Class 11 Biology Sample Solution- 3 | Biology Class 11 - NEET PDF Download

 Page 1


  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
CBSE 
Class XI Biology 
Sample Paper – 3 Solution 
 
SECTION A 
 
1. Bacteria, cyanobacteria and fungi were included in the plant kingdom in the earliest 
classification systems because they all have a cell wall. 
OR 
The storage bodies of green algae are called pyrenoids. They are located in the 
chloroplasts.  
 
2.   
i. They store food. 
ii. They take part in perennation. 
 
3. Outermost layer: Glycocalyx 
Innermost layer: Plasma membrane 
 
4. A mineral element is said to be toxic when it is in concentrations which reduce the dry 
weight of tissues by about 10%. 
OR 
Prokaryotes have the enzyme nitrogenase for the reduction of nitrogen into ammonia. 
Hence, nitrogen fixation is shown only by prokaryotes and not by eukaryotes. 
 
5. Synaptic knob 
SECTION B 
 
6. Certain cnidarians which exhibit both forms (polyp and medusa) exhibit alternation of 
generation. Polyps produce medusae asexually, while medusae form polyps sexually. 
This phenomenon is called metagenesis. Example: Obelia 
 
7. Plasmodesmata are cytoplasmic bridges. They transverse the primary cell wall and 
middle lamella and connect the adjacent cells.  
Function: They form transport channels between adjacent cells. 
OR 
Crossing over is defined as a phenomenon of exchange of equivalent segments between 
non-sister chromatids of homologous chromosomes during prophase I of  meiosis. The 
enzyme recombinase is responsible for it. 
 
Page 2


  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
CBSE 
Class XI Biology 
Sample Paper – 3 Solution 
 
SECTION A 
 
1. Bacteria, cyanobacteria and fungi were included in the plant kingdom in the earliest 
classification systems because they all have a cell wall. 
OR 
The storage bodies of green algae are called pyrenoids. They are located in the 
chloroplasts.  
 
2.   
i. They store food. 
ii. They take part in perennation. 
 
3. Outermost layer: Glycocalyx 
Innermost layer: Plasma membrane 
 
4. A mineral element is said to be toxic when it is in concentrations which reduce the dry 
weight of tissues by about 10%. 
OR 
Prokaryotes have the enzyme nitrogenase for the reduction of nitrogen into ammonia. 
Hence, nitrogen fixation is shown only by prokaryotes and not by eukaryotes. 
 
5. Synaptic knob 
SECTION B 
 
6. Certain cnidarians which exhibit both forms (polyp and medusa) exhibit alternation of 
generation. Polyps produce medusae asexually, while medusae form polyps sexually. 
This phenomenon is called metagenesis. Example: Obelia 
 
7. Plasmodesmata are cytoplasmic bridges. They transverse the primary cell wall and 
middle lamella and connect the adjacent cells.  
Function: They form transport channels between adjacent cells. 
OR 
Crossing over is defined as a phenomenon of exchange of equivalent segments between 
non-sister chromatids of homologous chromosomes during prophase I of  meiosis. The 
enzyme recombinase is responsible for it. 
 
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
8. Oxidative decarboxylation is the process in which pyruvic acid is decarboxylated, i.e. 
one carbon atom is removed as carbon dioxide, and then oxidised to form acetyl CoA or 
activated acetate. It occurs when pyruvate enters the mitochondria through a specific 
transport protein. 
 
9. The colour of a leaf kept in the dark frequently becomes yellow or pale green because 
chlorophyll is degraded, and there is no formation of chlorophyll. Carotenoid pigments 
are more stable. 
OR 
Differences between glycolysis and fermentation: 
Glycolysis Fermentation 
It is the process in which one molecule of 
glucose is broken down into two 
molecules of pyruvic acid. 
It is the process in which pyruvic acid is 
converted to alcohol or organic acid by 
certain microbes.  
Oxygen does not influence its reaction.  It occurs only in the absence of oxygen.  
 
 
10. Binary fission in bacteria: 
 
 
11. Areolar connective tissue serves as a support framework for epithelium.  
It contains mast cells, macrophages and fibroblasts. 
 
