Things to Remember form Bio class for Exam.

Element

A pure substance that cannot be broken down chemically.

Atom

The smallest unit of an element, consisting of protons, neutrons, and electrons.

Atomic Number

The number of protons in an atom that defines the element.

Mass Number

The sum of protons and neutrons in an atom.

Isotopes

Different forms of the same element with the same number of protons but different numbers of neutrons.

Valence Electrons

Electrons in the outermost energy shell that determine an atom's chemical reactivity.

Ionic Bonds

Result from the strong attraction between oppositely charged ions formed when atoms gain or lose electrons.

Covalent Bonds

Form when atoms share pairs of valence electrons.

Electronegativity

A measure of an atom’s attraction for shared electrons.

Hydrogen Bonds

A weak attraction between a partially positive hydrogen atom and a partially negative atom in another molecule.

Hydrophilic

Molecules that are polar or charged and dissolve easily in water.

Hydrophobic

Non-polar molecules that do not dissolve well in water.

Organic Compounds

Carbon-based molecules that can form diverse structures.

Isomers

Molecules with the same chemical formula but different arrangements of atoms.

Structural Isomers

Isomers that differ in the covalent arrangement of atoms.

Stereoisomers

Isomers that have different spatial arrangements.

Functional Groups

Reactive clusters of atoms that determine a molecule’s properties.

Macromolecules

Large molecules composed of smaller subunits, such as carbohydrates and proteins.

Activation Energy

The minimum energy required to trigger a chemical reaction.

Enzymes

Biological catalysts that speed up reactions by lowering activation energy.

Substrate

The specific reactant molecule that an enzyme recognizes and binds to.

Allosteric Regulation

Regulation of an enzyme by a molecule binding to a separate regulatory site.

Feedback Inhibition

A metabolic control mechanism where the final product of a pathway inhibits an enzyme earlier in that pathway.

Cofactors

Non-protein groups, often metal ions, that bind to enzymes and are essential for catalytic activity.

Coenzymes

Organic cofactors that assist enzymes in catalyzing reactions.

Photosynthesis

The process by which photoautotrophs convert light energy into chemical potential energy.

Glycolysis

The metabolic pathway that breaks down glucose into pyruvate.

Fermentation

An anaerobic process that regenerates NAD+ by converting pyruvate into alcohol or lactate.

Mitochondrial Respiration

Aerobic respiration that occurs in mitochondria, involving glycolysis, the Krebs cycle, and the electron transport chain.

Action Potential

An abrupt change in electrical voltage across a neuron's membrane.

Synapse

The connection site between a neuron and another cell, where neurotransmitters are released.

Neurotransmitters

Chemicals released from axon terminals to transmit signals across synapses.

Reflex Arc

The simplest neural circuit allowing for involuntary reactions.

Endocrine System

A system of glands that secrete hormones to regulate bodily processes.

Negative Feedback

A homeostatic mechanism where a stimulus triggers a response that counteracts the initial change.

ADH

A hormone regulating water balance, produced by the hypothalamus.

Nephron

The functional unit of the kidney responsible for filtering wastes from the blood.

Osmoregulation

The process of maintaining a constant balance of water and solutes.

Mitosis

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

Meiosis

The type of cell division that produces gametes with half the number of chromosomes.