Madhyamik Class 10 Life Science Solved Paper 2014

Madhyamik Class 10 Life Science Solved Paper 2014

Life Science

Time – Three Hours and Fifteen Minutes

(First fifteen minutes for reading the question paper only)

Full Marks – 90

(For Regular and Sightless Regular Candidates)

Full Marks – 100

(For External and sightless External Candidates)

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[Group A to C are common for both Regular and External Candidates. Group D is meant only for External Candidates]

Sightless Candidates will answer the alternative question as per the directive in Group C.

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Figures in the margin indicate full marks for each question Special credits will be given for answers which are brief and to the point.

Marks will be deducted for spelling mistakes, untidiness and bad handwriting.

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Group – A

[Candidates will have to answer question Nos. 1,2,3 and 4]

1. Complete the sentences choosing the correct answer (any five) : [1×5=5]

Question 1.1

Name of an efferent nerve is

1. Auditory
2. Olfactory
3. Optic
4. Oculomotor

Answer

Oculomotor.

Explanation:

The oculomotor nerve, also known as cranial nerve III, is an efferent nerve responsible for controlling the movements of certain eye muscles, including the superior rectus, inferior rectus, medial rectus, and inferior oblique muscles.

Question 1.2

Hormone that controls the tropic movement in the plant body is

1. Auxin
2. Thyroxine
3. Gibberellin
4. Cytokinin

Answer

Auxin

Explanation:

The hormone that controls tropic movements in the plant body is Auxin. Auxin is a class of plant hormones that regulate various growth and developmental processes in plants, including tropisms.

Question 1.3

The cell in a plant body which divides by meiosis is the

1. Spore mother cell
2. Cell of apical bud
3. Cell of a mature leaf
4. Cell of the root

Answer

Spore mother cell

Explanation:

The cell in a plant body that divides by meiosis is the spore mother cell. Meiosis is a type of cell division that produces haploid cells called spores.

Question 1.4

If hybridization is made between a hybrid tall pea plant and a pure tall pea plant, the percentage of tall off-springs in F1 generation might be

1. 25%
2. 50%
3. 75%
4. 100%

Answer

100%.

Explanation:

If hybridization is made between a hybrid tall pea plant and a pure tall pea plant, the percentage of tall offspring in the F1 generation be 100%.

Question 1.5

The earliest known Ancestor of horse is

1. Equus
2. Mesohippus
3. Eohippus
4. Merichippus

Answer

Eohippus

Explanation:

The earliest known ancestor of the horse is Eohippus, also known as Hyracotherium. Eohippus lived approximately 55 to 48 million years ago during the Eocene epoch.

Question 1.6

The adaptive feature which is not found in ‘Sundari’ plant is

1. Pneumatophore
2. Fruit with seed
3. Leaves with thick cuticles
4. Viviparous germination

Answer

Viviparous germination

Explanation:

The adaptive feature that is not found in the ‘Sundari’ plant is Viviparous germination. Viviparous germination refers to the germination of seeds while still attached to the parent plant, and the seedling grows out of the fruit.

Question 1.7

The disease which could be transmitted during blood transfusion is

1. Hepatitis
2. Cholera
3. Typhoid
4. Polio

Answer

Hepatitis

Explanation:

The disease that could be transmitted during blood transfusion is Hepatitis. Hepatitis is a viral infection that affects the liver.

Question 2.1 – 2.13

Answer in one sentence (any ten) : [1×10=10]

1. Name one plant alkaloid that lowers high blood pressure.
2. Name one inorganic substance that is reabsorbed from the renal tubule.
3. How ganglion is formed?
4. Name the hormone secreted from the corpus luteum of the ovary in adult females.
5. State one function of kinin.
6. A eukaryotic chromosome is composed of DNA, RNA and ____. (Fill in the blank).
7. The name of a multicellular animal that reproduces asexually by budding is_____. (Fill up the blank)
8. Mention one dominant trait of Drosophila.
9. Mention an organ present in another animal analogous to a butterfly’s wings.
10. ‘Inheritance of acquired characters’ who proposed it?
11. What is the advantage of a Spindle-shaped body in Rohu fish for adaptation?
12. Which food purchased from a sweet shop contains ‘Lacto- bacillus’?
13. What is ‘Bacteriophage’?

