AP Biology unit 1-4

What are elements in chemistry?

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

Which four elements are primarily used to build biological molecules?

Oxygen (O), carbon (C), hydrogen (H), and nitrogen (N).

What are trace elements?

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

What are subatomic particles?

Protons, neutrons, and electrons that make up an atom.

What is an ionic bond?

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

Define covalent bond.

A bond formed when electrons are shared between atoms.

What property of water allows for cohesion?

The hydrogen bonds that hold water molecules together.

What is the pH scale used for?

To measure the acidity or alkalinity of a solution.

What do organic molecules contain?

Carbon atoms.

What are monomers?

The individual building blocks of a polymer.

What is the difference between hydrophobic and hydrophilic?

Hydrophobic substances repel water, while hydrophilic substances attract water.

What is a disaccharide?

A sugar formed from two monosaccharides linked together.

What is the role of ribosomes in cells?

Sites of protein synthesis.

What is the main function of mitochondria in a cell?

Converting energy from organic molecules into ATP.

How do enzymes function as catalysts?

By lowering the activation energy of reactions.

What is the role of chlorophyll in photosynthesis?

To absorb light energy necessary for the process.

What happens during glycolysis?

Glucose is split into two molecules of pyruvic acid, producing a net of two ATP molecules.

What is the end product of aerobic respiration?

Carbon dioxide (CO2), water (H2O), and ATP.

What is the primary role of the nucleus in a cell?

To direct cell activities and store genetic information.

What is a homogeneous mixture?

A mixture that has a uniform composition throughout.

What occurs during prophase in mitosis?

The nuclear envelope disappears, and chromosomes condense.

What is the significance of crossing-over during meiosis?

It increases genetic diversity by exchanging genetic material between homologous chromosomes.

What is chemiosmosis?

The movement of ions across a selectively permeable membrane, generating ATP.

What are the three main types of signaling molecules in cellular communication?

Ligands, hormones, and neurotransmitters.

What is apoptosis?

Programmed cell death.

What is a tetrad in meiosis?

A structure formed by the pairing of homologous chromosomes during prophase I.

What are oncogenes?

Mutated genes that can convert normal cells into cancerous cells.

Define phenotypic plasticity.

The ability of an organism to change phenotype in response to environmental changes.