Important Questions For You!

Biology is one of the crucial subjects in ICSE Class 10. ICSE Class 10 Biology speaks about the cell as the basic unit of life, genes, and evolution and deals with how living organisms interact with the environment, including the behavior of living beings. TopperLearning is one of the premier online platforms which helps students of ICSE Class 10 to study various concepts in Biology.

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Further Reduced Syllabus for 2021

According to the further reduced syllabus introduced by CISCE for ICSE 10 Biology, the following chapters have been deleted for the year 2021 examination:
•    Genetics- Some Basic Fundamentals
•    Chemical Coordination in Plants
•    The Reproductive System
•    Human Evolution
•    Population – The Increasing Numbers and Rising Problems
•    Pollution – A Rising Environmental Problem
The below list covers the most important questions from the non-deleted chapters.

Name the following:

  1. Exchange of chromatid parts between the maternal and paternal chromatids of a pair of homologous chromosomes during meiosis                                                                                                       [1 M]
  2. Process of uptake of mineral ions against the concentration gradient using energy from the cell           [1 M]
  3. Process of conversion of ADP to ATP during photosynthesis                                                              [1 M]
  4. Phase of the cardiac cycle in which the auricles contract                                                                   [1 M]
  5. Structural and functional unit of the kidney                                                                                    [1 M]
  6. Fluid which provides protection and nourishment to the cells of the brain                                           [1 M]
  7. The layer of the eyeball that provides nourishment to the eye.                                                        [1 M]


Choose the correct answer from each of the four options given below:

1. The mineral ion needed for the formation of a blood clot is     [1 M]

A. Potassium
B. Sodium
C. Calcium
D. Iron

2. A plant cell may burst when                                 [1 M]
A. Turgor pressure equalises wall pressure
B. Turgor pressure exceeds wall pressure
C. Wall pressure exceeds turgor pressure
D. None of the above

3. Chromosomes get aligned at the centre of the cell during             [1 M]
A. Metaphase
B. Anaphase
C. Prophase
D. Telophase

4. Cretinism and myxoedema are due to                        [1 M]
A. Hypersecretion of thyroxine
B. Hypersecretion of growth hormone
C. Hyposecretion of thyroxine
D. Hyposecretion of growth hormone
 
5. After mitotic cell division, a female human cell will have            [1 M]
A. 44 + XX chromosomes
B. 44 + XY chromosomes
C. 22 + X chromosomes
D. 22 + Y chromosomes

6. A pulse wave is mainly caused by the                         [1 M]
A. Systole of atria
B. Diastole of atria
C. Systole of the left ventricle
D. Systole of the right ventricle

7. A plant is kept in a dark cupboard for 48 hours before conducting any experiment on photosynthesis to                                     [1 M]
A. Remove starch from the plant
B. Ensure that starch is not translocated from the leaves
C. Remove chlorophyll from the leaf of the plant
D. Remove starch from the experimental leaf

8. A reflex arc in man is best described as the movement of stimuli from     [1 M]
A. Receptor cell, sensory neuron, relaying neuron, effector muscles
B. Receptor cell, efferent nerve, relaying neuron, muscles of the body
C. Receptor cell, spinal cord, motor neuron, relaying neuron
D. Receptor cell, synapse, motor neuron, relaying neuron

In each set of terms given below, there is an odd one and cannot be grouped in the same category to which the others belong. Identify the odd term in each set and name the category to which the remaining belong.

  1. Cell wall, large vacuole, plastid, centrosome                                                                       [1 M]
  2. Thymine, cytosine, adenine, pepsin                                                                                   [1 M]
  3. Cortisone, somatotropin, adrenocorticotropic hormone, vasopressin                                       [1 M]
  4. Urethra, uterus, urinary bladder, ureter                                                                               [1 M]
  5. Transpiration, photosynthesis, phagocytosis, guttation                                                          [1 M]
  6. Sneezing, coughing, blinking, typing                                                                                   [1 M]
  7. Malleus, pinna, incus, stapes                                                                                              [1 M]
  8. Insulin, adrenaline, pepsin, thyroxine                                                                                  [1 M]


State the exact location of the following structures:

  1. Centromere                                                                                                                  [1 M]
  2. Chordae tendineae                                                                                                        [1 M]
  3. Thylakoids                                                                                                                    [1 M]
  4. Pulmonary semilunar valve                                                                                             [1 M]
  5. Corpus callosum                                                                                                            [1 M]
  6. Guard cells                                                                                                                    [1 M]
  7. Thyroid gland                                                                                                                [1 M]
  8. Organ of Corti                                                                                                               [1 M]


State the main function of the following:

  1. Cerebrospinal fluid                                     [1 M]
  2. Lenticels                                             [1 M]
  3. Ureter                                             [1 M]
  4. Chordae tendineae                                     [1 M]
  5. Vitreous humour                                     [1 M]
  6. Medulla oblongata                                     [1 M]
  7. Beta cells of the pancreas                                 [1 M]


