Specialized cells: connect a feature to the task
הוצג| English | משמעות |
|---|---|
| specialized cell/ˈspeʃəlaɪzd sel/ | תא ספציפי |
| root hair cell/ruːt heə sel/ | תא שורש |
What would explain this observation?
- A long root hair increases contact with soil, while a long nerve cell can carry information over a distance. Shape is useful when its effect on function is explained.
Build the model
- A sperm cell has a tail for movement, mitochondria providing energy through respiration and an acrosome containing enzymes that help entry into an egg.
- A nerve cell has a long extension carrying impulses and branches connecting with other cells.
- Muscle cells contain contractile structures and many mitochondria for the energy demand of contraction.
- specialized cell 特化细胞: A cell with structures suited to a particular function.
- root hair cell 根毛细胞: A root-surface cell with a projection that increases absorbing area.
Which explanation correctly links a root-hair feature with its function?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
The root hair is a long projection that pushes between soil particles, greatly increasing the surface area over which water and mineral ions are absorbed. The cell still respires, and its wall never replaces the membrane.
Match each technical term to its precise meaning.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- A root hair cell has a long projection increasing surface area for absorption.
- Xylem vessels are dead hollow cells joined into tubes, with strengthened lignified walls carrying water and supporting the plant.
- Phloem transports dissolved sugars through living tissue; its conducting cells work with companion cells.
- GCSE explanations should link each named feature to its role rather than give an unsupported list.
In the lab: Compare labelled teacher-provided cell diagrams at stated scales. Use the pattern feature → effect → function. For unfamiliar cells, read the supplied information and reason from it; do not assume every specialized cell has lost its nucleus or contains a tail.
Which two habits make the investigation or model in this case more defensible?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: a model root hair has an absorbing surface of 1.8 square units instead of 0.6 for a rounded model cell.
- The surface ratio is 1.8/0.6 = 3.
- This can increase exchange capacity under the same conditions, but transport also depends on concentration, membrane processes and available energy.
Your turn: Absorbing surface changes from 0.8 to 2.4 square units. Calculate the surface-area ratio.
Absorbing surface changes from 0.8 to 2.4 square units. Calculate the surface-area ratio.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 3 . Known: absorbing surface rises from 0.8 to 2.4 square units. Use ratio = final / initial. Ratio = 2.4/0.8 = 3. The surface triples; exchange capacity rises with it under matched conditions.
Check the conclusion and its limits
- More mitochondria does not mean mitochondria themselves contract or propel the cell.
- Xylem and phloem are different tissues and do not carry the same substances by the same mechanism.
- A cell adaptation is explained in the context of its task.
Not true: Every specialized cell has the same sub-cellular structures. Specialized cells differ precisely because their structures differ: a root hair, a sperm cell and a red blood cell carry different structures for different tasks, though all share the basic cell plan.
- A sperm cell has a tail for movement, mitochondria providing energy through respiration and an acrosome containing enzymes that help entry into an egg.
- A root hair cell has a long projection increasing surface area for absorption.
- Watch for: more mitochondria does not mean mitochondria themselves contract or propel the cell.
Specialized cells differ precisely because their structures differ: a root hair, a sperm cell and a red blood cell carry different structures for different tasks, though all share the basic cell plan.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
True. Specialized cells differ precisely because their structures differ: a root hair, a sperm cell and a red blood cell carry different structures for different tasks, though all share the basic cell plan.
A cell with structures suited to a particular function: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
specialized cell means A cell with structures suited to a particular function.