9th Grade Biology Comprehensive Vocabulary Review

Vocabulary terms and definitions in English based on the biology 9th grade lecture notes, covering scientific methodology, biochemistry, cell biology, and classification.

Scientific Method

A process that makes knowledge growth and scientific understanding continuous through testing research questions, making observations, and analyzing results.

Hypothesis

A testable proposition or explanation offered for the cause, connection, or result of a specific situation or event.

Scientific Law

Statements that explain 'how' natural events occur.

Scientific Theory

Statements that explain laws and attempt to answer 'why' natural events occur.

Anabolism

The synthesis process where simple small molecules are converted into more complex and larger molecules, also known as the building process.

Catabolism

The breakdown process where structurally large molecules are separated into smaller components, often to produce energy.

Homeostasis

A set of control mechanisms that keep the internal environment of an organism stable despite changing external conditions.

Adaptation

The sum of hereditary characteristics specific to a species that increase the chance of survival and reproduction in its environment.

Taxonomy

The branch of science that determines the principles and criteria necessary to classify living things.

Species

A group of organisms with common characteristics and genetic heritage that can interbreed and produce fertile offspring.

Binomial Nomenclature

A two-word naming system where the first word is the genus name (capitalized) and the second is the specific epithet (lowercase), both written in italics.

Prokaryotic Cell

Relatively small cells that do not have a distinct nucleus or membrane-bound organelles, such as bacteria and archaea.

Eukaryotic Cell

Cells that possess a distinct nucleus and membrane-bound organelles, such as plants, animals, and fungi.

Cohesion

The attractive force between molecules of the same type, such as water molecules sticking to each other.

Adhesion

The attractive force between different types of molecules, such as water molecules sticking to a leaf or glass.

Surface Tension

A property of the surface of a liquid that allows it to resist an external force, caused by the high cohesion of water molecules.

Monosaccharides

The simplest form of carbohydrates with the general formula $(CH_2O)_n$, including glucose, fructose, and ribose.

Polysaccharides

Long-chain organic molecules formed by the dehydration of a large number of monosaccharides, such as starch, glycogen, and cellulose.

Triglycerides

Lipid molecules consisting of one glycerol molecule bonded to three fatty acids via ester bonds; the primary form of stored energy in the body.

Phospholipids

The structural components of cell membranes consisting of a hydrophilic head (phosphate group) and two hydrophobic fatty acid tails.

Denaturation

The loss of a protein's natural three-dimensional shape due to changes in environmental conditions like high temperature, pH, or salt concentration.

Enzymes

Biological catalysts, usually proteins, that increase the rate of chemical reactions by lowering the activation energy.

Apoenzyme

The protein part of an enzyme that requires a helper component (cofactor or coenzyme) to become active.

Cofactor

Non-protein inorganic helper substances, such as zinc or iron ions, required for an enzyme to function.

Coenzyme

Organic helper molecules, such as vitamins, that assist enzymes in their catalytic activity.

Nucleotide

The monomer of nucleic acids consisting of a phosphate group, a five-carbon sugar (pentose), and a nitrogenous organic base.

Diffusion

The movement of molecules from an area of high concentration to an area of low concentration without using energy.

Osmosis

The diffusion of water molecules through a semi-permeable membrane from a region of low solute concentration to high solute concentration.

Active Transport

The movement of molecules from a low concentration area to a high concentration area using ATP and protein pumps.

Plasmolysis

The shrinking of a cell's cytoplasm away from the cell wall when placed in a hypertonic (more concentrated) environment due to water loss.

Endocytosis

The process of taking large molecules into the cell by forming pockets in the cell membrane, which requires energy.

Exocytosis

The process where large molecules are expelled from the cell via vesicles merging with the cell membrane.

Chloroplast

A double-membrane organelle found in plants and algae that performs photosynthesis to convert light energy into glucose.

Mitochondria

The double-membrane organelle known as the power center of the cell, responsible for producing ATP via cellular respiration.

Endoplasmic Reticulum

A labyrinthine network of biological membranes used for protein synthesis (rough) and lipid synthesis or detoxification (smooth).

Lysosome

A membrane-bound sac containing digestive enzymes used to break down cellular waste and foreign particles.

Biosphere

The area on Earth where all living things live and interact, including the land, sea, and atmosphere.