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Kerala State Syllabus 10th Standard Biology Solutions Chapter 2 Windows of Knowledge
Windows of Knowledge Questions and Answers
Windows Of Knowledge Kerala Syllabus 10th Chapter 2 Question 1.
Sense organs how helpful us?
Answer:
- For enjoyment.
- For escaping from accidents.
- For predation.
- For communication.
Sslc Biology Chapter 2 Kerala Syllabus Question 2.
Receptors help sense organs in receiving various stimuli from the surroundings. List various sense organs and the stimuli they receive.
Answer:
| Sense organ | Receptor | Stimulus |
| Eye | Photoreceptors | Light |
| Ear | Auditory receptors | Sound |
| Tongue | Taste receptors | Taste |
| Nose | Olfactory receptors | Smell |
| Skin | Various receptors | Pain, touch, pressure, cold, heat |
eye
Windows Of Knowledge Class 10 Notes Kerala Syllabus Chapter 2 Question 3.
How are our eyes protected?
Answer:
Eye socket orbit : Depressions in the skull protects the eyeball.
External eye muscles : Fixes the eyeball in the orbit.
Eyebrow : Protects the eye from dust and sweat.
Eyelashes : Protects the eye from dust.
Eyelids : Protects the eye from dust and external shock.
Conjunctiva : Secretes mucus which pro¬tects the anterior portion of the eyeball from being dry.
Tears : Clean and lubricate the anterior part of the eyeball. Lysozyme, the enzyme present in tears, destroys germs that enter the eyes.
Structure of Eye:
The Eye Parts and Function:
Conjunctiva – The layer which protects the sclera except the cornea.
Cornea – Slightly projected transparent.
anterior part of the sclera which refracts light rays to focus on the retina.
Iris – Part of the choroid seen behind the cornea. Presence of melanin gives the iris a dark colour.
Lens – Elastic transparent convex lens, connected to ciliary muscles by ligaments:
Ciliary muscles – Circular muscles seen around the lens. The contraction and relaxation of these muscles alter the curvature of lens.
Yellow spot – The part of the retina where plenty of photoreceptors are present. It is the point of maximum visual clarity.
Blindspot – The part of the retina from where the optic nerve begins. Photoreceptors are absent.
Optic nerve – Transmits impulses from photoreceptors to the visual center in the brain.
Fluids present in the eye and their functions:
- Aqueous humor – A watery fluid seen in the aqueous chamber (between cornea and lens), oozes from the blood. This fluid supplies nutrients and oxygen to cornea and lens.
- Vitreous humor – A jelly-like fluid filled within the vitreous chamber (between lens and retina), helps to maintain the shape of eyeball.
Nutrition of tissues in the eyes:
The blood and aqueous humor nourishes the tissue in eye.
Regulation Of Light In The Eye
The pupil dilates in dim light and constricts in bright light.
The size of the pupil is regulated by the action of circular muscles and radial muscles. When the radial muscles contract in dim light.
The size of the pupil increases. When the circular muscles contract in intense light, the size of the pupil decreases. Thus the amount of light falling on the lens is regulated according to the intensity of light.
Formation Of Image
Sslc Biology Chapter 2 Notes Kerala Syllabus Question 4.
We have a convex lens inside the eye. What are the peculiarities of image formed by this type of lens? List them.
Answer:
1. Real.
2. Small.
3. Inverted.
Sslc Biology Chapter 2 Questions Kerala Syllabus Question 5.
Observe and analyze table and figure. Write your inferences in the science diary.
| While viewing near objects | While viewing distant objects |
| Ciliary muscles contract | Ciliary muscles relax |
| Ligaments relax | Ligaments stretch |
| Curvature of lens increases | Curvature of lens decreases |
| Focal length decreases | Focal length increases |
Answer:
- While viewing near objects curvature of lens increases. So the focal length increases.
- While viewing near objects the ciliary muscle contracts and ligaments relax. So the focal length increases.
- While viewing distant objects the ciliary muscles relax and the ligament stretch. So the focal length decreases.
- The capacity of the eye to change the curvature of lens depending on the distance between the eye and the object by adjusting the focal length.
10 Biology Chapter 2 Kerala Syllabus Question 6.
Define the power of accommodation of the eye.
Answer:
The capacity of the eye to change the curvature of lens depending on the distance between the eye and the object by adjusting the focal length is called the power of accommodation of the eye.
Retina and The Photoreceptors
Receptor region of the rod cells is rod shaped and contain the pigment rhodopsin, which will be stimulated under dim light. Receptor region of the cone cells is cone shaped and contain the pigment photopsin (iodopsin) which will be stimulated under intense light.
Under dim light, rhodopsin dissociates to form retinal and opsin to produce impulses from rod cells. Under intense light, photopsin (iodopsin) dissociates to form retinal and opsin to produce impulses from cone cells.
Diversities in the cone cells due to the change in amino acid in the opsin molecules.
| Rod cell | Cone cell | |
| Pigment | Rhodopsin | Photopsin |
| Shape | Rod shape | Cone shape |
| Function | able to seethe object in dimlight | to detect the primary colour |
Chemistry of Vision
Sslc Biology Chapter 2 Questions And Answers Pdf Question 7.
Observe the chemical reaction given below. Discuss based on the indicators and write the inferences in your science diary?
Function of cone cells:
When light rays fall on pigment present in cone cells the photopsin dissociate into retinal and opsin.
Function of rod cells:
When light rays fall on pigments present in rod cells the rhodopsin dissociate into retinal and opsin.
The mechanism of vision:
The chemical change of pigments leads to the formation of impulses. These impulses are transmitted to cerebrum through the optic nerves and this enables vision.
Hss Live Biology 10 Kerala Syllabus Chapter 2 Question 8.
Complete the flowchart showing the process of vision.
Answer:
Light → Cornea → Aqueous humour → Pupil → Lens → Vitreous humour → Retina → Stimulus → Optic nerve → Cerebrum → Sense of sight
Binocular vision:
The images from two sides of the same object are formed in the left and right eye. These two images are combined-together in the visual area of our brain to form a three-dimensional image of the object. This is called binocular vision.
Food habits and health of the eyes:
The pigment present in photoreceptors is derived from vitamin A. The deficiency of vitamin A results in the low production of retinal. This inturn creates the deficiency of rhodopsin in rod cells. The resynthesis of rhodopsin also get blocked. This causes night blindness.
Due to prolonged deficiency of vitamin A, the conjunctiva and cornea will become dry and opaque. This causes xerophthalmia and leads ultimately to blindness. Hence it is necessary to include food containing vitamin Ain our diet.
Eye – Defects and Diseases
Hsslive Guru 10th Biology Kerala Syllabus Chapter 2 Question 9.
Prepare a table to show reason of various disorders and diseases that affect on our eyes. Suggest remedial measures also.
Answer:
10th Standard Biology Notes Kerala Syllabus Chapter 2 Question 10.
Prepare posters for an awareness program on the protection of eyes and donation of eyes.
Answer:
Kerala Syllabus 10th Standard Biology Chapter 2 Question 11.
Mention a few points to a discussion related with the health of our eyes.
Answer:
- Avoid falling of bright source of light directly to the eyes. Don’t look at the sun.
- Avoid reading under dim light.
- Do not watch TV or other screens continuously.
- Frequently wash our eyes.
- Include vitamin A contained items in our daily food.
Ear
External Ear: Ear pinna, Ear canal, Eardrum /Tympanum
Middle Ear: Malleus, Incus, Stapes, Eustachian tube.
Internal Ear: Cochlea, Vestibule (Sacule, Utricle), Semicircular canal, Auditory nerve
External Ear:
Biology Class 10 Chapter 2 Kerala Syllabus Question 12.
What are the parts of the external ear.
Answer:
Pinna and auditory canal, tympanum.
Hsslive Biology 10th Kerala Syllabus Chapter 2 Question 13.
How does the pinna help in hearing.
Answer:
Carries sound waves to the auditory canal.
Biology Class 10 Kerala Syllabus Chapter 2 Question 14.
What is the importance of ear wax?
Answer:
Prevent dust and foreign particles from entering the ear.
Middle ear:
Middle ear is a small chamber between the external ear and the internal ear. Ear ossicles namely malleus, incus and stapes are the important parts seen inside the middle ear. A bony wall separates the middle ear from the internal ear. In this bony wall, there are two openings which are covered by membranes.
The upper opening is oval window and the lower one is round window. The ear ossicles connect the tympanum the internal ear through the oval window. Eustachian tube that connects the middle ear to the pharynx.
Internal ear:
The internal ear, seen inside the bony labyrinth, as membranous labyrinth. A coiled tube-like cochlea and the vestibular apparatus (vestibule & three semicircular canals) are the parts of inner ear.
The membranous labyrinth is filled with a fluid, named endolymph and the space between the bony and membranous labyrinths is filled with another fluid, named perilymph.
Cochlea of the internal ear functions in hearing, while the vestibular apparatus helps to maintain body balance through transmitting impulses to the cerebellum.
Ear and Hearing
Cochlea is a coiled tube like a snail shell. It consists of three chambers. Specialized sensory hair cells which are present in basilar membrane that separates the middle and lower chambers, function as auditory receptors. The basilar membrane and sensory hair cells together constitute the organ of Corti. The sound waves which passes through the external ear vibrates the tympanum.
The vibration of the tympanum is transmitted to the ear ossicles which causes the vibration of the membrane in the oval window. Thus vibration causes the movement inside the cohlea. As a result, the sensory hair cells seen in the organ of Corti the cochlea are stimulated and impulses are generated. These impulses reach the cerebrum through the auditory nerve and hearing is affected.
Question 15.
Observe the figure given below. Prepare notes on process of hearing in the science diary.
Answer:
Structure of Cochlea:
Cochlea is a coiled tube like a snail shell. It consists of three chambers. Perilymph and endolymphs are filled inside this.
Auditory receptors in cochlea:
Specialized sensory hair cells which are present in basilar membrane that separates the middle and lower chambers, function as auditory receptors.
The process which sound waves becomes impulses:
The vibration of the tympanum is transmitted to the ear ossicles which causes the vibration of the membrane in the oval window. This vibration causes the movement of fluid inside the cochlea. As a result of the sensory hair cells seen in the organ of Corti of the cochlea are stimulated and impulses are generated.
Sense of hearing:
The impulses reach the cerebrum through the auditory nerve and hearing is affected.
Question 16.
Complete the flow chart of hearing?
Answer:
Ear and Body Balancing
Question 17.
Parts of the internal ear which help in body balance.
Answer:
The vestibular apparatus is constituted of structure namely utricle, saccule and three semicircular canals.
Question 18.
Peculiarities of receptors in the vestibule.
Answer:
Cluster of receptors in the form of hair cells, seen inside the vestibule and semicircular canals help in balancing of the body.
Question 19.
How does the cerebellum act in accordance with the variation in the balance of the body?
Answer:
Receptors (hair cells) seen inside the ampulla of semicircular canals, saccule and utricle are stimulated according to the movement of head. The impulses formed thus will be transmitted to the cerebellum through the vestibular nerve. Cerebellum functions so as to maintain the equilibrium of body.
To detect taste:
Chemoreceptors seen inside the mouth and tongue help us to detect taste. The chemoreceptors seen inside the papillae of the tongue are called as taste buds. Smell also influences taste.
Taste buds are stimulated by four types of taste namely sweet, salt, sour, bitter umami. Substances which dissolves in saliva, stimulate the taste buds and generate impulses. These impulses reach the brain and we experience taste.
Food particles dissolve in the saliva → Taste receptors (taste buds) are stimulated → Impulses form and transmit through nerves → Brain → Experience of taste.
To detect smell:
When particles enter the nose and disperse in the mucus, the olfactory receptors in the mucous membrane get stimulate and the impulses reach the brain through the olfactory nerve. Brain helps in the perception of smell.
Aromatic particles diffuse in the air and enter the nostrils → These aromatic particles dissolve in the mucus inside the nostrils → Impulses form and transmit through nerves → Brain → Experience of taste.
Sense Through Skin
Question 20.
What all receptors are seen in the skin to receive stimuli? Observe figure and write inference in your science diary.
Answer:
Heat, cold, touch, pressure and pain are felt by our skin. When these receptors are stimulated, impulses from the reach in the cerebrum for its perception.
Question 21.
Are these receptors uniformly distributed all over the skin?
Answer:
The fingertip contains more touch receptors.
Question 22.
Observe the illustration on the various receptors of certain organisms around us and their peculiarities. Write your inferences in your science diary.
Answer:
|
Living being |
Sense organ |
| Planaria | eyespot |
| Housefly | Ommatidia |
| Shark | Lateral line, highly sensitive olfactory receptors |
| Snake | Jacobson’s organ |
Windows of Knowledge Let Us Assess
Question 1.
When we view nearby objects.
a) Ciliary muscles relax.
b) Curvature of lens decreases.
c) Ciliary muscles contract.
d) Focal length increases.
Answer:
c) Ciliary muscles contract.
Question 2.
Identify the odd one and write down the common feature of others.
Malleus, Eustachian tube, Stapes, Incus.
Answer:
Eustachian tube. Others are ear ossicles.
Question 3.
Copy the figure. Identify the parts according to the hints and label them.
Hints :
a) The part where the muscles that regulate the size of the pupil are seen.
b) The chamber which is filled with vitreous humor.
c) The layer of eye where photoreceptors are seen.
Answer:
a) Iris.
b) Vitreous chamber.
c) Retina (label correctly).
Question 4.
Figure of Ear is given. Redraw it and name and label the parts mentioned.
a) Part that receives the vibrations of the eardrum.
b) The tube that connects the pharynx.
c) Part where the auditory receptors are seen.
Answer:
a) A thin circular membrane.
b) Eustachian tube.
c) Cochlea.
Windows of Knowledge Extended Activities
- Conduct a class seminar on the topic “Eye diseases and protection of the eyes”.
- Prepare notes on the peculiarities of sense organs of different organisms by collecting more information.
- Take the section of a bull’s or buffalo’s eye and observe the parts. Write your observation and inferences in the science diary.
Windows Of Knowledge More Questions and Answers
Question 1.
Find the odd one and write the peculiarities of others.
a) Iris, malleus, lens, retina.
b) Utricle, sacule, vestibular nerve, cochlea.
Answer:
a) malleus, others are the parts of eyes.
b) cochlea: others are related to body balancing.
Question 2.
Find the relation and fill in the blanks.
a) Cochlea : Auditory nerve.
Vestibule : ………
b) Rod cells : Rhodopsin.
Cone cells : ……..
c) Glaucoma : Laser surgery.
Cataract :
Answer:
a) Cochlea : Auditory nerve.
Vestibule : Vestibular nerve.
b) Rod cells : Rhodopsin.
Cone cells : Photopsin.
c) Glaucoma : Laser surgery.
Cataract : Replacing the lens through surgery.
Question 3.
Correct the sentence if it is wrong.
a) Conjunction is the outer layer which gives firmness the eye.
b) Aqueous humour nourishes the tissues of the eye.
c) Round window enables the vibration of conchleae fluid through the vibration of stapes.
d) Hair cells in cochlea are help in balancing the body.
Answer:
a) False conjunctiva is the layer which protects the sclera except the cornea.
b) Hair cells in the cochlea are help in hearing.
Question 4.
Slightly projected transparent anterior part of the sclera?
Answer:
Cornea.
Question 5.
The transparent membrane which protects the sclera, except the cornea?
Answer:
Conjunctiva.
Question 6.
The middle layer of eye, …… which contains a large number of blood vessels.
Answer:
Choroid.
Question 7.
The dark colored anterior part of choroid is,…… which contains the pigment melanin.
Answer:
Iris.
Question 8.
The aperture at the centre of iris?
Pupil.
Question 9.
The antagonistic muscles in the iris that regulate the size of eye pupil?
Answer:
Radial muscles (pupillary dilator) and Circular muscles (pupillary constrictor).
Question 10.
Vitamin A helps us for better vision. Give reason.
Answer:
Retinal, the visual pigment found in the photo receptors, is formed from vitamin A.
Question 11.
The bird, owl has no vision in daytime. Why?
Answer:
Owl’s retina is devoid of cone cells and hence no vision in daytime.
Question 12.
Analyze the statement that animals like cat and owl have more vision at night.
Answer:
Cat and owl have more rod cells in their retina so that they have more vision at night.
Question 13.
A kite can locate its prey even from high altitude. How is this possible?
Answer:
The eyes of kite are closer to each other and contain a large number of cone cells. Hence it has high power of vision.
Question 14.
“When the first chamber of the eye is cut open, its fluid spreads out but the second chamber is cut open, its fluid doesn’t spread out”. These words are taken from Rahul’s Practical Observation Record.
a) Name the fluids?
b) What are the functions of those fluids?
c) Name the eye-fluid related with Glaucoma?
Answer:
a) Aqueous humor and Vitreous humor
b) Aqueous humor supplies nutrients and oxygen to cornea and lens. Vitreous humor maintains the shape of eyeball.
c) Aqueous humor.
Question 15.
Analyse the illustration of image formation in retina and make a flowchart.
Light rays from the object → cornea → Aqueous humor/pupil → lens → vitreous humor → image on retina.
Question 16.
Though images of object are formed in both eyes, we can see only one object. Give reason.
Answer:
Cerebrum coordinates the two images and hence get a three-dimensional view of the object.
Question 17.
Carefully observe the above picture and make any two inferences we get from this picture.
Answer:
The process of seeing object through the coordination of impulses by the cerebrum. Binocular vision.
Question 18.
What is the need of closing one eye while shooting an object?
Answer:
Binocular vision help us to get a three-dimensional image of the object and to calculate the correct distance, depth, height and width of the object. But in the case of aiming an object, we need to get correct line instead of common focus through binocular vision.
Question 19.
The sight of one of the eyes of a participant in the hurdles competition has lost. Is the participant is apt for participating hurdles competition? Justify your answer.
Answer:
Since the participant lost one of his eyes’ sight, he has no binocular vision and he cannot calculate the correct distance, depth, height and width of the hurdles.
Question 20.
A patient having following symptoms consulted a doctor.
- Dry conjunctiva.
- Dry and opaque cornea.
- Vision problem.
- Name his defect. Should the patient take any change in his food habit?
Answer:
Xerophthalmia. He should include food containing more vitamin A in his diet.
Question 21.
Select correct answer from the box.
Hyper metropia, Myopia, Night blindness, Colour blindness, Cataract, Glaucoma, Conjunctivitis, Xerophthalmia.
a) Disorder related to the eye lens?
b) Disorder related to the aqueous humour?
c) Disorders due to the difference in the size of eyeball?
d) Disorder that can be rectified by convex lens?
e) An infection?
1) Genetic disorder?
g) Disorder due to the deficiency of vitamin A?
h) Disorder due to the prolonged deficiency of vitamin A?
Answer:
a) Cataract.
b) Glaucoma.
c) Hyper metropia and myopia.
d) Hyper metropia.
e) Conjunctivitis.
f) Colourblindness.
g) Night blindness.
h) Xerophthalmia.
Question 22.
The tube that connects the middle ear to the pharynx? What is its function?
Answer:
Eustachian tube. It helps to regulate the pressure inside the middle ear.
Question 23.
Why certain person feel ear pain as they goes higher altitudes?
Answer:
When we goes higher altitudes, the atmospheric pressure decreases. This creates low pressure on one side of the eardrum to cause pain.
Question 24.
Recognize the figure A and B.
Answer:
A. Taste bud.
B. Olfactory receptors.
Question 25.
Convert the following chart of sensing smell to a flow chart of feeling taste.
Olfactory particles dissolve in mucus → Stimulation in olfactory receptors → Formation of impulse → Transmission of impulses through nerve → Olfactory center in the cerebrum → Experiencing smell
Answer:
Food particles dissolve in the saliva → Taste receptors (taste buds) are stimulated → Impulses form and transmit through nerves → Brain → Experience of taste.
Question 26.
We are unable to recognize smell when we have cold. Can you say the reason?
Answer:
Smell influences tasting. During cold, excess mucus will be produced in the nasal cavity. This will obstruct the normal stimulation of olfactory receptors and hence, we are unable to recognize smell and feel the food tasteless.
Question 27.
The ability of shark to sense smell is sharp. Why?
Answer:
Shark has highly sensitive olfactory receptors.
Question 28.
Give example for animals in which the taste receptors are seen on its legs.
Answer:
Housefly.
Question 29.
Find out the odd one. Write down the common feature of other Cornea, Cochlea, Choroid, Sclera. (Model 2016)
Answer:
Cochlea. Others are part of eye.
Question 30.
‘Giddiness is felt when we turn round and round’. Analyze the statement. (Model 2016)
Answer:
This statement is true. When we turn round continuously, the endolymph inside the vestibular apparatus also move and there will be continuous stimulation of the receptors and passing of the impulses to the cerebellum. Thus our muscular coordination cannot be maintained to feel giddiness.
Question 31.
Redraw the diagram and label the parts that perform the following functions: (March 2016)
a) The tissues in the eye receive nutrients and oxygen.
b) Regular the amount of light entering the eye.
Answer:
a) Choroid layer
b) Iris/pupil.
Question 32.
Observe the diagram.
a) Redraw and label the diagram.
b) Complete the table appropriately. (Model 2015)
|
Part |
Name |
Function |
| A | ||
| B | ||
| C |
Answer:
|
Part |
Name |
Function |
| A | Semicircular canals | Body balancing |
| B | Cochlea | Hearing |
| C | Eustachian canal pressure inside | Maintaining |
Question 33.
Find out the relationship between the pair of words and fill up the blanks.
Rod cells : Rhodopsin
Cone cells : …….. (March 2015)
Answer:
Photopsin.
Question 34.
“Receptors are modified neurons”. Justify the statement with examples of receptors in different sense organs. (March 2015)
Answer:
Receptors are modified neurons. Rods and cones in the eyes, auditory receptors in the ear, taste receptors in the tongue are examples.
Question 35.
Name the process represented in following illustration? Write the peculiarity of image formed in labelled sense organ? (March 2015)
Answer:
Formation of image in the brain. Peculiarity of the image formed: Real, small.
Question 36.
The diagram given below shows the structure of ear:
a) Redraw the diagram.
b) Label the parts A, B, C, D.
c) Write down the name and function of E and F. (Model 2014)
Answer:
a)
b) A – tympannum (eardrum)
B – Auditory nerve.
C – Ear ossicles.
D – Eustachian tube-labelling.
c) E – Semicircular canal- balancing.
F – Cochlea – hearing.
Question 37.
Make a flow chart showing the sequential stages to feel the smell. (March 2015)
Answer:
Olfactory particles enter the nose through air → Olfactory particles dissolve in the mucus and reach the olfactory receptors → Olfactory receptors are stimulated and impulses are formed Olfactory center of brain → Sense of smell.
Question 38.
Find out ‘word pair relation’ and fill in the blanks.
a) Dim light : Rod cells.
Bright light : ……
b) Euglena : ……
Insects : Ommatidia.
c) Frog : Urea
Tadpole : …….. (March 2014)
Answer:
a) Cone cells.
b) Eye spot.
c) Ammonia.
Question 39.
Correct the mistakes and rearrange the given flow chart of hearing process.
Ear canal → Cochlea → Eardrum → Earossicles → Oval window → Auditory nerve. (March 2014)
Answer:
Ear canal → Eardrum → Ear ossicles → Oval window → Cochlea → Auditory nerve.
Question 40.
Analyse the word pair relationship and fill up the blanks.
Photopsin : Colourblindness.
………. : Night blindness. (Model 2013)
Answer:
Rhodopsin.
Question 41.
Redraw the picture.
a) Label the parts A, B and C.
b) Write down the functions of B, C & D.
Answer:
a) A – Lens.
B – Aqueous chamber .
C – Layers of the eye.
b) B – Aqueous chamber:
This is the chamber between lens and the cornea. It is filled with a watery fluid called aqueous humour which supplies nutrients arid oxygen to the cells of the cornea and the lens.
c – Layer of the eye:
Retina, the innermost layer of the eyeball it imparts the firmness to the eye ball.
b – Vitreous chamber:
This is the large chamber seen between the lens and the retina which is filled with the jelly like vitreous humor. This helps to maintain the shape of the eye ball.
Question 42.
The flow chart sound waves passing through the ear is shown below. Complete it.
a) Ear Canal.
b) ………
c) Mallius.
d) ……….
e) Stapes.
f) ……….
g) Cochlea.
h) Perilymph.
i) …………
j) Auditory receptors. (Model 2012)
Answer:
b) Tympanum / Eardrum.
d) Incus.
f) Oval window.
i) Endolymph.
Question 43.
Copy the figure. Label the name of following parts on the figure.
a) Part on which image form.
b) Circular anterior part of the choroid layer.
c) The main part which regulate the focal length of light rays. (Model 2012)
Answer:
Question 44.
Find the odd one, note down common features of the others.
Thyroxin, Prolactin, Ethylene, Oxytocin. (March 2012)
Answer:
Ethylene is a plant hormone, others are animal hormones.
Question 45.
Suku feels difficulty of vision in dimlight.
a) Identify the disease, from among the following.
i) Haemophilia.
ii) Night blindness.
iii) Glaucoma.
b) What is the reason for this disease? (March 2012)
Answer:
Night blindness, caused due to the deficiency of vitamin A.
Question 46.
“Allow anyone to take my eyes after my death”. These are the words of Raju, who was admitted to the hospital after a serious accident.
a) How will you react to this statement?
b) Is it difficult to donate eyes after death?
c) Is it possible to donate an organ while alive? (March 2012)
Answer:
a) Raju is a noble and kind hearted person because Eye donation is a noble deed, as it brings happiness into the dark life of a blind person.
b) No, Eyes can be removed within 6 hours and transplanted to the patient by surgery.
c) Certain organs like, kidney, liver can be donated by a live donor.
Windows of Knowledge SCERT Questions and Answers
Question 1.
Complete the flowchart filling the blanks: (Question Pool-2017)
Answer:
A. Pinna.
B. Ear ossicles.
C. Oval window.
D. Cochlea.
E. Hair cells.
F. Cerebrum.
Question 2.
Given below is the portion of a poster.
Don’t take high eye pressure easy.
It may lead to blindness in future.
a) Which is the eye disease mentioned in the poster?
b) What is the reason for this condition?
c) What is the remedy for this disease? (Question Pool -2017)
Answer:
a) Glaucoma
b) 1) Blockage of reabsorption of aqueous humour.
2) Increase in the pressure inside the eyes
D) Laser surgery.
Question 3.
Observe the figure given below and answer the question.
a) Identify A, B
b) Which is the pigment in A?
c) Which is the eye disorder related to B? (Question Pool-2017)
Answer:
a) A – Rod cells.
B – Cone cells.
b) Rhodopsin.
c) Colourblindness.
Question 4.
Processes related to maintaining the equilibrium of the body are given below. Analyse and arrange them in the correct order.
a) Impulses are formed.
b) Muscular movements are coordinated.
c) Maintains the equilibrium of the body.
d) Sensory hair cells of the vestibular apparatus are stimulated.
e) Impulses reach the cerebellum.
f) Body movements create the movement of fluid inside the vestibule and semicircular canal. (Question Pool – 2017)
Answer:
Question 5.
Analyse the illustration related to the power of accommodation of the eye and answer the questions.
a) Which figure indicates the change in the lens while viewing distant objects?
b) Give the reason for the change in the curvature of the lens in figure II than in figure 1. (Question Pool -2017)
Answer:
a) Figure 1
b) 1. While viewing nearby objects.
2. Ciliary muscles contract.
3. Ligaments relax.
Question 6.
Statements related to sense organs are given below:
Choose the correct ones.
a) Taste buds are the chemoreceptors seen in the papilla?
b) Receptors are uniformly distributed all over the skin.
c) Impulses from the olfactory receptors reach the cerebrum through the olfactory nerve.
d) We experience taste when impulses from the taste buds reach the cerebellum. (Question Pool-2017)
Answer:
a) Taste buds are the chemoreceptors seen in the papilla?
c) Impulses from the olfactory receptors reach the cerebrum through the olfactory nerve.
Question 7.
Complete the table suitably in accordance with the given model. (Question Pool -2017)
Answer:
a) Planaria.
b) Jacobson’s organ.
c) Detects smell.
d) Receptors in the lateral line.
Question 8.
Observe the figure and answer the questions.
a) What does the figure indicate?
b) Identify X,Y.
c) How do X and Y differ in function? (Question Pool-2017)
Answer:
a) Internal ear
b) 1. X-Vestibular nerve
2. Y – Auditory nerve
c)1. X- Transmits impulses form the vestibular apparatus to cerebellum.
2. Y-Transmits Impulses from the cochlea to the cerebrum.
Question 9.
Light rays which reflect from the object are focussed on the retina and an image is formed.
a) Write the peculiarities of this image.
b) How do the images formed in the two eyes combine? What is its advantage? (Question Pool 2017)
Answer:
a) Small, inverted, real.
b) 1. Three-dimensional image of the object is formed due to the activity of the brain.
2. Binocular vision becomes possible.
Question 10.
“The focal length of the lens in the eye can be adjusted to view distant and nearby objects.” Evaluate this statement and arjswerthe questions given below.
a) When does historical length of the lens decrease?
b) What is the change in the focal length of the lens while viewing distant objects? How does it become possible? (Question Pool-201?)
Answer:
a) While viewing nearby objects.
b) Focal length increases, while viewing distant object the ciliary muscles relax ligaments stretch and the curvature of lens decreases. So the focal length decreases.
Question 11.
Vision is enabled when the impulse from the retina reaches the cerebrum through the optic nerve.
a) Draw a flow chart showing the pathway of light from cornea to retina.
b) There is no vision at the point where the optic nerve starts. Why? (Question Pool 2017)
Answer:
a) Light → Cornea → Aqueous humor → Pupil → Lens → Vitreous humor → Retina.
b) Rod cells and cone cells are absent in the part from where the optic nerve starts photoreceptors are absent. So there is no vision.
Question 12.
Examine the terms given below and choose the parts related to the maintenance of equilibrium of the body.
Cerebrum, Eustachian tube, Sacule, Cochlea, Utricle, Vestibular nerve, Oval window, Cerebellum, Semi circular canals. (Question Pool 2017)
Answer:
Sacule, Utricle, Vestibular nerve, Cerebellum.
Question 13.
Redraw the diagram given below. Identify the parts and label it.
a) Connects the middle ear with the pharynx.
b) Auditory receptor hair cells are present.
c) Separates the external ear from the middle ear. (Question Pool 2017)
Answer:
a) Eustachian tube.
b) Cochlea.
c) Tympanum.
Question 14.
Analyse the statements given below and write reasons.
a) Tears have antiseptic properties.
b) We can see objects in three-dimension. (Question Pool 2017)
Answer:
a) Lysozyme the enzyme present in tears destroys germs that enter the eyes.
b) Binocular vision.
Question 15.
a) How is this reaction related to vision?
b) How does the deficiency of vitamin A cause poor vision in dim light? (Question Pool 2017)
Answer:
a) 1. When light rays fall rhodopsin dissociate into retinal and opsin.
2. Generates impulses.
3. When impulses reach the cerebrum vision is experienced.
b) Retinal, the visual pigment found in the photoreceptors, is formed from vitamin A. The deficiency of vitamin A results in the low production of retinal. This, in turn, creates the deficiency of rhodopsin in rod cells. The resynthesis of rhodopsin also gets blocked. This causes a condition called night blindness.
Question 16.
Prepare two placards to be used in a rally organized by the school Science Club to propagate the importance of eye donation. (Question Pool 2017)
Answer:
Appropriate idea
Example : Let the eyes glow even after death!
Eye donation great donation.
Question 17.
Redraw the diagram and label the parts given below.
a) Transparent anterior part of the sclera.
b) Fluid that nourishes the tissues of the eye.
c) The layer that has photoreceptors. (Question Pool 2017)
Answer:
a) Comea.
b) Aqueous humor.
c) Retina.
Question 18.
Observe the figure given below and answer the questions:
a) Which is the receptor seen in the figure?
b) Which sense organ is this receptor seen in?
c) What is the function of this receptor? (Question Pool 2017)
Answer:
a) Olfactory receptor
b) Nose
c) Gets stimulated by aromatic particles and generate impulses
Question 19.
A fluid is formed in the eye just as the cerebrospinal fluid is formed in the brain.
a) Name the fluid.
b) What is its function? (Question Pool 2017)
Answer:
a) Aqueous humor.
b) Nourishes the tissues of the eye.
Question 20.
Justify the statements given below:
a) Smell can be detected only in the presence of mucus.
b) Persons with colour blindness cannot distinguish. between green and red colours. (Question Pool 2017)
Answer:
a) Aromatic particles dissolve in the mucus and stimulate olfactory receptors.
b) Reduction/damage of cone cells that help to distinguish red and green colors.
Question 21.
Given below is a table related to eye diseases. Fill up suitably. (Question Pool -2017)
Answer:
a) Lens in the eye becomes opaque.
b) Glaucoma.
c) Laser surgery.
d) Xerophthalmia.
Question 22.
It is because of its taste that we like food. Given below are the different stages of experiencing taste. Analyze and arrange them in the correct order.
a) Experience of taste.
b) Causes impulses.
c) Food particles dissolve in saliva.
d) Reaches taste buds.
e) Impulses reach the brain.
f) Chemoreceptors get stimulated. (Question Pool 2017)
Answer:
c.
d.
f.
b.
e.
a.
Question 23.
Identify the odd one. Write the common feature of the others.
a) Cold, temperature, Pressure, Taste
b) Tympanum, Oval window, Cochlea, Papilla
c) Ommatidia, Pupil, Iris, Conjunctiva. (Question Pool 2017)
Answer:
a) 1. Taste.
2. Others senses through skin.
b) 1. Papilla.
2. Others are parts of the ear.
c) 1. Ommatidia.
2. Others are parts of eye.
Question 24.
Identify the word pair relationship and fill in the blanks.
a) Retina : The inner layer which has photoreceptors.
………. : The transparent anterior part of the sclera.
b) Blind spot : The part from where the optic nerve begins.
………. : The part where the image has maximum clarity.
c) ……… : Nourishes the tissues of the eye.
Vitreous humor : Shape of the eye. (Question Pool 2017)
Answer:
a) Cornea.
b) Yellow spot.
c) Aqueous humour.
Question 25.
Choose the correct statements from the following ones.
a) Cochlea helps in maintaining the equilibrium of the body.
b) The oval window helps in the movement of fluid inside the cochlea.
c) We detect smell when impulses from the olfactory receptors reach the cerebellum.
d) Glaucoma is a condition in which the lens of the eyes become opaque resulting in blindness. (Question Pool 2017)
Answer:
b) The oval window helps in the movement of fluid inside the cochlea.
Question 26.
Choose the correct pairs related to the eye defects from the pairs given felow.
a) Cataract – Reabsorption of aqueous humor does not occur.
b) Glaucoma – Rectified by Replacing the lens.
c) Colourblindness – Infection of conjunctiva.
d) Cataract – Lens of the eye becomes opaque.
e) Conjunctivitis – Rectified by Laser surgery.
f) Glaucoma – Rectified by Laser surgery.
g) Colorblindness-Inability to distinguish colours. (Orukkam 2017)
Answer:
Correct pairs:
d) Cataract – Lens of the eye becomes opaque.
f) Glaucoma – Rectified by Laser surgery.
g) Colour Blindness – Inability to distinguish colours.
Question 27.
Redraw the diagram and label the parts based on the functions given below.
a) The part which is adjusted with the intensity of light.
b) The part where photoreceptors are present.
c) The transparent anterior part of the sclera.
d) The muscles which help to alter the curvature of the lens.
e) Transmits impulses from photoreceptors to the visual center in the brain.
f) The chamber which is filled with a jelly-like substance.
g) The layer made up of connective tissues which to the eye. (Orukkam 2017)
Answer:
Question 28.
Rearrange the flowchart related to sense of vision.
Light → Lens → Pupil → Vitreous humor → Aqueous humor → Optic nerve → Retina → Cerebrum → Cornea → Impufse → Sense of vision. (Orukkam 2017)
Answer:
Light → Cornea → Aqueous humor → Pupil → Lens → Vitreous humor → Retina → Impulse → Optic nerve → Cerebrum → Sense of vision.
Question 29.
Select suitable words from the box and complete the flowchart given below related to hearing. (Orukkam 2017)
Lens, Cerebrum, Cochlea, Retina, Auditory canal, Oval window, Ear ossicles, Auditory nerve, Hair cells, Optic nerve, impulse, Cornea, Pinna.
Answer:
Question 30.
Stages related to the maintenance of body balance are given below. Rearrange these statements in order.
a) Generates impulses.
b) Body movements create movement of fluid inside the vestibule and semicircular canals.
c) Impulses are transmitted by the vestibular nerve to the cerebellum.
d) Creates movements of the sensory hair cells.
e) Maintains equilibrium of the body.
f) Cerebellum coordinates muscular activities. (Orukkam 2017)
Answer:
b) Body movements create movement of fluid inside the vestibule and semicircular canals.
d) Creates movements of the sensory hair cells, a) Generates impulses.
c) Impulses are transmitted by the vestibular nerve to the cerebellum.
f) Cerebellum coordinates muscular activities.
Question 31.
Prepare a poster for creating awareness about the importance of eye donation. (Orukkam 2017)
Answer:
– Eye donations noble deed.
– No magician can cure blindness, but you donate your eyes.
– May your eyes see more after your life too.
Question 32.
Explain the necessity of including Vitamin A rich food items in daily diet for the health our eyes? (Orukkam 2017)
Answer:
Retinal, the pigment presented in the photoreceptors, is formed from vitamin A.
Question 33.
Complete the flowchart related to the sense of smell. (Orukkam 2017)
Answer:
