Question 1

Question 1(i)The duration for which the leaf is kept in dark to get destarch is20-24 hrs24-48 hrs12-24 hrs12-42 hrs

Accepted Answer

24-48 hrsReason — The starch present in leaves is converted to soluble sugar at night and is then transported to different parts of the plant. This process takes 24-48 hrs.

Question 2

Question 1(vi)Assertion (A): Hypersecretion of adrenal cortex causes Cushing's syndrome.Reason (R): Symptoms of Cushing's syndrome are obesity, hyperglycemia, weakness, osteoporosis, salt and water retention.Both A and R are trueBoth A and R are falseA is true and R is falseA is false and R is true

Accepted Answer

Both A and R are trueReason — Hypersecretion of cortisone from adrenal gland causes Cushing's syndrome. Symptoms are obesity, hyperglycemia (high blood sugar), weakness, osteoporosis, salt and water retention.

Question 3

Question 1(xi)The difference between the birth rate and the death rate is callednatalitymortalitygrowth rate of populationpopulation density

Accepted Answer

growth rate of populationReason — The difference between the birth rate and the death rate of a country is called the growth rate of the population.

Question 4

Question 1(xiv)The cones contain the pigmentrhodopsinvisual purpleiodopsinBoth 1 and 2

Accepted Answer

iodopsinReason — Iodopsin is present in cone cells and is responsible for colour vision.

Question 5

Question 2(i)Name the following:(a) The centre of reflex action.(b) A gas responsible for greenhouse effect.(c) The site, where the sperm and ovum unite and fuse.(d) The cytoplasmic division of a cell.(e) The phase of cardiac cycle, in which the auricles contract.

Accepted Answer

(a) Spinal cord(b) CO2(c) Fallopian tube(d) Cytokinesis(e) Atrial systole

Question 6

Question 2(ii)Arrange and rewrite the terms in each group in correct order so as to be in a logical sequence beginning with the term that is underlined.(a) Chloroplast, Thylakoids, Grana, Stroma(b) Urinary bladder, Kidney, Urethra, Ureter(c) Conjunctiva, Retina, Cornea, Optic nerve, lens(d) Repolarisation, Depolarisation, Resting potential(e) Axial filament, Acrosome, Nucleus, Tail, Middle piece

Accepted Answer

(a) Chloroplast, Stroma, Grana, Thylakoids(b) Kidney, Ureter, Urinary bladder, Urethra(c) Conjunctiva, Cornea, Lens, Retina, Optic nerve(d) Resting potential, Depolarisation, Repolarisation.(e) Acrosome, Nucleus, Middle piece, Axial filament, Tail.

Question 7

Question 2(iii)Fill in the blanks with suitable words.Spleen is the largest (a) ............... , it acts as (b) ............... , produces (c) ............... destroys worn out (d) ............... and produces RBCs in (e) ............... .

Accepted Answer

Spleen is the largest (a) lymphatic organ, it acts as (b) blood reservoir, produces (c) lymphocytes, destroys worn out (d) RBCs and produces RBCs in (e) embryo.

Question 8

Question 2(iv)Choose the odd one out from the following terms and name the category to which the other belong.(a) Sneezing, Coughing, Typing, Blinking(b) Goitre, Dwarfism, Acromegaly, Cataract(c) Sewage, Radiation, Oil spills, Thermal pollution(d) ADH, TSH, NADP, ACTH(e) Colour blindness, AIDS, Haemophilia, Albinism

Accepted Answer

(a) Odd one: TypingCategory: Others are Natural reflexes(b) Odd one: CataractCategory: Others are Diseases due to hormonal imbalance.(c) Odd one: RadiationCategory: Others are Water pollution(d) Odd one: NADPCategory: Others are Hormones(e) Odd one: AIDSCategory: Others are Genetic diseases

Question 9

Question 2(v)Match the items given in Column I with the most appropriate ones in Column II and rewrite the correct matching pairs.Column IColumn IIGuttationPermanently openBleedingFallopian tubeLenticelsNeriumFertilisationInjured part of plantsSunken stomataPotometer Hydathodes

Accepted Answer

Column IColumn IIGuttationhydathodesBleedingInjured part of plantsLenticelsPermanently openFertilisationFallopian tubeSunken stomataNerium

Question 10

Question 3(ii)State the function of motor neuron and draw the path of reflex arc.

Accepted Answer

Motor neurons carry impulse from brain and spinal cord to effector organs.

Question 11

Question 3(iii)In a certain species of animals, black fur (B) is dominant over brown fur (b). Predict a genotype and phenotype of the offspring, when both parents are Bb or have heterozygous black fur.

Accepted Answer

BbBBBBbbBbbbIn the question it is given that B refers to black fur and b refers to brown fur. So the genotype and phenotype of the offspring will be:Genotype — 1 (Homozygous Black Fur) : 2 (Heterozygous Black Fur) : 1 (Homozygous Brown Fur)Phenotype — 3 (Black Fur): 1 (Brown Fur)

Question 12

Question 3(iv)Differentiate between grana and stroma.

Accepted Answer

Differences between grana and stroma are:GranaStromaThe stacks of thylakoids embedded in the stroma of a chloroplast is called grana.The colourless ground substance present in the chloroplast is called stroma.Light reaction occurs here.Dark reaction occurs here.

Question 13

Question 3(v)Draw a neat and labelled diagram showing the relationship of artery, capillaries and vein.

Accepted Answer

Diagram showing the relationship of artery, capillaries and vein is shown below:

Question 14

Question 4(ii)What are the functions of adrenaline - the emergency hormone?

Accepted Answer

Adrenaline causes stimulation of sympathetic nervous system and prepares body for any emergency. It increases heart beat and blood supply to muscles.

Question 15

Question 4(iii)Differentiate between fibrin and fibrinogen.

Accepted Answer

FibrinFibrinogenIt is a solid substance that forms threads in the process of blood coagulation.It refers to protein found in the blood plasma from which fibrin is produced during blood coagulation.It is insoluble.It is soluble in blood.

Question 16

Question 4(iv)Which gland secretes vasopressin? What is its effect on body?

Accepted Answer

Posterior pituitary gland secretes vasopressin. Its effects on the body are:It acts on the kidney increasing reabsorption of water from the kidneys tubules.It constricts blood vessels causing rise in blood pressure.

Question 17

Question 4(v)Draw a neat and labelled diagram of human sperm.

Accepted Answer

Labelled diagram of a human sperm is shown below:

Question 18

Question 5(ii)Why light reaction is also called the photochemical phase?

Accepted Answer

Light reaction is also called the photochemical phase because it is light dependent reaction. The chlorophyll on exposure to light energy becomes activated by absorbing photons. The absorbed energy is used in splitting the water molecule (H2O) into its two components (Hydrogen and Oxygen) and releasing electrons.

Question 19

Question 5(iii)Soil pollution leads to the accumulation of pesticides in birds. This affects calcium metabolism in them. What will be the effect of this on their egg shells?

Accepted Answer

Birds affected by pesticide accumulation may produce eggs with thinner, weaker shells. The eggshells may also have structural abnormalities and defects. Such fragile egg shells may break before hatching of the eggs leading to population decline and eventual extinction of the affected birds.

Question 20

Question 5(v)The diagram given below is of Malpighian capsule. Answer the questions that follows.(a) Name the parts labelled 1, 2 and 3.(b) Define ultrafiltration.(c) Name the fluid entering the renal tubule.

Accepted Answer

(a) Parts labelled 1, 2 and 3 are:1 → Afferent arteriole2 → Efferent arteriole3 → Bowman's capsule(b) The blood flows through the glomerulus under great pressure which is much greater than in the capillaries elsewhere. The high pressure causes the liquid part of the blood to filter out from the glomerulus into the renal tubule. This filtration under extraordinary force is called Ultrafiltration.(c) Glomerular filtrate

Solved Sample Paper 3

Section A

Section B