Category: ICSE Solutions

Frank ICSE Class 10 Biology Solutions – Health

PAGE NO : 162
Solution 1:

1. Disease: Any physical or physiological disorder in normal functioning of any organ or part of body is called disease.
2. Health: Health is a state of complete mental, physical and social well being.
3. Vaccinations: It is the practice of introducing vaccine (weakend or killed germs) into the body to develop immunity to a particular disease.
4. Immunity: It is the ability of the body to resist microorganisms that enter the body and thus prevent diseases.
5. Antiseptic: Antiseptics are chemicals applied on the body to prevent the growth of microorganisms.
6. Cancer: Cancer is the uncontrolled growth of abnormal cells in the body.
7. Allergy: Allergy is a hypersensitive state acquired through exposure to a particular allergen such as drugs, pollens or microorganisms.
8. Hypersensitivity: It refers to undesirable and excessive reactions in response to an allergen produced by the normal immune system.
9. Immunization: It is the process by which the body is protected against disease by inoculating the person with vaccine.
10. Disinfectant: Disinfectants are chemicals applied on the spots to prevent the growth of microorganisms.
11. Penicillin: It is an antibiotic which was discovered firstly from a fungus , Penicillium notatum.
12. Sulphonamide drugs: Sulphonamide drugs are a group of synthetic drugs which prevent the growth and multiplication of bacteria. They are commonly called as sulpha drugs.
13. Acquired disease: Acquired diseases are those diseases which are caused by a pathogen or deficiency diseases.
14. Prophylaxis: A prophylaxis is a measure taken to maintain health and prevent the spread of disease.
15. Antibiotic: Antibiotics are the chemical substances formed from microorganisms which kill or prevent the growth of disease causing microbes.

Solution 2:

Solution 3:
Artificial Respiration: It is a method of first-aid used to restore or maintain respiration in a person who has stopped breathing. The method uses mechanical or manual means to force air into and out of the lungs in a rhythmic fashion.

Solution 4:
DPT: Diphtheria, Pertussis and Tetanus.

Solution 5:
Antigens, that cannot stimulate the immune system of the body of a person, are called haptene.

Solution 6:
The three germ killing secretions of our body are:

1. Mucus secretions from windpipe
2. Hydrochloric secretions from stomach
3. Tears from eyes.

Solution 7:
BCG stands for: Bacillus Calmette Guerin.

Solution 8:

1. Antiseptic: Antiseptic are mild chemical applied on the body to kill the microorganisms. Example: Halogens (I)
2. Antibiotic: Antibiotic is a natural chemical substance produced by a microorganism, which inhibits or kills another microorganism. Example: Penicillin

Solution 9:

1. Passive acquired immunity
2. Antiseptics

Solution 10:
antibiotic

Solution 11:
Antiseptics are the chemical substances applied on the body to destroy or prevent the growth of microbes. It is harmless to skin and body. For example Alcohols, halogens can be used as antiseptic on skin.

Solution 12:
The two international health organisations are: WHO and Red Cross.

PAGE NO : 163

Solution 13:
Vaccination: It is the practice of artificially introducing the germs or the germ substances into the body for developing resistance to particular disease.

Solution 14:

1. Disinfectants: Disinfectants are chemicals applied on the spots to prevent the growth of microorganisms. It is a strong germ-killing substance. But it may cause harm to skin and body. Example: Lysol, DDT etc.
2. Penicillin: Penicillin is the first antibiotic discovered by Alexander Fleming. It is obtained from Penicillium notatum. It has a very high therapeutic value and used against a number of gram positive bacteria including those causing Rheumatic fever , pneumonia , sore throat etc.
3. Sulphonamides: Sulphonamides popularly called sulpha drugs are a group of synthetic drugs which possess bacteriostatic property because they are able to block the enzyme system of bacteria.
4. Vaccines: Vaccine is a preparation consisting of dead or weakend microbes which help to build immunity in the human body .When introduced in an individual, a vaccine stimulates the production of antibodies against the particular type of germs.

Solution 15:

1. proteins that react with antigens or invading germs
2. antigen
3. Penicillin, rheumatic fever

Solution 16:

1. True
2. False
3. True
4. True
5. False
6. True
7. False
8. True

Solution 17:

1. (a) Plasma Protein
2. (b) destroy micro-organisms
3. (a) I
4. (c) Jenner
5. (c) Tuberculosis
6. (d) 1985
7. (b) eradicating Polio by 2000.
8. (c) diphtheria
9. (b) virus
10. (c) Small Pox

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Frank ICSE Class 10 Biology Solutions – Human Population

PAGE NO : 153
Solution 1:

1. Population: It is the total number of individuals of a species found in a particular area.
2. Sanitation: It refers to the formulation and application of measures intended to protect public health.
3. Deforestation: It is the removal of a forest or stand of trees from an area and thereafter that area is converted to a no forest use.
4. Birth control: It is an attempt to control the number of births in a family so that a couple may not have more than two children.
5. Rhythm method: It is a natural method of birth control in which the couple attempts sexual intercourse a week before and a week after the menstrual cycle.
6. Abstainence: It is the act or practice of refraining from sexual intercourse.
7. Test-Tube baby: A test tube baby is one which is developed from an egg that was fertilized outside the body and then implanted in the uterus of the biological or surrogate mother.
8. Birth rate: It is the total number of live births per thousand people of the population per year.
9. Death rate: It is the number of deaths per thousand people of the population per year.
10. Population density: It is the total number of individuals of a particular species in relation to unit area at any given time.
11. Natality: It is the number of live births per thousand people of the population per year.

Solution 2:
Growth rate

Solution 3:
Demography

Solution 4:
The two important methods for birth control are:

1. Vasectomy
2. Tubectomy

Solution 5:
The two reasons for the rapid increase of population in India recently:

1. Advancement of science and technology
2. Better health care facilities

Solution 6:
The age restrictions for marriages by law for boys and girls in India are:
Boys: 21 years
Girls: 18 years

PAGE NO : 154
Solution 7:

1. “Our resources cannot keep pace with the rising population”.
   • Population increases geometrically while food production is increasing arithmetically.
   • Rising population is putting heavy pressure on natural resources like water, land forest etc.
   • Fuel shortage is increasing day by day.
2. The three steps which may be taken towards controlling the rapid rise in human population in India are:
   • Education: People should be educated about the advantages of a small family.
   • Marriageable age: Population can be controlled by raising the age limit for marriage.
   • Family planning: Voluntary family planning using birth control measures and contraceptives can check the growth of population.

Solution 8:
The main drawbacks of a large population are that it may lead to shortage of basic resources like food, water, fuel etc without which life would become impossible. In addition, overcrowding can also cause epidemics, poverty, unemployment etc.

Solution 9:
The steps taken by the Indian government to control population are:

1. Establishment of health centers to advice and help people about family planning.
2. Free distribution of barrier contraceptives like condoms.

Solution 10:
The two advantages of a small family are:

1. Children can be provided with good health and good education along with the basic needs of life.
2. Living standards of the family can be high.

Solution 11:
Population explosion: The exceptionally high rate of population growth is known as Population explosion.
The consequences of Population explosion may be overcrowding, shortage of resources like food, water, land, fuel etc. It can also result in unemployment, poverty, social unrest, epidemic, violence etc.

