ICSE Class 10 Biology — 2019 Paper

(i) Choroid

(ii) CFCs (Chlorofluorocarbon)

(iii) Umbilical Cord

(iv) Homologous Chromosome

(v) Carbaminohaemoglobin

(i) The theory of inheritance of Acquired Characters was proposed by Jean Baptiste de Lamark.

(ii) The protective sac which develops around the developing embryo is called amnion.

(iii) Maintaining balance of the body and coordinating muscular activities is carried out by the Cerebellum.

(iv) The kidney is composed of number of nephrons.

(v) The part of the eye which can be donated from a clinically dead person is cornea.

(i) The birth rate in India is very high because most of the rural population which forms the bulk of our society are illiterate, ignorant and superstitious. They are unaware of the need for family planning. Children are considered to be helping hands to increase the family income.

(ii) Haemoglobin has very strong affinity for carbon monoxide, forming a stable compound carboxyhaemoglobin. This cuts down the capacity of blood for transporting oxygen, sometimes resulting in death.

(iii) When excessive fertilizers are added to the moist soil close to the root hair cell, it will form a hypertonic solution as compared to root hair cells. Plasmolysis/exosmosis takes place resulting in the protoplasm to shrink. The plasma membrane withdraws itself from the cell wall. Hence, the root hairs become flaccid and droop.

(iv) Acid rain is harmful to the environment due to the following reasons:

1. It increases the acidity in the soil and destroys forests and crops.
2. It corrodes buildings, monuments, statues, bridges, fences and railings.
3. It poses a serious threat to human health, since it contaminates air and water.
4. Aquatic species are affected due to increased acidity of water in lakes and rivers.
5. It affects plant growth. Plant leaves get burnt and dry.

(v) All life on Earth is supported by Photosynthesis because photosynthesis is ultimately the source of energy and food for all living beings. It is the only biological process which releases oxygen in the atmospehre. Oxygen supports all the life on earth. The starting point of any food chain is always a plant. If green plants were to suddenly disappear, then so would virtually all life on Earth.

(i) Artery

(ii) Either X or Y Chromosomes

(iii) Capillary

(iv) 14^th day

(v) Age of the plant

(i) Odd term: Leukemia
    Category: Others are hormonal disorders.

(ii) Odd term: Pepsin
     Category: Others are hormones.

(iii) Odd term: Photon
      Category: Others are parts of nerve cell.

(iv) Odd term: Chicken pox
      Category: Others are genetic disorders / hereditary traits.

(v) Odd term: Polythene bag
     Category: Others are biodegradable waste.

(i) Abscisic acid

(ii) Indole-3-Acetic acid

(iii) Adenosine triphosphate

(iv) Deoxyribonucleic acid

(v) Thyroid stimulating hormone

(i) The above mentioned picture is of water pollution.

(ii) Sewage and oil spills are a few pollutants that cause water pollution.

(iii) Water pollution can cause many water borne diseases like Typhoid, Cholera, Jaundice, Dysentery, Diarrhoea, etc.

(iv) Setting up of sewage treatment plants in larger habitations and septic tanks in houses is an effective measure to control water pollution.

(v) Any such constituent the addition of which to air, water or land deteriorates the natural quality of the environment is termed as a Pollutant.
For example — Harmful gases, Smoke, Garbage, Dust, etc.

(i) The parts labelled 1 and 2 are:

• 1 → Radicle
• 2 → Plumule

(ii) The tropic movement shown in part 1 is Hydrotropism.

(iii) Part 1 is affected by Gravity and Water(moisture) — Water is stronger.

(iv) The growth movement of plant parts in response to touch stimulus is called Thigmotropism. Example: Plants such as Sweet Peas, Cuscuta and vines have tendrils that coil around other plants or other available support in response to one sided contact or touch.

(v) Directional movement of a plant part towards the stimulus is called positive tropic movement and away from the stimulus is called negative tropic movement.

(i) Testis are located in a thin-walled sac of skin called Scrotum.

(ii) Incus is located between Malleus and Stapes of ear ossicle which is found in the middle ear.

(iii) Thylakoids are located in grana of chloroplast.

(iv) Amniotic fluid is found in the amnion. It fills the space between amnion and foetus.

(v) It is located between the two cerebral hemispheres.

(i) The factor studied in this experiment is Sunlight.

(ii) It will be observed that only the parts of the leaf which could get sunlight turn blue black and the parts which were covered with black paper do not turn blue as they could not synthesize starch.

(iii) Photosynthesis is the process by which living plant cells, containing chlorophyll, produce food substances(glucose and starch), from carbon dioxide and water, by using light energy. Plants release oxygen as a by-product during photosynthesis.

(iv) Balanced chemical equation representing the process of photosynthesis is given below:

$6CO_2 + 12H_2O \space \space \overset{\text{light energy}}{\underset{\text{chlorophyll}}{\longrightarrow}} \space \space C_6H_{12}O_6 + 6H_2O + 6O_2 \uparrow$

(v) The below labelled diagram shows an experimental setup demonstrating that oxygen is released during photosynthesis:

(i) The function of Medulla Oblongata is to control the activities of the internal organs, for example, peristaltic movement of the alimentary canal, movement of breathing, beating of the heart and many other involuntary actions.

