Body Systems

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Cell Noun

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[sel]

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Cell

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The smallest structural and functional unit of an organism, which is typically microscopic and consists of cytoplasm and a nucleus.

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Example: This diagram shows a simple animal cell and labels its main parts, including the nucleus, cytoplasm, cell membrane, mitochondria, and vacuole.

Front

Molecule Noun

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[mol-uh-kyool]

Back

Molecule

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A group of two or more atoms bonded together, representing the smallest fundamental unit of a chemical compound.

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Example: This diagram shows a carbon dioxide (CO₂) molecule, where one carbon atom is chemically bonded to two oxygen atoms, forming a single unit.

Front

Glucose Noun

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[gloo-kohs]

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Glucose

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A simple sugar molecule that serves as a primary and important energy source for cells in living organisms.

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Example: This image shows glucose as a key ingredient, along with oxygen, that cells use in the process of cellular respiration to produce energy.

Front

Amino Acid Noun

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[uh-mee-noh as-id]

Back

Amino Acid

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A type of small organic molecule that serves as the fundamental building block for constructing larger protein molecules.

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Example: This image shows how individual units called amino acids (colorful circles) link together in a process to form larger structures like proteins.

Front

Oxygen Noun

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[ok-si-jen]

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Oxygen

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A molecule essential for cellular respiration, the process where cells convert nutrients into usable energy for bodily functions.

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Example: This image shows that the oxygen we breathe is a molecule made of two oxygen atoms, represented by the chemical formula O₂.

Front

Cell Membrane Noun

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[sel mem-breyn]

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Cell Membrane

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The semipermeable boundary surrounding a cell that regulates which substances are allowed to enter or exit the cell.

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Example: This diagram shows the cell membrane, which acts as a boundary controlling what enters and leaves a cell, with different proteins embedded within it.

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Tissue Noun

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[tish-oo]

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Tissue

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A group of similar cells from the same origin that work together to perform a specific, specialized function.

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Example: This diagram shows how multiple, similar heart muscle cells are grouped and connected, forming cardiac muscle tissue.

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Organ Noun

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[or-guhn]

Back

Organ

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A self-contained structure made of different types of tissues that work together to perform specific functions in an organism.

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Example: This image shows a human heart, which is an example of an organ: a structure made of different tissues that work together for a specific job.

Front

System Noun

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[sis-tuhm]

Back

System

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A group of interacting or interdependent parts, like organs, that form a complex whole to perform major bodily functions.

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Example: The nervous system is a group of parts, including the brain, spinal cord, and nerves, that work together to send and receive signals throughout the body.

Front

Digestive System Noun

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[dahy-jes-tiv sis-tuhm]

Back

Digestive System

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The body system responsible for ingesting food and breaking it down into smaller molecules for absorption and cellular use.

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Example: This diagram shows the major organs of the digestive system, like the stomach and intestines, and where they are located in the body.