AP Biology Ultimate Guide

Ultimate AP BIOLOGY (cont.)

Element

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

Trace elements

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

Atom

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

Proton

Positively charged particle found in the nucleus of an atom.

Neutron

Uncharged particle found in the nucleus of an atom.

Electron

Negatively charged particle that orbits the nucleus of an atom.

Isotope

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

Compound

Consists of two or more elements held together by chemical bonds.

Ionic bond

Bond formed when one or more electrons are transferred from one atom to another.

Ions

Charged forms of atoms.

Covalent bond

Bond formed when electrons are shared between atoms.

Non-polar covalent bond

Bond where electrons are shared equally between atoms.

Polar covalent bond

Bond where electrons are shared unequally.

Hydrogen bonds

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

Cohesion

The tendency of water molecules to stick together.

Adhesion

The tendency of water molecules to stick to other substances.

Capillary action

Ability of water to rise up through roots, trunks, and branches of trees due to cohesion and adhesion.

Surface tension

The tension at the surface of water caused by cohesive forces.

Acid

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

Base

A solution that releases hydroxide ions (OH–) when added to water.

Neutral pH

A pH level of 7, which indicates equal concentration of hydrogen and hydroxide ions.

pH scale

A scale from 1 to 14 used to measure the acidity or alkalinity of a solution.

Organic molecules

Molecules that contain carbon.

Inorganic compounds

Molecules that do not contain carbon.

Polymers

Chains of building blocks in macromolecules.

Monomers

Individual building blocks of a polymer.

Dehydration synthesis

Process of forming polymers by losing a water molecule.

Hydrolysis

Process of breaking down polymers into monomers using water.

Carbohydrates

Organic compounds containing carbon, hydrogen, and oxygen, usually in a 1:2:1 ratio.

Monosaccharides

Single sugar molecules, e.g., glucose and fructose.

Disaccharides

Sugars formed by the bond of two monosaccharides, e.g., maltose.

Glycosidic linkage

The bond formed between two monosaccharides when they join together

Polysaccharides

Complex carbohydrates made of many monosaccharides.

Starch

A polysaccharide that stores sugar in plants.

Glycogen

A polysaccharide that stores sugar in animals.

Cellulose

A structural polysaccharide made of β-glucose, important in plant cell walls.

Chitin

A polymer of β-glucose, serves as a structural molecule in fungi and arthropods.

Proteins

Macromolecules that play important roles in structure, function, and regulation of tissues and organs.

Amino acids

Building blocks of proteins, containing carbon, hydrogen, oxygen, and nitrogen.

Polypeptide

A chain of amino acids joined by peptide bonds.

Peptide bond

The bond formed between two amino acids linking them; forming a peptide

Enzymes

Biological catalysts that speed up reactions by lowering activation energy.

Substrate

The molecule upon which an enzyme acts.

Active site

The region of an enzyme where the substrate binds.

Induced-fit model

Concept that enzymes change shape to accommodate substrates.

Cofactors

Molecules that assist enzymes in catalyzing reactions, can be organic or inorganic.

Enzyme specificity

The selectivity of an enzyme for a particular substrate.

Competitive inhibition

Inhibition where a substance competes with the substrate for the active site of an enzyme.

Allosteric inhibition

Inhibition where a molecule binds to a site other than the active site, changing the enzyme's shape.

Cell cycle

The series of phases that a cell undergoes from one division to another.

The life cycle of a cell; including the processes of interphase and mitosis

Mitosis

The process of cell division resulting in two identical daughter cells.

Interphase

The phase of the cell cycle where the cell grows and replicates its DNA.

G1 phase

The first stage of interphase where the cell grows.

S phase

The stage of interphase where DNA replication occurs.

G2 phase

The second stage of interphase where the cell prepares for mitosis.

Cyclins

Regulatory proteins that control cell cycle progression.

CDK (Cyclin-dependent kinase)

Enzymes that, when activated, promote cell cycle progression.

Apoptosis

Programmed cell death.

Oncogenes

Mutated genes that can induce cancer.

Tumor suppressor genes

Genes that prevent the formation of tumors by regulating cell division.

Photosynthesis

The process by which light energy is converted into chemical energy in plants.

Cellular respiration

Process of breaking down sugar to produce ATP.

Glycolysis

First stage of cellular respiration that breaks down glucose into pyruvic acid.

Acetyl-CoA

A crucial molecule in cellular respiration formed from pyruvic acid.

Krebs cycle (Citric acid cycle)

Stage of cellular respiration that processes acetyl-CoA to produce energy carriers.

Electron transport chain

A series of protein complexes that transfer electrons to produce ATP.

Chemiosmosis

Process of ATP production driven by a proton gradient across a membrane.

ATP

Adenosine triphosphate, the primary energy carrier in cells.

NADH

An electron carrier produced during glycolysis and the Krebs cycle.

FADH2

An electron carrier produced during the Krebs cycle.

Fermentation

Process that occurs when oxygen is not present, allowing glycolysis to continue.

Chemotaxis

Movement of organisms in response to chemical stimuli.

Signal transduction

The process by which a signal is transmitted to the inside of a cell.

Ligands

Signaling molecules that bind to receptors to trigger a response.

Homeostasis

The set of conditions under which living things can successfully survive.

Negative feedback pathway

A feedback loop that inhibits a process to maintain homeostasis.

Positive feedback pathway

A feedback loop that stimulates a process.

Feedback inhibition

A negative feedback pathway that inhibits the process of a metabolic pathway

Interphase

The period from one cell division to the next, with stages G1, S, and G2.

Sister chromatids

Identical copies of a chromosome that are joined at the centromere.

Prophase

The first stage of mitosis where chromosomes condense and the nuclear envelope disappears.

Metaphase

The stage of mitosis where chromosomes align at the metaphase plate.

Anaphase

The stage of mitosis where sister chromatids are pulled apart.

Telophase

The final stage of mitosis where two new nuclei form.

Cytokinesis

The division of the cytoplasm to form two distinct daughter cells.

Cancer

Abnormal cell growth leading to tumors and spread to other parts of the body.

Proto-oncogene

A normal gene that can become an oncogene due to mutations.