Differentiate between the following pairs on the basis of what is mentioned within brackets:
1.    Rod cells and cone cells (pigment)                             [1 M]
2.    Ureter and urethra (function)                            [1 M]
3.    Diffusion and osmosis (definition)                             [1 M]
4.    Diabetes mellitus and diabetes insipidus (reason/cause)             [1 M]
5.    ATP and AIDS (expand the abbreviations)                     [1 M]
6.    Turgor pressure and wall pressure (explain)                     [1 M]
7.    Leaf and liver (form in which glucose is stored)                     [1 M]
8.    Bowman's capsule and Malpighian capsule (parts included)             [1 M]

Give the biological/technical term for the following:
1.    Removal of nitrogenous wastes from the body                     [1 M]
2.    Process of maintaining water and salt balance in the blood.            [1 M]
3.    Process by which white blood cells engulf bacteria                 [1 M]
4.    Solution in which the relative concentration of water molecules and the solute on either side of the cell membrane is the same                 [1 M]
5.    Permanently open structures seen on the bark of an old woody stem     [1 M]
6.    Squeezing of WBCs through the walls of the capillaries into the tissue     [1 M]
7.    Defect of the eye where the eye lens loses flexibility resulting in long sightedness in the elderly                                [1 M]

Explain the following terms:
1.    Reflex action                                        [1 M]
2.    Photophosphorylation                                    [1 M]
3.    Plasmolysis                                         [1 M]
4.    Turgor pressure                                    [1 M]
5.    Guttation                                            [1 M]
6.    Pulse                                            [1 M]
7.    Diapedesis                                         [1 M]
8.    Synapse                                             [1 M]

Give scientific reasons for the following statements:
1.    Injury to the medulla oblongata leads to death.                     [1 M]
2.    Blood flows in the arteries in spurts and is under pressure.             [1 M]
3.    There is frequent urination in winter than in summer.                [1 M]
4.    Balsam plants wilt during mid-day even if the soil is well watered.         [1 M]
5.    Wooden frames of doors get jammed during the monsoon season.         [1 M]
6.    Throat infection can lead to ear infection.                     [1 M]
7.    The wall of the ventricle is thicker than that of the auricle.             [1 M]
8.    A person walks unsteadily when drunk.                         [1 M]
9.    The pituitary gland is known as the ‘master gland’.                 [1 M]

Answer briefly:

  1. What is the difference between chromatin fibre and chromosome?        [1 M]
  2. When are the sounds "LUBB" and "DUP" produced respectively during heart beat?                         [1 M]
  3. Name the part of the human brain which is associated with the following:     [1 M]
    (a) Seat of memory     (b) Coordinates muscular activity
  4. If you sprinkle some common salt on grass growing on a lawn, it is killed at that spot. Why?            [1 M]
  5. Mention any two adaptations found in plants to favour the process of photosynthesis.                      [1 M]
  6. Why does one feel blinded for a short while on coming out of a dark room? [1 M]
  7. Why is iodine as a nutrient, important to our body?                [1 M]


Match the items in Column ‘A’ with those which are most appropriate in Column ‘B’. Rewrite the matching pairs.

1.                                                                                                                                             [5 M]



2.                                                                                                                                             [5 M]


3.                                                                                                                                               [5 M]


4.                                                                                                                                            [5 M]



5.                                                                                                                                            [5 M]

 

Diagram-based questions:
1. Diagram depicting a defect of the human eye. You may be asked to identify the defect, list its causes and state the corrective measures.                                                                                                            [5 M]

Example:
Given below is a diagram depicting a defect of the human eye, study the same and then answer the questions that follow:

  1. Name the defect shown in the diagram.
  2. What are the two possible reasons for this defect?
  3. Name the type of lens used to correct this defect.
  4. With the help of a diagram, show how the defect shown above is rectified using a suitable lens.


2. Diagrammatic representation of a part of the cross section of the root in the root hair zone. You may be asked to label the parts, list and define the processes taking place in this zone.                         [5 M]
Example:
The figure given below is a diagrammatic representation of a part of the cross section of the root in the root hair zone. Study the same and then answer the questions that follow:

  1. Name the parts indicated by the guidelines 1 to 4.
  2. Which is the process that enables the passage of water from the soil into the root hair?
  3. Name the pressure that is responsible for the movement of water in the direction indicated by the arrows. Define it.
  4. Due to an excess of this pressure, drops of water are sometimes found along the leaf margins of some plants in the early morning. What is the phenomenon called?
  5. Draw a well-labelled diagram of the root hair cell as it would appear if an excess of fertiliser is added to the soil close to it.