12. Functions of the centrioles: 
? They form spindle fibres which give rise to the spindle apparatus. 
? They form the basal body of cilia or flagella. 
 
  
Page 3


  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
CBSE 
Class XI Biology 
Sample Paper – 3 Solution 
 
SECTION A 
 
1. Bacteria, cyanobacteria and fungi were included in the plant kingdom in the earliest 
classification systems because they all have a cell wall. 
OR 
The storage bodies of green algae are called pyrenoids. They are located in the 
chloroplasts.  
 
2.   
i. They store food. 
ii. They take part in perennation. 
 
3. Outermost layer: Glycocalyx 
Innermost layer: Plasma membrane 
 
4. A mineral element is said to be toxic when it is in concentrations which reduce the dry 
weight of tissues by about 10%. 
OR 
Prokaryotes have the enzyme nitrogenase for the reduction of nitrogen into ammonia. 
Hence, nitrogen fixation is shown only by prokaryotes and not by eukaryotes. 
 
5. Synaptic knob 
SECTION B 
 
6. Certain cnidarians which exhibit both forms (polyp and medusa) exhibit alternation of 
generation. Polyps produce medusae asexually, while medusae form polyps sexually. 
This phenomenon is called metagenesis. Example: Obelia 
 
7. Plasmodesmata are cytoplasmic bridges. They transverse the primary cell wall and 
middle lamella and connect the adjacent cells.  
Function: They form transport channels between adjacent cells. 
OR 
Crossing over is defined as a phenomenon of exchange of equivalent segments between 
non-sister chromatids of homologous chromosomes during prophase I of  meiosis. The 
enzyme recombinase is responsible for it. 
 
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
8. Oxidative decarboxylation is the process in which pyruvic acid is decarboxylated, i.e. 
one carbon atom is removed as carbon dioxide, and then oxidised to form acetyl CoA or 
activated acetate. It occurs when pyruvate enters the mitochondria through a specific 
transport protein. 
 
9. The colour of a leaf kept in the dark frequently becomes yellow or pale green because 
chlorophyll is degraded, and there is no formation of chlorophyll. Carotenoid pigments 
are more stable. 
OR 
Differences between glycolysis and fermentation: 
Glycolysis Fermentation 
It is the process in which one molecule of 
glucose is broken down into two 
molecules of pyruvic acid. 
It is the process in which pyruvic acid is 
converted to alcohol or organic acid by 
certain microbes.  
Oxygen does not influence its reaction.  It occurs only in the absence of oxygen.  
 
 
10. Binary fission in bacteria: 
 
 
11. Areolar connective tissue serves as a support framework for epithelium.  
It contains mast cells, macrophages and fibroblasts. 
 
12. Functions of the centrioles: 
? They form spindle fibres which give rise to the spindle apparatus. 
? They form the basal body of cilia or flagella. 
 
  
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
SECTION C 
 
13. Double fertilisation is unique to angiosperms. 
In this phenomenon, two male gametes are discharged by a pollen tube into the embryo 
sac of an ovule. One male gamete fuses with the female gamete to form a zygote. This 
fusion is called syngamy. A second male gamete fuses with the secondary nucleus to 
form the primary endosperm nucleus. This is called triple fusion. 
 
14. The mouth parts of a cockroach consist of the following: 
A labrum (upper lip), a pair of mandibles each with two regions —the grinding region 
and incising region, a pair of maxillae, a labium (lower lip) and the hypopharynx within 
the cavity and enclosed by the other mouth parts. 
OR 
(a) The ovaries extend between the 4
th
 and 6
th
 abdominal segments. 
(b) 10 segments 
(c) Malpighian tubules are present at the junction between the midgut and hindgut of 
cockroaches or insects. 
 
15. It is true that the cork cambium forms tissues which form the cork. The cork cambium 
produces new cells on both outer surface and inner surface. The cells formed on the 
outer side differentiate into cork, also called phellem. The cells become impervious to 
water because of deposition of suberin and become thick-walled. 
 
