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Solutions for Biology, Class 10, ICSE
Which one of the following is mainly concerned with motor signalling?
Spinal cord
Reason — Spinal cord conducts motor responses from the brain to muscles of the trunk and limbs.
Which of the following hormones promotes lateral bud development in dicots?
Cytokinin
Reason — Cytokinin inhibits apical dominance and promotes lateral bud development.
The gap between the neurons is called
synapse
Reason — Synapse is the point of contact between the terminal branches of axon with the dendrites of another neuron separated by a fine gap.
Which part of the brain mainly controls body temperature?
Hypothalamus
Reason — Hypothalamus controls body temperature.
Leaf fall can be induced by
abscisic acid
Reason — Abscisic acid accelerates ageing and abscission of leaves.
Assertion(A): Loss of water as tiny drops along the margins of the tips of leaves, especially in the early morning is called guttation.
Reason: Excessive root pressure is responsible for guttation.
Both A and R are true
Reason — Guttation is loss of water as tiny drops from hydathodes of leaves. It occurs due to high root pressure.
Which one of the following does not affect the rate of transpiration?
Age of the plant
Reason — Transpiration is affected by light intensity, wind and humidity. Age of plant is not related to rate of transpiration.
The declining phase of a population occurs when
Mortality > Natality
Reason — When death rate (mortality) is higher than birth rate (Natality), there is decrease in population.
Harish was fond of eating dryfruits. He put some raisins in the water for 5-6 hours. After few hours, the raisins were all swelled up. This was due to
endosmosis
Reason — When raisins are placed in water (hypotonic), endosmosis occurs. Hence, they absorb water and swell up.
Acid rain is caused by a
SO2, NO2
Reason — SO2 combines with water to form sulphuric acid and NO2 combines with water to form nitric acid.
Why should we conserve forests and wildlife?
All of the above
Reason — Conservation of forests and wildlife is done to maintain ecological balance by maintaining normal food chain and to protect biodiversity.
Which of these is not a vestigial organ in human beings?
Gall bladder
Reason — Gall bladder is not a vestigial organ as it stores bile which is produced by liver.
Blood flows in arteries in spurts and is under pressure. Which of the following reasons support this statement?
P. Arteries transport blood from left ventricles.
Q. Blood in left ventricle is at a high pressure.
R. Arteries have valves.
Only P and Q
Reason — Left ventricle pumps oxygenated blood at a high pressure to the rest of the body through arteries. This high-pressure blood is what causes the blood in the arteries to flow in a pulsatile manner, resulting in spurts.
Statement R, "Arteries have valves," is not relevant to the blood flow in arteries. Valves are typically found in veins to prevent the backflow of blood, not in arteries.
The liquid which collects in the cavity of Bowman's capsule is
blood plasma minus blood proteins
Reason — During ultrafiltration almost all the liquid part of the blood i.e plasma and organic/inorganic substances are collected in Bowman's capsule.
The water absorbed by the root is carried through the stem to all parts of the plant.
Which of the following is/are involved in the process described above?
(1) Xylem (2) Phloem (3) Hydathodes (4) Guard cells
Only 1
Reason — The transportation of water in plants is done by xylem vessel.
Name the following.
(a) The instrument which is used to measure water uptake by the plant shoot during transpiration.
(b) Movement of substances into root cells without the expenditure of energy.
(c) The enzyme that is released from the injured cells and blood platelets of a wound.
(d) The hormone produced when a plant is exposed to stress.
(e) The part of the internal ear concerned with dynamic equilibrium of the body.
(a) Potometer
(b) Passive transport
(c) Thrombokinase
(d) Abscisic Acid
(e) Sensory cells in Semicircular canal
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) Cell wall, Nucleus, Nucleoplasm, Cell membrane, Cytoplasm
(b) Australopithecus, Homo erectus, Cro-Magnon, Homo habilis, Homo sapiens sapiens
(c) Head, Pulmonary artery, Right ventricle, Right auricle, Superior vena cava
(d) Menstrual phase, Luteal phase Ovulatory phase, Follicular phase
(e) Gamete formation, Zygote, Fertilisation, Embryo
(a) Cell wall, Cell membrane, Cytoplasm, Nucleus, Nucleoplasm,
(b) Australopithecus, Homo habilis, Homo erectus, Cro-Magnon, Homo sapiens sapiens
(c) Head, Superior vena cava, Right auricle, Right ventricle, Pulmonary artery.
(d) Menstrual phase, Follicular phase, Ovulatory phase, Luteal phase
(e) Gamete formation, Fertilisation, Zygote, Embryo
Fill in the blanks with suitable words.
The heart consists of four chambers (a) ............... and two (b) ............... . The atria have (c) ............... walls. The ventricles have (d) ............... walls. The right ventricle pumps blood only up to the (e) ............... for oxygenation.
The heart consists of four chambers (a) two atria and two (b) ventricles . The atria have (c) thin walls. The ventricles have (d) thick muscular walls. The right ventricle pumps blood only up to the (e) lungs for oxygenation.
Choose the odd one out from the following terms and name the category to which others belong.
(a) Cortisol, Calcitonin, Cytokinin, Insulin
(b) CO2, NO2, SO2, NH3
(c) Law of dominance, Law of segregation, Law of Linkage, Law of independent assortment
(d) Ovary, Fallopian tube, Ureter, Uterus
(e) 'A' blood group, 'B' blood group, 'O' blood group, 'AB' blood group
(a) Odd one: Cytokinin
Category: Others are human hormones.
(b) Odd one: NH3
Category: Others are the type of vehicular air pollutants.
(c) Odd one: Law of Linkage
Category: Others are Mendel's laws.
(d) Odd one: Ureter
Category: Others are parts of female reproductive system
(e) Odd one: 'O' blood group
Category: Others have antigen present on RBC in all blood groups.
Match the items given in Column I with the most appropriate ones in Column II and rewrite the correct matching pairs.
| Column I | Column II |
|---|---|
| Myxoedema | Hypersecretion of adrenaline |
| Diabetes insipidus | Hyposecretion of adrenaline |
| Pituitary dwarfism | Hypersecretion of growth hormone |
| Diabetes mellitus | Hyposecretion of growth hormone |
| Gigantism | Hyposecretion of insulin |
| Hyposecretion of ADH | |
| Hyposecretion of thyroxine |
| Column I | Column II |
|---|---|
| Myxoedema | Hyposecretion of thyroxine |
| Diabetes insipidus | Hyposecretion of ADH |
| Pituitary dwarfism | Hyposecretion of growth hormone |
| Diabetes mellitus | Hyposecretion of insulin |
| Gigantism | Hypersecretion of growth hormone |
Substances which are made up of cellulose or proteins are hydrophilic. What will happen to the wooden doors in rainy season?
The wooden doors will swell up during rainy season by absorbing moisture present in the air as cellulose being hydrophilic will imbibe (surface attraction) water.
What is apical dominance? Name the hormone that controls it.
The phenomenon of the suppression of growth of lateral buds by apical buds is called apical dominance. It is controlled by auxin.
Give differences between active transport and osmosis.
| Active Transport | Osmosis |
|---|---|
| Active transport is the passage of a substance from its lower to higher concentration through a living cell membrane using energy from the cell. | Osmosis is the movement of water molecules from their region of higher concentration to their region of lower concentration through a semi permeable membrane |
| There is expenditure of energy. | There is no expenditure of energy. |
| Occurs only when cell membrane is involved. | Occurs when any semipermeable membrane like cell membrane or cellophane is involved. |
| It occurs against concentration gradient. | It occurs along the concentration gradient. |
What is sex-linked inheritance? Give one example.
Inheritance of any character whose gene are present on sex chromosomes (either X or Y) is called sex linked inheritance. For example : Hemophilia is X-linked genetic disorder.
Draw a clear diagram of human kidney and label following parts on it, renal capsule, cortex, hilum and ureter.
Diagram of human kidney with renal capsule, cortex, hilum and ureter labelled is shown below:
Mention the exact location of dark reaction.
Dark reaction occurs in stroma.
Mention two reasons for the increase of population in India.
Two reasons for the increase of population in India are:
Differentiate between haemophilia and colour blindness.
Differences between haemophilia and colour blindness are:
| Haemophilia | Colour blindness |
|---|---|
| Haemophilia is a genetic disorder in which blood does not clot properly due to lack of blood-clotting proteins. | Colour blindness is a genetic disorder that affects a person's ability to perceive certain colors accurately. |
| It can be fatal in case of excessive bleeding. | It is not fatal. |
What is the function of coronary arteries? What will be their affect on human if they get blocked?
Coronary arteries supply blood to the heart muscles. When there is a blockage in any coronary artery or in any one or more of their branches, there is deadening of the corresponding area of heart muscles leading to myocardial infarction commonly referred to as a heart attack.
Draw a neat and labelled diagram to show hypermetropia.
Below labelled diagram shows hypermetropia:
Define sewage.
Sewage is the liquid waste from domestic activities. It contains kitchen wastes, toilet and other household waste water.
Enlist some of the consequences of population explosion.
Some of the consequences of population explosion are:
Two potted plants are fixed horizontally in clinostat. One is rotated and the other is not. What will be your observation after some time?
After sometime we can observe that the static potted plant will show positive geotropism in root and negative geotropism in shoot. The rotating plant will not show any bending. It is because gravitational force was equally applied to all its part.
Fixing of the embryo in the wall of uterus is A. Time taken by an embryo for full development in B. Name A and B.
A → Implantation
B → Gestation
The diagram given below is a representation of K+ transport mechanism of stomatal opening and closing. Study the same and answer the questions that follows:
(a) Name the cell labelled as A.
(b) Mention the states of guard cells represented by B and C.
(c) What causes closure of stomata during night?
(a) A represents epidermal cells.
(b) The state of guard cell represented by B is turgid and the state of guard cell represented by C is flaccid.
(c) During day, the guard cells have high concentration of K+ making it hypertonic. During night, the K+ ions are transported to epidermal cells due to which there is loss of water from guard cells making them flaccid. The stomata closes when guard cells are flaccid.
Give the exact location of pituitary gland.
Pituitary gland is located at the base of the midbrain below the hypothalamus.
Differentiate between metaphase and anaphase.
Differences between between metaphase and anaphase are:
| Metaphase | Anaphase |
|---|---|
| Chromosomes are lined up in equatorial plane. | Chromosomes start moving towards opposite poles. |
| Chromatids are attached at centromere. | Chromatids separate. |
| Spindles attach to centromere of chromosome. | Spindle fibres start shortening. |
A trait may be inherited but may not be expressed. Explain.
A dominant allele expresses itself while the recessive allele is masked in heterozygous condition. For example, when a plant with round (RR) seeds is crossed with a plant with wrinkled (rr) seeds, all F1 plants are with round seeds. Here, the genes are in heterozygous condition i.e., Rr. Allele 'r' is present but is not expressed as its effect is masked by allele 'R'. Therefore, we can say that a trait may be inherited but may not be expressed.
State the functions of pons and cerebellum.
Function of pons:
Function of cerebellum :
Study the given diagram and answer the questions that follows.
(a) Name the parts labelled A, B and C in the diagram.
(b) State the function of part labelled A and B.
(c) Name the audio receptor region present in the part labelled A.
(a) The parts labelled A, B and C are:
(b)
(c) Organ of Corti
Expand the abbreviation TSH.
Thyroid Simulating Hormone
State the function of epididymis.
The epididymis stores the sperms for some days during which they mature and become motile (capable of moving).
Give differences between turgidity and flaccidity.
Differences between turgidity and flaccidity are:
| Turgidity | Flaccidity |
|---|---|
| It is the state of a cell in which the cell wall is rigid and stretched by an increase in the volume of vacuoles due to the absorption of water. | It is the condition in which the cell content is shrunken and the cell is not tight. |
| It occurs when the cell is placed in a hypotonic solution. | It occurs when the cell is placed in hypertonic solution. |
| It is caused by endosmosis. | It is caused by exosmosis. |
| Water moves into the cell. | Water moves out of the cell. |
Explain why generally only the male child suffers from colour blindness and not the female?
Colour blindness is an X-linked recessive genetic disorder caused by mutations in genes located on the X chromosome. Since females typically inherit two X chromosomes, the chance of both X chromosomes carrying the recessive mutation is indeed rare. Therefore, the likelihood of a female developing colour blindness is extremely low.
The given figure shows a cell. Study the figure and answer the questions that follows.
(a) Identify the stage of cell cycle depicted by the cell.
(b) Write any two characteristic of this phase.
(c) Identify A and B.
(a) Interphase
(b) This phase of the cell is characterised by:
(c) A and B are:
Define dialysis.
The artificial method of filtering out the excretory product from the body when both the kidney of a person fails to do so either due to injury or disorder is called dialysis.
Name two types of passive transport.
Two types of passive transport are:
Which gland secretes thyroxine? What will happen if the secretion of thyroxine is insufficient?
Thyroid gland secretes thyroxine. Insufficient secretion of thyroxine is called hypothyroidism. It may leads to simple goitre, cretinism and myxoedema.
State two functions of placenta.
Two functions of placenta are:
The diagram below represents an experiment to demonstrate a particular aspect of a physiological process in plants. Study the diagram and answer the questions that follows.
(a) What is the aim of the experiment?
(b) What is the chemical substance named X in the diagram? What will be the effect of treatment with the solution of substance X?
(c) Out of the parts mentioned A and B, which will show blue-black colour in the presence of X. Why?
(a) The aim of the experiment is to show that sunlight is necessary for photosynthesis.
(b) The chemical substance named X in the diagram is iodine. After treatment with iodine solution, the part of the leaf, which contains starch will show blue-black colour. The part having no starch will turn brown.
(c) The portion A will show blue black colour because it received sunlight and starch was formed as a result of photosynthesis.