Are you searching for pdf files for MCQ questions of Biology, Chemistry, Physics, and Mathematics? You are in the right place. JEET MCQ provides educational material for all classes and competitive exams such as ACT, SAT, NEET, CBSE, and Pre boards. 

In this article, we will be providing you the MCQ questions from the biology chapter Biomolecules. You can download the questions in PDF format as well. 

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1. Which kinds of structures of proteins are shown in the figures given below
 
 a) A=1° structure, B = 2° structure, C = 3° structure, D = 4° structure
 b) A=4° structure, B = 2° structure, C = 3° structure, D = 1° structure
 c) A=1° structure, B = 4° sstructure, C = 3° structure, D = 2° structure
 d) A=4° structure, B = 3° structure, C = 2° structure, D = 1° structure

2. Lipids are found in acid-insoluble fractions during the analysis of the chemical composition of tissues. Given the reason
 a) It has a very high molecular weight
 b) It is a polymer
 c) It has a low molecular weight
 d) On grinding, the biomembranes are broken into pieces and form insoluble vesicles

3. Choose the element that is negligible in living matter
 a) Si
 b) Mg
 c) Ca
 d) S

4. Name the plant pigments present in the following
I. Carrots
II. Tomatoes
 a) I-Tycopene      II-Carotene
 b) I-Carotene       II-Lycopene
 c) I-Leucopene   II-Carotene
 d) None of the above

5. Which one of the following structural formulae of two organic compounds is correctly identified along with its related function?
 
 a) A- Triglyceride major- Source of energy
 b) B- Uracil- A component of DNA
 c) A-Lecithin- A component of cell membrane
 d) B-Adenine- A nucleotide that makes up nucleic acids

6. Silk consists of
 a) Central core of sericin
 b) Central core of fibroin
 c) Both (a) and (b)
 d) A fine mixture of fibroin and sericin

7. Which statement regarding coenzyme is incorrect?
 a) Every coenzyme is a cofactor and every cofactor is a coenzyme
 b) Every coenzyme is a cofactor but every cofactor is not a coenzyme
 c) Most of the coenzymes are nucleotides and are composed of vitamins
 d) Coenzymes are the active constituents of enzymes

8. The rate of the reaction doubles or decreases by half, for every ___°C change in either direction
 a) 10°
 b) 15°
 c) 20°
 d) 27°

9. Enzymes often have additional parts in their structures that are made up of molecules other than proteins. When this additional chemical part is an organic molecule, it is called
 a) Cofactor
 b) Coenzyme
 c) Substrate
 d) Both (a) and (b)

10. Which one is imino acid?
 a) Pepsin
 b) Proline
 c) Cysteine
 d) Rennin

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Are you looking for multiple choice questions in the class 11 biology chapter "Cell: Unit of Life"? You are in the right place. 

In this article, we will be sharing with you the 20 most important questions from this chapter along with answer keys and detailed solutions. 

For chapter-wise MCQ questions, visit the following links: 

• Biology MCQ Questions
• Chemistry MCQ Questions
• Physics MCQ Questions
• Mathematics MCQ Questions

Questions

1. What are those structures that appear as ‘beads-on-string’ in the chromosomes when viewed under an electron microscope?
 a) Nucleotides
 b) Nucleosomes
 c) Base pairs
 d) Genes

2. The two polynucleotide chains in DNA are
 a) Parallel
 b) Discontinuous
 c) Antiparallel
 d) Semi-conservative

3. Centrosome is not present in
 a) Cell of higher plants
 b) Cell of lower plants
 c) Cell of higher animals
 d) Cell of lower animals

4. Channel proteins are involved in
 a) Transport of enzymes
 b) Water transport
 c) Active transport of ions
 d) Passive transport of ions