 
3. Outline of the human body showing the important glands. You may be asked to identify the glands, list the hormones secreted by these glands and the disorders caused by the deficiency of these hormones.             [5 M]
Example:
The diagram given below represents an endocrine gland in the human body. Study the diagram and answer the following questions:

  1. Identify the endocrine gland. Where is it located?
  2. Why is the above gland referred to as the ‘master gland’?
  3. Name the hormone whose deficiency causes diabetes insipidus. How does this disorder differ from diabetes mellitus?
  4. Explain the term ‘hormone’.
    What is the role of tropic hormones in the human body?
  5. Which lobe of the above gland secretes
  1. Oxytocin
  2. ACTH
  3. Growth hormone


4.  Diagram of Ganong’s photometer. You may be asked to identify the apparatus, its working, use and limitations.                                                                                                              [5 M]
Example:
The diagram given below demonstrates a particular process in plants. Study the same and answer the questions that follow:

  1. Name the apparatus.
  2. Which phenomenon is demonstrated by this apparatus? Explain the phenomenon.
  3. State two limitations of using this apparatus.
  4. What is the importance of the air bubble in the experiment?
  5. Name the structures in a plant through which the above process takes place.


5. Diagrams showing the experiments on photosynthesis in green plants. You may be asked to identify and define the process, chemical equation for photosynthesis and the effect of alteration in the factors affecting photosynthesis.                                                                                                                                             [5 M]
Example:
A potted plant with variegated leaves was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for 24 hours and then placed in bright sunlight for a few hours. Observe the diagram and answer the questions

  1. What aspect of photosynthesis is being tested in the above diagram?
  2. Represent the process of photosynthesis in the form of a balanced equation.
  3. Why was the plant kept in the dark before beginning the experiment?
  4. What will be the result of the starch test performed on leaf ‘A’ shown in the diagram? Given an example of a plant with variegated leaves.
  5. Draw a neat and labelled diagram of a chloroplast.


6. Diagrams showing the experiments on transpiration in plants. You may be asked to identify and define the process, its significance, technical aspects of the experiment and adaptations in plants to minimise loss of water through transpiration.                                                                                                              [5 M]
Example:
The diagram below represents a process in plants. The setup was placed in bright sunlight. Answer the following questions:

  1. Name the physiological process depicted in the diagram.
    Why was oil added to the water?
  2. When placed in bright sunlight for four hours, what do you observe with regard to the initial and final weight of the plant?
    Give a suitable reason for your answer.
  3. What happens to the level of water when this setup is placed in
    1.    Humid conditions
    2.    Windy conditions
  4. Mention any three adaptations found in plants to overcome the process mentioned in (i).
  5. Explain the term ‘Guttation’.



7. Diagram showing the cross section of blood vessels. You may be asked to identify the blood vessels, their functions, type of blood that flows in each of these vessels and the structural differences between the blood vessels.     [5 M]
Example:
The diagrams given below are cross sections of blood vessels:

  1. Identify the blood vessels A, B and C.
  2. Name the parts labelled 1 to 3.
  3. Name the type of blood that flows through A.
  4. Mention one structural difference between A and B.
  5. In which of the above vessels does the exchange of gases actually take place?     


8. Diagrammatic/schematic representation of the human heart. You may be asked to label the parts, list details about their structure and functions and the process of blood circulation.                                              [5 M]
Example:
The diagram below represents the human heart in one phase of its function. Study the diagram carefully and answer the questions that follow:

  1. Name the phase.
  2. Which part of the heart is contracting in this phase? Give a reason to support your answer.
  3. Name the parts labelled 1 to 4.
  4. What type of blood flows through ‘2’?
  5. State the function of the part numbered ‘5’.
  6. Name the membrane that covers the heart.


9. Diagram showing the section of the spinal cord. You may be asked to label the parts and list their functions. There might be a question based on synapse.                                                                                          [5M]
Example:
The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the questions:

  1. Name the phenomenon that is depicted in the diagram. Define the phenomenon.
  2. Give the technical term for the point of contact between two nerve cells.
  3. Name the parts numbered 1, 2 and 3.
  4. How does the arrangement of neurons in the spinal cord differ from that of the brain?
  5. Mention two ways by which the spinal cord is protected in our body.


10. Diagram representing a stage during mitotic/meiotic cell division. You may be asked to identify the stage, the chromosome number at the given stage and details about the stages which follow the given stage.                 [5 M]
Example:
Study the diagram given below which represents a stage during mitotic cell division and answer the questions that follow:

  1. Identify the stage giving suitable reasons.
  2. Name the parts numbered 1 and 2.
  3. What is the technical term for the division of the nucleus?
  4. Mention the stage that comes before the stage shown in the diagram. Draw a neat and labelled diagram of the stage mentioned.
  5. Which is the cell division that results in half the number of chromosomes in daughter cells?

