Biology Unsolved Sample Paper Solutions ICSE Class 10
(i) (c) Urochrome
When urobilinogen gets exposed to air, it is oxidised to urochrome which gives urine its yellow colour.
(ii) (c) Iris
Iris is the coloured part of the eye which determines the colour of the eye and varies from person to person.
(iii) (a) Heterotrophs do not synthesize their own food.
Heterotrophs belong the trophic level of consumer and consume food made by the autotrophs. They do not contain chlorophyll to make their own food.
(iv) (d) Axonal end of the one neuron to the dendritic end of another neuron.
Synapse is defined as the close contact made by the presynaptic terminal (axonal end) and the post synaptic terminal (dendritic end).
(v) (c) TtWW
All the plants are violet means that the parent with violet flowers is homozygous for the violet allele whereas half of them were short means that the parent tall
plant was heterozygous for the tall allele.
(vi) (a) Gamete, zygote, embryo, seedling
The gametes are produced by the male and female reproductive systems, which fuse together to form a zygote and develops to form an embryo and finally
resulting in a seedling.
(vii) (b) Reproductive cells
Meiosis is a reductional division and occurs in only reproductive cell to form gametes of ploidy of n from 2n.
(viii) (a) DNA undergoes specific changes in germ cell
Germ cells are the cell which transfer their hereditary material to the offspring, if the changes occur in germ cells, a new species can be developed.
(ix) (d) Mouth → Oesophagus → Stomach → Small intestine → Large intestine
We ingest food through mouth which is connected to a tube called oesophagus which leads the food and other secretions from mouth to the stomach which is
further connected to the small intestine and finally transfers the food to the large intestine before eliminating the waste put of the body.
(x) (b) Grass, wood and plastic
All these three compounds can be decomposed by bacteria and hence, are biodegradable items.
(xi) (c) Wind, wood and Sun
All these three items are naturally occurring in nature and causes no harm to the environment when used.
(xii) (b) Grass, goat and human
Grass is an autotroph which produces its own food, goat consumes grass and goat is then further consumed by the animals.
(xiii) (b) Telophase
When the chromosomes reach at the poles in anaphase, spindle fibres disappears and the chromosomes began to uncoil at the poles, indication that phase
(xiv) (b) Ethylene
Plant hormones are chemicals and are liquid in nature except for the hormone called ethylene which is gaseous in nature.
(xv) (a) Diarrhoea
Diarrhoea is caused by the intake of parasitic bacteria through contaminated food and water.
|(i) (a) Metacentric||(b) Hepatic portal vein||(c) Medulla|
|(d) Cranium||(e) Antidiuretic hormone (ADH)|
|(ii) (a) Apical Meristem, shoot, Soil, Root||(b) Cerebrum, Corpus callosum, thalamus, medulla oblongata||(c) Left atrium, left ventricle, right atrium, right ventricle|
|(d) Buccal cavity, Oesophagus, stomach, duodenum||(e) Prophase, metaphase, anaphase, telophase|
|Column A||Column B|
|(a) Metaphase||(3) Chromosome become arranged in a horizontal plane at the equator.|
|(b) Heart attack||(5) Blocking of coronary artery.|
|(c) Renal artery||(4) That brings waste filled – blood from the aorta to the kidney.|
|(d) Cranial nerves||(2) Twelve pairs of nerves.|
|(e) Diffusion||(1) The process by which the molecules of perfume spread in the room when the bottle is open.|
|(iv) (a) Ovule||(b) ATP||(c) Potassium nitrate|
|(d) Progestin||(e) Scrotal sacs|
|(v) (a) Inguinal canal are two passages located on the lower portion of the anterior abdominal wall.||(b) Bundle of His arises firm atrioventricular nice and extends to intraventricular septum.||(c) Acetylcholine is releases from terminal end of axons.|
|(d) At the centre of the chromosomes.||(e) At the centre of the cell at the metaphase plate.|
(i) Leptotene: It is the first substage of prophase-I in meiosis in which the chromosomes become visible as single threads.
(ii) No, because mother has only one type of sex hromosomes i.e., X chromosomes but a father has two types of chromosomes X and Y chromosomes. So, all children
will inherit X chromosome from mother and whether X or Y bearing sperm from father fertilize the egg will determine the sex of new born.
(iii) The evaporation of water from the leaves of a plant is called transpiration. Functions of transpiration:
(a) It helps in the upward movement of water and minerals from root to the leaves through the stem.
(b) Helps in cooling the plant surface.