Answer

1. Rauwolfia serpentina
2. Sodium
3. Neural crest cells aggregate and form ganglia
4. Progesterone
5. Causes vasodilation
6. Histones
7. Hydra
8. Red eye color
9. Flippers in dolphins
10. Jean-Baptiste Lamarck
11. Increased surface area for respiration
12. Curd
13. Virus that infects bacteria

3. Attempt any six questions : [2×6=12]

Question 3.1

What is glomerulus? Where it is located ?

Answer

Glomerulus: A glomerulus is a network of capillaries located in the Bowman’s capsule of the kidney.

Function: It is responsible for filtering blood and producing urine.

Question 3.2

Mention two differences between the cerebellum and cerebrum.

Answer

	Cerebellum	Cerebrum
Location	Located at the back of the brain, below the cerebrum	Occupies the largest portion of the brain and is situated above the brainstem
Function	Primarily responsible for coordinating voluntary muscle movements, balance, and posture	Involved in higher cognitive functions such as memory, perception, reasoning, and language processing

Question 3.3

Mention two practical applications of synthetic plant hormones in agriculture.

Answer

The two practical applications of synthetic plant hormones in agriculture in very short points:

• Promote plant growth: Synthetic plant hormones can be used to promote plant growth by stimulating cell division and elongation. This can lead to larger and healthier plants.
• Prevent fruit and vegetable spoilage: Synthetic plant hormones can be used to prevent fruit and vegetable spoilage by delaying ripening and senescence. This can help to extend the shelf life of fruits and vegetables.

Question 3.4

Write two differences between plant and animal cell mitosis.

Answer

The two differences between plant and animal cell mitosis are

	Plant Cell	Animal Cell
Cytokinesis	Plant cells form a cell plate during cytokinesis to divide the cell into two daughter cells.	Animal cells form a cleavage furrow during cytokinesis to separate the cell into two daughter cells.
Centrioles	Plant cells lack centrioles, which are involved in organizing the spindle fibres during cell division.	Animal cells have centrioles that aid in the organization of spindle fibres during cell division.

Question 3.5

Name one vertebrate animal with external fertilization and another vertebrate animal with internal fertilization.

Answer

1. One vertebrate animal with external fertilization is the salmon, which releases eggs and sperm into the water for fertilization to occur externally.
2. One vertebrate animal with internal fertilization is the human, where fertilization occurs within the female reproductive system after sexual intercourse.

Question 3.6

Write the definition of a fossil.

Answer

A fossil is the preserved remains or traces of a once-living organism from a past geological age. For example, a dinosaur bone or a preserved insect trapped in amber can be considered fossil.

Question 3.7

Mention one adaptive feature each for the root and stem of the cactus.

Answer

One adaptive feature of the root of the cactus is:

• The extensive shallow root system for efficient water absorption.

One adaptive feature of the stem of the cactus is:

• Succulent stem for water storage and minimizing water loss.

Question 3.8

Mention one viral and one protozoan disease borne by a female mosquito.

Answer

One viral disease borne by a female mosquito is:

• Dengue fever, which is caused by the dengue virus transmitted by Aedes mosquitoes. The virus is passed to humans through the bite of an infected female mosquito.

One protozoan disease borne by a female mosquito is:

• Malaria, which is caused by the Plasmodium parasite transmitted by Anopheles mosquitoes. The parasites are injected into humans through the bite of an infected female mosquito.

4. Attempt any ten Questions : [3×10=30]

Question 4.1

Mention one role of each of ‘Liver’,’ ‘Lung’ and ‘Skin’ as ‘accessory excretory organ’.