16. Modification of the root is a change in the shape, size, structure and normal functioning 
of the root to perform some secondary functions or a particular adaptation. 
(a) Banyan tree: In banyan trees, long roots develop from branches which go deep 
down to reach the ground to provide additional mechanical support to the banyan 
tree. This modification is called a prop root.  
(b) Turnip: In turnip, the root is modified to store extra food. This modification is called 
napiform fleshy tap root. 
(c) Mangrove trees: The roots of mangrove trees get modified into pneumatic 
structures to provide additional oxygen to the plant. This modification of roots is 
called respiratory roots or pneumatophores. 
OR 
The perianth is the accessory whorls of a flower where the calyx and corolla cannot be 
distinguished.  
The constituent members of the perianth are called tepals. 
Example: Lily  
 
  
Page 4


  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
CBSE 
Class XI Biology 
Sample Paper – 3 Solution 
 
SECTION A 
 
1. Bacteria, cyanobacteria and fungi were included in the plant kingdom in the earliest 
classification systems because they all have a cell wall. 
OR 
The storage bodies of green algae are called pyrenoids. They are located in the 
chloroplasts.  
 
2.   
i. They store food. 
ii. They take part in perennation. 
 
3. Outermost layer: Glycocalyx 
Innermost layer: Plasma membrane 
 
4. A mineral element is said to be toxic when it is in concentrations which reduce the dry 
weight of tissues by about 10%. 
OR 
Prokaryotes have the enzyme nitrogenase for the reduction of nitrogen into ammonia. 
Hence, nitrogen fixation is shown only by prokaryotes and not by eukaryotes. 
 
5. Synaptic knob 
SECTION B 
 
6. Certain cnidarians which exhibit both forms (polyp and medusa) exhibit alternation of 
generation. Polyps produce medusae asexually, while medusae form polyps sexually. 
This phenomenon is called metagenesis. Example: Obelia 
 
7. Plasmodesmata are cytoplasmic bridges. They transverse the primary cell wall and 
middle lamella and connect the adjacent cells.  
Function: They form transport channels between adjacent cells. 
OR 
Crossing over is defined as a phenomenon of exchange of equivalent segments between 
non-sister chromatids of homologous chromosomes during prophase I of  meiosis. The 
enzyme recombinase is responsible for it. 
 
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
8. Oxidative decarboxylation is the process in which pyruvic acid is decarboxylated, i.e. 
one carbon atom is removed as carbon dioxide, and then oxidised to form acetyl CoA or 
activated acetate. It occurs when pyruvate enters the mitochondria through a specific 
transport protein. 
 
9. The colour of a leaf kept in the dark frequently becomes yellow or pale green because 
chlorophyll is degraded, and there is no formation of chlorophyll. Carotenoid pigments 
are more stable. 
OR 
Differences between glycolysis and fermentation: 
Glycolysis Fermentation 
It is the process in which one molecule of 
glucose is broken down into two 
molecules of pyruvic acid. 
It is the process in which pyruvic acid is 
converted to alcohol or organic acid by 
certain microbes.  
Oxygen does not influence its reaction.  It occurs only in the absence of oxygen.  
 
 
10. Binary fission in bacteria: 
 
 
11. Areolar connective tissue serves as a support framework for epithelium.  
It contains mast cells, macrophages and fibroblasts. 
 
12. Functions of the centrioles: 
? They form spindle fibres which give rise to the spindle apparatus. 
? They form the basal body of cilia or flagella. 
 
  
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
SECTION C 
 
13. Double fertilisation is unique to angiosperms. 
In this phenomenon, two male gametes are discharged by a pollen tube into the embryo 
sac of an ovule. One male gamete fuses with the female gamete to form a zygote. This 
fusion is called syngamy. A second male gamete fuses with the secondary nucleus to 
form the primary endosperm nucleus. This is called triple fusion. 
 