Solution 12:
Population density: It is the number of people per square kilometer at any given time.
Tubectomy is the operation made in women to prevent the flow of eggs into the oviduct.

Solution 13:
Following are the two reasons for the decline in death rate in India in recent times:

1. Advancement in the field of medical science which leads to reduced morality rate.
2. Longevity provided by better food and health services.

Solution 14:
The symbol of family welfare in our country is an ‘Inverted Red Triangle’.

Solution 15:
Family welfare centres are set up in hospitals and other health centres to advocate small families and to promote family welfare and planning. These centres advice people on issues such as family planning, gap between successive children etc without any cost.

Solution 16:
Following are the methods of fertility control in men and women:
Men: Vasectomy is a method of fertility control in men. In this method, a small portion of vas deferens is cut and is tied at both the ends.
Women: Tubectomy is a method of fertility control in women in which the fallopian tubes are cut and are tied at both the ends.

Solution 17:
Tubectomy is the surgical method of contraception in human female.

Solution 18:

1. Population density
2. Mortality

Solution 19:
The resources cannot keep pace with the rising population because:

1. The demand of resources is much more than the supply. The population is growing at geometric progression (1, 2, 4, 8) while the production of food can increase only arithmetically (1, 2, 3, 4, 5).
2. New towns and cities coming up to accommodate the growing population are putting strain on the agricultural land.

Solution 20:

1. False
2. False
3. True
4. True
5. True

Solution 21:

1. 2011
2. Population density
3. females, males
4. two
5. Natality
6. Mortality
7. Age ratio

Solution 22:

1. 
2. Vasectomy
3. Vas deferens
4. Tubectomy
5. The part which is ligated in females is Fallopian tube. This is done to prevent the flow of eggs into the oviduct and its fusion with the sperm.

PAGE NO : 155
Solution 23:

1. (b) 20
2. (d) 35 years
3. (d) 7 billion
4. (c) 840 million
5. (c ) biotic potential
6. (c ) loss and gain are equal
7. (c) decrease in death rate and increase in longevity
8. (d) copper-T
9. (d) progesterone
10. (c) to prevent the presence of sperms in the semen

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Frank ICSE Class 10 Biology Solutions – Reproductive System

Solution 1:

1. Testes
2. Ovary
3. Uterus
4. Oviduct
5. Fertilization
6. Parthenogenesis
7. Testes and ovaries

Solution 2:

1. penis
2. vagina
3. oviduct
4. female
5. oviduct

Solution 3:

1. Ovary: To produce ova and three female sex hormones i.e oestrogen, progesterone and relaxin.
2. Fallopian tube: To transport eggs from ovary to uterus and it a site of fertilization.
3. Uterus: To protect and provide nutrients for the developing embryo.
4. Vagina: To receive the seminal fluid.
5. Testes: To produce sperms and male sex hormone i.e. testosterone.
6. Penis: deposition of semen into the female’s vagina.

Solution 4:

1. Parthenogenesis: It is a type of asexual reproduction in which a female gamete or egg cell develops into an individual without fertilization.
2. Asexual reproduction: It is the type of reproduction in which the offspring are formed without the production of gametes.
3. Sexual reproduction: It is the type of reproduction in which the offspring are formed after the fusion of gametes.
4. Dioceious: It is the individual / organism having male and female reproductive organs in separate individuals.
5. Monoecious: It is the individual / organism having male and female reproductive organs in the same individual.
6. Clone: It is a group of genetically identical cells or organisms asexually descended from a common ancestor.

Solution 5:

1. Parturition: The expulsion of the foetus from the mother’s body is called parturition.
2. Ovulation: The process of release of an egg from the ovary is called ovulation.
3. Spermatogenesis: The production and development of sperms is called spermatogenesis.
4. Gestation: The period in which an embryo develops in the uterus is called gestation.
5. Implantation: The attachment of developing zygote to the uterine wall is called implantation.

Solution 6:

PAGE NO : 142
Solution 7:

1. Graafian follicle
2. Uterus
3. Ovulation is the process of releasing of egg from the ovary.
4. The hormones secreted by the ovary are: oestrogen and progesterone.

Solution 8:

1. Peritoneum
2. Ureter
3. Backbone
4. Rectum
5. Seminal vesicle
6. Glands
7. Anus
8. Vas deferens
9. Epididymis
10. Left testis
11. Scrotum
12. Penis
13. Urethra
14. Vascular erectile tissue
15. Bladder
16. Muscular wall of abdomen
    The two functions of part 6 are :
    • Prostate gland secretes an alkaline milky secretion into semen that aids in sperm motility.
    • Cowper’s gland also secretes a lubricant.
17. The three components of urine are urea, uric acid, amino acids, glucose, sodium, potassium, vitamins etc.
18. he main function of the part labelled 3 is backbone. Its function is to give support, movement and protection to the spinal cord.

Solution 9:

Solution 10:

1. Graafian follicle
2. Seminal vesicles and prostate gland
3. Uterus
4. Parturition
5. Oviduct

PAGE NO : 143
Solution 11:

1. Fallopian tube
2. Funnel like opening
3. Uterus
4. Sacrum
5. Rectum
6. Cervix
7. Anus
8. Vagina
9. Front of pelvis
10. Bladder
11. Muscular uterine wall
12. Muscular wall of abdomen
13. Peritoneum
14. Normally, after 28 days an ovary releases an egg.
15. During coitus, sperm are released in the vagina.
16. After ejaculation in vagina, sperms undergo fertilization where it fuses with an ovum of female to form zygote.
17. The function of sacrum is to protect the pelvic organs or reproductive organs of female.
18. The gestation period in human is 280 days.

Solution 12:

1. False
2. False
3. True
4. False
5. True

Solution 13:
False.
Pregnancy in women can be prevented by the method of tubectomy.

Solution 14:
Amnion.

Solution 15:

1. Menarche
2. Ovulation
3. Menstruation
4. Fertilization
5. Implantation

Solution 16:

1. (b) continuity of race
2. (b) asexual reproduction
3. (b) female gamete
4. (c) Parthenogenesis
5. (b) vagina
6. (c ) castration
7. (b) oviduct
8. (c ) puberty
9. (b) menarche
10. (c ) 20-30C below the body temperature
11. (d) menarche
12. (b) 10 days

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Frank ICSE Class 10 Biology Solutions – Endocrine System

PAGE NO :128
Solution 1:

1. Pituitary gland
2. Somatotrophin
3. Thyroxine
4. Pancreas
5. Liver
6. Adrenal gland
7. Adenohypophysis
8. Neurohypophysis
9. Thyroxine

Solution 2:

1. Somatotrophic Hormone – It is essential for the normal growth of an organism.
2. Thyroid-stimulating hormone – It stimulates the activity as well as the growth of thyroid glands.
3. Adrenocorticotrophic hormone – It stimulates the activity of the adrenal cortex.
4. Gonadotrophic hormone – It promotes the growth of ovarian follicles in females and the growth of sperms in males.
5. Insulin hormone – It lowers the blood sugar level.
6. Corpus luteum – It secretes progesterone.
7. Glucagon hormone – It raises the blood sugar level.

Solution 3:

1. Insulin
2. STH
3. Islets of Langerhans
4. STH
5. Insulin

Solution 4:

1. FSH – Follicle-stimulating hormone
2. LTH – Luteotropic hormone

Solution 5:

PAGE NO :129
Solution 6:

1. (b)
2. (c)
3. (a)
4. (e)
5. (d)

Solution 7:

1. True
2. False
3. False
4. False
5. False

Solution 8:

1. Hormone – The secretions of endocrine glands which are carried by blood to the target organs are called hormones.
2. Endocrine gland – The glands without ducts which secrete hormones are called endocrine glands.
3. Exocrine gland – The glands with ducts which secrete enzymes are called exocrine glands.
4. Hypothyroidism – It is the under secretion of thyroxine by thyroid gland which leads to retarded growth and mental development in infants.
5. Hyperglycemia – Increase in blood sugar level is called hyperglycemia.
6. Hypersecretion – The over activity of any gland leads to over secretion of hormones called hypersecretion.

Solution 9:

Solution 10:

1. Diabetes mellitus – Diabetes mellitus is a disease caused by the deficiency of insulin hormone.
2. Beta cells – Beta cells are the cells of pancreas that secrete insulin.
3. Exophthalmic goitre – The over activity of thyroid gland leads to its enlargement, producing a big swelling in the neck region called exophthalmic goiter.
4. Releasing hormones – A substance produced by the hypothalamus that is capable of accelerating the secretion of a given hormone by the anterior pituitary gland.

Solution 11:

Solution 12:
Insulin secreted by pancreas controls the level of glucose in blood.

Solution 13:
Adrenaline is called an emergency hormone because it brings rapid physiological responses to emergencies like danger, fear or other situations requiring vigorous action.

Solution 14:

Solution 15:



Solution 16:

1. Exophthalmic goiter – It is caused due to overactivity of the thyroid gland.
   Symptoms are – Enlargement and protrusion of the gland below the chin, increased pulse rate, nervousness, and bulging of the eyes.
2. Diabetes mellitus – It is caused due to less secretion of the insulin hormone.
   Symptoms are – Frequent urination, Sudden weight gain or weight loss, excessive thirst, and hunger.

Solution 17:
In hilly region, water has less iodine which is required for the production of thyroxine. So due to the deficiency of thyroxine, people suffer from goiter.

Solution 18:
Insulin is a protein hormone and if it is given orally it would be digested upon by the protein digesting enzymes in the alimentary canal.

Solution 19:

1. The endocrine cells present in pancreas are: alpha cells, beta cells and delta cells.
2. Insulin and glucagon.
3. Insulin – It lowers the glucose level in the blood.
4. Glucagon – It raises the level of glucose in the blood.

Solution 20:

1. Adrenaline
2. Insulin
3. Glucagon
4. Thyroxine
5. Calcitonin
6. Adrenaline
7. Growth stimulating hormone
8. Sex corticoids
9. Antidiuretic hormone
10. Non adrenaline

Solution 21:

1. (b) Diabetes
2. (b) Adrenal gland
3. (d) Pancreas
4. (b) Gigantism
5. (a) Insulin
6. (b) Liver
7. (c) Target
8. (c) under secretion of insulin
9. (a) beta cells of the pancreas
10. (d) glucagon
11. (c) progesterone

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Frank ICSE Class 10 Biology Solutions – Excretory System

PAGE NO : 97
Solution 1:
Separation and elimination of the metabolic nitrogenous wastes from the body is called excretion.
Kidneys, skin and lungs are important excretory organs.

Solution 2:
Carbon dioxide (CO2) and urine

Solution 3:
Ammonia is toxic in even small amounts and therefore it must be removed from the body. The urea cycle or the orinithin cycle, in the liver, involves the conversion of ammonia into urea. Then the urea is then transported to the kidneys where it is excreted.

Solution 4:
Nephron is the basic structural and functional unit of the kidney.
Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.

Solution 5:

PAGE NO : 98
Solution 6:
Dialysis is a process of separation of toxic substances from the blood stream through a membrane by kidney machine or artificial kidney.

Solution 7:

1. Ammonotelic.
2. Ureotelic.
3. Uricotelic.
4. Liver.
5. Nephron.
6. Urinary Bladder.
7. Glomerulus.

Solution 8:

1. Vein
2. Heart
3. Haemoglobin
4. Glomerulus
5. Nerve
6. Brain

Solution 9:

1. Separation and elimination of the metabolic nitrogenous wastes from the body is called excretion.
2. Nephron.
3. The cortex of kidney shows dotted appearance because it contains numerous complex structures called nephrons.
4. Formation of urine and osmoregulation are important functions of kidney.

Solution 10:

1. (a) kidney
2. (a) pigeon
3. (c) haematuria
4. (d) anuria
5. (d) Nothing will happen
6. (a) liver
7. (b) urease
8. (b) vitamin C
9. (b) liver
10. (c) nephron
11. (b) renal papilla

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Frank ICSE Class 10 Biology Solutions – Circulatory System

PAGE NO : 90
Solution 1: Circulatory system: It is a system of organs that takes part in the flow of materials in the body of an organism inside an extracellular fluid.
Circulatory system in humans:

1. The right atrium receives deoxygenated blood from all the parts of the body through large veins called vena cava.
2. When the right atrium is full of blood, it contracts and the blood is forced into right ventricle.
3. When the right ventricle is full of blood, it contracts and the blood is pumped into the pulmonary trunk.
4. From right ventricle, the pulmonary artery carries the blood to the lungs for oxygenation.
5. The oxygenated blood returns to the heart via pulmonary veins that empty into the left auricle.
6. When the left auricle contracts, the blood passes into the left ventricle by the opening of bicuspid valve.
7. On contraction of the left ventricle, the blood is pumped into the artery called aorta.
8. The aorta branches into vessels which transports blood to the heart and all the body parts.

Solution 2:

1. The SA is also called the pacemaker because it establishes the basic frequency at which the heart beats. It starts each heart beat and sets the pace for the whole heart.
2. There is no mixing of deoxygenated and oxygenated blood in the human heart because of double circulation of blood where the blood passes twice through the heart and the right half of the heart is concerned with pumping deoxygenated blood while the left is concerned with pumping of oxygenated blood.
3. The closed circulatory system is more efficient than the open system because in closed system the blood flows inside arteries or veins all the time which stops the mixing of blood with other bodily fluids and helps the transport of the blood around the body.
4. The left ventricle possess a thicker wall than the right ventricle because it pumps the blood at a higher pressure since blood from the left ventricle goes to all areas of the body while the right ventricle only has to pump blood to the lungs which is a much shorter distance, therefore less pressure is required.

Solution 3:

Solution 4:
The functions of blood plasma : It transports gases and other materials, maintains blood pH, body immunity, body heat regulation and also regulates the osmotic pressure of the blood.

Solution 5:
Double circulation means during one circulation blood passes twice through the heart. It includes both pulmonary and systemic circulation. It is necessary as it keeps oxygenated and deoxygenated blood separate.

Solution 6:
The materials which are carried by the blood are: oxygen, carbon dioxide, water, digested food, organic wastes, hormones and antibodies.

Solution 7:
The main function of erythrocytes is to transport the respiratory gases – CO2 and O2.

Solution 8:

1. Fibrinogen
2. Phagocytosis
3. Haemoglobin
4. Auricular systole
5. Angiology
6. Pericarditis
7. Tricuspid valve
8. Foramen ovale
9. Polycythemia
10. Lubb

PAGE NO : 91
Solution 9:

1. Histone
2. Foramen ovales
3. Nerve
4. RBC
5. Albumin

Solution 10:

1. Inferior vena cava, superior vena cava and coronary sinus
2. Ventricles
3. Function of bicuspid valve: It prevents the reverse flow of blood from the left ventricle into the left auricle.
4. Function of tricuspid valve: It prevents the reverse flow of blood from the right ventricle into the right auricle.

Solution 11:

Solution 12:

1. (c) Pulmonary vein
2. (b) Thebasius valve
3. (d) Aorta
4. (e) Pulmonary arch
5. (a) Clotting

Solution 13:

1. (d) 5 l
2. (c ) Left ventricle
3. (b) Capillaries
4. (a) bone marrow
5. (c ) 120 days
6. (a) myogenic
7. (a) Eustachian valve
8. (c ) ventricle
9. (b) 70-80
10. (c ) Monocytes
11. (d) 90%
12. (c) William Harvey
13. (b) Spleen
14. (d) all the above
15. (d) O

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Frank ICSE Class 10 Biology Solutions – Photosynthesis

PAGE NO : 74
Solution 1:

Solution 2:

1. Plant pigments – Plant pigments are a variety of different kinds of molecules present in plants that absorb certain wavelengths of light while reflecting others.
2. Quantum – Quantum are the discrete packets which stores energy and these particles can be changed from one form to another.
3. Organic food – The food that is produced by using methods that do not involve synthetic inputs such as synthetic pesticides and chemical fertilizers is called organic food.
4. Light reaction – The reaction of photosynthesis which takes place in the presence of light is called light reaction.
5. Photolysis in photosynthesis – The process of splitting of water by sunlight during light reaction of photosynthesis is called photolysis in photosynthesis.

Solution 3:

Solution 4:

Solution 5:

1. The aim of the experiment is to prove that CO2 is necessary for photosynthesis.
2. Potassium hydroxide absorbs CO2 from the surrounding. It is placed to remove CO2 within the conical flask.
3. The leaf inside the conical flask would be tested for the presence of starch by the application of iodine.
4. The expected result of the above test is – No change in the colour will be observed.
5. Yes, it is necessary to similarly test on the outer leaf also to show that leaves present in CO2 show photosynthesis.

Solution 6:

1. 1 – Upper Epidermis; 2 – Palisade layer / chloroplast; 3 – Xylem; 4 – Phloem; 5 – Guard cell
2. The two arrows show the release of oxygen and water vapours during the daytime and carbon dioxide and very less amount of oxygen is released during the night.
3. Yes, one more arrow can be added to show the absorption of carbon dioxide by the leaf.
4. One vein has been shown in this section.

Solution 7:

Solution 8:

Solution 9:

PAGE NO : 75
Solution 10:

1. The objective of this experiment is to prove that oxygen is released during photosynthesis.
2. Hydrilla
3. Oxygen
4. The rate of photosynthesis will increase and the rate of bubbling also increases when sodium bicarbonate is added.
5. Photosynthesis will not take place.

Solution 11:

1. The leaf is then treated with iodine solution.
2. The leaf from first plant will not show starch test while the leaf from second plant will become blue-black showing the presence of starch.
3. It is necessary to grease the glass sheet to prevent the entry of air containing CO2.
4. The hypothesis that CO2 is necessary for photosynthesis is being tested in this experiment.

Solution 12:
Light intensity is directly proportional to sunlight. Increase in intensity of light increases the rate of photosynthesis. Photosynthesis is maximum in red light followed by blue light and is least in green light.

Solution 13:

1. Advantages of photosynthesis:
   • To produce food for all the organisms on earth.
   • Release oxygen which is a life supporting gas.
2. Respiration is a catabolic process while photosynthesis is an anabolic process. During respiration oxygen is taken and carbon dioxide is given out while during photosynthesis carbon dioxide is taken and oxygen is given out.
3. Chlorophyll is a green coloured pigment found in green plants. it absorbs light energy which is utilized for the formation of ATP and reduction of NADP during photosynthesis.

Solution 14:

Solution 15:

Solution 16:
Coelus and mushroom.

Solution 17:
It is because the upper surfaces of broad leaves are directly exposed to sunlight which leads to maximize the rate of photosynthesis.

Solution 18:

Solution 19:
Chlorophyll.

Solution 20:
True

Solution 21:
False

Solution 22:
During the day transpiration and photosynthesis are interlinked as the stomata opens to facilitate the inward diffusion of carbon dioxide for photosynthesis which also leads to loss of water vapours to the outside during transpiration.

PAGE NO : 76
Solution 23:

1. Destarched plant is the plant which lacks starch. Destarching is done by keeping the plant in dark for 2-3 days or covering a part of a leaf with a black paper by clip.
2. (a) The leaf is plucked and is boiled in water and decolourized with alcohol.
   (b) The portion of leaf which received light turns blue with iodine because photosynthesis took place in that part of leaf.
   (c) The part of leaf which was covered with black paper remains colourless because photosynthesis could not take place in the absence of sunlight.

This shows that starch is not manufactured in the absence of light.

Solution 24:

1. Chloroplast.
2. Glucose and oxygen.
3. Fungi, insects and animals.
4. Photolysis.
5. Magnesium.
6. Chloroplast.

Solution 25:

1. True
2. True
3. False
4. True
5. True
6. True
7. False
8. False
9. True

Solution 26:

1. Photosynthesis
2. Atmosphere
3. Glucose
4. Yellow
5. Chloroplast
6. Glucose and oxygen
7. Stomata

Solution 27:

1. (d) During night
2. (e) Green plants
3. (f) Oxygen
4. (b) Light reaction
5. (a) Decomposers

Solution 28:
Chloroplasts are the cell organelles in green plants which have chlorophyll and thus serve as the main site of photosynthesis.

Solution 29:

1. Large surface area of leaves.
2. Presence of more stomata.
3. The thinness of leaves.

Solution 30:
Carbon cycle is a series of chemical reactions in which atmospheric carbon dioxide is used by the organisms and returned to the atmosphere. Photosynthetic plants use carbon as carbon dioxide from the air synthesizing organic compounds. By respiration, burning, decay, etc. the carbon is returned to the atmosphere.

Solution 31:
Carbon in the form of carbon dioxide enters living organisms and then goes back to the atmosphere through several pathways forming the true carbon cycle. Thus, it helps in maintaining the balance of nature.

Solution 32:
The amount of carbon dioxide in the atmosphere is increasing due to increased human activities like burning of fossil fuels, deforestation, etc. which cause the rise in global temperatures. This global warming result in melting of polar ice caps, floods in coastal areas, disturbance in hydrogenic cycle etc. Thus “Human activities are harmful to the balance of nature”.

Solution 33:
Carbon dioxide is removed from the atmosphere by:

1. Producers – Producers or green plants use carbon dioxide through photosynthesis. A small amount of carbon dioxide is used by chemosynthetic bacteria also.
2. Marine Organisms – Some amount of carbon dioxide is directly fixed by a few marine organisms and sea water absorbs carbon dioxide in the form of dissolved carbon dioxide, carbonic acid, carbonate and bicarbonates.

PAGE NO : 77
Solution 34:

1. Carbon dioxide is returned back to the atmosphere mainly through the following ways:
   • Respiration – Animals and plants respire and release carbon dioxide in the atmosphere.
   • Decay – Plants and animals decay organic matter with the help of bacteria and fungi and release carbon dioxide.
   • Combustion – Plants and animals which got buried under the soil changed into coal and oil and releases carbon dioxide when these are burnt.
   • Ocean water – Carbon dioxide occurs in the form of lime stone in molluscan shells and as by product of photosynthesis in marine water.
2. (i) To show that sunlight is needed for photosynthesis.
   (ii) Yes, the uncovered portion of the experimental leaf is the control.
   (iii) To destarch the leaf.
   (iv) 1. Boil the leaf in alcohol.

2. Wash the leaf in water to make it soft.
3. Add iodine solution on the leaf. The portion uncovered shows blue-black colour and the portion covered shows brown colour. This indicates that sunlight is needed for photosynthesis.

Solution 35:

1. (e) 5
2. (a) 1
3. (b) 2
4. (e) 5

Solution 36:

1. leaves
2. water
3. hydrogen ion
4. photolysis
5. hydrogen
6. NADPH2
7. ATP
8. photophosphorylation
9. glucose
10. polymerization

Solution 37:

1. (d) 3.5
2. (b) Oxygen
3. (c) Water
4. (c) Decrease because the temperature drops.
5. (b) Increases because more photosynthesis occurs.

PAGE NO : 78
Solution 38:

Solution 39:

1. (d) To stop synthesis process in the leaves.
2. (c) Chloroplasts
3. (d) split water
4. (c) Palisade mesophyll
5. (b) ADP
6. (b) liberate O2
7. (a) Grana
8. (b) Red light
9. (d) Carbon dioxide
10. (d) water, carbon dioxide, chlorophyll and sunlight

BiologyChemistryPhysicsMaths

Frank ICSE Class 10 Biology Solutions – Transpiration

PAGE NO:60
Solution 1:

1. Transpiration: It is the loss of water in the form of water vapour from aerial parts of the plant.
2. During transpiration, water comes out in the form of water vapour.
3. Transpiration takes place in leaves through stomata. Stomata consist of guard cells, epidermal cells, chloroplast and nucleus.
4. The important difference between transpiration and evaporation is that transpiration is the loss of water from the aerial parts of the plant while evaporation is loss of water from any surface.
5. Stomatal transpiration occurs mainly during the day time when the guard cells of stoma are fully turgid and the stomata are fully open.
6. Cuticular transpiration occurs through the cuticle which is present on the epidermis of leaves & herbaceous stem.
7. Rate of transpiration slows down at night because photosynthesis does not take place and the stomata remains closed.
8. There is a direct effect of temperature on transpiration as the increase in temperature results in increase in the rate of transpiration.
9. When the atmospheric pressure is higher, less water vapour is lost and the rate of transpiration lowers.
10. The relationship between transpiration water and water absorbed from the soil is that if the soil is deficient in water then the rate of water absorption decreases which hence decreases the rate of transpiration and if the soil has excessive water then the rate of water absorption increases which in turn increases the rate of transpiration.

Solution 2:

Solution 3:
There are three types of transpiration found in plants:

1. Cuticular transpiration
2. Lenticular transpiration
3. Stomatal transpiration

Solution 4:
The transpiration occurs highest during the day time as with the increase in light intensity the rate of transpiration increases.

Solution 5:

Solution 6:

Solution 7:
The three means of water loss in plants are:

1. Respiration
2. Guttation
3. Bleeding

PAGE NO :61
Solution 8:
The opening and closing of stomata depends upon the changes in the turgidity of their guard cells. Due to absorption of water the guard cells become turgid.Their inner walls are pulled apart by their outer wall.The gap between the guard cells become wider and stomata open.When guard cells are flaccid due to loss of water, the outer walls are not stretched , their inner walls are not pulled apart decreasing the gap between the guard cells and stomata close.

Solution 9:
Mechanism of stomata: Stomata are small pores present on the leaves which contains two kidney-shaped guard cells. The opening and closing of stomata depends upon the changes in the turgidity of their guard cells. Due to absorption of water the guard cells become turgid.Their inner walls are pulled apart by their outer wall.The gap between the guard cells become wider and stomata open.When guard cells are flaccid due to loss of water, the outer walls are not stretched, their inner walls are not pulled apart decreasing the gap between the guard cells and stomata close.

Solution 10:
Transpiration is important for plants because it evaporates excess water which produces a cooling effect to plants. This process also helps in ascent of sap and transportation of water and minerals to the various parts of the plants.

Solution 11:
Transpiration: It is the loss of water in the form of water vapour usually during day time.
Following are its importance in plants:

1. It causes transpirational pull which helps in the absorption of water.
2. It produces a cooling effect.
3. It helps in the ascent of sap.

Solution 12:
The typical structure of stomata:
Stomata are minute pores of elliptical shape surrounded by two specialized epidermal cells called guard cells.These guard cells are kidney shaped which control the opening and closing of stomata.It also consists of nucleus, stoma, epidermis and chloroplast.

Solution 13:
Following are the importance of transpiration :

1. It causes transpirational pull which helps in the absorption of water.
2. It produces a cooling effect.
3. It helps in the ascent of sap.

Solution 14:

Solution 15:

1. A windy day: On a windy day the water vapour released from the leaves by transpiration is removed faster and the leaf does not get saturated with water. So, transpiration is more during a windy day.
2. A foggy day: On a foggy day the area outside the leaf is saturated with water. So, water vapour from the leaves is removed very slowly thereby reducing transpiration.

Solution 16:
Transpiration increases the rate of water absorption because it causes the concentration of sap to rise. In this condition cells absorb water from their neighbours, leaf, stem and root which creates transpirational pull which finally helps in the absorption of water.

Solution 17:

1. Potometer
2. Potometer is used to measure the rate of transpiration.
3. The rate of movement of the air bubble will indicate the rate of transpiration.
4. The reservoir is used to provide water to the potometer.

Solution 18:

1. Movement of the air bubble will be decreased or slow.
   Reason: During dark, stomata remains closed due to which the rate of transpiration decreases which hence decreases the movement of air bubble.
2. Movement of the air bubble will be faster.
   Reason: During sunlight, stomata remains opened due to which the rate of transpiration increases which hence increases the movement of air bubble.
3. Movement of the air bubble will be faster.
   Reason: Moving air produces dry air which increases the rate of transpiration which hence increases the movement of air bubble.

Solution 19:

1. The level of mercury in the glass tube will rise.
2. Transpiration
3. Transpiration is the loss of water in the form of water vapour usually during day time.
4. The three advantages of transpiration to the plant are:
   • It causes transpirational pull which helps in the absorption of water.
   • It produces a cooling effect.
   • It helps in the ascent of sap.
5.  xylem

Solution 20:
A well-watered potted plant shows wilting of leaves on a hot sunny day. As during hot sunny day rate of transpiration is more than the rate of absorption of water.

Solution 21:
Xylem tissue

Solution 22:

Solution 23:
Stomata. Their main functions include exchange of gases and transpiration.

Solution 24:
Transpiration

Solution 25:
Potometer: It is an apparatus where the rate of the air bubble will indicate the rate of transpiration.It is used to measure the rate of transpiration.