Answer

The roles of the liver, lungs, and skin as accessory excretory organs:

• Liver: The liver helps to remove toxins from the blood, including ammonia, urea, and bilirubin. It also helps to regulate the levels of electrolytes and other substances in the blood.
• Lungs: The lungs remove carbon dioxide from the blood and release oxygen into the blood. They also help to remove water vapour from the blood.
• Skin: The skin helps to remove excess water, salts, and heat from the body. It also helps to remove toxins through sweat.

Question 4.2

Mention three structural features of Axon in Neurone.

Answer

Three structural features of the axon in a neuron are:

1. Axon Hillock: The region where the axon originates from the cell body.
2. Myelin Sheath: Protective covering that insulates certain axons, allowing for faster signal transmission.
3. Axon Terminals: Small branches at the end of the axon that release neurotransmitters to communicate with other neurons or target cells.

Question 4.3

Mention one function for each of the Tongue, Nose and Skin as sensory organs.

Answer

One function for each of the tongue, nose, and skin as sensory organs in very short:

• Tongue: Taste
• Nose: Smell
• Skin: Touch

Question 4.4

Mention one function for each of Thyroxine, Insulin and Progesterone.

Answer

One function for each of Thyroxine, Insulin and Progesterone in very short:

• Thyroxine: Regulates metabolism
• Insulin: Regulates blood sugar levels
• Progesterone: Prepares the uterus for pregnancy

Question 4.5

Write the full name of the following three synthetic plant hormones. NAA, IBA and IPA.

Answer

The full names of the three synthetic plant hormones NAA, IBA, and IPA:

• NAA: Naphthalene acetic acid
• IBA: Indole-3-butyric acid
• IPA: Indole-3-propionic acid

Question 4.6

Point out three differences between ‘Prokaryotic cell’ and ‘Eukaryotic cell’.

Answer

Feature	Prokaryotic Cell	Eukaryotic Cell
Size	0.2-2 micrometres	10-100 micrometres
Nucleus	No nucleus; DNA is located in a nucleoid	Nucleus; DNA is enclosed in a nuclear membrane
Organelles	Few or no membrane-bound organelles	Many membrane-bound organelles

Question 4.7

Mention three opposite events of Prophase and Telophase in Mitosis.

Answer

Prophase	Telophase
Chromosomes condense and become visible.	Chromosomes decondense and become chromatin again.
Spindle fibres form and the chromosomes line up at the metaphase plate.	Spindle fibres disappear and the chromosomes are pulled to opposite poles of the cell.
The nuclear envelope breaks down.	Nuclear envelope reforms around each set of chromosomes.

Question 4.8

Mention the contrasting expression of the following characters: Length of stem, Shape of the seed and Colour of cotyledon as selected by Mendel for his experiments on Pea Plant.

Answer

The contrasting expressions of the following characters: Length of the stem, Shape of the seed and Colour of cotyledon as selected by Mendel for his experiments on the Pea Plant:

• Length of stem: Mendel selected two contrasting forms of stem length, tall and dwarf. Tall plants were 60-120 cm tall, while dwarf plants were only 15-25 cm tall.
• The shape of the seed: Mendel selected two contrasting forms of seed shape, round and wrinkled. Round seeds were smooth and regular, while wrinkled seeds were bumpy and irregular.
• Colour of cotyledon: Mendel selected two contrasting forms of cotyledon colour, yellow and green. Yellow cotyledons were a bright yellow colour, while green cotyledons were a pale green colour.

Mendel conducted his experiments by crossing plants with different forms of the same character. For example, he crossed a tall plant with a dwarf plant to see what would happen. He found that the offspring were all tall, which showed that the tall trait was dominant over the dwarf trait.