5. Part of chromosome after secondary constriction is called
 a) Centriole
 b) Centromere
 c) Chromomere
 d) Satellite

6. Tubulin protein occurs in
 a) Digestive enzymes
 b) Rough endoplasmic reticulum
 c) Thylakoids
 d) Microtubules

7. Quantasomes are found in
 a) Mitochondria
 b) Chloroplast
 c) Lysosome
 d) Endoplasmic reticulum

8. In which one of the following would you expect to find glyoxysomes?
 a) Endosperm of wheat
 b) Endosperm of castor
 c) Palisade cells in leaf
 d) Root hairs

9. The non-membranous organelles are
 a) Centrioles
 b) Ribosomes
 c) Nucleolus
 d) All of these

10. Single stranded DNA is found in
 a) Polio viruses
 b) Rich dwarf virus
 c) TMV
 d) ϕ ×174

11. Ribosomes that occur exclusively in mitochondria is
 a) 70 S
 b) 55 S
 c) 30 S
 d) 50 S

12. Number of protofilament in microtubule is
 a) 13
 b) 12
 c) 5
 d) 10

13. …A… are granular structures first observed under electron microscope as dense particles by …B… (1953). Here, A and B refer to
 a) A-Ribosomes; B-Perner
 b) A-Lysosomes; B-de Duve
 c) A-Peroxisomes; B-Flemming
 d) A-Ribosomes; B-George Palade

14. Middle lamella is present
 a) Inside the secondary wall
 b) Inside the primary wall
 c) Outside the primary wall
 d) In between secondary and tertiary walls

15. Rough endoplasmic reticulum differs from smooth walled endoplasmic reticulum due to the presence of
 a) DNA
 b) Nucleus
 c) Ribosomes
 d) Ergastic substance

16. A widely accepted, improved model of cell membrane is
 a) Fluid mosaic model
 b) Robertson’s model
 c) Danielli and Davson’s model
 d) Unit membrane model

17. Organelle important in spindle formation during nuclear division is
 a) Golgi body
 b) Chloroplast
 c) Centriole
 d) Mitochondrion

18. Identify A to F in the sectional view of a chloroplast showing the different parts

 a) A-Inner membrane, B-Granum, C-Outer membrane, D-Stroma lamella, E-Stroma, F-Thylakoid
 b) A-Outer membrane, B-Inner membrane, C-Granum, D-Thylakoid, E-Stroma lamella, F-Stroma
 c) A-Thylakoid, B-Outer membrane, C-Stroma, D-Stroma lamella, E-Granum, F-Inner membrane
 d) A-Outer membrane, B-Stroma, C-Inner membrane, D-Granum, E-Thylakoid, F-Stroma lamella

19. Consider the following statements and choose the correct one
 a) Plant cells have centrioles which are absent in almost all animal cells
 b) Ribosomes are the site of protein synthesis
 c) The middle lamella is layer mainly of calcium carbonate which holds the different neighbouring cells together
 d) In animal cells, steroidal hormones are synthesised by smooth endoplasmic reticulum

20. The backbone of RNA consists of which of the following sugar?
 a) Deoxyribose
 b) Ribose
 c) Sucrose
 d) Maltose

Answer Key

1-b; 2-c; 3-a; 4-d 5-d; 6-d; 7-b; 8-b 9-d; 10-d; 11-b; 12-a 13-d; 14-c; 15-c; 16-a 17-c; 18-b; 19-b; 20-b

Solutions

1 (b)
Nucleosome is sub-microscopic sub-unit of chromatin which is formed by wrapping of DNA over a core of histone proteins. The term was coined by Oudetet.al.., (1975). It is oblate structure with a length of 10nm and a thickness of 5-5.7nm. Its core is called nu-body. The latter is formed of four pairs of histone molecules H₂, A, H₂B, H₃ and H₄. DNA makes 1.75 turns over the octamer to form a nucleosome. Two adjacent nucleosomes are connected by a short segment of unboud DNA called linker DNA. A fifth type of histone called H₁ is attached over the linker DNA. Nucleosomes appear as ‘beads-on-string’ in the chromosomes under electron microscope.  