(ii) Cytokinins inhibits apical dominance, stimulate cell division and cell elongation and prevent ageing of plant parts.

(iii) The functions of Tears include lubricating the surface of eyes, wash away dust particles, help in killing germs.

(iv) The Coronary Artery delivers blood to the heart muscles.

(v) Seminal vesicles produce a secretion which serves as a medium for transportation of the sperms.

(i) The diagram represents the Urinary/Excretory system.

(ii) The parts marked 2 and 4 are:

• 2 → Ureter
• 4 → Sphincter muscle

Part 5 is urethra. It's function is to expel urine outside the body from the urinary bladder at the time of urination (micturition)

(iii) The structural and functional units of kidneys are nephrons.

(iv) Fluid that accumulates is Urine. The main nitrogenous waste present in it is Urea.

(v) Below is the labelled diagram showing the longitudinal section of part 1 i.e., Kidneys:

(i) Pituitary gland. The pituitary gland is a small projection which hangs from the base of the mid-brain below the hypothalamus.

(ii) The above gland is popularly called the master gland because it controls practically all other endocrine glands.

(iii) Deficiency of Antidiuretic hormone (ADH) / Vasopressin causes diabetes insipidus.

Difference between Diabetes Mellitus and Diabetes Insipidus is summarised below:

(iv) Hormone is a secretion from some glandular part of the body, which is poured directly into blood and which acts on the target organs or cells of the same individual, bringing about coordination between distant parts of the body.

Tropic hormones stimulate other endocrine glands to produce their specific hormone.

(v) The lobe for the respective hormones is mentioned below:

1. Oxytocin → Posterior lobe
2. ACTH → Anterior lobe
3. Growth hormone → Anterior lobe

(i) The process being studied is Transpiration. Transpiration is the process during which water is lost in the form of water vapour through aerial parts of the plant.

(ii) The pot was enclosed in a rubber sheet to prevent evaporation of water from the soil.

(iii) Two external factors which can accelerate Transpiration are:

1. Bright sunlight
2. Low humidity

(iv) Two adaptations in plants to reduce the above process are:

1. Sunken stomata
2. Narrow leaves

(v) Stomatal apparatus is shown in the labelled diagram below:

(i) Picture A → Neanderthal man, Picture B → Australopithecus.

(ii) Two characteristic features of each are:

1. Neanderthal man — Height 160 cm, semi erect stooping posture, Cranial capacity 1450 cm³
2. Australopithecus — Height 120 cm, nearly upright posture, Cranial capacity 450 to 600 cm³

(iii) The theory of 'Natural Selection' was proposed by Charles Darwin.

(iv) Peppered moth (Biston bitularia) was the organism used as an example to explain 'Industrial Melanisum'.

(v) Two examples of vestigial organs in humans are:

1. Vermiform Appendix
2. Wisdom tooth

(i) Phenotype → Tall plants
    Genotype → Heterozygous tall plants

(ii) Below is the Punnett square board showing the gametes and offspring when both the parents are heterozygous for tallness:

(iii) Phenotypic ratio = 3:1
      Genotypic ratio = 1:2:1

(iv) Mendel's Law of Dominance — Out of a pair of contrasting characters present together, only one is able to express itself while the other remains suppressed. The one that expresses is the dominant character and the one that is unexpressed is the recessive. The recessive character can express only when the pair consists of both recessives (homozygous recessive).

(v) The cross in which two features of an organism / plant are taken together at a time.

(i) The stage represented in the diagram is Anaphase. In this phase the two sister chromatids of the chromosomes are pulled apart, towards the centrioles present at the opposite poles of the cell.

(ii) The cell is an animal cell because cell wall is absent and centrioles are present with asters.

(iii) Telophase follows Anaphase. Its diagram is shown below:

(iv) Each daughter cell will have four chromosomes.

(v) The four nitrogenous bases are:

1. Adenine
2. Guanine
3. Cytosine
4. Thymine

(i) In the brain, outer portion contains cyton which gives a grayish colour hence called as gray matter, while axon is inside forming the white matter.
In spinal cord, cyton is inside forming the gray matter and axon is outside forming white matter.

(ii) Dynamic balance — semicircular canal
     Static balance — utriculus and sacculus (vestibule)

(iii) When we move from dark or dim lit area to a brightly lit area, visual purple of rods is bleached reducing their sensitivity and pupil constricts to reduce the amount of light entering the eyes. This is light adaptation.
When we move from brightly lit area to dark area, visual purple of rods which were earlier broken due to bright light regenerates and pupil dilates to allow more light to enter. This is dark adaptation.

(iv) Parthenocarpy refers to the development of fruits without prior fertilization.
Examples — Apple, Grapes, Tomato.

(v) Two objectives of Swachh Bharat Abhiyan are:

1. To clean the streets, roads and infrastructure of the country's cities and towns.
2. To eliminate open defecation through the construction of individual, cluster and community toilets.

(i) Human female reproductive system.

(ii) Parts marked 5 and 6:

• 5 → Oviducal funnel
• 6 → Cervix

(iii) Oestrogen, Progesterone

(iv) Fertilisation – 2, (Oviduct/Fallopian tube)
      Implantation – 3 (Uterus)

(v) The surgical methods of contraception are mentioned below:

1. Human males — Vasectomy
2. Human females — Tubectomy