Question 4.9

Write short notes on any two of the following :

1. Adventitious bud
2. Bulbil
3. Fragmentation

Answer

1. Adventitious bud: An adventitious bud is a bud that arises from a place other than the usual site of bud formation, such as the stem, leaf, or root. Adventitious buds are often used for asexual reproduction, as they can be used to form new plants. For example, many plants can be propagated by rooting cuttings, which are pieces of stem or leaf that have adventitious buds.
2. Bulbil: A bulbil is a small, bulb-like bud that is produced on an aerial stem. Bulbils are often used for asexual reproduction, as they can be separated from the parent plant and grown into new plants. For example, the onion produces bulbils at the top of its stem.
3. Fragmentation: Fragmentation is a form of asexual reproduction in which a plant breaks into pieces, and each piece grows into a new plant. Fragmentation is often seen in plants that have rhizomes, which are horizontal stems that grow underground. When a rhizome breaks, each piece can grow into a new plant.

Question 4.10

What are the causes of the ‘Struggle for Existence’ among organisms in nature according to Darwin?

Answer

According to Darwin, the struggle for existence is caused by a number of factors, including:

• Limited resources: There are limited resources available in nature, such as food, water, and space. This means that organisms must compete with each other for these resources.
• Predation: Organisms are constantly being preyed upon by other organisms. This means that they must constantly be on the lookout for predators and take steps to avoid being eaten.
• Disease: Organisms are also susceptible to disease. This can weaken or kill them, making it more difficult for them to survive and reproduce.
• Environmental factors: Organisms must also contend with environmental factors, such as climate change, natural disasters, and pollution. These factors can make it difficult for organisms to survive and reproduce.

Question 4.11

Write one adaptive feature of stem and two adaptive features of the leaf of a lotus suitable for survival in the aquatic environment.

Answer

Adaptive features of the stem and leaf of a lotus suitable for survival in the aquatic environment:

Stem:

• Rhizome: The lotus has a thick, underground rhizome that helps it to anchor itself in the mud.
• Air spaces: The lotus stem has air spaces that help it to float in the water.

Leaf:

• Thick, waxy coating: The lotus leaf has a thick, waxy coating that helps to prevent water from evaporating from the leaf.
• Pustules: The lotus leaf has small pores called pustules that allow gas exchange to occur.

Question 4.12

Write down the names of three diseases against which Vaccination is done after birth in human babies.

Answer

The three diseases against which vaccination is done after birth in human babies are:

• Diphtheria: Diphtheria is a serious bacterial infection that can cause a thick, grey coating to form in the throat and on the skin. It can also lead to heart problems, paralysis, and death.
• Hepatitis B: Hepatitis B is a liver infection that can cause inflammation, scarring, and cancer. It can be spread through contact with blood or body fluids.
• Rotavirus: Rotavirus is a virus that causes diarrhoea. It is the most common cause of severe diarrhoea in young children.

Question 4.13

Name the microbes causing the following diseases Cholera, Tuberculosis and Typhoid.

Answer

The microbes causing the following diseases are:

• Cholera: Cholera is caused by a bacterium called Vibrio cholerae.
• Tuberculosis: Tuberculosis is caused by a bacterium called Mycobacterium tuberculosis.
• Typhoid: Typhoid is caused by a bacterium called Salmonella typhi.

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Group – B

(Answer any five)

Question 5

Mention two importance of excretion in an animal body. Write three means of removal of excretory products in plants with proper examples. [2+3]

Answer

The two importance of excretion in an animal body:

1. To maintain homeostasis: Excretion helps to maintain homeostasis in the body by removing waste products that can build up and disrupt the body’s balance. For example, the kidneys remove excess water, salts, and other waste products from the blood.
2. To protect against toxins: Excretion helps to protect the body against toxins by removing them from the body before they can cause harm. For example, the liver removes toxins from the blood, and the lungs remove toxins from the air that we breathe.

Here are three means of removal of excretory products in plants with proper examples:

1. Transpiration: Transpiration is the process by which plants lose water vapour through their leaves. This water vapour carries away dissolved waste products, such as excess salts and minerals.
2. Exudation: Exudation is the process by which plants release waste products through their roots. These waste products can include excess water, salts, and other materials.
3. Shedding: Plants can also shed parts of their body, such as leaves, flowers, and fruits. This can help to remove waste products that have accumulated in these tissues.

