Samacheer Kalvi Class 11 Bio Botany Solutions Chapter 12 Mineral Nutrition

Part -1

 

Question 1. Identify correct match.
1. Die back disease of citrus -(i) Mo
2. Whip tail disease - (ii) Zn
3. Brown heart of turnip -(iii) Cu
4. Little leaf -(iv) B
(a) 1 (iii) 2 (ii) 3 (iv) 4(i)
(b) 1(iii) 2(i) 3 (iv) 4 (ii)
(c) 1(i) 2(iii) 3 (ii) 4(iv)
(d) 1 (iii) 2 (iv) 3 (ii) 4(i)
Answer: (b) 1 (iii) 2 (i) 3 (iv) 4 (ii)
In simple words: This question tests your knowledge of plant diseases caused by mineral deficiencies. Matching each disease to its specific mineral helps in understanding plant health.

🎯 Exam Tip: Memorize the common plant deficiency diseases and their corresponding mineral causes, as these are frequently asked in exams. Create flashcards for effective revision.

 

Question 2. If a plant is provided with all mineral nutrients but, Mn concentration is increased, what will be the deficiency?
(a) Mn prevent the uptake of Fe, Mg but not Ca
(b) Mn increase the uptake of Fe, Mg and Ca
(c) Only increase the uptake of Ca
(d) Prevent the uptake Fe, Mg, and Ca
Answer: (a) Mn prevent the uptake of Fe, Mg but not Ca
In simple words: Too much manganese (Mn) in a plant stops it from taking in enough iron (Fe) and magnesium (Mg), but it doesn't affect calcium (Ca) intake. This shows how different minerals can interact inside a plant.

🎯 Exam Tip: Understand the concept of mineral antagonism, where an excess of one mineral can inhibit the absorption of another. This is key to understanding nutrient balance.

 

Question 3. The element which is not remobilized?
(a) Phosphorous
(b) Potassium
(c) Calcium
(d) Sulphur
Answer: (c) Calcium
In simple words: Calcium is a mineral that, once used by a plant, cannot be moved to new growing parts. It stays put, which is why older parts of the plant show signs of calcium deficiency first.

🎯 Exam Tip: Differentiate between mobile and immobile nutrients in plants. Immobile nutrients like calcium cause deficiency symptoms in younger leaves first because they cannot be relocated from older tissues.

 

Question 4. Match the correct combination.

(a) A-1 B-3 C-4 D-2
(b) A-2 B-1 C-3 D-4
(c) A-4 B-3 C-1 D-2
(d) A-4 B-2 C-1 D-3
Answer: (c) A-4 B-3 C-1 D-2
In simple words: This question matches minerals with their jobs in a plant. Molybdenum helps with nitrogenase, Zinc helps with auxin, Magnesium is part of chlorophyll, and Sulphur is part of methionine.

🎯 Exam Tip: Creating a table to summarize the functions of key minerals will help you remember these associations easily. Focus on the most unique roles of each element.

 

Question 5. Identify the correct statement:
(i) Sulphur is essential for amino acids Cystine and Methionine
(ii) Low level of N, K, S and Mo affect the cell division
(iii) Non - leguminous plant Alnus which contain bacterium Frankia
(iv) Denitrification carried out by nitrosomonas and nitrobacter.
(a) (i), (ii) are correct
(b) (i), (ii), (iii) are correct
(c) I only correct
(d) all are correct
Answer: (b) (i), (ii), (iii) are correct
In simple words: Statements (i), (ii), and (iii) are all true. Sulphur is vital for certain amino acids, low levels of specific nutrients slow down cell division, and Alnus is a non-legume plant that partners with Frankia bacteria for nitrogen. Denitrification is done by other bacteria, not nitrosomonas and nitrobacter.

🎯 Exam Tip: For true/false or correct statement questions, carefully analyze each statement individually. Knowing the specific roles of bacteria in nitrogen cycle processes is crucial.

 

Question 6. Nitrogen is present in the atmosphere in huge amounts but higher plants fail to utilize it. Why?
Answer:
1. Plants take in minerals from the soil mixed with water, using their roots. These minerals are absorbed in the form of salts.
2. A lot of nitrogen is in the air as a gas. However, plants cannot use this gaseous nitrogen directly. It must first be changed into nitrate salts in the soil before plant roots can absorb it. This change is an important process called nitrogen fixation.
3. Nitrogen fixation can happen in two main ways:
      • Non-Biological means: This happens through natural processes like lightning.
      • Biological means: This is done by certain bacteria or cyanobacteria fungi.
      Therefore, higher plants cannot directly use the nitrogen from the air.
In simple words: Plants can't use nitrogen directly from the air because it's a gas. It needs to be changed into a salt form called nitrate in the soil, which is done by tiny organisms or lightning, before roots can take it up.

🎯 Exam Tip: Highlight the key concept of "nitrogen fixation" and the distinction between gaseous nitrogen and its absorbable forms (nitrates). Mentioning both biological and non-biological methods ensures a complete answer.

 

Question 7. Why is that in certain plants, deficiency symptoms appear first in younger parts of the plants while in others, they do so in mature organs?
Answer: When plants don't get enough nutrients, signs of this problem might show up first in older or younger leaves. This mostly depends on how easily a specific mineral can move around inside the plant.
Based on their movement, minerals are grouped into two types:
a) Actively mobile minerals: These include Nitrogen, Phosphorus, Potassium, Magnesium, Chlorine, Sodium, Zinc, and Molybdenum. When these minerals are scarce, the plant moves them from older leaves to newer, younger leaves. Because of this, deficiency symptoms for these minerals appear first on the old or dying leaves.
b) Relatively immobile minerals: These include Calcium, Sulphur, Iron, Boron, and Copper. These minerals cannot easily move from one part of the plant to another. So, when there isn't enough of them, new, young leaves show the deficiency symptoms first, as they cannot get these nutrients from older leaves.
In simple words: Mineral deficiency shows up in different parts of plants depending on if the mineral can move. If it can move, older leaves get sick first. If it can't move, new leaves get sick first.

🎯 Exam Tip: Clearly define mobile versus immobile nutrients and explain how this affects the location of deficiency symptoms (older vs. younger leaves). Provide examples for each category to score full marks.

 

Question 8. Plant A in a nutrient medium shows whiptail disease plant B in a nutrient medium shows a little leaf disease. Identify mineral deficiency of plant A and B?
Answer: Mineral deficiency of plant A and B:
1. Plant A has whiptail disease, which means it is deficient in the mineral molybdenum (Mo).
2. Plant B has little leaf disease, which means it is deficient in the mineral zinc (Zn). A lack of molybdenum can severely affect leaf development, leading to the characteristic "whiptail" shape in some plants like cauliflower.
In simple words: Plant A needs more molybdenum because it has whiptail disease. Plant B needs more zinc because it has little leaf disease.

🎯 Exam Tip: Link specific plant diseases directly to their associated mineral deficiencies. Whiptail disease is a classic example of molybdenum deficiency.

 

Question 9. Write the role of nitrogenase enzyme in nitrogen fixation?
Answer: Nitrogen fixation is the very first step in the nitrogen cycle. During this process, nitrogen gas from the atmosphere is changed into a usable form for plants. This process needs a special group of enzymes called the nitrogenase enzyme complex. The nitrogenase enzyme only works when there is no oxygen (anaerobic condition). To create this oxygen-free environment, a reddish pigment known as leghaemoglobin is produced in the plant's root nodules. This leghaemoglobin acts like an "oxygen scavenger," removing any oxygen that might be present and allowing nitrogenase to do its job. Nitrogenase is very sensitive to oxygen and gets damaged if oxygen is present.
In simple words: The nitrogenase enzyme helps change nitrogen gas from the air into a form plants can use. It only works without oxygen, and a special red substance called leghaemoglobin helps keep oxygen away so the enzyme can do its job.

🎯 Exam Tip: Emphasize the anaerobic requirement of nitrogenase and the role of leghaemoglobin in maintaining this condition for effective nitrogen fixation.

 

Question 10. Explain the insectivorous mode of nutrition in angiosperms?
Answer: Plants that grow in areas where the soil lacks nitrogen have developed a special way of eating called insectivorous nutrition. They do this to get the nitrogen they need.
Here are some examples:
1. Nepenthes (Pitcher plant): The pitcher is a leaf that has changed shape. It has digestive juices inside. The rim of the pitcher has sweet glands to attract insects and acts like a lid. When an insect gets caught, special enzymes break down the insect.
2. Drosera (Sundew): This plant has long, sticky tentacles that look like tiny clubs. These tentacles release a sticky liquid that looks like dew, trapping insects.
3. Utricularia (Bladderwort): This plant lives underwater. Its leaves have changed into tiny bladders that catch insects floating in the water.
4. Dionaea (Venus flytrap): The leaves of this plant are like a colorful trap. They have two parts that fold together, with sensitive trigger hairs inside. When an insect touches these hairs, the trap quickly closes. These plants are fascinating examples of adaptation to nutrient-poor environments.
In simple words: Some plants eat insects to get nitrogen, especially if their soil doesn't have enough. They have special traps like pitchers, sticky tentacles, bladders, or snap-shut leaves to catch them.

