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Kerala SCERT Class 9 Biology Protectors of Biosphere Question Answer

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1.) Where do photosynthesis takes place?

Ans: Photosynthesis takes place in chloroplast.

2.) Where are pigments located in the plants?

Ans – Pigments that absorb sunlight are found in the grana of chloroplast

3.) What are accessory pigments?

Ans – pigments absorb light and transfer it to chlorophyll a. Hence, they are called accessory pigments.

4.) Which chloroplast works in light phase? / which chloroplast works in dark phase?

Ans – Grana works in light phase. / stroma works in dark phase.

5.) Difference between light and dark phase?

Light phase

Dark phase

Light is used.

Light is not used.
Water splits and oxygen is released. Hydrogen reaches stroma.

Light energy is converted to chemical energy and stored in ATP.

Energy in ATP is used to combine hydrogen and carbon dioxide to produce glucose.

ATP formed

ATP utilized

6.) What is known as Calvin cycle?

Dark phase follows the light phase. The cyclic chemical reactions in the dark phase were discovered by the scientist Melvin Calvin. Hence, this phase is known as Calvin cycle.

7.) While energy transfer ATP is converted to which reduced form?

The energy liberated during the break down of ATP into ADP (Adenosine diphosphate) and phosphate is used for the metabolic activities.

8.) How do plants utilize glucose?

  • glucose is easily soluble in water it cannot be stored in plant body.
  • Therefore, plants store glucose in the form of insoluble starch in leaves. Plants utilize starch as a source of energy for life activities and to prepare substances required for growth.
  • Starch is later converted to sucrose and is transported through phloem to various plant parts and stored there in different forms.

9.) In what forms do glucose is stored in plants?

Glucose is stored in the form of starch in tubers, protein in legumes, fats in oil seeds fructose in fruits, and sucrose in sugarcanes.

10.) What is chemosynthesis Explain?

The sulphur bacteria seen on land and in water are examples for this. They produce energy by breaking down chemical compounds. This process is called chemosynthesis.

More Notes by Expert Teacher:

Q1) The main reason for global warming is the increase in carbon dioxide concentration explains the cycle through which oxygen and carbon dioxide levels are maintained in the atmosphere?

Plants help at certain level to maintain the oxygen and carbon dioxide concentrations in atmosphere, plants for their process of photosynthesis take Co2 which is release by animals and humans in respiration with the help of sunlight and chlorophyll it converts it to O2 glucose.

Q2) Where does photosynthesis take place in a plant give a brief about various parts in it.

Photosynthesis takes place in leaves or any green structure where chloroplast is present. It has a pack of membranous sac called grana which helps to absorb sunlight. Some of the pigments help in absorption of light in which chlorophyll a play a significant role and all others like chlorophyll b, carotene, xanthophyll passes the light to chlorophyll a, hence are known as accessory pigments.

Q3) Case base question

Smita attended a science exhibition where she came to know about plants and photosynthesis the people over their introduced an unfamiliar word to her as Calvin cycle, stroma and grana and talked about the different process that take place between them on the next day she was asked by teacher to enlighten the others about the plants where she got confused. Help Smita to solve by answering some of the questions?

1.) Where does photosynthesis take place?

2.) Does photosynthesis occur in both phases?

3.) Whether ATP is a product of photosynthesis or used?

4.) What is the role played by both the phases?

5.) The glucose produced is converted into which form?

1)  Photosynthesis takes place in chloroplast.

2) Photosynthesis occurs in two phases, first in light phase in the grana of chloroplast and the dark phase in stroma.

3) ATP is produced in grana where light energy is converted to chemical energy and stored. In stroma the dark phase where the ATP is used to combine hydrogen and Co2 to form glucose.

4) Both the phases are necessary as one helps to spilt water to oxygen and hydrogen and further the hydrogen reaches to the stroma where it combines with the co2 to produce glucose.

5) Plants store glucose in the insoluble form as starch in leaves.

Q4) Assertion: – ATP is known as energy currency.

1) Reason: – ADP restores energy and gets converted back to ATP

2) Reason: – energy transaction is done by ATP

options

Both the reasons are wrong

Reason 1 is dependent on reason 2 both are correct for assertion

Reason 2 is dependent on reason 1 and reason 1 is wrong for assertion

Reason 2 is wrong and reason 1 is correct only

Answer: – Reason 1 is dependent on reason 2 both are correct for assertion

Q5) Explain the product of photosynthesis and separate ways in which the product can be stored in plants?

The process of photosynthesis has two products, one is oxygen which is used by the living organisms for the process of respiration and producing energy and the other is glucose.

The glucose is easily soluble in water it is not stored hence it is converted to starch which is insoluble form.

Starch is converted to sucrose and is transported to various plant parts through phloem.

Glucose is stored in different forms in various parts due to metabolic activity.

The sucrose transported is converted to proteins which are stored in legumes and the fats in oil seeds, fructose in fruits, starch in tubers and sucrose in form of sugarcane.

Q6) what is chemosynthesis?

The energy produced by Sulphur bacteria on land and in water does not require sunlight. They produce energy by breaking down chemical compounds. This process is called chemosynthesis.

Q7) What is Calvin cycle?

The scientist named Melvin Calvin discovered cyclic chemical reaction in dark phase which is known as Calvin cycle.

Q8) The ATP breakdown in which form?

During the glucose formation ATP breaks down into ADP and phosphate.

Q9) assertion: – 70-80% oxygen in the atmosphere is contributed by algae and phytoplankton present in seawater.

Reason1: – phytoplankton found in ocean are free floating that perform photosynthesis.

Reason 2: – pigments in cyanobacteria, sargassum, help in photosynthesis

Options

Assertion is false the reasons are correct

Reasons do not explain the assertion

Reason 1 is based on reason 2 and both explain the assertion

Answer Reason 1 is based on reason 2 and both explain the assertion

Q10) plants are biosphere protectors in different ways like by supporting carbon dioxide and oxygen concentration. List some other ways in which it helps the biosphere.

Some of the ways in which plants help the biosphere are like by proving various kind of food which is rich source of energy and helps in the survival of another kingdom

Some forests like mangrove forest help in controlling tsunami.

Bamboo forest lemongrass protect the riverbanks

Trees and bushes in mountains and hills prevent soil erosion and land slide.

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