Question 6

Mention two functions of the Nervous System. What do you mean by ‘Reflex Action’? Explain with one suitable example. [2+3]

Answer

The two functions of the Nervous System:

1. To control movement: The nervous system controls movement by sending signals from the brain to the muscles. These signals tell the muscles to contract, which allows us to move our bodies.
2. To receive information from the environment: The nervous system receives information from the environment through our senses, such as sight, hearing, touch, taste, and smell. This information is sent to the brain, where it is processed and interpreted.

Reflex Action: A reflex action is an involuntary response to a stimulus. It is a rapid, automatic response that does not require conscious thought. Reflex actions are important for survival, as they allow us to react quickly to threats or danger.

One example of a reflex action is the knee-jerk reflex. When the doctor taps your knee with a rubber hammer, your leg kicks out.

Question 7

Write the name of the ‘Emergency Hormone’. Write two functions of this hormone. Mention the site of secretion of the Gibberellin hormone. Write one function of Gibberellin. [1+2+1+1]

Answer

1. Emergency Hormone: Adrenaline
2. Functions of Adrenaline:
   • Increases heart rate and blood pressure
   • Increases blood flow to muscles
   • Increases blood sugar levels
   • Dilates the pupils
   • Relaxes the airways
3. Site of Secretion of Gibberellin Hormone:
   • Gibberellins are produced in the tips of roots and shoots.
4. The function of Gibberellin Hormone:
   • Gibberellins promote stem elongation.

Question 8

Write the definition of Chromatid and Centromere. Mention the number of chromosomes in the somatic cell of the human body. [2+2+1]

Answer

1. Chromatid: A chromatid is one of two identical halves of a duplicated chromosome. The two chromatids are joined together at a region called the centromere.
2. Centromere: The centromere is the region of a chromosome where the two chromatids are joined together. It is also the point where the spindle fibers attach during cell division.
3. Number of chromosomes in the somatic cell of the human body: Humans have 46 chromosomes in their somatic cells. These chromosomes are arranged in 23 pairs, with one chromosome from each pair coming from the mother and one coming from the father.

Question 9

A Pure Black (Dominant) Guineapig is crossed with a Pure White (Recessive) Guineapig. Explain the ‘Law of Segregation’ from the results of the 2nd Filial Generation. Write two reasons, why Mendel chose the Pea Plant for his experiments on Heredity. [3+2]

Answer

Law of Segregation: When a pure black guinea pig is crossed with a pure white guinea pig, all of the offspring will be black. However, when the offspring of these black guinea pigs are crossed, the law of segregation states that there will be a 3:1 ratio of black to white guinea pigs in the second filial generation (F2). This is because each offspring will receive one gene for black fur from each parent, and the black gene is dominant.

Reasons why Mendel chose the Pea Plant for his experiments on Heredity:

• Easy to grow and reproduce: Pea plants are annuals, which means that they complete their life cycle in one year. This makes them quick and easy to grow, which was important for Mendel because he wanted to be able to study many generations in a short period of time. Pea plants are also self-pollinating, which means that they can fertilize themselves. This allowed Mendel to control the breeding of his pea plants and ensure that he was only studying the effects of genes.
• Easily observable traits: Mendel chose pea plants because they have several easily observable traits, such as flower colour, seed shape, and pod colour. This made it easy for Mendel to track the inheritance of these traits from parents to offspring.

Question 10

What do you understand by ‘Homologous Organ’? How do the features of internal structures of the forelimbs of different vertebrate animals support the idea of evolution? [2+3]

Answer

1. Homologous organs are organs that have similar structures but different functions in different organisms. For example, the forelimbs of a human, a bat, and a whale are all homologous organs.
2. The features of internal structures of the forelimbs of different vertebrate animals support the idea of evolution because they show that these organisms share a common ancestor. The forelimbs of all vertebrates have the same basic structure, including a humerus, radius, ulna, carpals, metacarpals, and phalanges. This similarity suggests that these organisms all evolved from a common ancestor that had a forelimb with this same basic structure.

