

Semipermeable

The plasma membrane is semipermeable, regulating the movement of substances into and out of the cell.

Peripheral proteins

Proteins that are loosely associated with the lipid bilayer, located on the inner or outer surface of the membrane.

Integral proteins

Proteins that are firmly bound to the plasma membrane and are amphipathic.

Transmembrane proteins

Some integral proteins extend all the way through the membrane.

Fluid-mosaic model

This arrangement of phospholipids and proteins is known as the fluid-mosaic model.

Adhesion proteins

Proteins that form junctions between adjacent cells.

Receptor proteins

Proteins such as hormones that serve as docking sites for arrivals at the cell.

Transport proteins

Proteins that form pumps using ATP to actively transport solutes across the membrane.

Channel proteins

Proteins that form channels that selectively allow the passage of certain ions or molecules.

Cell surface markers

Markers such as glycoproteins and glycolipids exposed on the extracellular surface that play a role in cell recognition and adhesion.

Carbohydrate side chains

Found only on the outer surface of the plasma membrane.

Nucleus

The nucleus is usually the largest organelle in the cell, directing what goes on in the cell and responsible for the cell's ability to reproduce.

Hereditary information

DNA, which is organized into large structures called chromosomes.

Chromosomes

Structures that organize hereditary information (DNA) within the nucleus.

Nucleolus

The most visible structure within the nucleus where rRNA is made and ribosomes are assembled.