Cell structures: explain a function for every label
| English | Français |
|---|---|
| ribosome/ˈriːbəʊsəʊm/ | ribosome |
| permanent vacuole/ˈpɜːmənənt ˈvækjuːəʊl/ | permanent vacuole |
| cellulose/ˈseljuːləʊs/ | cellulose |
| cell membrane/sel ˈmembreɪn/ | membrane cellulaire |
What would explain this observation?
- An onion-storage cell may have no chloroplasts even though it is a plant cell. A useful cell diagram identifies structures present in the particular tissue.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- The nucleus contains genetic material controlling cell activities. Cytoplasm is where many chemical reactions occur. The membrane controls movement into and out of the cell. Mitochondria are sites of aerobic respiration, while ribosomes 核糖体 make proteins. Plant cells often also have chloroplasts for photosynthesis and a permanent vacuole 永久液泡 containing cell sap. A cellulose 纤维素 cell wall strengthens plant and algal cells.
- ribosome: A cell structure where proteins are made; cell membrane 细胞膜: The boundary controlling movement into and out of a cell; permanent vacuole: A plant-cell compartment containing cell sap; cellulose: A carbohydrate material strengthening plant and algal cell walls.
Which structure is directly associated with making proteins?
Link structure to function: chloroplasts contain chlorophyll to absorb light; the vacuole helps support a turgid cell; the membrane is a selective boundary rather than a rigid support. Most animal cells have the five named structures, but specialized cells can differ. Not all structures can be resolved clearly with a school light microscope.
Match each technical term to its precise meaning.
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Link structure to function: chloroplasts contain chlorophyll to absorb light; the vacuole helps support a turgid cell; the membrane is a selective boundary rather than a rigid support. Most animal cells have the five named structures, but specialized cells can differ. Not all structures can be resolved clearly with a school light microscope.
- For required practical 1, use school-prepared plant and animal material and teacher-approved staining. Start with low power, focus safely, then use higher power with fine focus. Draw what is visible using clear lines and separate labels, record the scale or magnification, and do not invent structures that the image does not show.
Which two habits make the investigation or model in this case more defensible?
For required practical 1, use school-prepared plant and animal material and teacher-approved staining. Start with low power, focus safely, then use higher power with fine focus. Draw what is visible using clear lines and separate labels, record the scale or magnification, and do not invent structures that the image does not show.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: a 20 mm drawing represents a cell 0.050 mm long. Magnification = image size/real size = 20/0.050 = 400. A 5 mm scale bar at this magnification represents 5/400 = 0.0125 mm, or 12.5 micrometres. Labelled structure and scale convey different kinds of evidence.
A 15 mm drawing represents a 0.030 mm cell. Calculate magnification. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
A 15 mm drawing represents a 0.030 mm cell. Calculate magnification.
The result is 500 . Known: a 20 mm drawing represents a cell 0.050 mm long. Magnification = image size/real size = 20/0.050 = 400. A 5 mm scale bar at this magnification represents 5/400 = 0.0125 mm, or 12.5 micrometres. Labelled structure and scale convey different kinds of evidence.
Check the conclusion and its limits
- A cell wall is outside the membrane and does not replace it. Root and storage cells need not contain chloroplasts. A nucleus is not responsible for every reaction directly; many reactions occur in the cytoplasm and specialized structures.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Every plant cell must contain chloroplasts. This claim is false: A cell wall is outside the membrane and does not replace it. Root and storage cells need not contain chloroplasts. A nucleus is not responsible for every reaction directly; many reactions occur in the cytoplasm and specialized structures.
Cell structures: explain a function for every label: Link structure to function: chloroplasts contain chlorophyll to absorb light; the vacuole helps support a turgid cell; the membrane is a selective boundary rather than a rigid support. Most animal cells have the five named structures, but specialized cells can differ. Not all structures can be resolved clearly with a school light microscope.
Every plant cell must contain chloroplasts.
A cell wall is outside the membrane and does not replace it. Root and storage cells need not contain chloroplasts. A nucleus is not responsible for every reaction directly; many reactions occur in the cytoplasm and specialized structures.
A cell structure where proteins are made: write the technical term.
ribosome means A cell structure where proteins are made.