Question 11

Mention the adaptive significance of the following organs:

1. Caudal tin of Rohu fish
2. Seeds of Lotus
3. Bones of Pigeon
4. Leaf surface of Sundari tree
5. Swim bladder of Rohu fish. [1+1+1+1+1]

Answer

1. Caudal fin of Rohu fish: Propulsion
2. Seeds of Lotus: Float on water
3. Bones of Pigeon: Lightweight and strong
4. Leaf surface of Sundari tree: Reduce water loss and protect from damage
5. The swim bladder of Rohu fish: Maintain buoyancy.

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Group – C

(Answer anyone)

Question 12

Draw a neat and scientific diagram of the vertical section of ‘Human Eyeball’ and label the following parts : [5+3=8]

1. Cornea
2. Sclera
3. Choroid
4. Lens
5. Retina
6. Blind Spot

Answer

13. Draw a neat and scientific diagram of the external feature of a ‘Rohu Fish’ and label the following adaptive features : [5+3=8]

1. scale
2. pelvic fin
3. Dorsal Fin
4. Pectoral Fin
5. Caudal Fin
6. Lateral line Sense Organ

Answer

[For sightless Candidates Only]

(Diagram not required)

Answer any one question

12(A). Describe the structure and function of any four parts of the ‘Human Eye’.

Answer

Here are the structure and function of the four parts of the human eye:

1. Cornea: The cornea is the clear, front part of the eye that covers the iris and pupil. It helps to focus light onto the retina.
2. Iris: The iris is the coloured part of the eye that controls the amount of light that enters the eye. It does this by expanding and contracting the pupil.
3. Pupil: The pupil is the black opening in the centre of the iris. It allows light to enter the eye.
4. Lens: The lens is a clear, flexible structure that helps to focus light onto the retina. It does this by changing shape.

13(A). Discuss any four adaptive features of ‘Rohu Fish’ and mention their importance.   

Answer

Feature	Importance
Gills	Breathe underwater
Swim bladder	Maintain buoyancy
Scales	Protect from predators and parasites
Barbels	Find food and navigate

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Group – D

[For External Candidates Only]

(Answer any one question)

14. Write four differences between living and non-living. Write two differences between plants and animals. Write the definition of a Eukaryotic cell and give two examples. [4+2+4=10]

Answer

Four differences between living and non-living

Feature	Living Things	Non living Things
Organization	Made up of cells	Not made up of cells
Metabolism	Able to use energy and convert it into other forms of energy	Do not use energy
Growth and development	Grow and develop over time	Do not grow or develop
Response to stimuli	Respond to changes in their environment	Do not respond to changes in their environment

The two differences between plants and animals

Feature	Plants	Animals
Nutrition	Autotrophic (make their own food)	Heterotrophic (obtain food from other organisms)
Movement	Usually immobile	Usually motile

 

A eukaryotic cell is a cell that has a nucleus and other membrane-bound organelles.

Here are two examples of eukaryotic cells:

• Animal cells
• Plant cells

15. Write the location and function of the Permanent tissue and Meristematic tissue in the plant body. Write four differences between Xylem and Phloem tissue. Write the location and function of the Centrosome. [2+2+4+2]

Answer

Permanent tissue

• Location: Found throughout the plant body, but is most abundant in the stems and leaves.
• Function: Provides support, conducts water and nutrients, and stores food.

Meristematic tissue

• Location: Found at the tips of roots and shoots, and in the cambium layer.
• Function: Responsible for plant growth by dividing and producing new cells.

Xylem

• Location: Transports water and minerals from the roots to the rest of the plant.
• Function: Carries water and minerals up from the roots to the leaves, where they are used for photosynthesis.

Phloem

• Location: Transports food from the leaves to the rest of the plant.
• Function: Carries food from the leaves to the rest of the plant, where it is used for growth, repair, and reproduction.

Centrosome

• Location: Found in the cytoplasm of animal and plant cells.
• Function: Helps to organize the cell’s microtubules, which are involved in cell division and movement.

Here are four differences between Xylem and Phloem tissue: