Living Things

Front

organism Noun

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[or-guh-niz-uhm]

Back

organism

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Any individual living being, such as an animal, plant, or bacterium, that is capable of independent existence.

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Example: This image shows a bacterium, an organism, highlighting its structure as a living being.

Front

cell Noun

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[sel]

Back

cell

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The smallest structural and functional unit of an organism, considered the basic building block of all life.

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Example: This diagram shows the basic structure of a cell, including the nucleus, cytoplasm, cell membrane, and mitochondria.

Front

unicellular Adjective

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[yoo-ni-sel-yuh-ler]

Back

unicellular

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Describing a living being that consists of only one single cell, which performs all vital life functions.

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Example: An amoeba is a single-celled organism performing all life functions within one cell.

Front

multicellular Adjective

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[muhl-tee-sel-yuh-ler]

Back

multicellular

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Describing a living being that is composed of many cells, which are often specialized to perform different tasks.

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Example: The image shows how skeletal muscle is made of many cells, each specialized for movement.

Front

stimulus Noun

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[stim-yuh-luhs]

Back

stimulus

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A change or signal in the internal or external environment that causes a detectable reaction by an organism.

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Example: A cactus prick is a stimulus that causes the girl to react by pulling her hand away.

Front

response Noun

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[ri-spons]

Back

response

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An action, movement, or change in behavior that an organism produces as a reaction to a specific stimulus.

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Example: A stimulus (glass of water) triggers a response (arm movement) through a neural pathway involving sensory, relay, and motor neurons.

Front

spontaneous generation Noun

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[spon-tey-nee-uhs jen-uh-rey-shuhn]

Back

spontaneous generation

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The incorrect historical hypothesis that living organisms could originate directly from nonliving matter without any parents.

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Example: Flies appear only in the open jar, showing that they come from outside, not from the meat itself.

Front

homeostasis Noun

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[hoh-mee-oh-stey-sis]

Back

homeostasis

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The process by which an organism maintains a stable, constant internal environment despite changes in external conditions.

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Example: The hypothalamus regulates body temperature by signaling sweat glands to cool down or muscles to shiver.

Front

characteristics Noun

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[kar-ik-tuh-ris-tiks]

Back

characteristics

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A distinguishing feature or quality that belongs to an organism and serves to identify or describe it.

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Example: The image labels different parts of a dog's body, showing characteristics that identify the organism.

Front

carbohydrates Noun

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[kahr-boh-hy-dreyts]

Back

carbohydrates

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A group of organic compounds, including sugars and starches, that serve as a primary source of energy for cells.

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Example: The image shows how starch (a carbohydrate) breaks down into glucose molecules, providing energy.