Prokaryote vs Eukaryote

Front

Prokaryote Noun

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[pro-kar-ee-oht]

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Prokaryote

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A microscopic single-celled organism that has no nucleus and lacks other membrane-bound organelles.

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Example: This diagram shows the structure of a bacterium, a type of prokaryote, highlighting the nucleoid area where its DNA is located instead of a nucleus.

Front

Eukaryote Noun

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[yoo-kar-ee-oht]

Back

Eukaryote

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An organism with cells that have a nucleus enclosing the genetic material and other membrane-bound organelles.

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Example: This diagram shows a cell's nucleus, the membrane-bound organelle containing genetic material. The presence of a nucleus is the defining feature of a eukaryotic cell.

Front

Cell Membrane Noun

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[sel mem-breyn]

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Cell Membrane

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The semipermeable outer layer of a cell that controls which substances can enter or leave the cell.

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Example: This diagram shows the cell membrane is a flexible barrier made of a phospholipid bilayer with various proteins and carbohydrates embedded within it.

Front

Cytoplasm Noun

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[sy-toh-plaz-uhm]

Back

Cytoplasm

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The jellylike substance that fills a cell, is enclosed by the cell membrane, and contains the organelles.

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Example: This diagram of a eukaryotic cell shows the cytoplasm as the jelly-like substance filling the cell, surrounding the nucleus and other organelles.

Front

Genetic Material Noun

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[juh-net-ik muh-teer-ee-uhl]

Back

Genetic Material

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The DNA or RNA that carries the instructions for making all of a cell's proteins and for replication.

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Example: This image compares where genetic material is stored in eukaryotic cells (inside a membrane-bound nucleus) and prokaryotic cells (in a region called the nucleoid).

Front

Ribosomes Noun

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[ry-buh-sohmz]

Back

Ribosomes

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Cellular structures responsible for synthesizing proteins by reading instructions from the cell's genetic material.

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Example: A ribosome reads instructions from an mRNA molecule to link amino acids together, forming a growing protein chain. This process is called translation.

Front

Nucleus Noun

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[noo-klee-uhs]

Back

Nucleus

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A large, membrane-bound organelle found in eukaryotic cells that contains the cell's genetic material.

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Example: This diagram shows the nucleus, a membrane-bound organelle containing genetic material (chromatin), which is a key feature found only in eukaryotic cells.

Front

Organelle Noun

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[or-guh-nel]

Back

Organelle

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A specialized subunit within a cell that has a specific function and is often enclosed by a membrane.

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Example: This image shows an organelle (a mitochondrion) taking in food and converting it into energy (ATP) for the cell to use.

Front

Flagellum Noun

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[fluh-jel-uhm]

Back

Flagellum

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A long, whip-like structure that projects from the cell body and is used for locomotion or movement.

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Example: This diagram shows a flagellum, a long tail that uses a propeller-like motion to move a cell, and contrasts it with shorter cilia.

Front

Mitochondrion Noun

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[my-toh-kon-dree-on]

Back

Mitochondrion

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A membrane-bound organelle that generates most of the cell's supply of chemical energy in the form of ATP.

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Example: This diagram shows the detailed structure of a mitochondrion, a key organelle with its own DNA found in eukaryotic cells but not prokaryotic cells.