Further Reduced Syllabus for 2021


Name the following:

  1. Exchange of chromatid parts between the maternal and paternal chromatids of a pair of homologous chromosomes during meiosis
    Solution: Crossing over

  2. Process of uptake of mineral ions against the concentration gradient using energy from the cell          
    Solution: Active transport

  3. Process of conversion of ADP to ATP during photosynthesis                                                             
    Solution: Photophosphorylation

  4. Phase of the cardiac cycle in which the auricles contract                                                                  
    Solution: Auricular systole

  5. Structural and functional unit of the kidney                                                                                   
    Solution: Nephron

  6. Fluid which provides protection and nourishment to the cells of the brain                                         
    Solution: Cerebrospinal fluid

  7. The layer of the eyeball that provides nourishment to the eye.                                                       
    Solution: Choroid


Choose the correct answer from each of the four options given below:

1. The mineral ion needed for the formation of a blood clot is    

A. Potassium
B. Sodium
C. Calcium
D. Iron
Solution: C. Calcium
Calcium ions are involved in the activation of the various clotting factors. Calcium is also required for the activation of thrombin from prothrombin. It works in association with vitamin K and fibrin strands to form the clot.


2. A plant cell may burst when                                
A. Turgor pressure equalises wall pressure
B. Turgor pressure exceeds wall pressure
C. Wall pressure exceeds turgor pressure
D. None of the above
Solution: C. Wall pressure exceeds turgor pressure
The cell wall is unable to bear the turgor pressure after a certain time; it ruptures and the cell contents burst out.

3. Chromosomes get aligned at the centre of the cell during            
A. Metaphase
B. Anaphase
C. Prophase
D. Telophase
Solution: A. Metaphase
During metaphase, the chromosomes align in the centre of the cell at the equatorial plate and the spindle fibres attach to the centromeres of the chromosomes.

4. Cretinism and myxoedema are due to                       
A. Hypersecretion of thyroxine
B. Hypersecretion of growth hormone
C. Hyposecretion of thyroxine
D. Hyposecretion of growth hormone
Solution: C. Hyposecretion of thyroxine
Less secretion of thyroxine causes cretinism in children and myxoedema in adults.

5. After mitotic cell division, a female human cell will have           
A. 44 + XX chromosomes
B. 44 + XY chromosomes
C. 22 + X chromosomes
D. 22 + Y chromosomes
Solution: A. 44 + XX chromosomes
Mitosis is an equatorial division that produces daughter cells with the same number of chromosomes as that of the parent cell. So, mitosis in a human female cell would produce progeny cells with 44 + XX chromosomes.

6. A pulse wave is mainly caused by the                        
A. Systole of atria
B. Diastole of atria
C. Systole of the left ventricle
D. Systole of the right ventricle
Solution: C. Systole of the left ventricle
Systole of the left ventricle results in the formation of a pulse wave.

7. A plant is kept in a dark cupboard for 48 hours before conducting any experiment on photosynthesis to                
A. Remove starch from the plant
B. Ensure that starch is not translocated from the leaves
C. Remove chlorophyll from the leaf of the plant
D. Remove starch from the experimental leaf
Solution: C. Remove chlorophyll from the leaf of the plant
The plants are kept in the dark in order to ensure that the leaves are free of starch. During the 48 hours when kept in the dark, all the starch stored in the leaves is used up and the plant cannot perform photosynthesis because of the absence of light.

8. A reflex arc in man is best described as the movement of stimuli from    
A. Receptor cell, sensory neuron, relaying neuron, effector muscles
B. Receptor cell, efferent nerve, relaying neuron, muscles of the body
C. Receptor cell, spinal cord, motor neuron, relaying neuron
D. Receptor cell, synapse, motor neuron, relaying neuron
Solution: A. Receptor cell, sensory neuron, relaying neuron, effector muscles
The impulse in a reflex arc travels from the receptor, to the sensory neuron, to the relay neuron, to the motor neuron and finally reaches the effector muscles which show the response.

In each set of terms given below, there is an odd one and cannot be grouped in the same category to which the others belong. Identify the odd term in each set and name the category to which the remaining belong.

  1. Cell wall, large vacuole, plastid, centrosome                                                                      
    Solution:
    Odd term: Centrosome
    Category: Others are parts of a plant cell.

  2. Thymine, cytosine, adenine, pepsin                                                                                  
    Solution:
    Odd term: Pepsin
    Category: Others are nitrogenous bases.

  3. Cortisone, somatotropin, adrenocorticotropic hormone, vasopressin                                      
    Solution:
    Odd term: Cortisone
    Category: Other hormones are secreted by the pituitary gland.

  4. Urethra, uterus, urinary bladder, ureter                                                                              
    Solution:
    Odd term: Uterus
    Category: Others are parts of the human excretory system.

  5. Transpiration, photosynthesis, phagocytosis, guttation                                                         
    Solution:
    Odd term: Phagocytosis
    Category: Others are processes associated with plants.

  6. Sneezing, coughing, blinking, typing                                                                                  
    Solution:
    Odd term: Typing
    Category: Others are involuntary actions.

  7. Malleus, pinna, incus, stapes                                                                                             
    Solution:
    Odd term: Pinna
    Category: Others are bones of the middle ear.

  8. Insulin, adrenaline, pepsin, thyroxine                                                                                 
    Solution:
    Odd term: Pepsin
    Category: Others are endocrinal hormones.


