To Life Processes Class 9 Extra Questions and Answers Kerala Syllabus Biology Chapter 1

A thorough understanding of Kerala Syllabus 9th Standard Biology Notes Pdf Chapter 1 To Life Processes Extra Questions and Answers can improve academic performance.

Kerala Syllabus Std 9 Biology Chapter 1 To Life Processes Extra Questions and Answers

Question 1.
What role do enzymes play in metabolism?
Answer:
Enzymes act as biological catalysts, speeding up the countless chemical reactions that occur constantly within an organism.

Question 2.
Why is homeostasis important for metabolism?
Answer:
Maintaining homeostasis, a stable internal environment, is crucial for the smooth functioning of metabolism.

Question 3.
What are the main components of the plasma membrane?
Answer:
The plasma membrane is primarily made up of phospholipid layers and proteins.

Question 4.
What is another name for the cell membrane?
Answer:
Plasma membrane

Question 5.
What are some examples of molecules that can easily pass through plasma membrane?
Answer:
Water, oxygen, and carbon dioxide

Question 6.
What is photosynthesis? What are the products formed after this process?
Answer:
Photosynthesis is the process by which green plants make their food in the presence of sunlight. Through this process, light energy is converted into chemical energy. During photosynthesis, carbon dioxide and water are utilized to form carbohydrates.
Glucose (C₆H₁₂O₆), Water, and Oxygen gas (O₂) are the products formed after photosynthesis.

Question 7.
How do blue-green algae obtain their nutrients?
Answer:
Through Photosynthesis.

Question 8.
What are mesophyll cells? Mention their role in photosynthesis.
Answer:
Mesophyll represents the middle layer of cells, which forms the ground tissue, located between the epidermal layers of a leaf. Mesophyll contains many chloroplasts and therefore represents the main site of photosynthesis in plants.

Question 9.
Explain briefly about the two phases of photosynthesis.
Answer:
Photosynthesis has two phases: Light phase and Dark phase.
Reactions that take place in the light phase of photosynthesis are called light reactions. The light phase happens inside the grana in the presence of light. Here water inside the plant cell splits into hydrogen and oxygen resulting in the liberation of oxygen gas as the byproduct of photosynthesis. During the light reaction, ATP (The energy currency of the cell) molecules are formed, and the hydrogen produced by the splitting of water reaches the stroma for the dark reaction to proceed.

The set of reactions, which do not utilize light, that happens during the dark phase are called dark reactions that take place within the stroma of chloroplast. The products of the light phase, energy (ATP) and hydrogen are utilized in the dark reaction to produce the end products of photosynthesis, ie, glucose. Glucose is formed by combining hydrogen and carbon dioxide.

Melvin Calvin.
He was awarded the Nobel Prize in Chemistry in 1961 for explaining the reactions in the dark phase. The dark phase of photosynthesis is explained with the help of a cycle termed as Calvin cycle.

Question 10.
Name the scientist who explained the reactions in the dark phase of photosynthesis.
Answer:
Melvin Calvin.

Question 11.
Why do plants store glucose in the form of starch in leaves?
Answer:
Since glucose is easily soluble in water it cannot be stored in the plant body as such. Therefore, plants store glucose in the form of insoluble starch in leaves.

Question 12.
If glucose is what all plants prepare, then how could we get starch, protein, and fat from vegetable food items?
Answer:
Glucose produced after photosynthesis undergoes many metabolic activities and converts glucose into many nutrient-rich sources like tubers containing starch, legumes containing proteins, oil seeds containing fats, fruits containing fructose, and sugarcane containing sucrose.

Question 13.
Differentiate between autotrophs and heterotrophs.
Answer:

• Carbohydrates, especially glucose is the end product of photosynthesis along with some amount of water and the liberation of oxygen gas.
• Plants store glucose in the form of starch
• Proteins, Vitamins and fats are the other substances that are produced from glucose when it undergoes various metabolic reactions.
• Plants grow in water as well as on land. Three-fourths of the earth is ocean.
• An ocean is divided into three zones based on the availability of sunlight.
• Pollution is the most serious threat the marine ecosystem faces. As a result, species become extinct in large numbers.

Glucose, produced as a result of photosynthesis, dissolves quickly in water so it is stored as insoluble starch. The energy required for the life processes of plants is obtained from starch. Many substances are produced when starch undergoes metabolism. They are:

• Carbohydrates
• Proteins
• Fats
• Vitamins

Nutrients produced by plants through metabolism reach herbivores through food. Herbivores are eaten by carnivores. So, plants can produce their own food by photosynthesis and are called autotrophs. While animals are heterotrophs because they depend on other organisms for their food.

Question 14.
Mention the economic importance of plants.
Answer:
Besides food and medicines, plants and trees play an essential role in industries. Many raw materials are obtained from plants and giant trees, and used to produce various industrial products, including paper, spices, cosmetics, pencils, rubber, furniture, and other household products.

Question 15.
What are the services provided by plants to the biosphere?
Answer:

• Provide food
• Provide oxygen
• Decrease the level of global warming by the absorption of CO₂
• Mitigate natural calamities
• Act as the storehouse of biodiversity
• Provide economically important resources

Question 16.
What is metabolism and what are its two main parts?
Answer:
Metabolism refers to all the chemical reactions happening within an organism. It is divided into two main processes:

• Anabolism: This builds molecules by combining smaller ones.
• Catabolism: This breaks down larger molecules into smaller ones, releasing energy.

Question 17.
What are the two main categories of metabolic processes?
Answer:
The two main categories of metabolic processes are anabolism and catabolism.

Question 18.
Name the biomolecules formed in cells to aid and regulate metabolism?
Answer:
Enzymes and hormones

Question 19.
How does the plasma membrane control what enters and leaves the cell?
Answer:
The plasma membrane is selectively permeable, meaning it only allows specific molecules to pass through. Small, uncharged molecules like water, oxygen, and carbon dioxide can pass through easily. Larger or charged molecules require channels or pores in the membrane for passage.

Question 20.
What is osmosis?
Answer:
Osmosis is the movement of water molecules from an area of higher concentration to an area of lower concentration through a semi-permeable membrane.

Question 21.
Photosynthesis occurs within the ………… cell organelles
Answer:
Chloroplasts.

Question 22.
Two steps in the process of food formation (photosynthesis) that take place in chloroplasts?
Answer:
Light phase, Dark phase

Question 23.
The parts of the chloroplast that appear as stacks of thylakoids containing chlorophyll and the light phase of photosynthesis that occur are ………….
Answer:
Grana

Question 24.
Find the odd one. Write the common feature of others. Chlorophyll a, Chlorophyll b, Carotene, Xanthophyll
Answer:
Chlorophyll a, others are accessory pigments.

Question 25.
Choose the correct statement related to chlorophyll b
i) Participate directly in photosynthesis
ii) Absorb light and transfer it to chlorophyll a
iii) Found in the stroma of chloroplast
a) (i), (ii) correct
b) (i) only correct
c) (ii) only correct
d) (iii) only correct
Answer:
b) (ii) only correct

Question 26.
Select the correct statement from the list below.
a) Pigments involved in photosynthesis are found in stroma.
b) The light phase takes place in grana.
c) ATP is formed during the dark phase
Answer:
b) The light phase takes place in grana

Question 27.
Observe the picture of chloroplast and answer the following.

a) What does ‘X’ indicate?
b) Write any two accessory pigments found in ‘ X ‘.
Answer:
a) X-Grana
b) Chlorophyll b, Carotene, and Xanthophyll (Any two).

Question 28.
a) When does the splitting of water happen in photosynthesis?
b) What are the end products of photosynthesis?
Answer:
a) Water splitting occurs in the light phase of photosynthesis to produce hydrogen and oxygen. –
b) Glucose, water, and oxygen are the end products.

Question 29.
Observe the figure and answer the questions.

i) Which is the cell organelle?
ii) Identify and write the parts $A$ and $B$.
Answer:
i) Chloroplast
ii) A – Grana, B – Stroma lamellae

Question 30.
Choose the suitable ones from the given hints and complete the illustration related to the phase of photosynthesis.
Hints:

• Produces glucose
• Releases oxygen
• Glucose
• Hydrogen
• Water splits

Answer:
a) Water splits
b) Produces glucose
c) Hydrogen, oxygen
d) Glucose, Releases oxygen

Question 31.
Give reason for the following:
a. Light phase takes place in grana.
b. Xanthophyll and Carotene are called accessory pigments.
Answer:
a. Pigments that absorb sunlight are found in the grana of chloroplast.
b. Pigments other than chlorophyll a, absorb light and transfer it to chlorophyll

Question 32.
One of the phases of photosynthesis is known as the Calwin cycle.
a. Identify the phase.
b. Why it is known as the Cavin cycle?
Answer:
a) Dark phase.
b) The reactions in the dark phase were discovered by the scientist Melvin Calvin.

Question 33.
Complete the illustration related to photosynthesis suitably.

Answer:
i) Light Phase
ii) Water

Question 34.
Observe the illustration showing the chemical reactions in the process of photosynthesis and answer the questions.

a) Identify ‘A’ and ‘B’
b) How does ‘A’ reach the leaves?
c) How do plants utilize starch?
Answer:
a) A – H₂O, B – C₆H₁₂O₆ (Glucose)
b) Water reaches leaves through the absorption by roots.
c) Plants use starches to store energy which they use at night during the process of cellular respiration. Plants store starches in an organelle called amyloplast, which is a leucoplast.

Question 35.
Redraw the diagram of chloroplast and answer the questions.

a) Name and label the parts according to the following hints.
Hints:
(i) The part where synthesis of glucose takes place.
(ii) The part where dissociation of water takes place.
Answer:

b) Which are the phases of photosynthesis that take place in parts (i) and (ii)?
Answer:
(i) Stroma – Dark phase
(ii) Grana – Light phase

Question 36.
Plants cannot store glucose, the product of photosynthesis as such. Which of the following is the reason for this?

• Glucose is soluble in water.
• Glucose is insolublé in water.
• Glucose can be converted into other forms.
• Glucose is an unstable compound.

Answer:
Glucose is soluble in water.

Question 37.
Who is the chief producers in the ocean ecosystem?
Answer:
Algae and Phytoplanktons.

Question 38.
Choose the stored form of glucose in legumes
(starch, fat, fructose, protein)
Answer:
Protein

Question 39.
As shown in the model, make suitable pairs using the information given in the box.
Model: Tubers – Starch
Starch, Oilseeds, Legumes, Protein, Fats, Tubers, Fructose, Sucrose, Fruits, Sugarcane
Answer:
Oil seeds – Fat
Legumes – Proteins
Sugarcane – Sucrose
Fruits – Fructose

Question 40.
Analyse the statement and answer the questions.
“Photosynthesis in Ocean ecosystem plays an important role in the existence of the living world.”
a) Who are the chief producers in the ocean ecosystem?
b) How they become inevitable for the existence of the living world?
Answer:
c) Algae and phytoplanktons
d) Phytoplankton is the base of several aquatic food webs. Desmids, golden algae and cyanobacteria are examples of phytoplanktons. In a balanced ecosystem, they provide food for a wide range of sea creatures. Phytoplankton, also known as microalgae, are similar to terrestrial plants in that they contain chlorophyll and require sunlight in order to live and grow. They are responsible for most of the transfer of carbon dioxide from the atmosphere to the ocean. Carbon dioxide is consumed during photosynthesis, and the carbon is incorporated in the phytoplankton, just as carbon is stored in the wood and leaves of a tree.

Question 41.
Observe the illustrations and answer the questions.

a. Why glucose is converted to starch?
b. How does plants utilise starch?
c. How does starch reach different parts of the plant?
Answer:
a) Since glucose is readily soluble in water, it can not be stored. Hence it is converted in to insoluble starch.
b) Starch is utilized as a source of energy for life activities and to prepare substances required for growth. in plants
c) Starch is converted to sucrose and is transported through phloem to various plant parts and stored there in different forms.

Question 42.
Ocean pollution reduces the level of oxygen in the atmosphere.
a. Do you agree with this statement? Why?
b. Write any two causes of ocean pollution.
Answer:
a) Yes, agree. About 70-80% atmospheric oxygen is released by the algae and planktons living the ocean.
b) Pollutants expelled from factories, Oil refineries, Mining, Plastics etc.

Question 43.
Make corrections if any in the underlined portions of the following statements.
a) Glucose is converted into fructose and stored in oil seeds.
b) Glucose is transported to various parts of the plant body through phloem tubes.
c) Plants store glucose in the form of starch in the leaves.
d) Glucose is converted into protein and stored in fruits.
Answer:
a) Fat
b) Sucrose
d) Fructose

Question 44.
Who is the Keralite environmental activist who made us aware of the ecological importance of mangrove forests?
Answer:
Kallen Pokudan.

Question 45.
Mention any economically important plant and its value-added products.
Answer:
Coconut tree – Coconut oil.

Question 46.
Write two suitable examples indicating the role of plants in the mitigation of natural disasters.
Answer:

• Mangrove forests help in controlling Tsunami to some extent.
• Bamboo forests, reed, vetiver, lemongrass, etc. protect the river banks from collapsing during flood.
• Trees and bushes prevent soil erosion and landslides.

Question 47.
What is the ecological importance of mangrove forests?
Answer:

• They are a repository of biodiversity.
• They are a source of fish wealth.

Question 48.
Write any two services that plants provide to the living world?
Answer:

• Provide food.
• Provide oxygen.

Question 49.
List the economically important plants.
Answer:

• Coconut, Rubber
• Coffee plant
• Tea plant