Where the glucose goes
הוצג| English | משמעות |
|---|---|
| starch/stɑːtʃ/ | עמילן |
| cellulose/ˈseljuːləʊs/ | תאית |
| nitrate ion/ˈnaɪtreɪt ˈaɪɒn/ | יון ניטרט |
What would explain this observation?
- A leaf makes glucose, but a growing plant also needs strong walls, stored material and proteins. Glucose can supply carbon to several products with different functions.
Build the model
- Glucose made by photosynthesis can be used in respiration.
- It can be converted into insoluble starch 淀粉 for storage or into fat or oil for storage.
- It can also be used to make cellulose 纤维素, which strengthens cell walls.
- Plants use glucose and nitrate ions 硝酸根离子 absorbed from soil to form amino acids; these are used to synthesize proteins.
- cellulose: A carbohydrate that strengthens plant cell walls.
- starch: An insoluble carbohydrate used for storage in plants.
- nitrate ion: A mineral ion supplying nitrogen for plant amino-acid and protein formation.
Why are nitrate ions needed alongside glucose for plant protein production?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Amino acids contain nitrogen, and glucose contains none - so nitrate ions supply the nitrogen needed to turn glucose products into amino acids and proteins. Light supplies energy, not elements.
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
- Storage, structure and energy transfer are separate roles.
- Starch is insoluble, so it can be stored without behaving like an equivalent amount of dissolved glucose.
- Cellulose is structural.
- Nitrate supplies needed nitrogen for amino acids; sunlight alone does not supply every element a growing plant needs.
In the lab: Sort glucose-use cards by product and function. Link nitrate absorption by roots to protein production rather than to oxygen release. Interpret teacher-provided results of starch, glucose and protein tests with controls. Actual testing follows approved reagents, heating and disposal; a negative test concerns the stated sample and detection conditions.
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 fictional allocation model has 100 carbon units from glucose.
- It assigns 35 to respiration, 25 to starch, 20 to cellulose and 10 to oils.
- The remaining 10 can be assigned to other products in this model.
- These are accounting units, not a fixed biological percentage or a balanced synthesis equation.
Your turn: A fictional 80-unit allocation assigns 24 units to storage. Calculate the storage percentage.
A fictional 80-unit allocation assigns 24 units to storage. Calculate the storage percentage.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 30 %. Known: 24 of 80 units go to storage. Use percentage = share / total x 100. Percentage = 24/80 x 100 = 30%. The allocation is a model accounting exercise, not a fixed biological constant.
Check the conclusion and its limits
- Photosynthesis makes glucose rather than directly making every protein.
- Plants need mineral nutrients as well as light, water and carbon dioxide.
- A glucose molecule cannot supply nitrogen that it does not contain; nitrate is relevant to amino acids and proteins.
Not true: Sunlight supplies every element needed to make proteins. Sunlight provides energy only. The elements for protein - carbon, hydrogen, oxygen AND nitrogen - come from glucose (from photosynthesis) plus mineral ions such as nitrate absorbed from the soil.
- Glucose made by photosynthesis can be used in respiration.
- Storage, structure and energy transfer are separate roles.
- Watch for: photosynthesis makes glucose rather than directly making every protein.
Sunlight provides energy only.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
True. Sunlight provides energy only. The elements for protein - carbon, hydrogen, oxygen AND nitrogen - come from glucose (from photosynthesis) plus mineral ions such as nitrate absorbed from the soil.
A carbohydrate that strengthens plant cell walls: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
cellulose means A carbohydrate that strengthens plant cell walls.