BIOLOGY

PLEASE SOLVE THESE QUESTIONS AFTER YOU HAVE REVISED THE CHAPTER.

Biology - The Endocrine System Question .1. Name the following : (i) The hormone secreted by beta cells of islets of langerhans. (ii) An endocrine gland. (iii) The endoctine gland which produces emergency hormone. Question .2. State true or false. Write correct statement by changing first word only. estosterone is an androgen. Question .3. Pick the odd one out : (i) Thyroid, adrenal, pituitary, prostate. (ii) Cretinism, myxedema, exophthalmic goiter, scurvy. (iii) Insulin, glugagons, diabetes insipidus, dibetes mellitus. (iv) Insulin, bllod sugar, adrenalin, thyroxine. (v) Oestrogen, progesterone, testosterone, prolactin. Question .4. Give the category and select the odd one out : (i) Goitre, dwarfism, acromegaly, cataract. (ii) ADH, TSH, NADP, ACTH. (iii) Steroids, cortisone, testosterone, adrenalin, prolactin. (iv) Adrenal, liver, thyroid, ptutiary. (v) Adrenalin, penicillin, insulin, thyroxine. Question .5. Choose : (i) Which of the following gland has both endocrine and exocrine function (Pitutiary, thyroid, pancreas, adrenal). (ii) (Myxedema, simple goiter, exophthalmic goiter) is a disorder caused by excess thyroid hormone. Question .6. Complete the following table : Gland Secretions Effect on Body 1 Oestrogen 2 Alpha cells of pancreas 3 4 5 6 Protruding eyes Lachrymal 7 8 9 10 Gigantism Question .7. Complete the following table by filling in the blank space 1 to 8. Name of Gland Substance Produced One important function Beta cells Islets of Langerhans. 1. ………….. . 2. ………… . 3. ………….. . Adrenalin 4. ………….. . 5. ………….. . Thyroxine 6. …………… . 7. …………… . LH 8. …………… . Question .8. Define endocrine gland. Question .9. Differentiate between : (i) Diabetes mellitus and Diabetes insipidus. (ii) Acromegaly and Myxedema. Question .10. Answer the following questions : (i) Name the endocrine cells present in the pancreas. (ii) Name two hormones secreted by the above mentioned cells. (iii) Mention one main function of each hormonenamed in (ii). Question .11. Why people living in hilly regions usually suffer from simple goiter. Question .12. Name the hormones produced by the following glands. In each case state one function of the hormone : 1. Thyroid. 2. Pancreas. 3. Adrenal medulla. Question .13. Give logic for why insulin is injected into the body of a highly diabetic patient and not given orally ? Question .14. Write briefly about : (i) Exophthalmic goitre (Symptoms and cause). (ii) Diabetes mellitus (Symptom and cause). Question .15. Given figure is the outline of the human body. Redraw the same and then place the following organs in the correct position and label them : Fig. 1 – Thyroid gland; 2 – Windpipe; 3 – Diaphragm; 4 – Right and left lungs; 5 – Right and left kidneys; 6 – Adrenal glands. (i) Name the hormone produced by the thyroid gland and state its function in the body. (ii) What would a child suffer from if there was hyposecretion of this gland ? (iii) What role does the diaphragm play in the inspiration of air. Explain briefly. Question .16. Given below are the diagrammatic sketches of some endocrine glands. Observe the figures and answer the following questions. (i) Label the parts 1 to 5. (ii) Name the hormone secreted by 2 and 5. (iii) Which chemicals in our body are greatly affected by hormones ? (iv) What is the chemical nature of hormones? (v) Name the elements related with the functioning of hormones secreted by the structure (2). SOLUTIONS FOR ENDOCRINE GLANDS Q1. Solution: (i) Insulin. (ii) Adrenal, thyroid / pituitary. (iii) Adrenal gland. Q2. Solution: True. Q3. Solution: (i) Prostate. (ii) Exophthalmic goiter. (iii) Diabetes insipidus. (iv) Blood sugar. (v) Testosterone. Q4. Solution: Category Odd one (i) Hormonal diseases Cataract (ii) Hormones NADP (iii) Hormones Steroids (iv) Endocrine glands Liver (v) Hormones Penicillin. Q5. Solution: (i) Pancreas.  (ii) Exophthalmic goitre. Q6. Solution: 1 – Ovary. 2 – Responsible for developing secondary sexual characters of females. 3 – Secrete glucagons. 4 – Glucagon helps to convert glycogen stored in liver to glucose. 5 – Thyroid. 6 – Thyroxin. 7 – Tears. 8 – Tears lubricate the eyes and prevent dust from entering in the eye. 9 – Pitutiary gland. 10 – Growth hormone (somatotropin). Q7. Solution: 1 – Insulin.  2 – Regulates blood sugar level.  3- Adrenal gland.  4 – Prepare the body for ‘Flight’ or ‘fight’ actions. 5- Thyroid gland.  6 – Promotes tissue metabolism, growth and differentiation.  7 – Anterior lobe of pituitary gland.  8 – Stimulates ovulation, maintaenance of corpus luteum and secretion of progesterone in female and secretion of testosterone in males. Q8. Solution: Endocrine glands are ductless glands which secretes hormones. Q9. Solution: (i) Diabetes mellitus Diabetes insipidus 1. It is caused by the deficiency of insulin. 1. It is caused by the deficiency of ADH. 2. Patient’s urine contains glucose. 2. Glucose is not present in the urine. (ii) Acromegaly Myxedema Due to oversecretion of growth hormone in adult. Due to low secretion of thyroxine in adults. Q10. Solution: (i) Islets of langerhans. (ii) Insulin and glucagons. (iii) Insulin lowers the blood glucose level. Glucagon increases the blood glucose level. Q11. Solution: The soil and water in hilly region is deficient in Iodine. Q12. Solution: 1 – Thyroid – Thyroxine and calcitonin – Thyroxine controls metabolic rates of carbohydrate, protein and fat. 2 – Pancreas – Insulin and glucagon – insulin decreases blood glucose level. 3 – Adrenal medulla – Adrenalin – Increases heart beat and blood pressure. Q13. Solution: Insulin is a protein. It is not given orally as it will be digested in the intestine. Thus it is injected directly into the blood. Q14. Solution: (i) Exophthalmic goiter – Symtoms – Thyroid enlarged, eyes protrude out, high blood pressure and increase in body temperature, patient loses weight. Cause – Exess of thyroxine secreted by thyroid gland. (ii) Diabetes mellius – Symtoms – Increased thrust and urination, increased appetite, presence of glucose in urine. Cause – Under secretion of insulin. Q15.  Q16. Solution: (i) 1 – Larynx; 2 – Left lobe of thyroid gland; 3 – Trachea; 4 – Oesophagus; 5 – Parathyroid. (ii) Part – 2 secretes thyroxine and calcitonin. Part – 5 secretes paratharmonewhich works with calcitonin in regulation of blood calcium. (iii) Enzymes. (iv) Either protines or amino acids or steroids. (v) Iodine is related with the function of gland.  Biology - Absorption by Roots Question .1. Name the following : (i) The tissue that transports manufactured starch from the leaves to all parts of plants.   (ii) The tissue responsible for the ascent of sap in plants. (iii) The pressure responsible for the movement of water molecules across the cortical cells of the root. (iv) Condition of a cell placed in hypotonic solution. (v) The process by which water enters the root hair cell. (vi) The pressure exerted by cell contents on a plant cell wall. (vii) Tissue concerned with upward conduction of water in plants. (viii) Condition of cell in which the cell contents are shrunken. (ix) The inward movement of solvent molecules through the plasma membrane of a cell. (x) The process by which raisin swell up when placed in a beaker of water. (xi) Marine fish when thrown under tap water bursts because of : (a) Endosmosis (b) Exosmosis (c) Diffusion (d) Plasmolysis. (xii) Name the structure which transports manufactured food from leaves to other parts of the plant. (xiii) Name the kind of cells that constitute the cortex of a root. (xiv) Name the process by which intact plants lose water in the form of droplets. Question .2. State true or false : (i) Cells that have lost their water content are said to be deplasmolysed. (ii) Xylem is the water conducting tissue in plants. (iii) Spreading of particles by mixing is called diffusion. (iv) Root hairs are extension of epidermal cells. Question . 3. Arrange the following in correct order so as to be in a logical sequence: (i) Endodermis, root hair, xylem, soil water, cells of cortex. (ii) Cortical cell, root hair, xylem, water, veins. Question .4. Define the following : (i) Hypotonic solution. (ii) Active transport. (iii) Diffusion. Question .5. Explain the term plasmolysis. Give one application of this phenomenon in our daily life. Question .6. Differentiate between : - (i) Cobalt chloride paper and goats bladder. (ii) Osmosis and diffusion Question .7. Choose the correct alternative : (i) Marine fish when thrown under tap water bursts because of (endosmosis, exosmosis, diffusion, plasmolysis). (ii) The space between the cell wall and plasma membrane in plasmolysed cell is filled with (isotonic solution, hypotonic solution, hypertonic solution, water). (iii) Osmosis involves diffusion of (suspended particles from lower to higher concentration, suspended particles from higher to lower concentration, water from the more concentrated solution to the less concentrated solution, water from the less concentrated solution to the more concentrated solution). (iv) The process by which molecules distribute themselves evenly with in the space they occupy is termed as (osmosis, diffusion, active transport, imbibition). (v) Synthesized food in green leaves is transported through (phloem, xylem, pith). Question .8. Give biological reasons for : (i) Salt and sugar are used in preserving food. (ii) Some plants show wilting of their leaves during mid day even when the soil is well watered. (iii) On sprinkling common salt on grass growing in a lawn, the grass is killed. (iv) Wilted lettuce leaves if kept in cold water become crisp. (v) Plants growing in fertilized soil are often found to wilt if the soil is not adequately watered. (vi) Grapes shrink when immersed in a very strong sugar solution. (vii) Root hairs become flaccid, when fertilizers are added to the moist soil around it. (viii) Transplanting of seedling to a flower bed in the evening is better than doing so in the evening. (ix) Strips of potato placed in 50% sucrose solution appear soft and shriveled. Question .9. Potato cubes 1 cm in size were placed in two containers, one containing water, the other containing concentrated sugar solution. After about 24 hours when the cubes were examined, then those placed in water were found to be firm and had increased in size by a few millimeters. Those placed in concentrated sugar solution were found to be soft and had decreased in size. Use the above information to answer the questions that follow : (i) Account for the firmness and increase in size of the potato cubes which were placed in water. (ii) Account for the softness and decrease in size of the potato cubes which were placed in the sugar solution. (iii) Name and define the physical process being investigated in this experiment. Question .10. The diagram below represents an experimental set up to demonstrate a vital process. Study the same and then answer the questions that follow :     Fig.   (i) Name the above process. (ii) Define the above named process. (iii) Mention two advantages of this process to the plant. (iv) Name two liquids that could be used in this experiment. (v) Why did the level of the liquid in the vertical tube rise ? Question .11. The figure given below is a diagrammatic representation of a part of cross section of the root in the root hair zone. Study the same and then answer the question that follow:     (i) Name the parts indicated by guidelines ‘1’ to ‘5’. (ii) Is the root hair cell unicellular or multi-cellular ? (iii) Draw a labelled diagram of the root hair cell as it would appear if some fertilizer is added to the soil close to it. (iv) Name the process responsible for the entry of water molecules from the soil into A1 and then A2. (v) What pressure is responsible for the movement of water in the direction indicated by arrows ? (vi) How is this pressure set up ? Question .12. Given below is the diagrammatic representation of the transverse section of a part of a plant. Study the same and answer the questions that follow :  Fig.  (i) Name the part of the plant that is shown. (ii) Label the parts 1 to 6, indicated in the diagram. (iii) Write the functions of parts 3 and 5. Question .13. Given below are the diagrams of a certain structure in plants in two conditions : Fig. (i) Name the structure shown. (ii) Name the parts numbered 1 – 5. (iii) What is the most apparent difference between A and B in the structure shown ? (iv) Describe the mechanism which brings about the change in the structures depicted in A and B. Biology - Sense Organs QUESTIONS Question .1. Name the following : (i) The eye defect caused due to the shortening of the eyeball from front to back. (ii) The region of distinct vision in the eye. (iii) The tube which connects the cavity of the middle ear with the throat. (iv) The nerve which transmits impulses from the ear to the brain. (v) The part of eye responsible for its shape. (vi) Helps to change the focal length of the eye lens. (vii) The opening through which light enters the eye.  (viii) The photosensitive pigment present in the rod cells in the retina. (ix) The part of eye responsible for change in the size of the pupil. (x) The ear ossicle in contact with oval window of inner ear. (xi) Adjustment of eye in order to obtain a clear vision of objects at different distances. (xii) The cells of the retina that are sensitive to colour. Question .2. State true or false. Rewrite the wrong statements by changing the words. (i) Cones are photoreceptor cells that are sensitive to dim light. (ii) Deafness is caused due to rupturing of pinna. (iii) Cones are receptor cell in retina of eye sensitive to dim light. (iv) Hypermetropia is a defect of eye caused due to eyeball being elongated. Question .3. Write in logical sequence : (i) Ear ossicles, oval window, tympanum, auditory canal, cochlea. (ii) Yellow spot, conjunctiva, pupil, comea, lens, vitreous humour, aqueous humour. Question .4. Eye : Optic nerve : : Ear : ……… . Question .5. Pick the odd one and write the category. (i) Semicircular canal, malleus, cochlea, utriculus, sacculus. (ii) Myopia, hypermetropia, xerophthalmia, astigmatism. Question .6. Mention two functions of the choroids coat in the eye. Question .7. Give exact location and function of : (i) Pinna. (ii) Ear ossicles. (iii) Fovea. Question .8. Structure and functional activity. Organ of corti and ……… .  Question .9. Describe the function of : (i) Eustachian tube. (ii) Iris of the eye. (iii) Ear ossicles. Question .10. Choose the correct answer : Yellow spot and ciliary muscles are found in (eye, ear, heart). Question .11. State briefly : (i) Myopia (symptom and cause). (ii) Tympanum (location and function). (iii) Yellow spot (location and importance). Question .12. Differentiate between : (i) Choriod and sclerotic layers of eye. (ii) Dynamic balance and static balance. (iii) Rod and cone cells. (iv) Myopia and hypermetropia. Question .13. What is meant by power of accommodation ? Name the muscles of the eye responsible for the same. Question .14. Answer briefly : (i) What is a lacrimal gland ? (ii) In what two ways is yellow spot different from blind spot ? (iii) Name an old age eye defect. Why is it caused ? (iv) Mention the characteristics of the image that falls on the retina of the eye. (v) Name the photoreceptors found in retina of eye. Question .15. Draw a labelled diagram of the inner ear. Name the parts of the inner ear that is responsible for static balance in human beings. Question .16. The diagram given below represent the parts of the human ear : Fig. (i) Name the parts labelled 1 to 8. (ii) What is the function of the parts marked 2 and 7 ? (iii) Why is it harmful to use a pin or any sharp object to remove the wax from the ear ? (iv) Give the function of ear wax. Question .17. The given diagram refers to the ear of a mammal : Fig. I. Label the parts 1 to 10 which the guidelines point. II. Which structure : (i) Converts sound waves into mechanical vibrations ? (ii) Converts vibrations into nerve impulses ? (iii) Responds to change in position ? (iv) Transmits impulses to the brain ? (v) Equalizes atmospheric pressure and pressure in the ear ? Question .18. Given below is the diagram of a part of the human ear : Fig. Study the same and then answer the questions that follow : (i) Give the biological term for Malleus, Incus and Stapes. (ii) Name the parts labelled A, B and C in the diagram. (iii) State the functions of the parts labelled ‘A’ and ‘B’. (iv) Name the audio receptor region present in the part labelled ‘A’.

Sense organ answers

Q1 Solution:

(i) Hypermetropia.

(ii) Macula / fovca / yellow spot.

(iii) Eustachian tube.

(iv) Auditory nerve.

(v) Vitreous humour.

(vi) Ciliary muscles.

(vii) Pupil.

(viii) Rhodopsin.

(ix) Iris.

(x) Stapes.

(xi) Accomodation.

(xii) Cones.

Q2 Solution:

(i) False. Rods are photoreceptor cells that are sensitive to dim light.

(ii) False. Deafness is caused due to rupturing of tympanum.

(iii) False. Rods are receptor cells in retina of eye sensitive to dim light.

(iv) False. Myopia defect of eye is caused due to eyeball being elongated.

Q3 Solution:

(i) Auditory canal, tympanum, ear ossicles, oval window, cochlea.

(ii) Conjunctiva, cornea, aqueous humour, pupil, lens, vitreous humour, yellow spot.

Q4 auditary nerve

Q5 Solution:

(i) Parts of inner ear. Malleus.

(ii) Disease of eye. Xerophthalmia.

Q6 Solution:

Choroids forms nutritive layer of eye. Contains iris. It prevents reflection of light inside the eye.

Q7 Solution:

(i) Side of head, collects sound waves.

(ii) Middle ear, increases the magnitude of vibrations.

(iii) Axis of eye in retina, more clear and distinct image is formed.

Q8 hearing

Q9 Solution:

(i) It serves to adjust the pressure inside the middle ear to the change in the atmospheric pressure for normal hearing so that the tympanum is not affected by high pressure.

(ii) The radial and circular muscles of the iris contract or relax and hence the size of the pupil is adjusted.

(iii) It transmits and increase the magnitude of vibrations to inner ear.

Q10 eye

Q11. Solution:

(i) Myopia : – It is also called short sightedness.

Symptom – Near vision is clear and distant vision is blurred.

Cause – Eye ball becomes too longer i.e. eye lens is too convex and hence focal length is shortened. The image of distant object is formed in front of the retina.

(ii) Tympanum : – Location – It is located between external and middle ear. 

Function – Sound waves from outside cause tympanum to vibrate which are ultimately transmitted across the middle ear and produce sound.

(iii) Yellow spot : – Location – At the back of the eye almost at the centre of the horizontal axis of the eye ball.

Importance –Place the best focus of the rays of light that enters and a very clear image is seen in the normal eye.

Q12 Solution:

(i)

Choriod	Sclerotic
Absorb light and prevent total internal reflection that may cause blurring of image.	Provides and maintains shape of eye ball.

(ii)

Dynamic balance	Static balance
The sensory cells in cristae of internal ear are concerned with balance while body is in motion.	The sensory cells in ear which are located in Maculae of vestibule are responsible for static balance in human beings by detecting change in the head or body at rest. Concerned with positional balance with respect to gravity.

(iii)

Rod cells	Cone cells
Rhodopsin	Iodopsin

(iv)

Myopia	Hypermetropia
Lens too convex	Flattened condition of lens

Q13 Solution:

Power of accommodation is the ability of eye to see objects equally clear from various distance. Muscle – Ciliary muscles.

Q14 Solution:

(i) Present on the lateral aspects of eye. They secrete tears which contains lysozymes which kills bacteria.

(ii)

Yellow spot	Blind spot
1. Area of best vision.	1. Area of no vision.
2. Contains maximum cone cells.	2. Contains no rod and cones.

(iii) Presbyopia.

(iv) Real, inverted and diminished.

(v) Rod and cone cells.

Q16 Solution:

(i) 1 – Stapes, 2 – Semicircular canal, 3 – Auditory nerve, 4 – Cochlea,

5 – Eustachian tube, 6 – Ear drum or Tympanum, 7 – Malleus, 8 – Pinna.

(ii) Function of Part 2 – It brings about the dynamic equilibrium which help to maintain body position in response to movement.

Function of Part – 7 – The hammer or Malleus is fastened to the ear drum whose vibrations are transmitted through these three bones (malleus, incus and stapes) to the membrane across the oval window. These bones act as a lever and increases the magnitude or power of vibrations.

(iii) As the pin or any sharp object may injure the ear drum. Hence it is harmful to use pin or any sharp object and must be avoided.

(iv) Ear vax has insect repellent properties and prevent their entry in the auditory canal. It also check the entry of dust particles in the ear. Thus it lubricates and protects the ear drum. 

Q17. Solution:

I. 1 – Cochlea, 2 – Auditory nerve, 3 – Semicircular canals, 4 – Ear ossicles,

5 – Auditory canal, 6 – Pinna, 7 – Ear drum, 8 – Oval window or fenestra ovalis,

9 – Eustachian tube, 10 – Malleus or hammer.

II. (i) Ear drum. 

(ii) Cochlea. 

(iii) Semicircular canal. 

(iv) Auditory nerve. 

(v) Eustachian tube.

Q18. Solution:

(i) Ossicles.

(ii) (A) Cochlea,

(B) Semi-circular canals,

(C) Vestibular apparatus.

(iii) (A) Hearing,

(B) Dynamic balancing.

(iv) Organ of Corti.

Biology - Human Population QUESTIONS COMPILED BY SOUVIC JATI

Question .1. Name the following :

(i) The surgical method of sterilization in the human female.

(ii) A statistical study of human population of a region .

(iii) The number of persons per square kilometer at any one given time.

Question .2. Define the following :

(i) Birth rate.

(ii) Death rate.

Question .3. Rewrite the wrong statement by inserting a word/words.
Death rate is the number of deaths of a given population per year.

Question .4. Mention two reasons for increase in population in India.

Question .5. Answer the following :

(i) What are the age restriction for marriage by law for boys and girls in India ?

(ii) Name two surgical techniques that can be used to prevent pregnancy.

(iii) Give two advantage of small family.

Question .6. The need to limit the size of the family is more vital today than ever before. Give two reasons.

Question .7. Why resources cannot keep pace with the rising population ? Give two examples.

 Populations answers compiled by souvic jati

Q1Solution:

(i) Tubectomy.

(ii) Demography.

(iii) Population density.

Q2 Solution:

(i) Number of births per thousand people of a given population per year in a particular area is called the birth rate.

(ii) The number of deaths per thousand of people of a given population per year in a particular area is called the death rate.

Q3 Solution:

Death rate is the number of deaths per 1000 people of a given population per year.

Q4 Solution:

(i) Illiteracy.

(ii) Poverty.

Q5 Solution:

(i) For boys – 21 years. For girls – 18 years.

(ii) For males – Vasectomy. For females – Tubectomy.

(iii) 1. Parents can provide better education to their children.

2. There is chances of good health of the mother and child.

Q6 Solution:

(i) Due to population growth, the country has to spend more on food, clothing and shelter (housing).

(ii) More population produces more wastes causing pollution and ecological imbalance.

Q7 Solution:

(i) Population grows by geometric progression but food production increases by arithmetic progression.

(ii) Indiscriminate cutting of trees for agriculture is one of the serious consequences of overpopulation.

QUESTIONS Photosynthesis

COMPILED BY SOUVIC SIR

Question .1. Name the following :

(i) The structure where photosynthesis takes place.

(ii) The part of the chloroplast where the dark reaction of photosynthesis takes place.

(iii) Plants that prepare their own food from basic raw materials.

(iv) The energy currency of the cell.

(v) The process by which green plants prepare their own food.

(vi) The product of photosynthesis.

(vii) A plant that does not perform photosynthesis.

(viii) A gas released by green plants during photosynthesis.

(ix) The raw materials needed for photosynthesis.

(x) The site of light reaction.

(xi) The substance from which oxygen is evolved during photosynthesis.

Question .2. State true or false :

(i) Photosynthesis occurs in all the cells of a plant.

(ii) Stomata is stimulated by light.

(iii) Grana helps in diffusion of gases.

(iv) Photosynthesis results in the loss of dry weight of the plant.

(v) The unit of light absorbed by the chlorophyll during photosynthesis is the proton.

(vi) Photosynthesis stops to occur at a temperature above 35 ºC.

(vii) Plants can be destarched by keeping in dark for 48 hours.

Question .3. Choose the correct alternative :

(i) A plant is kept in a dark cupboard for about 48 hours before conducting any experiment on photosynthesis to (remove chlorophyll from leaves, remove starch from the plant , ensure that no photosynthesis occurs, ensure that leaves are free from starch).

(ii) The site of light reaction in the cells of a leaf is (grana, cytoplasm, stroma).

(iii) The chemical substance used to test the presence of starch in the cell of a leaf is (cobalt chloride paper, iodine solution, Benedict’s solution).  

(iv) The specific function of light energy in the process of photosynthesis is to (reduce carbon dioxide, synthesise glucose, activate chlorophyll, split water).

(v) If the rate of respiration becomes more than the rate of photosynthesis plants will (continue to live but will not be able to store food, be killed instantly, grow more vigorously because more energy will be available, stop growing and gradually die of starvation).

(vi) Which one of these reaction occurs during photosynthesis ? (carbon dioxide is reduced and water is oxidized, water is reduced and carbon dioxide is oxidized, carbon dioxide and water both are oxidized, carbon dioxide and water both are reduced).

Question .4. Give exact location and function of :

(i) Stoma,

(ii) Thylakoids,

(iii) Guard cell,

(iii) Grana.

Question .5. (i) Explain the following terms : Photolysis.

(ii) What is meant by photolysis of water ?

Question .6. Answer the following :

(i) Name the two phases of photosynthesis.

(ii) What is the role of light in this process ?

(iii) Describe any three adaptation in a green leaf for photosynthesis.

(iv) Describe an experiment to show that light is necessary for photosynthesis.

Question .7. Define :

(i) Photophosphorylation.
Question .8. Re-write the correct form of statement by inserting a suitable word/words at right place. Do not delete any word in the statement :

(i) Destarching a plant means removing the starch from the plant.

(ii) The splitting of water molecules into hydrogen and hydroxyl ions is termed photolysis.

Question .9. Re-write the terms in correct order in a logical sequence :

(i) Water molecules, oxygen, grana, hydrogen and hydroxyl ions, photons.

Question .10. Complete the following process to show how the oxygen in the air reaches a mesophyl cell of the leaf.

Oxygen in air → −− → −− → Mesophyl cell.

Question .11. Fill in the blanks : Chloroplasts and _______.

Question .12. Distinguish between the following :

(i) Light reaction and Dark reaction.

(ii) Autotrophs and Heterotrophs.

(iii) Stroma and Grana.

(iv) Photosynthesis and Respiration.

(v) Chloroplast and chlorophyll.

Question .13. Enumerate the steps involved in testing a green leaf for the presence of starch.

Question .14. Write the full form of NADP and ATP.

Question .15. A healthy Croton plant bearing variegated leaves was kept in a dark cupboard to destarch it, after which it was placed in sunlight for few hours. One of the leaves was then plucked and an outline of the leaf marking the green and non-green regions was drawn. The leaf was then tested for starch. Using the above information, answer the following questions:

(i) State the aim of the above experiment.

(ii) Name the chemical used for testing the presence of starch.

(iii) Why is the leaf boiled in water and alcohol before testing for the presence of starch ?

(iv) What change is seen on the leaf after the starch test ?

(v) Give the chemical equation to represent the process of syarch formation in plants.

Question .16. A candidate in order to study the importance of certain factors in photosynthesis, took a potted plant and kept in the dark for over 24 hours. Then in the early hours of the morning she covered one of the leaves with black paper in the centre only. She placed the potted plant in the sunlight for a few hours and then tested the leaf which was covered with black paper for starch.

(i) What aspect of photosynthesis was being investigated ?

(ii) Is there any control in this experiment ? If so state the same.

(iii) Why was the plant kept in the dark before the experiment ?

(iv) Describe step by step how the candidate proceeded to test the leaf for the presence of starch.

Question .17. Give biological reasons :

(i) A tiger owes its existence to chlorophyll.

(ii) Oxygen given out during photosynthesis comes from water.

Question .18. (i) Fill in the blank in the following equations for two chemical reactions :

1. ______ + 12H₂O → C H O + ________ + ______.

2. _______ + 6O₂ → 6 ______ +   6 _______ + Energy.

(ii) Name the two process represented by the above two reactions.

(iii) Which one of these two reactions is the support of all life on earth.

Q.19. Draw a neat labeled diagram of the experimental set up to show that green plants give out oxygen during photosynthesis.

SOLUTION TO PHOTOSYNTHESIS QUESTIONS.

1. Solution:

(i) Thylakoid/grana.

(ii) Stroma.

(iii) Autotrophs.

(iv) ATP.

(v) Photosynthesis.

(vi) Glucose, water and oxygen.

(vii) Mushroom/Fungus.

(viii) Oxygen.

(ix) Carbon dioxide and water.

(x) Grana of chloroplast.

(xi) Water.

2. Solution:

(i) F

(ii) T

(iii) F

(iv) F

(v) F

(vi) T

(vii) T.

3. Solution:

(i) Ensure that leaves are free from starch.

(ii) Grana.

(iii) Iodine solution.

(iv) Activate chlorophyll.

(v) Stop growing and gradually die of starvation.

(vi) Carbon dioxide is reduced and water is oxidized.

4. Solution:

(i) Stoma : Location – Epidermis of leaves. Function – Exchange of gases for photosynthesis/respiration/loss of water as water vapour during transpiration.

(ii) Thylakoids : Location – Granum of chloroplast. Function – Help in traping sun-light (photosynthesis).

(iii) Guard cell : Location – Around stomata mostly under the surface of a dorsiventral leaf. Function – Allow diffusion of gases.

(iv) Grana : Location – Inside chloroplast. Function – Help in trapping sunlight.

5. Solution:

(i) Splitting of water by light in photosynthesis.

(ii) Splitting of water into hydrogen and hydroxyl ion in presence of sunlight.

6. Solution:

(i) 1. Light reaction (Photolysis of water).

2. Dark reaction (CO₂reduction). 

(ii) Light has energy giving photons which activate and ionize chlorophyll to release electrons. The electrons (split) ionize water molecules. This process is called photolysis.

