40 Questions
What is the role of chlorophyll during the day in desert plants?
To absorb energy that is used to act on an intermediate
What can be observed under a microscope in a leaf cross-section?
Cell organelles called chloroplasts which contain chlorophyll
What is the purpose of Activity 6.1?
To show that chlorophyll is essential for photosynthesis
What is the role of the intermediate in desert plants?
It is prepared during the night and acted upon during the day
Why are variegated leaves used in Activity 6.1?
Because they have distinct green areas
What happens to the starch in a plant when it is kept in a dark room for three days?
It is used up
What is necessary to observe the effect of chlorophyll on photosynthesis?
A potted plant with variegated leaves, a dark room, and sunlight
What is the purpose of marking the green areas in Activity 6.1?
To compare the effect of sunlight on different parts of the leaf
What is the primary reason for the development of a specialized tissue for excretion in multi-cellular organisms?
To enable the transportation of waste away from cells
Which of the following is a characteristic of autotrophs?
They obtain energy from inorganic sources in the form of carbon dioxide and water
What is the primary function of enzymes in heterotrophic organisms?
To break down complex substances into simpler ones
Why do multi-cellular organisms like humans require a transportation system?
To transport waste away from cells to excretory tissues
What is the primary source of energy and materials for living organisms?
The food we eat
Which of the following is a characteristic of heterotrophic organisms?
They use bio-catalysts to break down complex substances
Why are autotrophs essential for the survival of heterotrophs?
Because autotrophs are a source of complex substances for heterotrophs
What is the primary function of the transportation system in multi-cellular organisms?
To transport oxygen to cells and waste away from cells
What is the primary function of carbohydrates in autotrophic organisms?
To provide energy to the plant
What is the role of chlorophyll in photosynthesis?
To absorb light energy from the sun
What is the fate of excess carbohydrates in autotrophic organisms?
They are stored in the form of starch
What is the byproduct of water molecule splitting during photosynthesis?
Hydrogen and oxygen
What is the energy source for autotrophic organisms?
Sunlight and chlorophyll
What is the similarity between autotrophic organisms and humans in terms of energy storage?
Both store energy in the form of glycogen
What is the sequence of events during photosynthesis?
Light energy absorption, water molecule splitting, and carbohydrate synthesis
What is the primary role of photosynthesis in autotrophic organisms?
To fulfill carbon and energy requirements
What is the purpose of using potassium hydroxide in the experiment?
To absorb carbon dioxide
What is the main function of roots in terrestrial plants?
To absorb water and minerals from the soil
What is the essential element used in the synthesis of proteins and other compounds?
Nitrogen
Why are the plants kept in a dark room for three days?
To prevent photosynthesis
What is the purpose of using vaseline to seal the bottom of the jars?
To make the set-up air-tight
What is the conclusion that can be drawn from the experiment?
Sunlight is essential for photosynthesis
What is the role of autotrophs in the ecosystem?
They produce their own food through photosynthesis
What is the significance of checking for the presence of starch in the leaves?
To determine if photosynthesis is occurring
What is the primary purpose of heating the beaker containing alcohol in the starch test?
To facilitate the dissolution of starch in the alcohol
What is the role of the guard cells in the stomatal pore?
To control the opening and closing of the stomatal pore
What is the significance of the starch test in understanding plant physiology?
It helps to identify the areas of the leaf where photosynthesis is occurring
What is the purpose of dipping the leaf in a dilute solution of iodine in the starch test?
To detect the presence of starch in the leaf
What is the significance of the stomatal pore in plant physiology?
It facilitates the exchange of gases across the leaf surface
What is the result of the guard cells shrinking in the stomatal pore?
The stomatal pore closes, reducing gas exchange
What is the purpose of observing the colour of the leaf before and after the starch test?
To identify the areas of the leaf where starch is present
What is the significance of the variegated leaf in the starch test?
It helps to identify the areas of the leaf where photosynthesis is occurring
Study Notes
Nutrition in Multi-Cellular Organisms
- In multi-cellular organisms, specialized tissues are developed for excretion, requiring a transportation system to transport waste away from cells to the excretory tissue.
- Energy and materials from outside are necessary for growth, development, synthesizing protein, and other substances needed in the body.
Autotrophic Nutrition
- Autotrophs, such as green plants and some bacteria, use simple food materials obtained from inorganic sources, like carbon dioxide and water, to fulfill their energy and material requirements.
- Photosynthesis is the process by which autotrophs convert substances from the outside into stored forms of energy.
- Carbon dioxide and water are converted into carbohydrates in the presence of sunlight and chlorophyll, which provide energy to the plant.
Process of Photosynthesis
- Light energy is absorbed by chlorophyll.
- Light energy is converted into chemical energy, and water molecules are split into hydrogen and oxygen.
- Carbon dioxide is reduced to carbohydrates.
- These steps can occur separately, and the plant may prepare an intermediate product at night, which is acted upon by the energy absorbed during the day.
Role of Chlorophyll
- Chlorophyll is essential for photosynthesis.
- Chloroplasts, which contain chlorophyll, are cell organelles found in green dots in leaf cells.
Importance of Stomata
- Stomata are tiny pores present on the surface of leaves, allowing for massive gaseous exchange during photosynthesis.
- Stomata are also present on stems, roots, and leaves.
- Guard cells control the opening and closing of stomata, and they swell when water flows into them, causing the stomatal pore to open.
Experiment to Demonstrate Photosynthesis
- Activity 6.1 demonstrates the importance of chlorophyll in photosynthesis.
- Activity 6.2 shows the effect of carbon dioxide on photosynthesis.
- These activities can be used to design an experiment to demonstrate the importance of sunlight for photosynthesis.
Learn about the nutrition process in multi-cellular organisms and autotrophic nutrition in green plants and some bacteria. Understand how they obtain energy and materials.
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