2 (c)
In 1953, James Watson and Francis Crick suggested that in a DNA molecule there are two polynucleotide chains arranged antiparallel or in opposite directions.

3 (a)
Centrosome is an organelle containing two cylindrical structures called centrioles and occurs in most algal cells (except red algae) and most animal cells. They are absent in prokaryotes, red algae, yeast, gymnosperms and angiosperms and some non-flagellated or non-ciliated protozoans.

4 (d)
There are two major classes of membrane transport proteins carrier proteins and channel proteins. Carrier proteins involved with active as well as passive transport of ions or solutes while channel proteins are involved only with passive transport.

5 (d)
Normally, the primary constriction is known as kinetochore. In some cases, chromosome contains non-staining secondary constriction called satellite

6 (d)
The ciliary microtubules are made up of tubulin. The two subfibres A and B are composed of α and β tubulin having mol. Wt. 56,000 and 58,000 respectively.

7 (b)
On the inner side of the thylakoid membranes of chloroplasts are present a paracrystalline array of particles (20×10 nm); these were called quantosomes by Park and Pon (1963).

8 (b)
Glyoxysomes were reported from the endosperm of germinating seeds, rich in fatty acids, by Beevers (1969). They serve as enzymatic site for reactions including the conversion of stored fatty acids to carbohydrate. Therefore, glyoxysomes will be present in endosperm of castor but not in endosperm of wheat, which is carbohydrate rich.

9 (d)
Nucleolus, ribosomes and centrioles are non-membranous cell organelles.

10 (d)
Single stranded DNA virus: Bacteriophageϕ×174, coliphage S 13, bacteriophage M13.

11 (b)
Besides DNA, a mitochondrion has RNA and its ribosomes also. Thus, a complete protein synthesising machinery is present in mitochondria. The ribosomes of mitochondria are small, i.e., 55-60 S type, with a large subunit of 40 S and a small subunit of 30 S. The large subunit contain 16-17 S and 5S rRNA and the small subunit 12-13 S rRNA.

12 (a)
Microtubules are electron microscopic structures found only in the eukaryotic cellular structures like cilia, flagella, centriole, etc. The wall of microtubule is 50Å thick, which is formed of 13 parallel prototubules.

13 (d)
Ribosomes are granular structures, first observed under electron microscope as dense particles by George Palade (1953)

14 (c)
Middle lamella is a thin binding layer between the cell wall of adjacent plant cells. It is chemically formed of pectates of calcium and magnesium. It is present towards the outside of primary wall.

15 (c)
Rough Endoplasmic Reticulum (RER) differs from Smooth Endoplasmic Reticulum (SER) due to the presence of ribosomes. Some other differences are as follows:

16 (a)
A widely accepted, improved model of the cell membrane is a fluid mosaic model

17 (c)
The centrioles appear as two cylindrical structures. They are formed of microtubules. In higher animals, they form the mitotic pole, ie, they are involved in the formation of spindles.

18 (b)
A-Outer membrane, B-Inner membrane, C-Granum, D-Thylakoid, E-Stroma lamella and F-Stroma

19 (b)
Ribosomes are the site of protein synthesis, also called protein factories. In the testes, ovary, and adrenal cortex, SER has a role in the synthesis of steroid hormones.

20 (b)
The backbone of RNA is made up of ribose sugar (5-carbon), whereas DNA consists of deoxyribose sugar. 

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Hello Students. In this article, I have brought to you multiple-choice questions from the Biology chapter "Structural Organization in Animals". In this chapter, we study how cells work together to form tissues, organs, and organ systems in animals. I have also provided detailed solutions and explanations for the answers to all the questions. 

For chapter-wise MCQ questions, visit the following links: 

• Biology MCQ Questions
• Chemistry MCQ Questions
• Physics MCQ Questions
• Mathematics MCQ Questions

Questions

1. Lymphoid tissue is found in
 a) Thymus
 b) Tonsils
 c) Lymph nodes
 d) All of these

2. Earthworm lives in the burrows made by boring and swallowing the soil to
 a) Uptake food
 b) Get moisture
 c) Procreation
 d) Avoid opponents

3. Which of the following cells are round and biconcave in shape?
 a) White blood cells
 b) Red blood cells
 c) Columnar epithelial cells
 d) Nerve cells

4. Given below the diagram of the internal organs of a frog and identify A to F

 a) A-Gall bladder, B-Lungs, C-Testis, D-Kidney, E-Urethra, F-Urinary bladder
 b) A-Gall bladder, B-Lungs, C-Fat bodies, D-Kidney, E-Rectum, F-Urinary bladder
 c) A-Gall bladder, B-Lungs, C-Ovary, D-Kidney, E-ileum, F-Urinary bladder
 d) A-Gall bladder, B-Lungs, C-Fat bodies, D-Kidney, E-Colon, F-Urinary bladder

5. The clitellum divides the body of the earthworm into …… regions
 a) 3
 b) 2
 c) 4
 d) 5

6. Identify A, B and C in the given diagram of adipose tissue
 
 a) A-Cytoplasm, B-Nucleus, C-Cell wall
 b) A-Fat storage area, B-Mast cell, C-Plasma membrane
 c) A-Cell fluid, B-Collagen fibres, C-Plasmalemma
 d) A-Fat storage area, B-Nucleus, C-Plasma membrane

7. How many litres of blood is present in the normal human body?
 a) 6.8 L
 b) 6.0 L
 c) 5.9 L
 d) 7.2 L

8. The lining of body cavities, ducts and tube are made up of
 a) Compound epithelium
 b) Simple epithelium
 c) Cuboidal epithelium
 d) Keratinised epithelium

9. Which of the following metalloproteins is found in the blood of earthworms?
 a) Haemoglobin
 b) Hemerytherin
 c) Hemocyanin
 d) Myoglobin

10. Histamine, serotonin and heparin are secreted by
 a) Lymphocytes
 b) Monocytes
 c) Neutrophils
 d) Basophils

11. Find out the wrongly matched pair.
 a) Squamous epithelium - Skin of frog
 b) Columnar epithelium - Peritoneum of body cavity
 c) Ciliated epithelium - Bronchioles
 d) Stratified squamous epithelium  - Oesophagus

12. The body wall of the earthworm is covered by which of the following layers (externally or externally)?
 a) Epidermis, cuticle, coelomic epithelium, longitudinal muscle, circular muscles.
 b) Cuticle, epidermis, circular muscles, coelomic epithelium, longitudinal muscle.
 c) Non-cellular cuticle, epidermis, circular muscles, longitudinal muscles, coelomic epithelium.
 d) Coelomic epithelium, epidermis, cuticle, circular muscles, longitudinal muscles.

13. The number of pairs of cranial nerves arising from the brain of a frog is
 a) 10
 b) 9
 c) 8
 d) 7

14. The ova of the earthworms are fertilised by the sperm within the
 a) Cocoon
 b) Seminal vesicles
 c) Soil
 d) None of the above

15. Which of the following tissues provides a covering layer for some of the body parts?
 a) Connective tissues
 b) Muscular tissues
 c) Epithelial tissues
 d) Neural tissues

16. Consider the following statements about the connective tissue
I. Their special function is linking and supporting the other organs tissues of the body
II. It is the most abundant type of animal tissue
III. Blood is a specialised connective tissue which contains collagen
IV. The cells of connective tissue secrete mucous
Which of the statements given above are incorrect?
 a) I and II
 b) II and III
 c) III and IV
 d) I, II, III and IV

17. Which of the following types of connective tissue is present at the tip of the human nose?
 a) Cartilage
 b) Bone
 c) Adipose tissue
 d) None of these

18. The tissue which forms the glands in humans is
 a) Muscular tissue
 b) Nervous tissue
 c) Epithelium tissue
 d) Connective tissue

19. How many species of Pheretima are found all over the world?
 a) 200
 b) 300
 c) 400
 d) 500

20. In which of the following segments of earthworm, septal nephridia is present?
 a) 15-last
 b) 8-15
 c) 18-last
 d) 15-17

Answers

1-d; 2-b; 3-b; 4-b5-a; 6-d; 7-a; 8-b9-a; 10-d; 11-b; 12-c13-a; 14-a; 15-c; 16-c 17-a; 18-c; 19-d; 20-a

Solutions

1 (d)
Lymphoid tissue consists of spleen, tonsils, lymph nodes, thymus gland, Peyer’s patches, liver, etc. Such organs secrete lymph, producing lymphocytes which are known as lymphoid organs. The spleen is the largest mass of lymphatic tissue in the body. Lymphoid tissue shares responsibility with myeloid tissue (red bone marrow) for producing agranular leucocytes. 

2 (b)
Earthworm is a reddish-brown terrestrial invertebrate that lives in moist soil, rich in humus. They are soft and naked and, hence cannot survive on the dry earth. Therefore, they live in burrows made by boring and swallowing the soil.

3 (b)
Red blood cells (RBC_S) or erythrocytes are the most abundant of all the cells in blood. They are devoid of nuclei in most mammals and are round or biconcave in shape. It is biconcave because such a shape has increased surface area (for O_2transfer) and allows easy squeezability of the RBC_S through the blood vessels.

4 (b)
A-Gall bladder; B-Lungs; C-Fat bodies; D-Kidney; E-Rectum; F-Urinary bladder.

5 (a)
Clitellum divides the body of earthworm into three regions; preclitellar, clitellar and postclitellar. segments.

6 (d)
A-Fat storage area
B-Nucleus
C-Plasma membrane

7 (a)
An average adult person has about 6.8 litres of blood.

8 (b)
Simple epithelium is composed of a single layer of cells and functions as a lining for body cavities, ducts and tubes.

9 (a)
In earthworms, the blood glands are present on the 4th, 5th and 6th. They produce blood cells and haemoglobin which gets dissolved in the blood plasma. Blood contains leucocytes only.

10 (d)
Basophils (one of the types of granulocytes) secrete histamine, serotonin, heparin, etc., and are involved in inflammatory reactions. They are probably like mast cells of connective tissue.

11 (b)
Squamous epithelium - Skin of frog
Columnar epithelium - Stomach
Ciliated epithelium - Bronchioles
Stratified squamous epithelium - Oesophagus
Glandular epithelium - Salivary gland

12 (c)
The body wall of the earthworm is covered by a non-cellular cuticle, epidermis, circular muscles and longitudinal muscles, and coelomic epithelium.

13 (a)
There are ten pairs of cranial nerves arising from the brain of the frog.

14 (a)
In Pheretima fertilization is external (outside the body) within specialised structures called cocoons. These are hard shell structures containing mature sperm, egg cells and nutritive fluid. These hard structures are developed due to the hardening of clitellar secretions.

15 (c)
Epithelial tissue has a free surface, which faces either a body fluid or the outside environment and thus provides a covering to body parts.

16 (c)
Specialised connective tissues include cartilage, bone, adipose and blood. In all connective tissues, except blood the cells secrete collagen. Blood is a fluid connective tissue containing plasma, RBCs and WBCs. Cells of connective tissues secrete fibres of structural proteins called collagen or elastin. These fibres provide strength, elasticity and flexibility to the tissues.

17 (a)
Cartilage is a specialised connective tissue, which is solid, pliable and resists compression.

18 (c)
The glandular epithelium consists of specialised columnar or cuboidal cells, which are specialised for secretion. They may be unicellular, e.g., goblet cells of the alimentary canal or multicellular, e.g., salivary gland.

19 (d)
There are about 500 species of earthworms all over the world.

20 (a)
Septal nephridia, present on both sides of the intersegmental septa from segment 15 to the last opens into the intestine of earthworm’s excretory system.

These were the 20 questions from Structural Organization in Animals. Thanks for visiting. 

Are you preparing for competitive exams such as NEET, ACT or SAT? You are in the right place. 

In this article, I am about to share the 30 most probable objective questions from the chapter "Mineral Nutrition", which might be helpful for your exam preparation. This chapter discusses the ways by which plants and animals get their nutrition from inorganic materials. Alongside the questions, we have also provided detailed explanations for every answer so that you can clear your doubts. 

For chapter-wise MCQ questions, visit the following links: 

• Biology MCQ Questions
• Chemistry MCQ Questions
• Physics MCQ Questions
• Mathematics MCQ Questions

Questions

1. Enzyme nitrogenase is responsible for
a) Nitrification
b) Nitrogen fixation
c) Nitrite reduction
d) Nitrate reduction 

2. Nitrifying bacteria
a) Liberate ammonia
b) Change ammonia into ionic form
c) Oxidise ammonia to nitrate
d) Oxidise ammonia to nitrite 

3. Plants growing near the nuclear test sites take up and accumulate which of the following elements?
a) Gold
b) Selenium
c) Strontium
d) All of these 

4. Name the minerals responsible for maintaining cation-anion balance in the plant cells
a) K⁺ and Fe⁺³
b) Cl^- and K⁺
c) Ca⁺² and Mg⁺²
d) Cl^- and Mg⁺² 

5. What is the major function of air stone?
a) Remove CO₂ content from the nutrient solution
b) Dissolves O₂ in the nutrient solution
c) Increases the level of N₂ in the nutrient solutions
d) Removes O₂ from the nutrient solution 

6. In hydroponic vegetables, the pH preferred by most vegetables is slightly
a) Alkaline
b) Neutral
c) Acidic
d) Basic 

7. Which of the following are considered the roles of iron (Fe) in plants? I. An important constituent of cytochrome II. Activator of catalase III. Essential for chlorophyll synthesis Choose the correct option
a) Only I
b) Only III
c) Only II
d) All of these 

8. By applying which of the following practices, contamination of hydroponics plants can be reduced?
a) Change the medium every week
b) Do not use tools from the outdoor garden
c) Complete aeration in a hydroponic tank
d) All of the above 

9. An essential element is that which
a) Improves the health of the plant
b) Is irreplaceable and indispensable for the growth of plants
c) Is found in plant ash
d) Is available in the soil 

10. Essential elements perform many functions which include I. Permeability of the cell membrane II. Maintenance of osmotic concentration of the cell sap III. Major constituents of macromolecules and coenzymes IV. Buffering action Choose the correct option
a) Only III
b) I and III
c) Only I
d) I, II and III 

11. Which of the following metals causes harmful effects?
a) Lead
b) Cobalt
c) Uranium
d) All of these 

12. Nitrogen is mainly absorbed in the form of
a) Nitrate
b) Nitrite
c) Ammonium
d) All of these 

13. In the initial phase of minerals absorption ions are taken up
a) Slowly
b) Rapidly
c) Fluently
d) Simultaneously 

14. Which of the following is true regarding manganese toxicity in plants?
a) Induction deficiencies of iron, magnesium, and calcium
b) Appearance of brown spots surrounded by chlorotic veins
c) Inhibition of Ca^(2+) ions translocation in the shoot apex
d) All of the above 

15. Sulphur is found as a constituent in which of the following amino acids?
a) Cysteine
b) Methionine
c) Both (a) and (b)
d) None of the above 

16. What is the key principle of the EBB and flow system in hydroponics?
a) It floods and drains periodically
b) It makes a tide flowing over the roots
c) It sprays a mist of nutrients on the roots
d) None of the above 

17. Hydroponics has been successfully employed as a technique for which of the following vegetables?
a) Seedless cucumber
b) Tomato
c) Lettuce
d) All of these 

18. For the uptake of ions in the second phase of absorption of minerals, the pathway followed is called
a) Passive uptake
b) Active uptake
c) Neutral
d) None of these 

19. How many essential mineral elements have been discovered yet?
a) 17
b) 107
c) 110
d) 150 

20. Which of the following is a rootless aquatic plant in which a portion of the leaf forms a tiny sac for trapping insects?
a) Nepenthes
b) Drosera
c) Utricularia
d) Dionaea 

21. Which of the given options is correct for hydroponics? Select the correct pair I. Hydroponics technique is useful in areas having infertile and dry soils II. Hydroponics can regulate pH optimum for a particular crop III. It increases the labor cost IV. It increases the problem of weeding
a) I and IV
b) I and II
c) I and III
d) Only I 

22. Phosphorus is absorbed by the plants as I. H_2 PO_4^- II. HPO_4 III. HPO_4^(2-) IV. H_2 PO^-
a) Only I
b) Only III
c) I and III
d) Only II 

23. Insectivorous plants eat the insect for
a) Na-K
b) Nitrogen
c) Chlorine
d) Phosphorus 

24. Aeroponics are
a) Aerial plants
b) Aerated plants
c) Soilers cultivated plants
d) None of these 

25. The given diagram belongs to bacteroids in the nodule. Identify A and B and choose the correct option accordingly

a) A-Bacteria; B-Bacteroids
b) A-Leghaemoglobin; B-Bacteroides
c) A-Bacteroids; B-Bacteria
d) A-Bacteroids; B-Leghaemoglobin 

26. Insectivorous plants eat insects for their requirement of
a) Sodium-potassium
b) Nitrogen
c) Chlorine
d) Phosphorus 

27. Molybdenum is the essential constituent of
a) Nitrogenase
b) Respiratory chain
c) Growth regulators
d) Chlorophyll 

28. Select the correct statement.
a) Legumes are incapable of fixing nitrogen
b) Legumes fix nitrogen through bacteria living in fruits
c) Legumes fix nitrogen only by bacteria present in root nodules
d) None of the above 

29. Which among the following are used as media for hydroponics?
a) Coco air
b) Rock cool
c) Gravel
d) All of these 

30. The core metal of chlorophyll is
a) Fe
b) Mg
c) Ni
d) Cu

Answers

1-b 2-c 3-c 4-b 5-b 6-c 7-d 8-d 9-b 10-d 11-d 12-a 13-b 14-d 15-c 16-a 17-d 18-b 19-a 20-c 21-b 22-c 23-b 24-c 25-c 26-b 27-a 28-c 29-c 30-b 

Solutions

1 (b)
The fixation of nitrogen in root nodules of legumes takes place in the presence of the enzyme ‘nitrogenase’. This enzyme is an enzyme complex consisting of two components called protein-1 and protein-2. The active nitrogenase complex contains protein-1 and protein-2 components in a ratio of 1:2.

2 (c)
Ammonia produced by the degradation of manures and organic matter may not be available to plants because it is readily leached from soil. It is converted to nitrate with the help of certain microorganisms, i.e., called nitrification (the used bacteria, nitrifying bacteria).
     2 NH₃ + 3 O₂ → 2 NO₂^- + 2H⁺ + 2 H₂O
      2NO₂^- + O₂ → 2 NO₂^-
Ammonia is first oxidized to nitrite by the bacteria Nitrosomonas and/or Nitrosococcus. The nitrite is further oxidized to nitrate with the help of the bacterium Nitrobacter.

3 (c)
Some plant species accumulate selenium, some others gold, while some plants growing near nuclear test sites take up radioactive strontium.

4 (b)
Functions of Cl^- It helps photolysis of water, maintenance of solute concentration, and ionic balance.
The function of K Potassium plays an important role in the opening and closing of stomata. These both can alter the osmotic potential of a cell

5 (b)
An air pump used in conjunction with an air stone is an excellent way to dissolve oxygen in the nutrient solution

6 (c)
An ideal pH range for most hydroponic crops is between 5.5 and 6.5.
It is important because it affects the availability and absorption of several of the 16 atomic elements needed for plant growth

7 (d)
Functions of Fe It is involved in the transfer of electrons like ferredoxin and cytochromes. It is reversibly oxidized from Fe²⁺ and Fe³⁺ during electron transfer. It activates catalase enzymes and is essential for the formation of chlorophyll

8 (d)
All of the above

9 (b)
Essential element has the following features:
1. It is indispensable for the growth of plants.
2. Cannot be replaced by any other element.
3. Absence/deficiency produces disorders.
4. Has nutritive value.
5. Necessary for completion of the vegetative or reproductive phase.
6. These are- C, H, O, N, P, K, S, Mg, Ca, Fe, B, Mn, Cu, Zn, Mo and Cl.

10 (d)
Essential elements perform several functions. They participate in various metabolic processes in the plant cells, such as permeability of the cell membrane, maintenance of osmotic concentration of the cell sap, electron transport systems, buffering action, enzymatic activities, and acts as a major constituent of macromolecules and coenzymes

11 (d)
All lead, cobalt, and uranium cause harmful effects.

12 (a)
Nitrogen is mainly absorbed in the form of nitrate from soil.

13 (b)
In the initial phase, ions are taken up rapidly.

14 (d)
The prominent symptom of manganese toxicity is the appearance of brown spots surrounded by chlorotic veins.
It is important to know that manganese competes with iron and magnesium for its uptake by the plants and with magnesium for its binding with enzymes. Manganese also inhibits calcium translocation in the shoot apex. Therefore, excess of manganese may induce deficiencies of iron, magnesium, and calcium.

15 (c)
Plant obtains sulfur in the form of sulfate (SO₄^2-). Sulfur is present in two amino acids-cysteine and methionine and is the main constituent of several coenzymes, vitamins, and ferredoxin.

16 (a)
The EBB and flow system works by temporarily flooding the grown tray with nutrition solution and then draining the solution back into the reservoir.

17 (d)
Hydroponics has been successfully employed as a technique for the commercial production of vegetables such as tomatoes, seed less cucumbers, and lettuce.

18 (b)
For the uptake of ions in the second phase, the pathway followed is called active uptake.

19 (a)
17 elements are essential for plant growth.

20 (c)
Utricularia or bladderwort is an insectivorous submerged aquatic plant. In which the rootless floating stem bears highly dissected leaves. A portion of the leaf is modified into sacs, like bladders of about 1.3 mm in diameter. Each bladder is guarded by a small valve which opens inwardly. Small insects flow into the bladder with water, but cannot come out due to the valve.

21 (b)
Hydroponics technique is useful in areas having infertile and dry soils and can regulate the pH optimum for a particular crop.

22 (c)
Phosphorus is absorbed by the plants from soil in the form of phosphate ions either as H₂PO₄^- or HPO₄^2-.

23 (b)
Insectivorous plants are autotrophic in their mode of nutrition but they grow in marshy or muddy soils, which are generally deficient in nitrogen, and in other to fulfil their nitrogen requirements, these plants catch and digest small insects.

24 (c)
Aeroponics is soilless cultivated of plants

25 (c)
A-leghaemoglobin, B-bacteroids

26 (b)
Insectivorous plants eat insects for nitrogen

27 (a)
Enzyme nitrogenase is required for biological nitrogen fixation. It is a metal protein. The metal present in the nitrogenase enzyme is molybdenum. Hence, molybdenum is an important element for nitrogen fixation.

28 (c)
The legumes (papilionaceous plants) are incapable of nitrogen fixation. The Rhizobium bacteria are present symbiotically in the root nodules of these plants which have the capability of nitrogen fixation.

29 (c)
Coco air, perlite, rock cool, and gravel all are used as media for hydroponics

30 (b)
In the center of each chlorophyll molecule is found a magnesium metal.

These questions will be helpful in the preparation and revision of the chapter "Mineral Nutrition". Thanks for visiting my website.