The H+ reduces CO₂ to form crbohydrates. 

(iii) 1. Large surface area : The surface area of the leaves is very large due to which maximum light energy is absorbed from the sunlight. 

2. Leaf arrangement : The arrangement of leaves on the stem are in such a way that maximum surface area is exposed to sunlight.

3. Chloroplasts : Chloroplasts containing chlorophyll are concentrated in the upper surface of the leaf which helps in trapping maximum radiant energy from the sunlight quickly.

(iv) Aim : To demonstrate that light is necessary for photosynthesis.

Requirements : A destarched potted plant, Gangon’s light screen.

Procedure :

1. Gangon’s light screen is fixed to one of the leaves of the potted plant (destchared) as shown in figure below.

2. The plant is then fixed in light at least for 6 hours.

3. The starch test is performed.

Fig. Ans. 20 (iv)/page – 38 [evergreen]

Observation : We observe that the portion of screen that allows the light to fall on leaf gives positive starch test and the portion covered with light screen gives negative starch test.

Inference : Light is necessary for photosynthesis.

7. Solution:

(i) Conversion of low grade energy ADP into high potential chemical energy ATP is called photophosphorylation.

8. Solution:

(i) Destarching the plant means removing the starch from the leaves of plant.

(ii) The splitting of water molecules into hydrogen and hydroxyl ions by light is termed photolysis.

9. Solution:

(i) Photons, grana, water molecules, hydrogen and hydroxyl ions, oxygen.

10. Solution:

Oxygen in air → stoma → substomatal space → Mesophyl cell.

11. Solution:

Photosynthesis.

12. Solution:

(i)

Light Reaction	Dark Reaction
1. Presence of light is must.	1. It does not require light.
2. It occurs in the grana of chloroplast.	2. It occurs in the stroma of chloroplast.
3. Its product are ATP and NADPH2.	3. Its product are organic compounds.

(ii)

Autotrophs	Heterotrophs
1. They can produce their own food.	1. They can prepare their own food.
2. They contain chlorophyll.	2. They do not contain chlorophyll.

(iii)

Stroma of Chloroplast	Grana of Chloroplast
1. Here dark reaction takes place.	1. Here light reaction takes place.
2. It is a non-green granular matrix.	2. It is a green flattened sac-like structure.

(iv)

Photosynthesis	Respiration
1. It is an anabolic process.	1. It is a catabolic process.
2. It takes place only in chlorophyll bearing cells.	2. It takes place in all cells.
3. Oxygen and glucose released as end-products.	3. Carbon dioxide and water released as end-product.
4. It takes place only in presence of light.	4. Light is not required.

(v)

Chloroplast	Chlorophyll
1. It is an organelle of the cell.	1. It is the green pigment in chloroplast.
2. It is living.	2. It is non-living.

13. Solution:

Step I – The leaf is dipped in boiling water for a minute to kill the cells.

Step II – The leaf is boiled in methylated spirit to remove chlorophyll.

Step III – The leaf is put in normal water to make it soft.

Step IV – Iodine solution is put which turns starch blue black.

14. Solution:

NADP – Nicotinamide adenine dinucleotide phosphate.

ATP – Adenosine tri phosphate.

15. Solution:

(i) To prove that chlorophyll is necessary for photosynthesis.

(ii) Iodine solution.

(iii) Cells are killed by boiling and chlorophyll is dissolved in alcohol.

(iv) The green parts turn blue black and non-green parts turn brown.

(v) 

16. Solution:

(i) To show that sunlight is necessary for photosynthesis.

(ii) Yes, the uncovered portion of the experimental leaf is the control.

(iii) To destarch the leaf.

(iv) 1. The leaf is boiled in alcohol to remove chlorophyll.

2. The leaf is washed in water to make it soft.

3. The iodine solution is added to the leaf.

The uncovered portion shows blue-black colour and the portion covered shows brown colour. This indicate that sunlight is necessary for photosynthesis.

17. Solution:

(i) Green plants synthesizes food by photosynthesis using chlorophyll. Tiger feed on animal which feed on green plants. Thus they obtain their food indirectly from green plants. That is existence of tiger depends upon chlorophyll. 

(ii) Due to photolysis of water oxygen is released during photosynthesis.

18. Solution:

(i)

(ii) Photosynthesis and respiration.

(iii) Photosynthesis.

19.