State the exact location of the following structures:

  1. Centromere                                                                                                                 
    Solution: Centromere: It is located at the joining place of two chromatids of a chromosome.

  2. Chordae tendineae                                                                                                       
    Solution: Chordae tendineae: Apices of the valves of the heart are attached to the wall of the ventricles by chordae tendineae.

  3. Thylakoids                                                                                                                   
    Solution: Thylakoids: They are present in the stroma of chloroplasts.

  4. Pulmonary semilunar valve                                                                                            
    Solution: Pulmonary semilunar valve: It is located at the opening of the right ventricle into the pulmonary artery.

  5. Corpus callosum                                                                                                           
    Solution: Corpus callosum: It is located underneath the cerebrum at the midline of the brain.

  6. Guard cells                                                                                                                   
    Solution: Guard cells: They are present in the epidermis of the leaf.

  7. Thyroid gland                                                                                                               
    Solution: Thyroid gland: It is present below the larynx in the neck region.

  8. Organ of Corti                                                                                                              
    Solution: Organ of Corti: It is located in the middle cochlear canal in the inner ear.


State the main function of the following:

  1. Cerebrospinal fluid                                                                                                      
    Solution: Cerebrospinal fluid: It protects the brain from mechanical shocks.

  2. Lenticels                                                                                                                    
    Solution: Lenticels: They help in the exchange of gases between the outer atmosphere and the internal tissue of the stem.

  3. Ureter                                                                                                                       
    Solution: Ureter: It carries urine from the kidneys to the urinary bladder.

  4. Chordae tendineae                                                                                                     
    Solution: Chordae tendineae: They prevent the valves of heart from movement by holding the flaps tightly against the strong flow of blood and ensure blood flow in one direction.

  5. Vitreous humour                                                                                                        
    Solution: Vitreous humour: It helps the eye hold its shape, with light being transmitted through it to the retina.

  6. Medulla oblongata                                                                                                     
    Solution: Medulla oblongata: It is responsible for reflexes like vomiting, coughing, sneezing and swallowing.

  7. Beta cells of the pancreas                                                                                           
    Solution: Beta cells of the pancreas: They are responsible for the storage and release of insulin hormone in response to the change in blood glucose concentration.


Differentiate between the following pairs on the basis of what is mentioned within brackets:
1.    Rod cells and cone cells (pigment)                            
Solution:


2.    Ureter and urethra (function)                           
Solution:


3.    Diffusion and osmosis (definition)                            
Solution:


4.    Diabetes mellitus and diabetes insipidus (reason/cause)             
Solution:


5.    ATP and AIDS (expand the abbreviations)                    
Solution:


6.    Turgor pressure and wall pressure (explain)                    
Solution:


7.    Leaf and liver (form in which glucose is stored)                    
Solution:


8.    Bowman's capsule and Malpighian capsule (parts included)            
Solution:


Give the biological/technical term for the following:

  1. Removal of nitrogenous wastes from the body                    
    Solution: Excretion

  2. Process of maintaining water and salt balance in the blood.           
    Solution: Osmoregulation

  3. Process by which white blood cells engulf bacteria               
    Solution: Phagocytosis

  4. Solution in which the relative concentration of water molecules and the solute on either side of the cell membrane is the same                
    Solution: Isotonic solution

  5. Permanently open structures seen on the bark of an old woody stem
    Solution: Lenticels

  6. Squeezing of WBCs through the walls of the capillaries into the tissue    
    Solution: Diapedesis

  7. Defect of the eye where the eye lens loses flexibility resulting in long sightedness in the elderly         
    Solution: Presbyopia


Explain the following terms:

  1. Reflex action                                       
    Solution: Reflex action: Reflex action is a sudden, involuntary reaction of the body in response to a stimulus.

  2. Photophosphorylation                                   
    Solution: Photophosphorylation: The process of the formation of ATP from ADP and phosphate molecule using light energy during photosynthesis is called photophosphorylation.

  3. Plasmolysis                                        
    Solution: Plasmolysis: Plasmolysis is the shrinkage of protoplasm from the cell wall when a cell is placed in a hypertonic solution.

  4. Turgor pressure                                  
    Solution: Turgor pressure: Turgor pressure is the main pressure of the cell contents against the cell wall in turgid plant cells.

  5. Guttation                                           
    Solution: Guttation: Natality is the total number of live births per thousand individuals of a population per year.

  6. Pulse                                           
    Solution: Pulse: Pulse is the rhythmic contraction and expansion of the arteries with each beat of the heart.

  7. Diapedesis                                        
    Solution: Diapedesis: The process of squeezing out of WBCs through the walls of the capillaries into the tissue fluid is called diapedesis.

  8. Synapse                                            
    Solution: Synapse: Synapse is the junction between the ends of two neurons through which nerve impulses pass from one neuron to another.


