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Vacca Luigina

E. Answer in detail.1. How will you test for the presence of starchin a leaf?2. Briefly describe what happens duringphotosynthesis.3. Why is photosynthesis important?4. Differentiate between autotrophs andheterotrophs.5. Write a short note on heterotrophic plants.6. Explain with an example each.(i) total parasite(ii) symbiont(iii) saprophyte7. How are nutrients returned to soil afterbeing absorbed by plants?​

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1. Iodine solution is used to test leaves for the presence of starch.heat a plant leaf in boiling water for 30 seconds (this stops its chemical reactions)

heat it in boiling ethanol for a few minutes (this removes most of its colour)

wash with water and spread onto a white tile

add iodine solution from a dropping pipette

2. During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose.

3. Photosynthesis is the main source of food on earth. It releases oxygen which is an important element for the survival of life. Without photosynthesis, there will be no oxygen on earth. Photosynthesis fixes carbon dioxide and releases oxygen, thereby reducing the greenhouse effect and global warming.



-Usually members of the plant kingdom and certain unicellular organisms like cyanobacteria.

-Autotrophs are producers which prepare their own food.

-These can be classified as photoautotrophs and chemoautotrophs.

-The chloroplast helps in preparing food.

-They obtain energy from inorganic sources by converting light energy into chemical energy.

-Autotrophs can store light energy and chemical energy.

-They are placed at the primary level in the food chain.

-They cannot move from their place.

-Examples: Green plants, algae and a few photosynthetic bacteria are examples of autotrophs.


-All members of the animal kingdom.

-Heterotrophs are the consumers who depend on other sources for their food.

-These can be classified as photoheterotrophs and chemoheterotrophs

-They do not contain chloroplast, so cannot prepare food.

-They obtain energy directly or indirectly from other organisms.

-Heterotrophs cannot store energy.

-These are placed in the secondary or tertiary level in the food chain.

-Can move from one place to another in search of food and shelter.

-Examples: Cows, buffaloes, tigers, horses, humans are examples of heterotrophs.

5. Some plants cannot produce their own food and must obtain their nutrition from outside sources—these plants are heterotrophic. This may occur with plants that are parasitic or saprophytic. Some plants are mutualistic symbionts, epiphytes, or insectivorous.

6. 1) Total parasite

Total parasite plants are heterotrophic plants that depend entirely on the host plant, including shelter, water, food, for all their requirements.

Examples: Orobanche aegyptiaca, cuscuta reflexa and striga asiatica.

2) Symbiont

Symbiont is the term used to refer to an organism living in a symbiosis. Symbiosis is a close and prolonged interaction between organisms of different species.

An example is the hermit crab whose shell offers a niche for anemones to exist in which the anemone can defend the crab with its stinging capabilities. Another example is the interaction between Rhizobia species and the plant legumes.

3) Saprophyte

Saprophytes are living organisms that obtain their nutrition either directly from dead organic matter or indirectly by parasitizing fungi. 

For example, include fungi like mushrooms and bacteria like Lactobacillus.  

7. Vegetable plants transpire water from their leaves, creating suction on the water at the root surface that draws the nutritious surface soil solution toward the plant roots. This process of mass flow caused by leaf transpiration explains how most plant nutrients (98 percent) move from the soil to the root surface.

Hope it helps you

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