🎯 Exam Tip: When describing insectivorous plants, name specific examples and briefly explain their unique trapping mechanisms. Focus on how these adaptations help them acquire nitrogen.

 

Part - II

11th Bio Botany Guide Mineral Nutrition Additional Important Questions And Answers

I. Choose The Correct Answers

 

Question 1. Plants naturally obtain nutrients from:
(a) atmosphere
(b) water
(c) soil
(d) All of the options
Answer: (d) All of the options
In simple words: Plants get their food from the air, water, and soil. They use different parts to collect nutrients from all these places.

🎯 Exam Tip: Remember that while soil provides many minerals, water is essential for transport and absorption, and the atmosphere supplies carbon dioxide for photosynthesis.

 

Question 2. The minerals placed under the list of unclassified minerals are
(a) Carbon. Hydrogen, & Oxygen
(b) Sodium. Silicon. Cobalt and selenium
(c) Copper, Iron, Cadmium, and selenium
(d) Magnesium, Sulphur, & Manganese
Answer: (b) Sodium, Silicon, Cobalt, and Selenium
In simple words: Minerals like sodium, silicon, cobalt, and selenium are not put into the main groups of essential plant nutrients, but some plants still need them for special jobs.

🎯 Exam Tip: Recognize that some elements are beneficial or essential for certain plants, even if they aren't universally classified as macronutrients or micronutrients.

 

Question 3. Who coined the term 'Hydroponics':
(a) Julius Von Sachs
(b) William Frederick Goerick
(c) Liebig
(d) Wood word
Answer: (b) William Frederick Goerick
In simple words: The word 'hydroponics,' which means growing plants in water without soil, was first used by William Frederick Goerick. His work helped show that plants could thrive even without traditional soil.

🎯 Exam Tip: Key scientists associated with important concepts often appear in MCQs. Remember Goerick for coining "hydroponics" and Sachs for his early work on nutrient solutions.

 

Question 4. Skeletal elements are
(a) Carbon, Hydrogen, and Oxygen
(b) Nitrogen, Phosphorus, and Calcium
(c) Potassium, Magnesium, and Sulphur
(d) Nitrogen, Sulphur and Phosphorus
Answer: (a) Carbon, Hydrogen, and Oxygen
In simple words: The main building blocks of a plant's structure, like its "skeleton," are carbon, hydrogen, and oxygen. These elements form the basic organic molecules in plants.

🎯 Exam Tip: Understand that carbon, hydrogen, and oxygen are the fundamental elements that make up the bulk of plant dry weight, forming their structural components.

 

Question 5. Actively mobile minerals are:
(a) nitrogen and phosphorus
(b) iron and manganese
(c) sodium and cobalt
(d) silicon and selenium
Answer: (a) nitrogen and phosphorus
In simple words: Nitrogen and phosphorus are minerals that plants can easily move from older leaves to newer, growing parts when needed.

🎯 Exam Tip: Mobile nutrients (like N, P, K) show deficiency symptoms in older leaves first, as the plant moves them to newer growth. Immobile nutrients show symptoms in new growth.

 

Question 6. Which chelating agent found in soil are produced by bacteria?
(a) Siderophores
(b) EDTA
(c) Auxin
(d) Gibberellin
Answer: (a) Siderophores
In simple words: Siderophores are special substances made by bacteria in the soil. They grab onto iron and help plants get this important mineral, especially when iron is hard to find.

🎯 Exam Tip: Siderophores are crucial for iron uptake in plants, particularly in alkaline soils where iron is less soluble. Remember their bacterial origin and chelating function.

 

Question 7. Molybdenum is essential for the reaction of:
(a) hydrolase enzyme
(b) nitrogenase enzyme
(c) carboxylase enzyme
(d) dehydrogenase enzyme
Answer: (b) nitrogenase enzyme
In simple words: Molybdenum is a very important part of the nitrogenase enzyme. This enzyme is needed to change nitrogen gas from the air into a form plants can use.

🎯 Exam Tip: Molybdenum is a key component of nitrogenase and nitrate reductase, making it vital for nitrogen metabolism in plants and symbiotic nitrogen-fixing bacteria.

 

Question 8. Minerals that play important role for activation of enzymes involved in Respiration are
(a) Molybdenum and Boron
(b) Boron and Silicon
(c) Calcium and Magnesium
(d) Magnesium and Manganese
Answer: (d) Magnesium and Manganese
In simple words: Magnesium and manganese are two minerals that help turn on enzymes used in a plant's breathing process, called respiration. They act as helpers to make sure these reactions happen correctly.

🎯 Exam Tip: Many enzymes require specific mineral cofactors for their activity. Magnesium is notable for its role in respiration and photosynthesis.

 

Question 9. Essential component of aminoacids like Cystine, Cysteine and Methionine is
(a) Potassium
(b) Magnesium
(c) Sulphur
(d) Calcium
Answer: (c) Sulphur
In simple words: Sulphur is a must-have part of important amino acids like Cystine, Cysteine, and Methionine. These amino acids are like building blocks for proteins.

🎯 Exam Tip: Remember that sulphur is a structural component of proteins through its presence in sulfur-containing amino acids, making it essential for protein synthesis and structure.

 

Question 10. Which of the element is involved in the synthesis of DNA and RNA:
(a) calcium
(b) magnesium
(c) sulphuric
(d) potassium
Answer: (b) magnesium
In simple words: Magnesium is an important element that helps in making DNA and RNA, which are like the instruction manuals for life in plants. It plays a role in keeping their structure stable.

🎯 Exam Tip: Magnesium is crucial for nucleic acid synthesis and stability, acting as a cofactor for many enzymes involved in these processes.

 

Question 11. Delay in flowering is due to the deficiency of
(a) N, S, Mo
(b) Ca, Mg, Mn
(c) C, H, O
(d) N,P,K
Answer: (a) N,S,Mo
In simple words: If a plant doesn't get enough nitrogen (N), sulfur (S), or molybdenum (Mo), it might not flower on time. These minerals are important for the plant's growth and development cycle.

🎯 Exam Tip: Note the critical role of nitrogen, sulfur, and molybdenum in overall plant development and their specific impact on flowering time.

 

Question 12. Kheria disease of Rice and Internal cork of Apple are caused by the deficiency of
(a) Calcium and Maganese
(b) Zinc and Boron
(c) Copper and Manganese
(d) Boron and Nickel
Answer: (b) Zinc and Boron
In simple words: Kheria disease in rice happens when there isn't enough zinc, and internal cork in apples occurs due to a lack of boron. Both are specific problems caused by missing key minerals.

🎯 Exam Tip: Memorize specific disease-deficiency pairs like Kheria (Zinc) and Internal Cork (Boron), as these are common examples of mineral deficiency symptoms in crops.

 

Question 13. Indicate the correct statements:
(i) Iron is the essential element for the synthesis of chlorophyll and carotenoid
(ii) Iron is the activator of carboxylene enzyme
(iii) Iton is the component of cytochrome
(iv) Ivon is the component of plastocyanin
Answer: (d) (i) and (iii)
In simple words: Statements (i) and (iii) are correct. Iron is very important for making chlorophyll and carotenoids, which give plants their color, and it is also a part of cytochromes, which help in energy transfer.

🎯 Exam Tip: Iron's primary roles include chlorophyll synthesis and as a component of electron transport chain proteins (like cytochromes), essential for photosynthesis and respiration.

 

Question 14. The enzyme that is a constituent of urease and dehydrogenase are
(a) Molybdenum
(b) Boron
(c) Nickel
(d) Zinc
Answer: (c) Nickel
In simple words: Nickel is an important part of enzymes like urease and dehydrogenase. These enzymes help plants process certain chemicals, like turning urea into ammonia.

🎯 Exam Tip: Nickel is a micronutrient crucial for the activity of urease, an enzyme that catalyzes the hydrolysis of urea, releasing ammonia that plants can utilize.

 

Question 15. A membrane bound bacterium formed inside the nodule is called
(a) Bacteriod
(b) Plasmid
(c) Nucleoid
(d) Noduloid
Answer: (a) Bacteriod
In simple words: Inside the root nodules of certain plants, bacteria change into a special form surrounded by a membrane. This form is called a bacteriod, and it helps the plant fix nitrogen.

🎯 Exam Tip: The term "bacteroid" specifically refers to the swollen, pleomorphic bacterial cells within root nodules that are actively engaged in nitrogen fixation.

 

Question 16. The increased concentration of manganese in plants will prevent the uptake of:
(a) calcium and potassium
(b) sodium and potassium
(c) boron and silicon
(d) iron and magnesium
Answer: (d) iron and magnesium
In simple words: If a plant has too much manganese, it will stop taking in enough iron and magnesium. This shows how high levels of one mineral can block the absorption of others.

🎯 Exam Tip: Excessive manganese is known to induce deficiencies of iron and magnesium due to competitive inhibition, a common example of mineral toxicity interactions.

 

Question 17. Plants need one of the following minerals for ATP and meristematic tissue formation
(a) K, N
(b) N, Cu
(c) N, Ca
(d) P, N
Answer: (d) P, N
In simple words: Plants need phosphorus (P) to make ATP, which is their energy currency, and nitrogen (N) for making new growing tissues. Both are vital for growth.

🎯 Exam Tip: Phosphorus is a fundamental component of ATP (energy) and nucleic acids, while nitrogen is crucial for protein synthesis and meristematic (growing) tissue development.

 

Question 18. The techniques of Aeroponics was developed by:
(a) Goerick
(b) Amon and Hoagland
(c) Soifer Hillel and David Durger
(d) Von Sachs
Answer: (c) Soifer Hillel and David Durger
In simple words: Soifer Hillel and David Durger were the scientists who created the method of aeroponics, where plants grow with their roots suspended in air and misted with nutrients.

🎯 Exam Tip: Distinguish between the pioneers of hydroponics (Sachs, Goerick, Knop, Hoagland) and those who developed aeroponics (Hillel and Durger) for specific knowledge recall.

 

Question 19. Mo is a part of enzyme ..........................
(a) Reverse transcriptase
(b) Restriction endonuclease
(c) Hexokinase
(d) Nitrogenase
Answer: (d) Nitrogenase
In simple words: Molybdenum (Mo) is a key part of the enzyme nitrogenase. This enzyme helps change nitrogen gas into a form that plants can use.

🎯 Exam Tip: Molybdenum is a metallic cofactor for nitrogenase, an enzyme critical for biological nitrogen fixation. This is a common and important association.

 

Question 20. Which of the bacterium causes denitrification?
(a) Azotobacter
(b) Nitrobacter
(c) Nitrosomonas
(d) Pseudomonas
Answer: (d) Pseudomonas
In simple words: Pseudomonas is a type of bacteria that causes denitrification. This process changes nitrates back into nitrogen gas, releasing it into the atmosphere.

🎯 Exam Tip: Understand the specific roles of bacteria in the nitrogen cycle: Nitrosomonas and Nitrobacter for nitrification, and Pseudomonas for denitrification.

 

Question 21. Beside paddy fields, cyanobacteria are also found inside the vegetative parts of
(a) Psiloturn
(b) Pinus
(c) Cycas
(d) Equiseturn
Answer: (c) Cycas
In simple words: Cyanobacteria, which are tiny organisms, are found not only in rice fields but also living inside the plant parts of Cycas. They help Cycas get nitrogen.

🎯 Exam Tip: Cyanobacteria form symbiotic associations, particularly with Cycas (in coralloid roots) and in rice paddies, contributing significantly to nitrogen fixation.

 

Question 22. The legume plants secrete phenolics to attract:
(a) Azolla
(b) Rhizobium
(c) Nitrosomonas
(d) Streptococcus
Answer: (b) Rhizobium
In simple words: Legume plants release special chemicals called phenolics. These chemicals act like a signal, drawing in Rhizobium bacteria from the soil to form a helpful partnership for nitrogen fixation.

🎯 Exam Tip: The interaction between legumes and Rhizobium bacteria is a classic example of symbiosis. Remember that phenolics act as chemical attractants from the plant host.

 

Question 23. Element involved in Nitrogen fixation is
(a) Zinc
(b) Copper
(c) iron
(d) Chlorine
Answer: (c) iron
In simple words: Iron is a very important part of the enzymes that help plants take nitrogen from the air and turn it into a form they can use. Without enough iron, this process would not work well.

🎯 Exam Tip: Remember key mineral roles: Iron is crucial for electron transfer, which is a vital part of nitrogen fixation.

 

Question 24. The nitrogenase enzyme is active:
(a) only in aerobic condition
(b) only in anaerobic condition
(c) both in aerobic and anaerobic condition
(d) only in toxic condition
Answer: (b) only in anaerobic condition
In simple words: The special enzyme called nitrogenase only works when there is no oxygen around. Oxygen stops it from doing its job of changing nitrogen.

🎯 Exam Tip: Recall that leghaemoglobin helps maintain anaerobic conditions in root nodules for nitrogenase to function effectively.

 

Question 25. Plants that can grow in marshy places where there is scarcity of Nitrogen are
(a) Halophytes
(b) Psammophytes
(c) Bryophytes
(d) insectivorous plants
Answer: (d) insectivorous plants
In simple words: Plants that grow in wet, boggy areas often do not get enough nitrogen from the soil. So, they become insectivorous, meaning they eat insects to get the nitrogen they need.

🎯 Exam Tip: Insectivorous plants adapt to nutrient-poor soils by supplementing their diet with nitrogen from trapped insects.

 

Question 26. Decomposition of organic nitrogen (proteins and amino acids) from dead plants and animals into ammonia is called:
(a) nitrification
(b) ammonification
(c) nitrogen fixation
(d) denitrification
Answer: (b) ammonification
In simple words: When plants and animals die, their bodies break down. The nitrogen in their proteins and amino acids turns into ammonia during this process, which is called ammonification.

🎯 Exam Tip: Ammonification is the first step in the nitrogen cycle where organic nitrogen returns to an inorganic form for other organisms.

 

Question 27. Internal cork of apple and Exanthema in citrus and whiptail disease of cauliflower are produced by the deficiency of
1. Copper
2. Zinc
3. Boron
4. Molybdenum
(a) 2,3, 1
(b) 2, 3, 4
(c) 4, 3, 1
(d) 3, 1,4
Answer: (d) 3,1,4
In simple words: The internal cork disease in apples happens due to a lack of boron. Exanthema in citrus fruit is caused by not enough copper. The whiptail disease in cauliflower is a sign of molybdenum deficiency.

🎯 Exam Tip: Remember these specific deficiency symptoms, as they often link directly to the trace mineral responsible.

 

Question 28. Necrosis means
(a) Discolouration of leaf
(b) Stunted growth
(c) Death of the tissue
(d) Death of the root
Answer: (c) Death of the tissue
In simple words: Necrosis is when parts of a plant, like leaves or stems, start to die. It shows up as dead spots on the plant's tissues.

🎯 Exam Tip: Necrosis is a common symptom of various plant diseases and nutrient deficiencies, leading to localized tissue death.

 

Question 29. The transfer of amino group (NH2) from glutamic acid to keto group of keto acid is termed as:
(a) Transamination
(b) Hydrogenation
(c) Nitrification
(d) Denitrification
Answer: (a) Transamination
In simple words: Transamination is a chemical step where a part of an amino acid (the amino group) is moved to another molecule (a keto acid). This helps in making new amino acids.

🎯 Exam Tip: Transamination is a crucial reaction in amino acid metabolism, allowing for the synthesis of non-essential amino acids.

 

Question 30. Denitrification process deplete important nutrients from soil. It also cause
(a) Acidification of soil
(b) Alkalification of soil
(c) Neutralization of soil
(d) Ammoniafication of soil
Answer: (a) Acidification of soil
In simple words: When denitrification happens, the soil loses important nutrients. This process can also make the soil more acidic over time.

🎯 Exam Tip: Denitrification not only reduces available nitrogen but also impacts soil pH, often leading to increased acidity.

 

Question 31. Availability of Nitrogenase enzyme depend on
(a) Non avoulability of ATP
(b) Availability of Nitric acid
(c) Availability of ATP
(d) Non availability of Nitric acid
Answer: (c) Availability of ATP
In simple words: The nitrogenase enzyme needs energy to work. This energy comes from ATP, so the amount of nitrogenase activity depends on how much ATP is available.

🎯 Exam Tip: Nitrogen fixation is an energy-intensive process, making ATP availability a critical factor for nitrogenase activity.

 

Question 32. Obligate or Total parasites are
(a) Santalum albumn and orabanche
(b) Vanda and Venilla
(c) Cuscuta and Rafflesia
(d) Viscum and Loranthus
Answer: (c) Cuscuta and Rafflesia
In simple words: Plants like Cuscuta and Rafflesia are called obligate or total parasites. This means they cannot live on their own and must get all their food and water from another plant.

🎯 Exam Tip: Obligate parasites lack chlorophyll and fully depend on their host for all their nutritional needs, unlike partial parasites.

 

Question 33. The association of mycorrhizae with higher plants is termed as:
(a) Parasitism
(b) Mutualism
(c) Symbiosis
(d) Saprophytic
Answer: (c) Symbiosis
In simple words: Mycorrhizae are fungi that live with plant roots in a helpful relationship. This type of living together, where both the fungus and the plant benefit, is called symbiosis.

🎯 Exam Tip: Symbiotic relationships like mycorrhizae are essential in ecosystems, with both organisms benefiting from the association.

 

Question 34. Major role of minor elements inside living organism is to act as
(a) Binder of cell structure
(b) Constituent of hormone
(c) Building blocks of important amino acids
(d) Co factors of enzymes
Answer: (d) Co factors of enzymes
In simple words: Many small amounts of elements, called minor elements, work as helpers for enzymes in living things. They are needed for these enzymes to do their jobs properly.

🎯 Exam Tip: Micronutrients often function as cofactors, enabling enzymes to catalyze metabolic reactions crucial for life processes.

 

Question 35. Lichens are the indicators of:
(a) carbon monoxide
(b) nitrogen oxide
(c) sulphur di oxide
(d) hydrogen sulphide
Answer: (c) sulphur di oxide
In simple words: Lichens are very sensitive to air pollution. They cannot grow well where there is a lot of sulphur dioxide, so they are used to show if the air is polluted with this gas.

🎯 Exam Tip: Lichens are bioindicators; their presence or absence and health directly reflect the air quality, especially regarding sulphur dioxide pollution.

 

Question 36. Free living aerobic nitrogen fixing bacterium is
(a) Azotobacter, Beijemeckia and Derxia
(b) Nostoc, Anabaena, and Oscullatoria
(c) Saccharomyces, Pullularia, Pseudomonas
(d) Chlorobium and Rhodospirillum
Answer: (a) Azotobacter, Beijerneckia and Derxia
In simple words: Azotobacter, Beijerneckia, and Derxia are types of bacteria that live freely in the soil and can take nitrogen from the air. They need oxygen to do this.

🎯 Exam Tip: Free-living nitrogen fixers enrich soil fertility without needing a symbiotic relationship with plants.

 

Question 37. Leguminous plants does not include
(a) Black gram
(b) Bengal gram
(c) Pongamia
(d) Casuarina
Answer: (d) Casuarina
In simple words: Casuarina is a tree that can fix nitrogen, but it is not a leguminous plant like black gram, bengal gram, or pongamia. It forms a nitrogen-fixing partnership with a different type of bacteria called Frankia.

🎯 Exam Tip: While many nitrogen-fixing plants are legumes, some non-legumes like Casuarina also fix nitrogen through different symbiotic associations.

 

Question 38. Cyanobacteria does not include
(a) Nostoc
(b) Anabaena
(c) Clostridium
(d) Oscillatoria
Answer: (c) Clostridium
In simple words: Clostridium is a type of bacteria, but it is not a cyanobacterium. Nostoc, Anabaena, and Oscillatoria are all types of cyanobacteria.

🎯 Exam Tip: Cyanobacteria are photosynthetic bacteria, often called blue-green algae, and are different from heterotrophic bacteria like Clostridium.

 

II. Match The Following & Find Out The Correct Option

 

Question 39. Identify correct match.
Cuscuta - A) Giant flower
Dianaea – B) Pitcher plant
Rafflesia – C) Dodder
Utricularia – D) Venus fly trap
Nepenthus – E) Bladder wort
(a) D C E A B
(b) C D A E B
(c) C A E B D
(d) C D E B A
Answer: (b) C D A E B
In simple words: The correct match is: Cuscuta is also known as Dodder, Dianaea is the Venus fly trap, Rafflesia has a Giant flower, Utricularia is a Bladder wort, and Nepenthes is a Pitcher plant. Each plant name matches its special feature.

🎯 Exam Tip: Matching questions often test your knowledge of common names or distinguishing features of different organisms.

 

Question 40. Match the columns.

(a) A-1 B-3 C-4 D-2
(b) D-A-B-C
(c) A-4 B-3 C-1 D-2
(d) A-4 B-2 C-1 D-3
Answer: (b) D-A-B-C
In simple words: For plants, carbon, hydrogen, and oxygen make up most of their dry weight. Potassium helps keep cells firm. Manganese is important for water splitting in photosynthesis. Magnesium helps activate enzymes like RuBP and PEP carboxylase.

🎯 Exam Tip: Knowing the general function of each macronutrient and micronutrient will help you match them correctly.

 

Question 41. Match the columns.

(a) D-A-B-C
(b) D-B-A-C
(c) B-D-C-A
(d) D-B-A-C
Answer: (a) D-A-B-C
In simple words: Potassium helps stomata open and close. Calcium is important for cell division. Sulphur is found in certain vitamins. Nitrogen is a key part of amino acids and nucleic acids.

🎯 Exam Tip: Understand the specific roles of each major element to accurately match them with their functions.

 

Question 42. Identify correct match.
I) Criteria required for essential minerals was given by – A) Julius von Sachs
II) Word – Hydroponics Was coined by – B)SoiferHillel& David Durger
III) Hydroponics was developed by – C)Amon& Stout
IV) Aeroponics was developed by – D) William Frederick Goerick
(a) A C B D
(b) C B A D
(c) C D A B
(d) D A B C
Answer: (c) C-D-A-B
In simple words: The rules for what makes a mineral essential were set by Amon and Stout. The word "hydroponics" was first used by William Frederick Gericke. Julius von Sachs developed the first methods for growing plants without soil. Soifer, Hillel, and Durger are known for developing aeroponics techniques.

🎯 Exam Tip: Knowing the historical figures and their contributions to plant nutrition, such as essentiality criteria and different growing methods, is important.

 

III. Find Out The Incorrect Statement With Reference To Potassium

 

Question 43. Identify the incorrect statement:
a. It is essential for opening & closing of stomata
b. It is an essential component of vitamins, hormones, alkaloids and chlorophyll
c. It maintains osmotic potential of the cell
d. It maintain anion, cation balance by ion exchange.
Answer: (b) It is an essential component of vitamins, hormones, alkaloids and chlorophyll
In simple words: Potassium helps with many plant processes, like opening and closing stomata and keeping cells firm. But it is not a part of vitamins, hormones, or chlorophyll itself. Magnesium is a component of chlorophyll.

🎯 Exam Tip: Focus on the specific functions and structural roles of each element; many elements are cofactors but not direct components of complex molecules like chlorophyll.

 

Question 44. Identify the incorrect statement:
a. Magnesium is a constituent of chlorophyll
b. Iron is essential for the formation of chlorophyll
c. Phosphorus is a component of ATP
d. Copper is essential for the synthesis of IAA
Answer: (d) Copper is essential for the synthesis of IAA
In simple words: Magnesium is a part of chlorophyll, and iron helps in making chlorophyll. Phosphorus is found in ATP, which is energy for plants. However, copper is not needed to make IAA, which is a plant hormone.

🎯 Exam Tip: Distinguish between elements that are structural components, those that are activators, and those with specific roles like hormone synthesis.

 

Question 45. Find out wrong choice with reference to symbiotic mode of Nutrition
a. Lichens
b. Mycorrhizae
c. Coralloid roots of cycas
d. Viscum
Answer: (d) Viscum
In simple words: Lichens, mycorrhizae, and coralloid roots of cycas are all examples of symbiotic relationships where different organisms help each other. Viscum, however, is a partial parasite, meaning it takes things from another plant without giving much back, so it is not a symbiotic relationship in the same way.

🎯 Exam Tip: Symbiotic nutrition involves mutual benefit, while parasitism involves one organism benefiting at the expense of another.

 

Question 46. The deficiency of which two exhibit competitive behaviour and the two showing same symptoms.
(I) Iron
(II) Magnesium
(III) Calcium
(IV) Manganese
(a) I & II
(b) II & III
(c) III & IV
(d) I & IV
Answer: (d) I & IV
In simple words: Iron and Manganese often compete with each other when plants try to take them up. This means that if there is too much of one, the plant might not get enough of the other, and they can show similar signs of not having enough nutrients.

🎯 Exam Tip: Be aware of competitive interactions between micronutrients, as excess of one can induce deficiency of another.

 

Question 47. Statement
(I) Alnus and Casuarina are nonlegume nitrogen fixers containing bacterium Frankia
(II) Nostoc and Anabaena are present in the corolloid roots of cycas.
(a) Both (I) & (II) are correct
(b) (I) is correct (II) is wrong
(c) (I) is wrong (II) is correct
(d) Both (I) & (II) are wrong
Answer: (a) Both (I) & (II) are correct
In simple words: Both statements are true. Alnus and Casuarina are trees that are not legumes but can still fix nitrogen with the help of Frankia bacteria. Also, Nostoc and Anabaena, which are types of cyanobacteria, can be found in the special roots of Cycas plants.

🎯 Exam Tip: Remember that nitrogen fixation is not limited to legumes with Rhizobium; other plants form symbiotic relationships with different bacteria and cyanobacteria.

 

Question 48. Statement
(I) Dionaea is a submerged hydrophyte in which leaf is modified into a bladder to trap insects
(II) Loranthus is a partial stem parasite, absorb water and minerals from the xylem of the host
(a) Both (I) & (II) are correct
(b) (I) is correct (II) is wrong
(c) (I) is wrong (II) is correct
(d) Both (I) & (II) are wrong
Answer: (c) (I) is wrong (II) is correct
In simple words: The first statement is incorrect because Dionaea (Venus flytrap) is a land plant, not a water plant, and its leaves form traps, not bladders. The second statement is correct, as Loranthus is a partial parasite that takes water and minerals from its host plant.

🎯 Exam Tip: Understand the unique adaptations and classifications of different plant types, especially insectivorous and parasitic plants.

 

Question 49. Assertion: A Manganese is a Micro element, Reason: R Micro elements are required in traces only, less than 1 mg/gm of dry matter
(a) Both A and R are True and R is the correct explanation of A
(b) Both A and R are True, but R is not the correct explanation of A
(c) A is True but 'R' is False
(d) A& Rare False
Answer: (a) Both A and R are True and R is the correct explanation of A
In simple words: Manganese is a microelement, which means plants only need it in very small amounts, less than 1 milligram for every gram of dry plant material. This small requirement is exactly why it is classified as a microelement.

🎯 Exam Tip: For assertion-reason questions, ensure the reason not only states a true fact but also explains the assertion. A good way to check is to say "because" between the assertion and reason.

 

Question 50. Assertion: Calcium is a constituent of cell wall, Reason: R Calcium is required in mitotic division.
(a) Both A and R are True and R is the correct explanation of A
(b) Both A and R are True but 'R' is not the correct explanation of A
(c) A is True but 'R' is False
(d) A& Rare False
Answer: (b) Both A and R are True but 'R' is not the correct explanation of A
In simple words: Calcium is indeed a part of plant cell walls, and it is also needed for cells to divide properly. However, these two facts are true on their own and one does not explain the other.

🎯 Exam Tip: While both statements may be true, always evaluate if the reason directly provides an explanation for the assertion.

 

Question 51. Assertion: A Deficiency of sulphur causes chlorosis in plants, Reason: R Sulphur is a constituent of chlorophyll
Answer: (c) A is True but 'R' is false
In simple words: It is true that plants turn yellow (chlorosis) when they don't have enough sulphur. But sulphur is not a part of chlorophyll. Magnesium is the central element in chlorophyll.

🎯 Exam Tip: Carefully distinguish between elements required for chlorophyll *synthesis* (like iron) and elements that are *constituents* of the chlorophyll molecule (like magnesium).

 

Question 52. Assertion: A Plants absorb Nitrogen in the form of Nitrate only, Reason: R Nitrogen is the most critical element
Answer: (d) Both A and R are false
In simple words: Plants can absorb nitrogen in more than just the nitrate form, for example, as ammonium ions. Also, while nitrogen is very important, saying it is the "most" critical element above all others is not entirely accurate. Therefore, both statements are incorrect.

🎯 Exam Tip: Remember that plants can utilize nitrogen in multiple forms (nitrate and ammonium) and that the "most critical" element can vary depending on context and definition.

 

Question 53. Assertion: A Mineral salt absorption is an active process. Reason: R Metabolic energy is not used in active absorption.
Answer: (c) A is true but 'R' is false
In simple words: It is true that plants actively absorb mineral salts, meaning they use energy to do so. However, the statement that metabolic energy is *not* used for active absorption is false; active absorption always requires energy.

🎯 Exam Tip: Distinguish between active absorption (requires ATP) and passive absorption (does not directly require ATP) for mineral uptake in plants.

 

IV. 2 Mark Questions

 

Question 1. Define micronutrients of plants.
Answer: Micronutrients are essential minerals that plants need in very small amounts to grow and function properly. These are still vital, even though only a little bit is required. The word "micro" highlights their tiny quantity. For example, zinc and iron are micronutrients.
In simple words: Micronutrients are important minerals that plants need in tiny amounts.

🎯 Exam Tip: Remember that "micro" refers to the quantity needed, not their importance; plants cannot complete their life cycle without them.

 

Question 2. Is there any mnemonic for remembering essential minerals?
Answer: Yes, there is a mnemonic to help remember essential minerals. It is: "CHOPKNS Cafe Mg B Mn Cu Zn Mo CI (C) HOPKINS (name) Cafe managed by Mine CUZINS, Mo tnd Claude". This helps in recalling the names of various essential elements needed by plants.
In simple words: Yes, a special phrase or mnemonic helps remember all the important minerals plants need.

🎯 Exam Tip: Using mnemonics is a great way to memorize long lists of items, like essential elements in biology.

 

Question 3. What is the role of molybdenum in the conversion of nitrogen into ammonia?
Answer: Molybdenum (Mo) plays a crucial role in changing nitrogen from the air into ammonia. It is an essential part of the nitrogenase enzyme, which carries out this conversion. This process, called nitrogen fixation, is vital for plant growth. Molybdenum acts like a key ingredient that helps the enzyme function.
In simple words: Molybdenum helps an enzyme change nitrogen gas from the air into ammonia, which plants can use.

🎯 Exam Tip: Highlight molybdenum's specific role as a component of nitrogenase, connecting it directly to nitrogen fixation.

 

Question 4. What are the minerals classified as unclassified minerals and why?
Answer: Some minerals like Sodium, Silicon, Cobalt, and Selenium are called unclassified minerals. They are not always included in the main list of essential nutrients for all plants, but they can still play specific important roles for some plants. For example, Silicon helps some plants, like Equisetaceae, Cyperaceae, and Gramineae, fight off pests, prevent them from falling over, and makes their cell walls stronger.
In simple words: Minerals like Sodium, Silicon, Cobalt, and Selenium are unclassified because not all plants need them, but some plants use them for special tasks like pest resistance.

🎯 Exam Tip: Remember that "unclassified" or "beneficial" elements are not universally required by all plants but can significantly improve growth or stress resistance in specific species.

 

Question 5. What are the deficiency symptoms of nitrogen?
Answer: When plants do not get enough nitrogen, they show several signs. Their leaves may turn yellow, a condition called chlorosis. Their growth can slow down, leading to stunted plants. Also, a purple or reddish color, known as anthocyanin, might appear on leaves or stems due to poor nutrient balance. Nitrogen is key for making proteins and chlorophyll.
In simple words: If a plant lacks nitrogen, its leaves turn yellow, it grows slowly, and sometimes it gets a reddish-purple color.

🎯 Exam Tip: Nitrogen deficiency symptoms appear first in older leaves because nitrogen is a mobile element and moves to younger, growing parts.

 

Question 6. Distinguish between Hydroponics & Aeroponics
Answer: Hydroponics involves growing plants with their roots immersed in a nutrient-rich water solution, where air is supplied using a tube. Aeroponics is a system where plant roots hang in the air and are regularly sprayed with a mist of nutrient solution using a motor-driven rotor. Both methods allow growing plants without soil, providing precise control over nutrient delivery.
In simple words: Hydroponics grows plants in water with nutrients. Aeroponics grows plants with roots in the air, sprayed with nutrient mist.

🎯 Exam Tip: The key difference lies in the medium where the roots are located: water for hydroponics and air/mist for aeroponics.

 

Question 7. Define the term Siderophores.
Answer: Siderophores are special agents produced by bacteria that help carry iron. They bind tightly to ferric iron (\( \text{Fe}^{3+} \)) from the environment, making it easier for bacteria and plants to absorb this essential nutrient. These molecules are like tiny helpers that go and fetch iron. This process is very important in soils where iron is not easily available.
In simple words: Siderophores are chemicals made by bacteria that grab iron from the soil, helping plants and other organisms get enough iron.

🎯 Exam Tip: Siderophores are critical for iron uptake in various organisms, especially in iron-limited environments, as ferric iron is often insoluble.

 

Question 8. What are called critical elements and complete fertilizers?
Answer: Critical elements are macro elements that are often missing from the soil. The main critical elements are Nitrogen (N), Phosphorus (P), and Potassium (K). A complete fertilizer is one that contains these critical elements, usually in specific ratios like 15:15:15 (N:P:K). Such fertilizers ensure that plants receive all the major nutrients they need for healthy growth.
In simple words: Critical elements are important nutrients like N, P, K that soils often lack. Complete fertilizers contain all these main critical elements.

🎯 Exam Tip: Understanding NPK ratios in fertilizers helps in selecting the right product to address specific plant nutrient requirements.

 

Question 9. Why is Iron kept between Macro and Micro nutrients?
Answer: Iron is considered to be between macro and micro nutrients because plants need it in amounts larger than typical micronutrients but less than macronutrients. This means iron is required in quantities that place it in an intermediate category, sometimes referred to as a mesoelement. Its intermediate requirement means it can sometimes be grouped with either depending on context or plant species. Iron is essential for chlorophyll synthesis and electron transport.
In simple words: Iron is needed in amounts that are more than tiny but less than large. So, it sits in the middle of macro and micro nutrients, as it is very important for plants.

🎯 Exam Tip: Recognize that some elements, like iron, bridge the gap between macro and micronutrient classifications due to their specific quantitative requirements for plant health.

 

Question 10. Write down the deficiency symptoms of molybdenum in plants.
Answer: When plants do not have enough molybdenum, they can show signs like chlorosis (yellowing of leaves), necrosis (tissue death), and delayed flowering. Their growth might be slower than usual, and cauliflower plants can develop a specific problem called whip tail disease. Molybdenum is vital for converting nitrogen into a usable form for the plant.
In simple words: Not enough molybdenum makes plants turn yellow, die in spots, flower late, grow slowly, and can cause a "whiptail" disease in cauliflower.

🎯 Exam Tip: Remember to list at least three distinct symptoms when asked about deficiency, and if a specific disease is associated, include it for full marks.

 

Question 11. List two purpose for which you think Magnesium is required essentially to the plants.
Answer: Magnesium is very important for plants for two main reasons:
(I) It is a key part of chlorophyll, the green pigment that helps plants make their food through photosynthesis. Without enough magnesium, plants cannot produce chlorophyll properly.
(II) It plays a role in the formation of nodules in legumes, which are structures on roots that help with nitrogen fixation. These nodules are crucial for legumes to get nitrogen from the air.
In simple words: Magnesium is needed for plants to make chlorophyll (which makes them green and helps them eat) and to form root nodules in beans and peas for getting nitrogen.

🎯 Exam Tip: When listing purposes, try to connect them to core plant processes like photosynthesis or nutrient absorption, as these are critical functions.

 

Question 12. Define Aeroponics.
Answer: Aeroponics is a special method of growing plants where their roots hang freely in the air. Instead of soil or water, the roots are regularly sprayed with a fine mist of nutrient-rich water. This system uses a motor-driven rotor to ensure the roots get all the necessary nutrients evenly. It's a soil-less cultivation technique that saves space and water.
In simple words: Aeroponics is a way to grow plants by hanging their roots in the air and spraying them with nutrient mist instead of planting them in soil or water.

🎯 Exam Tip: Highlight the key characteristic "roots suspended in air" and the "nutrient mist" delivery method when defining aeroponics.

 

Question 13. What is meant by Toxicity of Minerals
Answer: Mineral toxicity happens when a plant has too much of a particular mineral nutrient, more than its normal concentration. While a little bit of each mineral is good, an excess amount can harm the plant. This "toxic" concentration is usually defined as the point where the dry weight of the plant tissue is reduced by 10% or more. High levels of some minerals can interfere with how other minerals are used, creating additional problems.
In simple words: Mineral toxicity means a plant has too much of a mineral, which starts to hurt it, usually by making it grow 10% less.

🎯 Exam Tip: Emphasize that toxicity is about excess, not just presence, and relate it to a measurable negative impact on plant growth, like the 10% dry weight reduction.

 

Question 14. Give examples for Nitrogen Fixation with out nodulation.
Answer: Nitrogen fixation is the process of converting atmospheric nitrogen into forms usable by plants. Some organisms can do this without forming root nodules on host plants. Here are some examples:

Nitrogen fixation is a critical biological process for life on Earth.
In simple words: Some plants and simple organisms can change air nitrogen into plant food without making special bumps called nodules. Examples include lichens, Azolla, and Cycas, which partner with tiny organisms like Anabaena and Nostoc.

🎯 Exam Tip: When listing examples, try to provide both the plant (or lichen) and the associated nitrogen-fixing microorganism if applicable, to show a complete understanding.

 

Question 15. Give examples for Non - symbiotic Nitrogen fixation by bacteria and Fungi.
Answer: Non-symbiotic nitrogen fixation means that organisms can fix nitrogen on their own, without needing to live in a close partnership with a host plant or form nodules. Here are some examples for different conditions:

These free-living organisms contribute significantly to the nitrogen available in the soil.
In simple words: Some bacteria and fungi can change air nitrogen into plant food all by themselves, without needing a plant partner. Azotobacter works with air (aerobic), and Clostridium works without air (anaerobic).

🎯 Exam Tip: Clearly distinguish between aerobic and anaerobic examples when discussing non-symbiotic nitrogen fixers, as it shows a deeper understanding of their environmental requirements.

 

Question 16. Define the term Nitrate assimilation.
Answer: Nitrate assimilation is the process where plants take up nitrate (a form of nitrogen) from the soil and convert it into ammonia. This ammonia is then used to build important organic molecules like amino acids and proteins. This entire conversion pathway is a crucial part of the larger nitrogen cycle, allowing plants to access and use nitrogen for growth. This process is essential because plants cannot directly use nitrate.
In simple words: Nitrate assimilation is how plants change nitrate from the soil into ammonia, which they then use to make their own building blocks, like proteins.

🎯 Exam Tip: Focus on the transformation from "nitrate" to "ammonia" and its role in building "organic molecules" like amino acids to define nitrate assimilation effectively.

 

Question 17. What are the negative effects of denitrification.
Answer: Denitrification is a process that changes nitrates in the soil back into gaseous nitrogen, which then goes into the atmosphere. This has several negative effects:

• Nitrate in the soil is converted back to atmospheric nitrogen, making it unavailable for plants.
• This process removes important nutrients from the soil, reducing its fertility.
• Denitrification can also cause the soil to become more acidic, which affects plant growth and the types of plants that can grow there.

Plants need nitrate to grow, so its loss is a big problem.
In simple words: Denitrification is bad because it turns useful soil nitrogen back into air gas, taking away plant food, making the soil less fertile, and sometimes making it too acidic.

🎯 Exam Tip: When listing negative effects, emphasize the loss of useful nitrogen, reduction in soil fertility, and potential for soil acidification.

 

Question 18. Name 2 hormones involved in Nodule formation.
Answer: During the formation of root nodules in leguminous plants, two important hormones play a key role. Cytokinin, produced by bacteria, and Auxin, produced by the host leguminous plant, work together. These hormones stimulate the plant cells to divide and grow, leading to the formation of the nodules. This interaction is a beautiful example of plant-microbe communication.
In simple words: Cytokinin from bacteria and Auxin from the plant are two hormones that help make root nodules grow in leguminous plants.

🎯 Exam Tip: Remember to name both hormones (Cytokinin and Auxin) and mention their respective sources (bacteria and host plant) for a complete answer.

 

Question 19. Give two examples of symbiotic mode of nutrition.
Answer: Symbiotic nutrition is a close relationship between two different organisms where both benefit. Here are two examples:
1. Lichens: These are a partnership between algae (or cyanobacteria) and fungi. The algae make food through photosynthesis, and the fungi absorb water and provide a protective structure, known as the thallus. Both organisms thrive together.
2. Mycorrhizae: This is a helpful association between fungi and the roots of higher plants, including gymnosperms (like Pinus trees). The fungi help the plant roots absorb water and nutrients from the soil, while the plant provides sugars to the fungi. This increases the plant's ability to take in nutrients.
In simple words: Lichens (algae and fungi working together) and Mycorrhizae (fungi and plant roots helping each other) are two examples where different living things team up and both get something good from it.

🎯 Exam Tip: For each example, clearly state the two organisms involved and how each benefits from the association.

 

Question 20. Decreased availability of the element results in early fall of fruits and flowers. Identify the element.
Answer: The element whose decreased availability causes fruits and flowers to fall off early is Phosphorus, Magnesium, or Copper. Any one of these three elements can cause such symptoms. For example, phosphorus is vital for energy transfer, magnesium is key for chlorophyll, and copper plays a role in enzyme activity. If a plant lacks these essential nutrients, its reproductive parts, such as flowers and fruits, suffer first. This is a sign of severe nutrient stress.
In simple words: If fruits and flowers drop off plants too soon, it might be because the plant doesn't have enough Phosphorus, Magnesium, or Copper.

🎯 Exam Tip: When an answer provides multiple possible correct elements, listing any one of them is acceptable, but being aware of all common ones strengthens your knowledge.

 

Question 21. Name any 3 diseases caused by copper deficiency.
Answer: Copper is an important micronutrient for plants. When plants do not get enough copper, they can develop several diseases, including:
1. Die back of Citrus: This disease causes the tips of citrus branches to dry out and die, moving downwards.
2. Reclamation disease of cereals & legumes: This affects cereal grains and legumes, leading to poor growth and development, often making the soil appear "reclaimed" or infertile.
3. Exanthema in Citrus: This condition causes rough, dark spots on citrus fruits and twigs, often accompanied by gum formation on the bark.
Copper is crucial for many enzyme functions and chlorophyll synthesis in plants.
In simple words: A lack of copper in plants can cause three problems: citrus branches dying from the tip, grains and beans getting sick (reclamation disease), and citrus trees getting rough spots (exanthema).

🎯 Exam Tip: Focus on linking specific diseases to copper deficiency, especially those unique to certain crops like citrus.

 

Question 22. Notes on unclassified minerals.
Answer: Unclassified minerals are elements that are needed by some plants for specific functions, but only in very small, or trace, amounts. These minerals are not considered "essential" for all plants, but they are vital for the particular plants that require them. Examples of such minerals include Sodium, Silicon, Selenium, and Cobalt. For instance, Silicon can help some plants become more resistant to pests and improve cell wall formation. These minerals highlight the diverse nutrient needs across different plant species.
In simple words: Unclassified minerals are small amounts of elements like Sodium, Silicon, Selenium, and Cobalt that only some plants need for special jobs, not all plants.

🎯 Exam Tip: Remember that "unclassified" doesn't mean "unimportant" – it means their essentiality is not universal across all plant species. Provide a few examples to illustrate.

 

Question 23. Explain Nitrate Assimilation.
Answer: Nitrate assimilation is the process by which plants convert nitrate, a common form of nitrogen absorbed from the soil, into ammonia. This ammonia is then used to synthesize essential organic compounds like amino acids. The process happens in several steps and is a key part of the nitrogen cycle within the plant. Here are the main steps:
Nitrate reductase
\( NO_3^- \xrightarrow{Mo} NO_2^- \)
Nitrite reductase
\( NO_2^- \xrightarrow{Cu, Fe} NH_4^+ \)
This conversion is vital because plants cannot directly use nitrate in its absorbed form to build proteins. The element Molybdenum is an essential cofactor for the first enzyme, nitrate reductase. It allows plants to create their own proteins and other nitrogen-containing molecules.
In simple words: Nitrate assimilation is how plants change nitrate (a type of nitrogen they get from the soil) into ammonia, which they use to make their body parts, like proteins. It involves a few chemical steps inside the plant.

🎯 Exam Tip: When explaining biochemical processes, always include the key reactants, products, and any significant enzymes or cofactors involved to demonstrate a thorough understanding.

 

Question 24. Explain Aluminium Toxicity.
Answer: Aluminium toxicity occurs when there are excessively high levels of aluminium in the soil, which can be very harmful to plants. This condition is more common in acidic soils. Aluminium interferes with several vital plant processes, causing:

• Precipitation of Nucleic acid: Aluminium can bind to nucleic acids, affecting their function.
• Inhibition of ATP ase: It can block the activity of ATPase enzymes, which are crucial for energy production in cells.
• Inhibition of cell division and binding of Plasma membrane with Calmodulin: Aluminium also stops cells from dividing properly and affects the plasma membrane by binding with calmodulin, a protein involved in cell signaling.

All these effects lead to poor root growth and overall stunted plant development. This toxicity severely limits crop yields in many parts of the world.
In simple words: Aluminium toxicity means too much aluminium in the soil hurts plants. It stops cells from dividing, blocks energy-making enzymes, and damages cell membranes, making plants grow poorly.

🎯 Exam Tip: List specific impacts on cellular processes (e.g., nucleic acids, enzymes, cell division) to clearly explain the mechanism of aluminium toxicity.

 

Question 25. Differentiate between Nitrification & Denitrification
Answer: Nitrification and denitrification are two opposite processes in the nitrogen cycle that involve different microorganisms and outcomes for nitrogen availability in the soil.

Nitrification makes nitrogen available to plants, while denitrification removes it from the soil. Both are important for balancing nitrogen levels.
In simple words: Nitrification is when bacteria turn ammonia into nitrate, which plants can use. Denitrification is when other bacteria turn nitrate back into nitrogen gas, sending it into the air, making it unavailable for plants.

🎯 Exam Tip: Clearly state the starting and ending forms of nitrogen for each process, and name the key bacteria involved in both nitrification and denitrification.

 

Question 26. Organisms like Pseudomonas and Thiobacillus are of great significance in nitrogen cycle. How?
Answer: Organisms like Pseudomonas and Thiobacillus are very important in the nitrogen cycle because they perform denitrification. This process converts nitrates (which plants can use) back into gaseous nitrogen, which then returns to the atmosphere. Even though this removes nitrogen from the soil, it is essential for maintaining a constant and balanced level of nitrogen in the atmosphere. Without these organisms, all nitrogen would eventually be locked in the soil, and the atmospheric nitrogen needed for other processes would deplete. They play a vital role in completing the global nitrogen cycle.
In simple words: Pseudomonas and Thiobacillus are important because they send nitrogen from the soil back into the air (denitrification), which helps keep the amount of nitrogen in the atmosphere balanced.

🎯 Exam Tip: Explain the role of these bacteria by naming the specific process (denitrification) and its significance (maintaining atmospheric nitrogen balance).

 

Question 27. What is meant by Symbiotic association give examples?
Answer: A symbiotic association refers to a close and often long-term interaction between two different biological organisms where both organisms benefit from the relationship. This mutual benefit is a key characteristic. These partnerships are common in nature and help organisms survive and thrive. An example of this close relationship where both organisms are benefited is known as symbiosis.
Eg. 1. Nitrogen fixing bacteria Nitrosomonas living in the root nodules of leguminous plants. In this partnership, the bacteria get a protected environment and nutrients, while the plant gets fixed nitrogen.
2. Fungi associated with roots of higher plants is a symbiotic association known as Mycorrhiza. Here, the fungi help the plant absorb water and minerals, and in return, the plant provides sugars to the fungi.
In simple words: Symbiotic association is when two different living things live closely together and help each other. For example, bacteria in bean plant roots give nitrogen, and fungi on tree roots help the tree get water.

🎯 Exam Tip: Define symbiosis as a mutually beneficial relationship, and for each example, clearly state the two partners and how each one gains from the interaction.

 

Question 28. What is the use of FTWS.
Answer: FTWS stands for Floating Treatment Wetlands. This technology uses plants growing on floating mats to treat wastewater. FTWS works on the principle of hydroponics, where plants absorb pollutants directly from the water through their roots. Recently, FTWS has been used to address pollution caused by eutrophication. This method helps to clean water bodies naturally by removing excess nutrients and pollutants, making it an eco-friendly solution for water treatment. Plants act as natural filters in these systems.
In simple words: FTWS (Floating Treatment Wetlands) uses plants on floating mats to clean dirty water by soaking up pollution, like in hydroponics, especially for problems like eutrophication.

🎯 Exam Tip: Specify what FTWS stands for, its operational principle (hydroponics), and its primary application (solving pollution, especially eutrophication).

 

Question 29. Notes on Lichens.
Answer: Lichens are fascinating organisms that are actually a symbiotic association between two different life forms: a fungus and an alga (or sometimes a cyanobacterium). This partnership allows them to survive in harsh environments. Here are some key points about lichens:

• Lichens are pioneer species in xeric succession. This means they are often the first organisms to colonize barren or dry environments, preparing the ground for other plants.
• Lichens are nothing but symbiotic association of Algae and Fungi partners. The alga performs photosynthesis, making food, while the fungus provides protection, water, and minerals.
• Lichens are also indicators of \( SO_2 \) pollution. Their presence or absence can tell us about the air quality because they are very sensitive to sulfur dioxide.

Their unique structure and biology make them important indicators in ecological studies.
In simple words: Lichens are a team of fungus and alga living together. They are the first to grow in new places and can show us if the air is polluted with sulfur dioxide.

🎯 Exam Tip: When describing lichens, include their composite nature (fungus + alga), their ecological role (pioneer species), and their use as bio-indicators (for \( SO_2 \) pollution).

 

Question 30. Notes on Haustoria.
Answer: Haustoria are special structures developed by parasitic plants or fungi that allow them to absorb nutrients from a host organism. These structures act like tiny roots or projections that penetrate the host plant's tissues, specifically the phloem (for sugars) and xylem (for water and minerals). These special absorbing structures are known as Haustoria. They are crucial for the parasite's survival, as they enable it to tap into the host's nutrient supply. This is a common strategy for obligate and partial parasites to obtain their necessary resources.
In simple words: Haustoria are special parts of parasitic plants or fungi that poke into other plants to steal food and water, helping the parasite to live.

🎯 Exam Tip: Define haustoria as specialized absorbing structures and mention their function: nutrient absorption from a host, specifically from xylem and phloem.

 

Question 31. Identify the diagram A.
Answer: The diagram A represents Cycas coralloid roots. These roots have a unique structure that grows above the ground and branches like coral. They form a symbiotic association with Nostoc, a type of cyanobacterium. This partnership is very important because Nostoc helps to fix atmospheric nitrogen, providing a crucial nutrient for the Cycas plant. The coralloid roots create a suitable environment for the Nostoc to thrive and perform nitrogen fixation. These roots are a distinctive feature of Cycas plants.
Answer: The deficiency diseases and symptoms for minerals are:
1. Chlorosis (Overall): This includes interveinal chlorosis and marginal chlorosis.
2. Necrosis: This means the death of plant tissue.
3. Stunted growth: Plants do not grow to their normal size.
4. Anthocyanin formation: The plant parts develop a reddish or purplish color.
5. Delayed flowering: Plants take longer to produce flowers.
6. Die back of shoot, Reclamation disease, Exanthema in citrus (gums on bark): These are specific symptoms.
7. Hooked leaf tip: The tips of the leaves become curved.
8. Little Leaf: Leaves remain smaller than usual.
9. Brown heart of turnip and Internal cork of apple: These are specific internal issues.
10. Whiptail of cauliflower and cabbage: A condition where the leaf blade is severely reduced.
11. Curled leaf margin: The edges of the leaves curl.

Deficiency Minerals:
1. Nitrogen, Potassium, Magnesium, Sulphur, Iron, Manganese, Zinc and Molybdenum are common deficiency minerals.
2. Magnesium, Potassium, Calcium, Zinc, Molybdenum and Copper.
3. Nitrogen, Phosphorus, Calcium, Potassium and Sulphur.
4. Nitrogen, Phosphorus, Magnesium and Sulphur.
5. Nitrogen, Sulphur and Molybdenum.
6. Copper
7. Calcium
8. Zinc
9. Boron
10. Molybdenum
11. Potassium
In simple words: Plants show many problems if they don't get enough minerals. These problems include leaves turning yellow, parts of the plant dying, or slow growth. Different minerals cause different problems, like twisted leaves or small fruits.

🎯 Exam Tip: When describing deficiency symptoms, always link a specific symptom (like chlorosis) to the general mineral category (macronutrient/micronutrient) or specific mineral if known. This helps demonstrate a comprehensive understanding.

 

Question 4. Why are NPK fertilizers important to plants?
Answer: NPK fertilizers are very important for plants because they provide essential nutrients needed for healthy growth and development. These three main nutrients are Nitrogen (N), Phosphorus (P), and Potassium (K), each having specific roles.

Nitrogen:
* It helps plants grow and develop well.
* It is needed in large amounts by plants.
* Nitrogen is a key part of proteins, amino acids, nucleic acids, vitamins, hormones, and chlorophyll. Chlorophyll is essential for photosynthesis.

Phosphorus:
* It is an important part of cell membranes, proteins, nucleic acids, ATP (which gives energy), and NADP (used in photosynthesis). Phosphorus helps plants store and use energy.

Potassium:
* It helps plants stay firm (turgidity) and controls water movement (osmotic potential) in cells.
* It helps the stomata (small pores on leaves) open and close, which is vital for gas exchange.
* It is involved in moving food (phloem translocation) throughout the plant.
* Potassium also helps with ion exchange.
* Farmers use all three nutrients in the right amounts to get more yield from their crops. These elements are crucial for various metabolic processes in plants.
In simple words: NPK fertilizers give plants three main food types: Nitrogen for growth, Phosphorus for energy, and Potassium for water balance and overall health. They are like a balanced meal for plants to grow strong and produce more crops.

🎯 Exam Tip: When discussing NPK, highlight the specific role of each element (e.g., Nitrogen for vegetative growth, Phosphorus for roots/flowers, Potassium for overall health/stress resistance) and mention how their combined effect boosts yield.

 

Question 5. Tabulate the mode of absorption, function and deficiency symptoms of any 5 microelements.
Answer: Here is a table showing the mode of absorption, functions, and deficiency symptoms of five microelements:

In simple words: This table shows how plants get five small but important nutrients (like Zinc and Boron), what these nutrients do for the plant, and what happens if the plant doesn't get enough of them, leading to specific plant diseases.

🎯 Exam Tip: When tabulating, ensure clarity in each column. For deficiency symptoms, try to include one or two characteristic visual cues that an examiner would instantly recognize as linked to that mineral.

 

Question 6. What are the stages of Root nodule formation.
Answer: Root nodule formation is a complex process involving several stages:
1. Attraction: Legume roots release special chemicals called phenolics that attract Rhizobium bacteria.
2. Infection: The Rhizobium bacteria reach the area around the root (rhizosphere), then interact with the root hairs, causing them to curl. The bacteria then enter the root hair.
3. Spreading & multiplication: The infection thread, which contains the bacteria, grows inwards into the root. The infected area then separates from the normal plant tissue.
4. Bacteroid formation: Inside the plant cells, the bacteria change into a special form called bacteroids. These bacteroids are enclosed within a membrane.
5. Nodule formation: Hormones from both the bacteria (cytokinin) and the legume roots (auxin) work together. They promote cell division in the root, which leads to the formation of the root nodule. These nodules are where nitrogen fixation takes place.
In simple words: Root nodules form in steps: first, roots call out to bacteria, then bacteria enter root hairs and make them curl. The bacteria multiply inside, change form, and then, with help from plant and bacterial hormones, the roots grow special bumps called nodules.

🎯 Exam Tip: Remember the key players (Rhizobium, legumes) and the sequence of events, especially the role of chemical signals and hormones in initiating and developing the nodule structure.

 

Question 7. Explain the fate of Ammonia or Assimilation of Ammonia.
Answer: Ammonia ions \( (\text{NH}_4^+) \) are poisonous to plants, so they cannot build up in the plant. Instead, ammonia must be converted into amino acids through a process called ammonia assimilation. There are mainly three methods by which this is done:

I) Reductive amination:
In this method, ammonia reacts with \( \alpha \)-ketoglutaric acid to form glutamic acid. This reaction needs energy from \( \text{NADPH} \).
\( \alpha \text{-Ketoglutarate} + \text{NH}_4^+ + \text{NADPH} \xrightarrow{\text{Glutamate Dehydrogenase}} \text{Glutamate} + \text{H}_2\text{O} + \text{NADP}^+ \)

II) Transamination:
This process involves transferring an amino group from one amino acid to the keto group of another keto acid. Glutamic acid is the main amino acid formed, and it then donates its amino group to other keto acids to produce various new amino acids. This transfer is critical for building all necessary proteins.

\( \text{R}_1\text{-C-COO}^- + \text{R}_2\text{-C-COO}^- \)
\( || \qquad \qquad \quad || \)
\( \text{NH}_3^+ \qquad \qquad \text{O} \)

\( \implies \)

\( \text{R}_1\text{-C-COO}^- + \text{R}_2\text{-C-COO}^- \)
\( || \qquad \qquad \quad || \)
\( \text{O} \qquad \qquad \quad \text{NH}_3^+ \)
The enzyme Transaminase, with Pyridoxus phosphate, helps these reactions.

III) Catalytic Amination (GS/GOGAT pathway):
This pathway involves two enzymes, Glutamine Synthetase (GS) and Glutamate Synthase (GOGAT), for efficient ammonia assimilation.
\( \text{Glutamate} + \text{NH}_4^+ \xrightarrow{\text{Glutamine Synthetase}} \text{Glutamine} \)

\( \text{Glutamine} + \text{Ketoglutaric acid} \xrightarrow{\text{GOGAT (enzyme)}} 2 \text{Glutamate} \)
This cycle effectively incorporates ammonia into organic compounds.
In simple words: Ammonia, which is harmful to plants, is quickly changed into amino acids. This happens through processes like adding ammonia directly to a keto acid, or by moving amino groups between different molecules. These steps help plants make all the proteins they need to grow.

🎯 Exam Tip: For ammonia assimilation, focus on the toxicity of free ammonia and the two main pathways: reductive amination (forming glutamate) and transamination (transferring amino groups). Mentioning the GS/GOGAT pathway shows deeper understanding.

 

Question 8. Explain parasitic mode of Nutrition.
Answer: Parasitic nutrition is when an organism gets its nutrients from another living organism, called a host, and causes harm or disease to the host in the process. The parasite lives on or inside the host. Parasitic plants are categorized based on their dependence on the host and the part of the plant they parasitize. Here are the main types:

Types:
1. Obligate or Total parasite: These parasites depend entirely on their host for survival and often develop special structures called haustoria to absorb nutrients.
* Total stem parasite: These plants are leafless and twine around the host, like Cuscuta on Ziziphus or citrus. They absorb nutrients from the host's stem.
* Total root parasite: These plants do not have a stem axis and grow on the roots of host plants, producing haustoria. Examples include Rafflesia, Orobanche, and Balanophora.
2. Partial parasite: These plants have chlorophyll and can perform photosynthesis, but they still depend on the host for water and minerals.
* Partial stem parasite: These plants grow on trees like fig and mango. They absorb water and minerals from the xylem of the host through haustoria. An example is Loranthus.
* Partial root parasite: These plants produce haustoria in their juvenile stages, which grow on the roots of many forest trees. An example is Sandalwood (Santalum album), which is famous for its fragrant wood.
In simple words: Parasitic nutrition is when one plant lives off another, stealing its food and water. Some parasites need the host for everything (total parasites), while others can make some of their own food but still rely on the host for water and minerals (partial parasites).

🎯 Exam Tip: Clearly distinguish between total and partial parasites, giving examples for each. Emphasize the role of haustoria as the specialized structures for nutrient absorption by parasites.

 

Question 9. Describe Saprophytic mode of nutrition in Angiosperms?
Answer: Saprophytic nutrition is a mode where organisms get their nutrients from dead and decaying organic matter. In angiosperms (flowering plants), this is a less common but fascinating way to obtain food. These plants often live in environments rich in decaying material.

Saprophytic Angiosperms:
* Neottia (Bird's nest orchid): The roots of Neottia form a close association with mycorrhizae (fungi). These fungi then help the orchid absorb nutrients from the decaying leaf litter in the soil. The orchid benefits from this fungal partnership.
* The plant leaves lack chlorophyll: These plants, like Neottia, do not have green leaves and cannot perform photosynthesis. They depend entirely on the mycorrhizae to absorb nutrients from decomposed litter in the soil.
* Monotropa (Indian pipe): Similar to Neottia, Monotropa also lacks leaves and chlorophyll. It absorbs nutrients from the soil through its mycorrhizal association, relying on the fungi to break down organic matter.
In simple words: Saprophytic plants get their food from dead and rotting things. They don't make their own food through sunlight because they often don't have green leaves. Instead, they work with special fungi in the soil to get nutrients from decaying plant matter.

🎯 Exam Tip: When explaining saprophytic angiosperms, highlight their lack of chlorophyll and their dependence on mycorrhizal fungi to extract nutrients from decaying organic matter in the soil.