Solution 26:
The three factors that enhance the rate of transpiration are:
1. High intensity of light 2. High temperature 3. Low humidity

PAGE NO :62
Solution 27:
Plants absorb more water than what is required. Out of 100%, only 5% of the water is used in metabolic reactions while the remaining 95% is released into the atmosphere as transpiration.
The three uses of this phenomenon are:

1. It helps in transportation of water and minerals to the various parts of the plant.
2. It produces a cooling effect to the plants.
3. It evaporates excess water.

Solution 28:

1. False
2. Cobalt chloride (CoCl2) paper

Solution 29:

Solution 30:
Potometer is the instrument used for measuring the rate of transpiration.

Solution 31:
Cobalt chloride paper.

Solution 32:
False

Solution 33:
Loss of water as droplets through leaves of an intact plant is termed guttation.

Solution 34:
The three adaptations found in plants to reduce transpiration are:

1. Sunken stomata
2. Modification of leaves into spines
3. Presence of thick cuticle

Solution 35:

1. The aim of the experiment is to demonstrate transpiration.
2. To prevent the evaporation of water from the surface.
3. The level of water in test tube (a) will decrease.
4. The fall in the water level in the test tube (a) is because of transpiration through aerial parts of the plant.
5. Test tube (b) has been taken as a control experiment. Since no transpiration takes place without the plant.

Solution 36:

1. (d) stop growing and gradually die of starvation.
2. (a) open stomata, dry atmosphere and moist soil.

Solution 37:
Cuticle, lenticels and stomata are the three openings through which transpiration occurs.

Solution 38:
Hydathodes: Guttation

Solution 39:

1. The plant was kept in the dark to destarch the leaves.
2. Sodium hydroxide absorbs CO2 thereby making the flask CO2 free.
3. (1) C, (2) E
4. Sunlight

PAGE NO :63
Solution 40:

1. To absorb the moisture formed by transpiration.
2. Yes, the weight of CaCl2 vials kept on the lower side will be more because transpiration will be more on the lower surface and the moisture absorbed.
3. To check the outside and inside pressure.
4. Transpiration is the loss of water from the aerial parts of the plant in the form of water vapour.

Solution 41:

1. A = Guard cell
   B = Stomatal aperture
2. Stomata
3. The function of the guard cells are that they help to regulate the rate of transpiration by opening and closing the stomata thus preventing excessive water loss.
4. The two structural features of guard cells are :
   • The guard cells have thin outer wall and thick inner wall.
   • Guard cells contain chloroplast in their cytoplasm.
5. These are present on the lower surface of the dorsiventral leaf.
6. Transpiration is the loss of water in the form of water vapour from aerial parts of the plant.
7.  Five

Solution 42:

1. (b) Root pressure
2. (d) environmental conditions may dry
3. (a) do photosynthesis and synthesis osmotically active
4. (d) Transpiration
5. (d) hydathodes
6. (b) guttation
7. (b) From the lower surface of leaf
8. (a) Potometer
9. (c) 90
10. (d) atmosphere is dry and temperature is high
11. (c) layering the bottom with vaseline
12. (a) approximately 10%
13. (a) suction force
14. (d) all of the above
15. (a) xerophyte
16. (a) Curtis

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Frank ICSE Class 10 Biology Solutions – Absorption by Roots

PAGE NO:48
Solution 1:

1. Osmosis – Osmosis is the movement of solvent molecules from a region of higher concentration to a region of lower concentration through a semi-permeable membrane.
2. Diffusion – It is the movement of molecules or ions from a region of higher concentration to a region of lower concentration to equalize the concentration of the two regions.
3. Turgor Pressure – It is the actual hydrostatic pressure developed inside a cell as a result of entry of water into it.
4. Hypertonic solution – A solution whose concentration is more than that of cell sap is called hypertonic solution.
5. Plasmolysis – The shrinkage of cytoplasm of a living cell as a result of exosmosis is known as plasmolysis.

Solution 2:

Solution 3:

Solution 4:
The pressure of water developed inside the roots due to active absorption of water when transpiration is very low and the rate of absorption is high is known as root pressure.

Solution 5:
Permeability is the property of a membrane to allow the passage of both solute and solvent molecules.

Solution 6:
Root hairs absorb maximum water because in this region, the xylem is not fully mature but the epidermis and endodermis are still permeable to water.

Solution 7:

1. Roots help in the absorption of water.
2. They also help in the absorption of minerals.

Solution 8:

Solution 9:
Plasmolysis helps in the preservation of meat and fish by salting. It is also helpful in the preservation of jellies and jams by adding concentrated sugar solution to them. It helps in plasmolysing the spores of bacteria and fungi.

Solution 10:
Turgor pressure keeps the soft organs like flowers, young shoots, leaves, etc. in stretched form. It is also essential for the growth of the cells. Changes in the turgor pressure causes opening and closing of stomata.

Solution 11:

1. The epidermis and endodermis of root hairs are permeable to water.
2. Root hairs have a very large surface area.

Solution 12:

1. The main root with its many branches form a network in the soil. The root hairs get entangled in the soil particles and remain in close contact with the capillary water surrounding the soil particles. The epidermal cells of root hairs have vacuoles which contain cell sap. Generally, the cell sap is more concentrated than the soil solution. As a result the water enters inside the root hair cells by endosmosis. This water dilutes the epidermal cell sap solution. Then water enters into the cortical cells by osmosis and reaches the endodermal cells and then pericycle cells. From this layer water then enters in the xylem tissue. In this way, the water is absorbed and translocated up to xylem of In this way, the water is absorbed and translocated up to xylem of the root by osmosis.
2. (a) Cell wall separates the two solutions – cell sap and soil solution and is permeable which means it allows the water to enter inside the root hair cells by endosmosis.
   (b)The cytoplasm contains vacuoles having cell sap or solution of mineral salts. This cell sap being more concentrated than the soil solution help in water absorption by endosmosis.
3. If the soil was watered with extremely concentrated solution of sodium chloride, the water will move out from the root hair due to osmosis and thus, plasmolysis will take place.

PAGE NO :49

Solution 13:

1. Osmosis
2. Root hair
3. Sugar solution
4. The level of the liquid in the capillary tube rises.

Solution 14:

1. Osmotic pressure
2. Isotonic solutions
3. Cohesive force
4. Active absorption
5. Xylem
6. Plasmolysis
7. Endosmosis
8. Endosmosis
9. Diffusion

Solution 15:

1. 1. Cell wall; 2. Cell membrane; 3. Vacuole; 4. Cytoplasm; 5. Nucleus.
2. Cell wall It is freely permeable.
   Cell membrane – It allows only water to pass through it as it is semi-permeable.
   Vacuole – It contains cell sap. The concentration of cell sap is more than the soil water. So, endosmosis takes place.
3. If a cell is placed in a concentrated cane sugar solution, plasmolysis takes place. If the plasmolysed cell is placed in water, deplasmolysis takes place.

Solution 16:
Xylem

Solution 17:
Plasmolysis

Solution 18:
The root hairs become flaccid when fertilisers are added to the moist soil around them because fertilisers with moist soil become hypertonic which causes plasmolysis in the cells of the root hair. The turgidity is lost and the cell becomes flaccid.

Solution 19:
Diffusion

Solution 20:
Endosmosis

Solution 21:

1. Plasmolysed cell
2. Plasma membrane
3. Large vacoule
4. The chloroplasts would be present in the shrunken protoplast.
5. Cell wall

PAGE NO:50

Solution 22:

1. The raisins swell up when placed in water because the water is hypotonic as compared to the raisins so the water enters inside the raisins as a result of endosmosis.
2. Saline water is hypertonic. So any infectious agent such as bacteria in the throat gets plasmolysed and this cures the infection.
3. Jam, jellies and pickles are kept in hypertonic solution of sugar or salt in which plasmolysis of bacteria and fungi takes place. This kills the bacteria and fungi and hence, pickles, jam and jellies are preserved properly.
4. The leaves of the wilted lettuce become crisp when kept in cold water because they take up water due to endosmosis in hypotonic solution.

Solution 23:
Ascent of sap is the movement of water from the roots to the upper part of the plant.

Solution 24:
Plants die when salt is sprinkled over them due to plasmolysis of cells. The salt makes the solution hypertonic inside the plant cells which lead to shrinkage of cells or exosmosis.

Solution 25:
Root Pressure is the pressure exerted on the liquid contents of the cortical cells of the root, under fully turgid condition, forcing a quantity of water into the xylem vessels and through them upwards into the stem up to a certain height.
Demonstration of Root pressure:

1. Take a well matured healthy herbaceous plant.
2. The stem of the plant is cut a few centimeters above the base with a sharp knife and attached to a manometer through a rubber tube.
3. After a few hours, the level of mercury rises in the manometer.
4. This is due to the pressure created by water exuded from the cut end of the plant on account of root pressure generated due to entry of water in the root cells.

Solution 26:

1. Water is one of the raw materials for photosynthesis.
2. Water is important for seed germination.
3. Water controls the opening and closing of stomata.

Solution 27:
Plants begin to die when concentrated solution of a fertilizer is given to potted plants because fertilizer along with soil water act as a hypertonic solution resulting in exosmosis.

Solution 28:

1. Plants absorb water by their roots.
2. Roots supply water to the stem and leaves of the plant.
3. In root hairs, the xylem is not fully mature and the endodermis and epidermis are permeable to water.
4. Water is absorbed by the plants through xylem in all directions.
5. The food on the other hand is transported with the help of phloem.

Solution 29:

1. The aim of the experiment is to show that conduction of water in plants takes place through xylem.
2. In shoot, (a) phloem has been removed. In shoot (b), xylem has been removed.
3. In shoot (b), xylem has been removed so the leaves are wilted. But in shoot (a), xylem has not been removed so the leaves are turgid.

Solution 30:

1. In (c), the water would move up the fastest.
2. In (b), the water would move up slowly.
3. To prevent evaporation of water.
4. Absorption of water by the roots.

PAGE NO 51

Solution 31:

1. (c) Water from the more concentrated solution to the less concentrated solution.
2. (d) plasmalemma
3. (c) hypertonic solution
4. (b) plasmolysis
5. (a) endosmosis
6. (b) endosmosis
7. (a) Plasmalemma
8. (b) imbibition
9. (c) reaching of water upwards against gravitational force
10. (b) by xylem
11. (d) Xylem
12. (b) root hairs
13. (d) none of the above
14. (a) xylem
15. (c) hydrostatic pressure in the root
16. (b) xylem is blocked

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Frank ICSE Class 10 Biology Solutions – Principles of Genetics

PAGE NO:35
Solution 1:
Gregor Johann Mendel.

Solution 2:
Genetics is the branch of biology that deals with the study of transmission of characters from parents to offspring.

Solution 3:
The term heredity may be defined as the transmission of genetically based characteristics from parents to offspring.

Solution 4:
Monohybrid cross.

Solution 5:
Dihybrid cross ratio is 9:3:3:1.

Solution 6:

Solution 7:

1. Genotype – The genetic expression of a character in terms of alleles written in symbols is called genotype.
2. Phenotype – The physical or external and observable expression of a character is called phenotype.
3. Homozygous – Diploid condition where both the alleles are identical is called homozygous.
4. Heterozygous – Diploid condition where both the alleles are different is called heterozygous.
5. Allele – Alternative forms of the same gene which determine contrasting characters is called an allele.
6. Dominant – An allele which expresses itself externally when present in homozygous or heterozygous conditions.
7. Recessive – An allele which expresses itself externally when present in homozygous condition but remains suppressed in heterozygous condition.

Solution 8:
Gregor Johann Mendel was a biologist who carried out experiments on garden pea and derived a few fundamental principles in genetics. He is called the ‘Father of Genetics’.

Solution 9:
Mendel’s laws are:

1. Law of Dominance
2. Law of Segregation
3. Law of Independent Assortment

Solution 10:
Monohybrid cross is one where the parents used for hybridization differ in only one pair of contrasting characters or alleles.

Solution 11:

Solution 12:
The law of segregation explains that the characteristics of an organism are determined by internal alleles that occur in pairs. These allele pairs separate during meiosis in gamete formation and the pair gets restored upon random fusion in zygote.

Solution 13:
Law of segregation is also called the law of purity of gametes because the two members of a pair of factors do not blend but segregate or separate into different gametes.

Solution 14:
According to the law of independent assortment when there are two pairs of contrasting characters, the distribution of the members of one pair into the gametes is independent of the distribution of the other pair.

Based on dihybrid ratio of 9:3:3:1 in F2 generation, Mendel observed that when a plant with two dominant alleles was crossed with another having the corresponding recessive alleles it was possible to obtain new combinations of characters where a plant had one dominant and the other recessive allele. These were new recombinations were not present in either parent or F1 generation.

PAGE NO :36
Solution 15:
Importance of Mendel’s Laws:

1. Dominant and recessive characters can be found.
2. A hybrid with desired characters can be produced easily.
3. Crops can be improved.
4. Pure recessive characters can be used where needed.
5. Genotypes and phenotypes of next generation can be predicted even before cross is made.

Solution 16:
Exceptions to Mendel’s Laws:

1. Incomplete Dominance – In few cases, F1 generation has an intermediate phenotype between dominant and recessive alleles.
2. Linkage – Genes on the same chromosomes are said to be linked and are inherited together.
3. Multiple Allelism – Each character may have more than two alleles which can’t be explained by Mendel’s laws.

Solution 17:
Mendel performed his experiments on the garden pea plant or Pisum sativum.

Solution 18:
Sex chromosomes determine the sex of a child in humans.

Solution 19:

Solution 20:

Solution 21:
Mendel’s work did not receive much notice till 1900. Then three scientists: Hugo de Vries, Carl Correns and Erich von Tschermak working independently rediscovered his work and brought Mendel’s experiment to limelight.

Solution 22:

1. Autosomes – The chromosomes other than sex chromosomes present in the body are called autosomes.
2. Sex chromosomes – The chromosomes which determine the sex of an individual are called sex chromosomes.
3. Sex-linked characters – Such characters or traits that are controlled by genes occurring on sex chromosomes are called sex linked characters.

Solution 23:
The sex of the zygote is determined by the sperm which fertilizes the ovum. If an X bearing sperm fuses with an ovum in man, the offspring would be female and if a Y chromosome bearing sperm fuses with an ovum the offspring will be a boy.

Solution 24:
The inheritance of sex linked genes controlling sex linked characters is called sex linkage or sex linked inheritance.

Solution 25:
Haemophilia is X-linked inherited disease in which the diseased person is unable to synthesize a normal blood protein called Antihaemophilic globulin that helps in clotting. Haemophilia is also called Bleeder’s disease as the haemophilic person bleeds for a long time even from a minor cut.

Solution 26:
Colour blindness is a sex-linked inherited disease in which the diseased person is not able to distinguish between red and green colour.

Solution 27:
Cause of Haemophilia – Haemophilia is an X-linked inherited disease. Homozygosity for recessive haemophilia gene is must to be seen in a female while a single affected X chromosome makes the male a haemophilia victim.
Cause of Colour Blindness – Colour blindness is the effect of a recessive gene. In case of female, both the X chromosomes must have the recessive gene but as males have only one X chromosome, just a single affected chromosome causes colour blindness.

Solution 28:
More males are affected by sex linked diseases because they have a single X chromosome and the sex linked diseases occur due recessive gene on X chromosome.

Solution 29:
A man can never transfer a sex-linked gene directly to his son because the son inherits only the Y chromosome from his father and the sex linked diseases are present on the X chromosome.

Solution 30:
The progeny of the woman and the haemophilic man will have one son and one daughter as colorblind, one daughter as a carrier and one son will be normal.

Solution 31:
Haemophilia

Solution 32:
The inheritance of sex linked genes controlling sex linked characters is called sex linkage or sex linked inheritance.

Solution 33:

Solution 34:

PAGE NO :37

Solution 35:

1. Father is color blind.
2. 3 daughters and two sons.
3. Child 1 is color blind.
4. All daughters from 2-5 are carriers while all the sons are normal.
5. X chromosome.
6. Haemophilia.

Solution 36:

1. (b) garden pea
2. (d) 100%
3. (c) 7
4. (d) Mendel
5. (a) dominant
6. (c) Law of Independent Assortment
7. (a) alleles
8. (b) heterozygous
9. (a) dihybrid cross
10. (a) Czechoslovakia
11. (c) X and Y
12. (a) X chromosome
13. (b) autosomes
14. (b) one X chromosome
15. (b) X chromosomes in male
16. (c) 50%
17. (c) sons are colour blind and daughters are carriers
18. (b) daughter

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Frank ICSE Class 10 Biology Solutions – Structure of Chromosomes

PAGE NO-20:
Solution 1:
Chromatin is an extremely thin, long nuclear fibre occurring in the nucleus before cell division.

Solution 2:
In interphase, the chromatin appears as a network of long, extremely thin fibres.

Solution 3:
During prophase of mitosis, the chromatin fibres shorten and become thick to form chromosomes.
During metaphase, the chromosomes appear more distinct and clear and each consists of two parallel strands called chromatids joined by a centromere.

Solution 4:
Chromosomes are the thread like structures or chromatin material present inside the nucleus.
Chromosomes are so called because they take up certain basic dye and stain very rapidly. The word chromosome comes from two words “chromos” meaning colour and “soma” meaning body.

Solution 5:

1. Strasburger – He observed thread like structures during cell division.
2. Balbiani – Described rod like structures in nucleus before cell division.
3. Waldeyer – Coined the term ‘chromosomes’.
4. Sutton and Boveri – They described chromosomes as physical structures and transmitters of hereditary traits.

Solution 6:
Chromosomes are the thread like structures present in the nucleus of the cell. They are covered with a sheath made up of proteins and filled with granular matter called matrix. Inside the matrix, there are two threads called chromonemata.
The chromosome consists of two symmetrical strands called chromatids. Each chromosome consists of a distinct constriction called centromere which gets attached to the spindle network.

Solution 7:

1. Sheath – It is a proteinaeous covering present around the chromosomes.
2. Matrix – It is a granular matter present inside the sheath.
3. Chromonemata – They are the subunits of chromatids.
4. Centromere – A constriction in the chromosome is called centromere.
5. Secondary Constriction – A constriction other than primary constriction is called a secondary constriction.
6. Telomere – The ends of the chromosomes is termed as telomere.

Solution 8:
Chromosomes are best observed at metaphase

Solution 9:
The chromosomes other than sex chromosomes present in the human body are called autosomes.
22 pairs of autosomes are present in man.

Solution 10:
The chromosomes which determine the sex of an individual are called sex chromosomes.

Solution 11:
Sex chromosomes are significant as they determine the sex of an individual.

Solution 12:
In man, there is a pair of sex chromosomes. In males, it is X and Y while in female, the sex chromosomes are X and X which are identical to each other.

Solution 13:
Chromosomes are the main source of chemical information which determines that the cell should become like its parent cell.

During the developmental stage they also determine that the cells of the organism will give the animal or the plant, the characteristic features of its species.

Solution 14:
DNA and RNA are the two nucleic acids.
Frederick Miescher discovered DNA

Solution 15:
Nucleic acids are made up of three types of molecules:

1. a pentose sugar,
2. nitrogenous bases
3. a phosphate

Solution 16:
The chemical composition of chromosome consists of:

1. Approximately 40% of DNA
2. 50% of Histone proteins
3. 8.5% Non histone proteins
4. Metallic ions like magnesium and calcium in traces.

Solution 17:
Two nitrogenous bases present in DNA are:

1. Purines – Adenine and Guanine.
2. Pyrimidines – Cytosine and Thymine.

Solution 18:

Solution 19:
Features of DNA:

1. DNA consists of two strands which are spirally arranged around an axis. This is called a double helical arrangement.
2. Each DNA strand is made up of nitrogenous bases, pentose sugar and phosphate.
3. Sugars are pentose type; bases are adenine, guanine, cytosine and thymine.
4. Both strands are connected with hydrogen bonds. There are two bonds between adenine and thymine and three bonds between guanine and cytosine.
5. In the DNA, bases are inside and sugars are outside and two sugars are connected with phosphoric acid.
6. Each DNA strand replicates and from each replicated DNA a new DNA is formed. This is called replication of DNA.

Solution 20:
Watson and Crick described the detailed structure of DNA.

Solution 21:
Importance of DNA:

1. DNA is most important because it is the hereditary material.
2. It acts as the director of protein synthesis.
3. Some DNA of chromosomes forms nucleolus.
4. DNA in presence of enzymes forms mRNA which acts as messenger.

Solution 22:
The rungs of “DNA ladder” are made up of two types of nitrogenous bases:

1. Purines: Adenine and Guanine
2. Pyrimidines: Cytosine and Thymine.

Solution 23:
Repeating components of each DNA strand length wise are pentose sugar and phosphate group

Solution 24:

1. Interphase
2. histone proteins
3. RNA, DNA
4. Protein
5. Nitrogen

PAGE NO 21
Solution 25:

1. False
2. False
3. True
4. True

Solution 26:

1. This diagram represents the structure of chromosome.
2. ‘d’ is centromere which gets attached to the spindle fibres.
3. ‘b’ is heterochromatin which is darkly stained region when stained with acetocarmine and ‘c’ is euchromatin which when stained with acetocarmine or felugen gets lightly stained.
4. Waldeyer
5. Matrix
6. No, secondary constriction or ‘e’ is not present in all chromosomes.

Solution 27:

1. (d) chromatin
2. (c) Waldeyer
3. (a) centromere
4. (c) secondary constriction
5. (a) interphase
6. (d) prophase
7. (a) DNA and histones
8. (a) 46
9. (a) I shaped
10. (b) metacentric
11. (c) XY
12. (b) sex chromosomes
13. (a) Watson and Crick
14. (a) nitrogen base
15. (c) Uracil
16. (b) thymine
17. (a) DNA

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