Give scientific reasons for the following statements:

  1. Injury to the medulla oblongata leads to death.
    Solution: The medulla oblongata controls involuntary functions such as heartbeat, rate of respiration, secretion of saliva, gut peristalsis etc. Injury to the medulla oblongata may stop important activities (such as heartbeat, respiration etc.) and may result in death.
                       
  2. Blood flows in the arteries in spurts and is under pressure.
    Solution: As the ventricles of the heart contract, they push blood into the small lumen of the arteries with a great force, thus making the blood in the arteries flow in spurts and under pressure.

  3. There is frequent urination in winter than in summer.
    Solution: In winter, there is no sweating and most of the excess water is eliminated from body in the form of urine. Hence, there is frequent urination in winter than in summer.

  4. Balsam plants wilt during mid-day even if the soil is well watered.
    Solution: On a hot day, herbaceous plants wilt even in well-watered soil because their rate of transpiration exceeds the rate of water absorption by the roots. Due to less water in the cells, they become flaccid and the leaves become soft and wilt. Since Balsam is a herbaceous plant, it wilts during mid-day even if the soil is well-watered.

  5. Wooden frames of doors get jammed during the monsoon season.
    Solution: Wooden doors swell up and get stuck during the rainy season. This phenomenon is due to imbibition. Imbibition is the displacement of one fluid by another immiscible fluid. This process is controlled and affected by a variety of factors.

  6. Throat infection can lead to ear infection.
    Solution: The Eustachian tube is a part of the middle ear. It also connects the cavity of the middle ear to the throat. Hence, throat infection can lead to ear infection.

  7. The wall of the ventricle is thicker than that of the auricle.
    Solution: Since ventricles have to pump blood into various organs and the pressure of the blood flowing in them is more than that of blood flowing in the auricles, the ventricles have thicker muscular walls than the auricles.

  8. A person walks unsteadily when drunk.
    Solution: A drunk person walks clumsily because the cerebellum is unable to coordinate muscular movements properly due to the effect of alcohol.

  9. The pituitary gland is known as the ‘master gland’.
    Solution: The pituitary gland is called the master gland because it secretes hormones that control the functioning of other glands.


Answer briefly:

  1. What is the difference between chromatin fibre and chromosome?
    Solution: Chromatin fibre is unfolded, uncondensed, extended DNA. It is only visible when cell under goes division whereas chromosomes are condensed DNA and they are visible when the cell is divided.

  2. When are the sounds "LUBB" and "DUP" produced respectively during heart beat?
    Solution: The first sound LUBB is produced when the atrio-ventricular valves i.e. tricuspid and bicuspid valves close at the start of ventricular systole. The second sound DUP is produced at the beginning of ventricular diastole, when the pulmonary and aortic semilunar valves close.

  3. Name the part of the human brain which is associated with the following:
    (a) Seat of memory     (b) Coordinates muscular activity
    Solution: (a) Seat of memory: Cerebrum    (b) Coordinates muscular activity: Cerebellum

  4. If you sprinkle some common salt on grass growing on a lawn, it is killed at that spot. Why?
    Solution: Common salt when sprinkled on the grass causes the Plasmolysis of grass cell ultimately leading them to death. Hence, if we sprinkle some common salt on grass growing on a lawn, it is killed at the spot.

  5. Mention any two adaptations found in plants to favour the process of photosynthesis.
    Solution: Adaptations found in plants to favour the process of photosynthesis: (Any two)
    •    A large number of chloroplasts in the upper layer of leaves to trap more sunlight.
    •    Orientation of leaves such that maximum sunlight falls on the leaf.
    •    Numerous stomata present on the leaves for rapid exchange of gases.

  6. Why does one feel blinded for a short while on coming out of a dark room?
    Solution: One feels blinded for a short while on coming out of a dark room. This is called light adaptation of the eye. It is due to the constriction of the pupil to prevent the entry of light into the eye and the pigment rhodopsin is bleached to reduce the sensitivity of the rods.

  7. Why is iodine as a nutrient, important to our body?
    Solution: Iodine is an active ingredient in the production of the thyroxine hormone secreted by the thyroid gland. Thyroxine hormone is a very essential hormone for our body. In case of its abnormal secretions a person may suffer certain sever disorders. Therefore, it is an important nutrient for our body.


Match the items in Column ‘A’ with those which are most appropriate in Column ‘B’. Rewrite the matching pairs.

1.                                                                                                                                            

Solution:


2.                                                                                                                                            

Solution:


3.                                                                                                                                              

Solution:


4.                                                                                                                                           


Solution:


5.                                                                                                                                           

Solution: 


Diagram-based questions:
1. Diagram depicting a defect of the human eye. You may be asked to identify the defect, list its causes and state the corrective measures.                                                                                                           

Example:
Given below is a diagram depicting a defect of the human eye, study the same and then answer the questions that follow:

  1. Name the defect shown in the diagram.
  2. What are the two possible reasons for this defect?
  3. Name the type of lens used to correct this defect.
  4. With the help of a diagram, show how the defect shown above is rectified using a suitable lens.