(iv) Plant hormones or phytohormones are the chemical substances present in plants which coordinate and control various activities of plants like growth, development,
response to stimuli etc. There are different types of hormones like auxins, gibberellins, cytokinins, abscisic acid, ethylene etc.
|(v) (a) Red blood cells||(b) RBCs side view||(c) Basophil|
(i) ATP – Adenosine triphosphate
(ii) Nitrogenous bases: Adenine and Guanine (others: Cytosine, Thymine, Uracil)
|(iii) (a) Pea: Pisum sativum||(b) The two genetic disorders are: Sickle cell anaemia and Down syndrome (Trisomy 21)|
|(iv) (a) Ovulation||(b) Menarche|
(v) (a) The light factor is being studied in this experiment.
(b) The plant was kept in a dark room to destarch its leaves, i.e., to remove all the starch present in the leave of the plant.
(c) The exposed parts of the leaf will turn black – blue, i.e., will show the presence of starch, and the part covered with paper will remain brown, showing the
absence of starch.
(i) Natality: The number of children born per 1000 of living population per year is termed as natality.
|Glucose is stored in the form of starch.||Glucose is stored in the form of glycogen.|
|(b) Hypotonic solution||Hypertonic solution|
|Even endosmosis can be considered.||Even exosmosis can be considered.|
|(iii) (a) Karyotype||(b) Diapedesis|
|(iv) (a) Amniotic fluid||(b) Biodegradable waster|
|(v) (a) Flaccidity||(b) Hypertonic solution|
|(c) 1. Nucleus, 2. Plastids, 3. Small vacuole, 4. Hypertonic solution. called coordination.|
(i) Coordination: The working together of various organs of the body of an organism in a proper manner to generate a proper reaction in response to a stimulus is
|(a)||A single parent cell divides into two daughter cells.||It results in production of many daughter cells.|
|(b)||Nucleus divides once and then each nucleus gets surrounded by cytoplasm to form two individuals.||Nucleus divides repeatedly to form many nuclei and each gets surrounded by cytoplasm to form many daughter cells.|
|(a) Corpus callosum||Corpus luteum|
|Transfers information from one cerebral hemisphere to the other.||It secrets progesterone and oestrogen.|
|(b) Sensory neuron||Motor neuron|
|Carries impulses from receptors to nervous system.||Carries impulses from central nervous system, to the effector organ / muscle.|
(iv) (a) Root pressure: The pressure developed in the cortical cells of the root which pushes the water into the xylem vessels of the stem is called as root pressure.
(b) Turgidity creates root pressure which helps in the ascent of sap.
(v) Self-pollination among F1
TtRr × TtRr
Genotypes: 9 Tall Red (TTRR, TTRr, TtRR, TtRr) : 3 Tall white (TTrr, Ttrr,) : 3 Dwarf red (ttRR, ttRr) : 1 Dwarf white (ttrr)
(c) A dominant allele is variation of a gene that will produce a certain phenotype, even in the presence of other alleles. When a dominant allele is completely dominant over another allele, the other is known as recessive allele.
(i) Biodegradable wastes: Biodegradable wastes can be defined as the wastes that can be broken down into simpler compound by the decomposers present in the nature.
(ii) (a) Water is the raw material as well as the product in the chemical reactions of the photosynthesis.
(b) Spinal cord controls mainly the reflex action. So, reflex actin and involuntary action will get disrupted.
(iii) (a) Leaf appears green due to the presence of green pigment called chlorophyll. When a visible light falls on chlorophyll pigment, it absorbs mainly violet, blue, red,
orange colours but reflects green colour hence chlorophyll appears green.
(b) Non – biodegradable substances cannot be degraded by microbes through biological process to simpler forms, hence they persist in environment for a longer period of time.
|Adenosine triphosphate system.||Indole-3-acetic acid|
|Ureter carries urine from kidneys to the urinary bladder.||Urethra carries urine from urinary bladder to the outside of the body|
(v) (a) 1 – Vitreous humour, 2 – Blind spot, 3 – Lens, 4 – Pupil.
(b) the defect is Myopia or near sightedness and it can be corrected by using concave lens.
(c) Myopia corrected by concave lens is depicted in diagram shown below:
(i) Cerebrospinal fluid: It is a clear, colourless, slightly alkaline fluid present in ventricles of brain, central canal of spinal cord and spaces between meninges
which protects brain and spinal cord from injury and shocks.
|(ii) (a) Dihybrid cross||(b) Diapedesis|
|(iii) (a) Sulphur dioxide||(b) Mortality|
(iv) (a) Sperms are produced in the seminiferous tubules of testes.
(b) Semen is milky fluid that consist of mixture of sperms and secretions from accessory glands.
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