Teacher answer key · Grades 6–8 · about 20 minutes

Answer key: Cell Organelles Activity

For teachers. This page is hidden from search engines and not linked from student pages, but it is not password-protected, so please don’t share the link with students. Student activity: Cell Organelles Activity.

Goal: Identify the main organelles of animal and plant cells, describe what each one does, and explain how the parts of a cell work together.

Connects to NGSS MS-LS1-2 (Develop and use a model to describe the function of a cell as a whole and how parts of cells contribute to it.)

Completed results table

Every value is the tool’s own readout for that setting, calculated with the same code as the Cell atlas.

Organelle	Main function	In animal cells?	In plant cells?
Nucleus	Stores the DNA and controls which genes are expressed	Yes	Yes
Mitochondrion	Aerobic respiration: makes most of the cell’s ATP	Yes	Yes
Chloroplast	Photosynthesis: builds sugar from CO₂ and water using light	No	Yes
Ribosome	Translates mRNA into protein	Yes	Yes
Golgi apparatus	Modifies, sorts, and packages proteins into vesicles	Yes	Yes
Lysosome	Digests worn-out parts, food particles, and bacteria	Yes	Rare (the vacuole digests)
Vacuole	Stores water, ions, and waste; keeps plant cells turgid	Small, temporary	One large central vacuole
Cell wall	Rigid cellulose layer that supports and protects	No	Yes

Answers

Which structures did you find in the plant cell but not in the animal cell?
Chloroplasts, a cell wall and one large central vacuole. Animal cells have no chloroplasts or cell wall, and only small, temporary vacuoles.
Which structure did you find in the animal cell but not in the plant cell?
Centrioles, which organize the spindle when the cell divides. Lysosomes are also rare in plant cells, where the vacuole does much of the digesting.
Plant cells have chloroplasts. Why do they also need mitochondria?
Chloroplasts use light energy to make sugar by photosynthesis, but mitochondria break that sugar down in aerobic respiration to make ATP, the energy the cell uses day and night. Both animal and plant cells have mitochondria.
Which three organelles are surrounded by a double membrane?
The nucleus, the mitochondrion and the chloroplast.
Follow a protein that the cell will release. List the organelles it passes through, in order, starting with its gene.
Nucleus (the gene is copied into mRNA) → ribosome on the rough endoplasmic reticulum (the protein is built and folded) → Golgi apparatus (it is modified, sorted and packaged) → vesicle → cell membrane (released by exocytosis).
Challenge: ribosomes have no membrane. Why does every living cell, even a bacterium, have ribosomes?
Ribosomes translate mRNA into protein, and every cell must make proteins to survive. Prokaryotes and eukaryotes both have ribosomes, even though prokaryotes lack membrane-bound organelles.

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