Solution:

  1. Myopia
  2. Two possible reasons are
    •    Eyeball is lengthened from front to back.
    •    Lens is too curved.
  3. Concave lens


2.    Diagrammatic representation of a part of the cross section of the root in the root hair zone. You may be asked to label the parts, list and define the processes taking place in this zone.                        
Example:
The figure given below is a diagrammatic representation of a part of the cross section of the root in the root hair zone. Study the same and then answer the questions that follow:

  1. Name the parts indicated by the guidelines 1 to 4.
  2. Which is the process that enables the passage of water from the soil into the root hair?
  3. Name the pressure that is responsible for the movement of water in the direction indicated by the arrows. Define it.
  4. Due to an excess of this pressure, drops of water are sometimes found along the leaf margins of some plants in the early morning. What is the phenomenon called?
  5. Draw a well-labelled diagram of the root hair cell as it would appear if an excess of fertiliser is added to the soil close to it.

Solution:

  1. 1: Root hair, 2: Soil particle, 3: Xylem vessel, 4: Vacuoles
  2. Osmosis is the process which enables the passage of water from the soil into the root hair.
  3. Root pressure is responsible for the movement of water. It is the pressure developed in the roots because of the inflow of water.
  4. Guttation

 
3. Outline of the human body showing the important glands. You may be asked to identify the glands, list the hormones secreted by these glands and the disorders caused by the deficiency of these hormones.            
Example:
The diagram given below represents an endocrine gland in the human body. Study the diagram and answer the following questions:

  1. Identify the endocrine gland. Where is it located?
  2. Why is the above gland referred to as the ‘master gland’?
  3. Name the hormone whose deficiency causes diabetes insipidus. How does this disorder differ from diabetes mellitus?
  4. Explain the term ‘hormone’.
    What is the role of tropic hormones in the human body?
  5. Which lobe of the above gland secretes
  1. Oxytocin
  2. ACTH
  3. Growth hormone

Solution:

  1. Pituitary gland. It is located at the base of the mid-brain below the hypothalamus.
  2. The pituitary gland is referred to as the master gland because it controls the functioning of the other endocrine glands.
  3. Diabetes insipidus: Deficiency of antidiuretic hormone (ADH)
  4. Hormones are secretions from specific cells or glands in the body and are carried to all parts of the body through blood, but their effect is produced in one or more specific parts only.  Tropic hormones in the human body stimulate the other endocrine glands to release their hormones.  
  5.    
    1.    Oxytocin: Posterior pituitary lobe
    2.    ACTH: Anterior pituitary lobe
    3.    Growth hormone: Anterior pituitary lobe


4.  Diagram of Ganong’s photometer. You may be asked to identify the apparatus, its working, use and limitations.    Example:
The diagram given below demonstrates a particular process in plants. Study the same and answer the questions that follow:

  1. Name the apparatus.
  2. Which phenomenon is demonstrated by this apparatus? Explain the phenomenon.
  3. State two limitations of using this apparatus.
  4. What is the importance of the air bubble in the experiment?
  5. Name the structures in a plant through which the above process takes place.

Solution:

  1. The apparatus is called Ganong’s potometer.
  2. The phenomenon is called transpiration. The evaporative loss of water in the form of water vapour from the aerial parts of plants is known as transpiration.
  3. Two limitations are
    •    It is not easy to introduce the air bubble into the capillary.
    •    The twig may not remain fully alive for a long time.
  4. The air bubble helps measure the rate of transpiration.
  5. Transpiration occurs through the roots.


5. Diagrams showing the experiments on photosynthesis in green plants. You may be asked to identify and define the process, chemical equation for photosynthesis and the effect of alteration in the factors affecting photosynthesis.
Example:
A potted plant with variegated leaves was taken in order to prove a factor necessary for photosynthesis. The potted plant was kept in the dark for 24 hours and then placed in bright sunlight for a few hours. Observe the diagram and answer the questions

  1. What aspect of photosynthesis is being tested in the above diagram?
  2. Represent the process of photosynthesis in the form of a balanced equation.
  3. Why was the plant kept in the dark before beginning the experiment?
  4. What will be the result of the starch test performed on leaf ‘A’ shown in the diagram? Given an example of a plant with variegated leaves.
  5. Draw a neat and labelled diagram of a chloroplast.

Solution:

  1. Presence of chlorophyll is tested in this experiment.
  2.    
  3. The plant was kept in the dark to destarch it.
  4. The green part turns blue-black and the pale yellow part turns brown.
  5. Structure of chloroplast


6. Diagrams showing the experiments on transpiration in plants. You may be asked to identify and define the process, its significance, technical aspects of the experiment and adaptations in plants to minimise loss of water through transpiration.
Example:
The diagram below represents a process in plants. The setup was placed in bright sunlight. Answer the following questions:

  1. Name the physiological process depicted in the diagram.
    Why was oil added to the water?
  2. When placed in bright sunlight for four hours, what do you observe with regard to the initial and final weight of the plant?
    Give a suitable reason for your answer.
  3. What happens to the level of water when this setup is placed in
    1.    Humid conditions
    2.    Windy conditions
  4. Mention any three adaptations found in plants to overcome the process mentioned in (i).
  5. Explain the term ‘Guttation’.

