These questions ask you to match a cellular activity with the structure that performs it, sometimes selecting several activities for one structure. Focus on the action word and keep related stages separate.
Follow the job through the cell
Ask whether the task concerns instructions, synthesis, energy transfer, movement, chemical reactions, processing, storage, support, or breakdown. For example, making a product and packaging that product are different stages, so they should not automatically be assigned to the same structure.
| Job signal | Cell component |
|---|---|
| Contains most cellular DNA and its instructions in a eukaryotic cell | Nuclear compartment |
| Carries out aerobic respiration and produces most ATP | Mitochondria |
| Builds proteins from amino acids | Ribosomes |
| Selectively regulates movement into and out of the cell | cell membrane |
| Hosts many enzyme-controlled metabolic reactions | The fluid cell interior, although cellular reactions also occur elsewhere |
| Absorbs light and performs photosynthesis | chloroplast structures |
| Stores cell sap and contributes to turgor | Central vacuole |
| Provides rigid support and resists excessive expansion as water enters | Plant cell wall |
For the internal membrane system, track the phase. Attached ribosomes make proteins; rough endoplasmic reticulum helps process and transport those proteins. Smooth ER is involved in lipid synthesis. The Golgi body modifies, sorts, and packages proteins and lipids into vesicles. Lysosomes contain digestive enzymes that break down unwanted material. A short example is a secreted protein: synthesis begins at ribosomes, then later handling can involve rough endoplasmic reticulum and Golgi compartments.
Function swaps to avoid
| Tempting swap | How to correct it |
|---|---|
| Assigning protein synthesis or usable energy release directly to the nuclear compartment | The nuclear compartment stores instructions; ribosomes build proteins and mitochondria are the main aerobic ATP-producing sites. |
| Treating cellular respiration as breathing or photosynthesis | Breathing is organism-level gas exchange, while photosynthesis captures light energy; aerobic respiration occurs mainly in mitochondria. |
| Giving selective entry control to the plant wall | The wall is porous and supportive. The surface membrane provides the main selective control. |
| Using a vacuole as a protein-building site | Separate storage and turgor from synthesis; the central vacuole stores sap, while ribosomes build proteins. |
| Swapping rough and smooth ER | Use both the product and the surface clue: protein handling with attached ribosomes points to rough endoplasmic reticulum, while lipid synthesis without them points to smooth ER. |
| Choosing a ribosome, centrosomes, or chloroplast for intracellular digestion | Match digestion to enzyme-containing digestive vesicles; the other structures have different roles. |
Try it
Consider two claims: many enzyme-controlled metabolic reactions occur in cytoplasm; every cellular reaction occurs in cytoplasm. Enter the number of claims supported by school-level cell biology.
Which activities are functions of chloroplasts in photosynthetic plant cells? Select all that apply.
- Carrying out aerobic respiration
- Absorbing light energy
- Digesting unwanted cell material
- Carrying out photosynthesis
Which tasks belong to the Golgi apparatus? Select all that apply.
- Modifying and sorting proteins and lipids
- Performing the initial synthesis of proteins
- Packaging cell products into vesicles
- Producing most ATP by aerobic respiration