14. The mouth parts of a cockroach consist of the following: 
A labrum (upper lip), a pair of mandibles each with two regions —the grinding region 
and incising region, a pair of maxillae, a labium (lower lip) and the hypopharynx within 
the cavity and enclosed by the other mouth parts. 
OR 
(a) The ovaries extend between the 4
th
 and 6
th
 abdominal segments. 
(b) 10 segments 
(c) Malpighian tubules are present at the junction between the midgut and hindgut of 
cockroaches or insects. 
 
15. It is true that the cork cambium forms tissues which form the cork. The cork cambium 
produces new cells on both outer surface and inner surface. The cells formed on the 
outer side differentiate into cork, also called phellem. The cells become impervious to 
water because of deposition of suberin and become thick-walled. 
 
16. Modification of the root is a change in the shape, size, structure and normal functioning 
of the root to perform some secondary functions or a particular adaptation. 
(a) Banyan tree: In banyan trees, long roots develop from branches which go deep 
down to reach the ground to provide additional mechanical support to the banyan 
tree. This modification is called a prop root.  
(b) Turnip: In turnip, the root is modified to store extra food. This modification is called 
napiform fleshy tap root. 
(c) Mangrove trees: The roots of mangrove trees get modified into pneumatic 
structures to provide additional oxygen to the plant. This modification of roots is 
called respiratory roots or pneumatophores. 
OR 
The perianth is the accessory whorls of a flower where the calyx and corolla cannot be 
distinguished.  
The constituent members of the perianth are called tepals. 
Example: Lily  
 
  
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
17. The cell theory was proposed by Schleiden and Schwann. 
The main postulates of the cell theory are 
i. All living organisms are composed of cells and their products.  
ii. New cells arise from pre-existing cells. 
 
18. A mesosome is a membrane complex formed by infolding of the plasma membrane in 
prokaryotic cells. If the mesosome is attached to a nucleoid, it is called a septal 
mesosome. A mesosome free from the nucleoid is called a lateral mesosome. A lateral 
mesosome is rich in respiratory enzymes and thus takes part in respiration. A septal 
mesosome takes part in the separation of daughter nucleoids, the formation of the 
plasma membrane for rapid elongation and the formation of the septum. 
 
19.  
i. Chemical nature: Enzymes are generally complex macromolecules of globular 
proteins. They do not initiate a chemical reaction but increase the rate of a chemical 
reaction. 
ii. Molecular weight: Being proteinaceous in nature, the enzymes are giant molecules 
with a molecular weight of 6000 to 4,600,000 kDa. 
iii. Changeless form: Enzymes are not transformed in the chemical reaction. They 
combine temporarily with the substrate molecules but are neither consumed nor 
changed permanently in the reaction they catalyse. 
OR 
Steps involved in the catalytic action of an enzyme: 
? The substrate binds to the active site of the enzyme. 
? The binding of the substrate induces the enzyme to alter its shape, fitting more 
tightly around the substrate. 
? The active site of the enzyme, which is now in proximity to the substrate, breaks the 
chemical bonds of the substrate and hence an enzyme –product complex is formed. 
? The enzyme releases the products and is free to run through the catalytic cycle 
again.   
 
20.   
i. The disease is diabetes mellitus. 
ii. The failure of the ß-cells of the islets of Langerhans of pancreas to produce adequate 
amounts of insulin is the root cause of this disease. 
iii. Undersecretion of insulin impairs the following functions: 
(a) Use and uptake of glucose by adipocytes and hepatocytes 
(b) Conversion of glucose to glycogen by the above target cells 
 
  
Page 5


  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
CBSE 
Class XI Biology 
Sample Paper – 3 Solution 
 
SECTION A 
 
1. Bacteria, cyanobacteria and fungi were included in the plant kingdom in the earliest 
classification systems because they all have a cell wall. 
OR 
The storage bodies of green algae are called pyrenoids. They are located in the 
chloroplasts.  
 
2.   
i. They store food. 
ii. They take part in perennation. 
 
3. Outermost layer: Glycocalyx 
Innermost layer: Plasma membrane 
 
4. A mineral element is said to be toxic when it is in concentrations which reduce the dry 
weight of tissues by about 10%. 
OR 
Prokaryotes have the enzyme nitrogenase for the reduction of nitrogen into ammonia. 
Hence, nitrogen fixation is shown only by prokaryotes and not by eukaryotes. 
 
5. Synaptic knob 
SECTION B 
 
6. Certain cnidarians which exhibit both forms (polyp and medusa) exhibit alternation of 
generation. Polyps produce medusae asexually, while medusae form polyps sexually. 
This phenomenon is called metagenesis. Example: Obelia 
 
7. Plasmodesmata are cytoplasmic bridges. They transverse the primary cell wall and 
middle lamella and connect the adjacent cells.  
Function: They form transport channels between adjacent cells. 
OR 
Crossing over is defined as a phenomenon of exchange of equivalent segments between 
non-sister chromatids of homologous chromosomes during prophase I of  meiosis. The 
enzyme recombinase is responsible for it. 
 
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
8. Oxidative decarboxylation is the process in which pyruvic acid is decarboxylated, i.e. 
one carbon atom is removed as carbon dioxide, and then oxidised to form acetyl CoA or 
activated acetate. It occurs when pyruvate enters the mitochondria through a specific 
transport protein. 
 
9. The colour of a leaf kept in the dark frequently becomes yellow or pale green because 
chlorophyll is degraded, and there is no formation of chlorophyll. Carotenoid pigments 
are more stable. 
OR 
Differences between glycolysis and fermentation: 
Glycolysis Fermentation 
It is the process in which one molecule of 
glucose is broken down into two 
molecules of pyruvic acid. 
It is the process in which pyruvic acid is 
converted to alcohol or organic acid by 
certain microbes.  
Oxygen does not influence its reaction.  It occurs only in the absence of oxygen.  
 
 
10. Binary fission in bacteria: 
 
 
11. Areolar connective tissue serves as a support framework for epithelium.  
It contains mast cells, macrophages and fibroblasts. 
 
12. Functions of the centrioles: 
? They form spindle fibres which give rise to the spindle apparatus. 
? They form the basal body of cilia or flagella. 
 
  
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
SECTION C 
 
13. Double fertilisation is unique to angiosperms. 
In this phenomenon, two male gametes are discharged by a pollen tube into the embryo 
sac of an ovule. One male gamete fuses with the female gamete to form a zygote. This 
fusion is called syngamy. A second male gamete fuses with the secondary nucleus to 
form the primary endosperm nucleus. This is called triple fusion. 
 
14. The mouth parts of a cockroach consist of the following: 
A labrum (upper lip), a pair of mandibles each with two regions —the grinding region 
and incising region, a pair of maxillae, a labium (lower lip) and the hypopharynx within 
the cavity and enclosed by the other mouth parts. 
OR 
(a) The ovaries extend between the 4
th
 and 6
th
 abdominal segments. 
(b) 10 segments 
(c) Malpighian tubules are present at the junction between the midgut and hindgut of 
cockroaches or insects. 
 
15. It is true that the cork cambium forms tissues which form the cork. The cork cambium 
produces new cells on both outer surface and inner surface. The cells formed on the 
outer side differentiate into cork, also called phellem. The cells become impervious to 
water because of deposition of suberin and become thick-walled. 
 
16. Modification of the root is a change in the shape, size, structure and normal functioning 
of the root to perform some secondary functions or a particular adaptation. 
(a) Banyan tree: In banyan trees, long roots develop from branches which go deep 
down to reach the ground to provide additional mechanical support to the banyan 
tree. This modification is called a prop root.  
(b) Turnip: In turnip, the root is modified to store extra food. This modification is called 
napiform fleshy tap root. 
(c) Mangrove trees: The roots of mangrove trees get modified into pneumatic 
structures to provide additional oxygen to the plant. This modification of roots is 
called respiratory roots or pneumatophores. 
OR 
The perianth is the accessory whorls of a flower where the calyx and corolla cannot be 
distinguished.  
The constituent members of the perianth are called tepals. 
Example: Lily  
 
  
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
17. The cell theory was proposed by Schleiden and Schwann. 
The main postulates of the cell theory are 
i. All living organisms are composed of cells and their products.  
ii. New cells arise from pre-existing cells. 
 
18. A mesosome is a membrane complex formed by infolding of the plasma membrane in 
prokaryotic cells. If the mesosome is attached to a nucleoid, it is called a septal 
mesosome. A mesosome free from the nucleoid is called a lateral mesosome. A lateral 
mesosome is rich in respiratory enzymes and thus takes part in respiration. A septal 
mesosome takes part in the separation of daughter nucleoids, the formation of the 
plasma membrane for rapid elongation and the formation of the septum. 
 
19.  
i. Chemical nature: Enzymes are generally complex macromolecules of globular 
proteins. They do not initiate a chemical reaction but increase the rate of a chemical 
reaction. 
ii. Molecular weight: Being proteinaceous in nature, the enzymes are giant molecules 
with a molecular weight of 6000 to 4,600,000 kDa. 
iii. Changeless form: Enzymes are not transformed in the chemical reaction. They 
combine temporarily with the substrate molecules but are neither consumed nor 
changed permanently in the reaction they catalyse. 
OR 
Steps involved in the catalytic action of an enzyme: 
? The substrate binds to the active site of the enzyme. 
? The binding of the substrate induces the enzyme to alter its shape, fitting more 
tightly around the substrate. 
? The active site of the enzyme, which is now in proximity to the substrate, breaks the 
chemical bonds of the substrate and hence an enzyme –product complex is formed. 
? The enzyme releases the products and is free to run through the catalytic cycle 
again.   
 
20.   
i. The disease is diabetes mellitus. 
ii. The failure of the ß-cells of the islets of Langerhans of pancreas to produce adequate 
amounts of insulin is the root cause of this disease. 
iii. Undersecretion of insulin impairs the following functions: 
(a) Use and uptake of glucose by adipocytes and hepatocytes 
(b) Conversion of glucose to glycogen by the above target cells 
 
  
  
 
CBSE XI  |  BIOLOGY 
Sample Paper – 3 Solution 
 
     
 
21. In the mesophyll cells of sugarcane plant (a C4 plant), phosphoenol pyruvate (PEP) is 
the primary acceptor of CO2 which is carboxylated by the enzyme PEP-carboxylase to 
form a 4C-compound, oxaloacetic acid (OAA). 
In the bundle sheath cells, RuBP is the primary acceptor of CO2. The reaction catalysed 
by RuBisCO results in the formation of a 6C compound which breaks into two molecules 
of a 3C-compound, 3-phosphoglyceric acid (3-PGA). 
 
22. Deficiency symptoms appear first in the young plants for elements which are relatively 
immobile inside the plant. Examples:  Calcium and sulphur. They appear first in mature 
organs for those elements which are mobilised from senescing regions for supply to 
younger regions. Examples: Phosphorus, nitrogen and potassium. Thus, mobility of an 
element determines whether the deficiency symptoms appear in younger parts or in 
older parts. 
 
23. ECG is electrocardiograph. It is a graphical representation of the electrical activity of the 
heart during a cardiac cycle.  
 
 
 
A human electrograph shows five waves or deflections —P, Q, R, S and T.  
The P-wave represents depolarisation or the electrical excitation of the atria. This leads 
to the contraction of both atria.  
The QRS complex represents the depolarisation of the ventricles, which initiates the 
ventricular contraction. The contraction starts shortly after Q and marks the beginning 
of the systole.  
The T-wave represents repolarisation, i.e. the return of the ventricles from the excited 
to the normal state. The end of the T-wave marks the end of the systole. 
OR 
The juxtaglomerular apparatus (JGA) secretes the enzyme renin into the blood stream 
which changes the plasma protein angiotensinogen into a peptide, angiotensin II. 
Angiotensin II increases the blood pressure by causing arterioles to constrict. It also 
increases the blood volume by inducing the proximal convoluted tubules to reabsorb 
more NaCl and water. It stimulates the adrenal glands to secrete a hormone called 
aldosterone which induces the distal convoluted tubule to absorb more Na
+
 and water.