Solution:

  1. Transpiration
    Oil was added to water to prevent the loss of water through evaporation.
  2. The initial and final weight of the plant will be constant. However, the water level of the flask will drop due to the loss of water through transpiration. So, the final weight of the setup will be less than its initial weight.
  3.    
    1. The water level will not drop that much because the rate of transpiration will be less in humid conditions.
    2. The water level drops to a greater extent because the rate of transpiration increases in windy conditions.
  4.    
    •    Thick cuticle
    •    Sunken stomata
    •    Modification of leaves into spines
  5. Loss of water in the form of droplets through hydathodes is called guttation.


7. Diagram showing the cross section of blood vessels. You may be asked to identify the blood vessels, their functions, type of blood that flows in each of these vessels and the structural differences between the blood vessels. 
Example:
The diagrams given below are cross sections of blood vessels:

  1. Identify the blood vessels A, B and C.
  2. Name the parts labelled 1 to 3.
  3. Name the type of blood that flows through A.
  4. Mention one structural difference between A and B.
  5. In which of the above vessels does the exchange of gases actually take place?     

Solution:


  1. A – Artery
    B – Vein
    C – Blood capillary
  2. 1 – External layer of connective tissue
    2 – Lumen
    3 – Middle layer of smooth muscles and elastic fibres
  3. Oxygenated blood flow through A
  4. Structural difference between A (artery) and B (vein):
  5. The exchange of gases takes place in blood capillaries.


8. Diagrammatic/schematic representation of the human heart. You may be asked to label the parts, list details about their structure and functions and the process of blood circulation.                                            
Example:
The diagram below represents the human heart in one phase of its function. Study the diagram carefully and answer the questions that follow:

  1. Name the phase.
  2. Which part of the heart is contracting in this phase? Give a reason to support your answer.
  3. Name the parts labelled 1 to 4.
  4. What type of blood flows through ‘2’?
  5. State the function of the part numbered ‘5’.
  6. Name the membrane that covers the heart.

Solution:

  1. Ventricular systole
  2. Ventricles are contracting in this phase. In the given diagram, the tricuspid and bicuspid valves are closed, while the semi-lunar valves are open.
  3. 1 – Pulmonary artery
    2 – Aorta
    3 – Bicuspid valve
    4 – Semilunar valve (aortic semilunar valve)
  4. Oxygenated blood flows through ‘2’, i.e. aorta.
  5. ‘5’ is pulmonary semilunar valve. It prevents the backflow of blood into the right ventricle at the time of ventricular diastole.
  6. Pericardium covers the heart.


9. Diagram showing the section of the spinal cord. You may be asked to label the parts and list their functions. There might be a question based on synapse.                                                                                         
Example:
The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the questions:

  1. Name the phenomenon that is depicted in the diagram. Define the phenomenon.
  2. Give the technical term for the point of contact between two nerve cells.
  3. Name the parts numbered 1, 2 and 3.
  4. How does the arrangement of neurons in the spinal cord differ from that of the brain?
  5. Mention two ways by which the spinal cord is protected in our body.

Solution:

  1. Reflex action. An involuntary response on the stimulation of the peripheral nervous system which requires the involvement of a part of the central nervous system is called reflex action.    
  2. Synapse    
  3. 1 - Sensory neuron, 2 - Motor neuron, 3 - Grey matter
  4. The exterior surface of the brain is composed of millions of neuron bodies, and the interior surface is made up of myelinated axons.
    In the spinal cord, it is the reverse, i.e. the exterior surface of the spinal cord is composed of myelinated axons and the interior surface is composed of neuron bodies.
  5. Protection of the spinal cord in our body:
    •    The three meninges protect the spinal cord from damage.
    •    The cerebrospinal fluid protects the brain from damage.


10. Diagram representing a stage during mitotic/meiotic cell division. You may be asked to identify the stage, the chromosome number at the given stage and details about the stages which follow the given stage.                
Example:
Study the diagram given below which represents a stage during mitotic cell division and answer the questions that follow:

  1. Identify the stage giving suitable reasons.
  2. Name the parts numbered 1 and 2.
  3. What is the technical term for the division of the nucleus?
  4. Mention the stage that comes before the stage shown in the diagram. Draw a neat and labelled diagram of the stage mentioned.
  5. Which is the cell division that results in half the number of chromosomes in daughter cells?
    Solution:
    1. Telophase
    2. 1 – Daughter chromosome, 2 – Nuclear membrane
    3. Karyokinesis is the technical term for the division of a nucleus.
    4. Anaphase
    5. Meiosis

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