Question 1

Question 1(b)Correct and rewrite the statement by changing the biological term that is underlined for each statement: [5](i) The theory of Inheritance of Acquired Characters was proposed by Watson and Crick.(ii) The protective sac which develops around the developing embryo is called the Pericardium.(iii) Maintaining balance of the body and coordinating muscular activities is carried out by the cerebrum.(iv) The kidney is composed of a number of neurons.(v) The part of the eye which can be donated from a clinically dead person is the Retina.

Accepted Answer

(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.

Question 2

Question 1(f)Identify the ODD term in each set and name the CATEGORY to which the remaining three belong : [5]     Example: Glucose, starch, cellulose, calcium     Odd term: Calcium.     Category: Others are different types of carbohydrates(i) Addison's disease, Cushing's Syndrome, Acromegaly, Leukemia.(ii) Insulin, Adrenaline, Pepsin, Thyroxine.(iii) Axon, Dendron, Photon, Cyton.(iv) Chicken pox, Colour blindness, Haemophilia, Albinism.(v) Polythene bag, Crop residue, Animal waste, Decaying vegetable.

Accepted Answer

(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.

Question 3

Question 2(a)Given below is an experimental setup to demonstrate a particular tropic movement in germinating seeds. Study the diagram and answer the questions that follow : [5](i) Label the parts 1 and 2.(ii) Name the tropic movement shown by part 1.(iii) Part 1 is affected by two stimuli. Name them. Which one of the two is stronger?(iv) What is Thigmotropism ? Give one example.(v) What is meant by 'Positive' and 'Negative' tropic movements in plants?

Accepted Answer

(i) The parts labelled 1 and 2 are:1 → Radicle2 → 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.

Question 4

Question 3(a)The diagram given below represents an experiment to prove the importance of a factor in photosynthesis. Answer the questions that follow : [5](i) Name the factor studied in this experiment.(ii) What will you observe in the experimental leaf after the starch test?(iii) Explain the process of Photosynthesis.(iv) Give a balanced chemical equation to represent the process of photosynthesis.(v) Draw a neat, labelled diagram of an experimental setup to show that oxygen is released during photosynthesis.

Accepted Answer

(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:6CO2+12H2O  ⟶chlorophylllight energy  C6H12O6+6H2O+6O2↑6CO_2 + 12H_2O \space \space \overset{	ext{light energy}}{\underset{	ext{chlorophyll}}{\longrightarrow}} \space \space C_6H_{12}O_6 + 6H_2O + 6O_2 \uparrow6CO2​+12H2​O  chlorophyll⟶​light energy​  C6​H12​O6​+6H2​O+6O2​↑(v) The below labelled diagram shows an experimental setup demonstrating that oxygen is released during photosynthesis:

Question 5

Question 3(b)State the main functions of the following : [5](i) Medulla Oblongata(ii) Cytokinins(iii) Tears(iv) Coronary Artery(v) Seminal Vesicles

Accepted Answer

(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.

Question 6

Question 4(a)The diagram given below represents an organ system in the human body. Study the same and answer the questions that follow: [5](i) Identify the system.(ii) Label the parts marked 2 and 4. Mention the function of part 5.(iii) Name the structural and functional units of the part marked 1.(iv) What is the fluid that accumulates in part 3? Which is the main nitrogenous waste present in it?(v) Draw a neat, labelled diagram showing the longitudinal section of part 1.

Accepted Answer

(i) The diagram represents the Urinary/Excretory system.(ii) The parts marked 2 and 4 are:2 → Ureter4 → Sphincter musclePart 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:

Question 7

Question 5(a)Given alongside is an apparatus which was set up to investigate a physiological process in plants. The setup was placed in bright sunlight. Answer the questions that follow : [5](i) Name the process being studied. Define the process.(ii) Why was the pot enclosed in a rubber sheet?(iii) Mention two external factors which can accelerate the above process.(iv) List two adaptations in plants to reduce the above process.(v) Draw a neat, labelled diagram of a stomatal apparatus.

Accepted Answer

(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:Bright sunlightLow humidity(iv) Two adaptations in plants to reduce the above process are:Sunken stomataNarrow leaves(v) Stomatal apparatus is shown in the labelled diagram below:

Question 8

Question 5(b)Given below are two stages in the evolution of man. Study them and answer the questions that follow: [5](i) Identify Australopithecus and Neanderthal man from the above pictures.(ii) Mention two characteristic features each for the two stages.(iii) Who proposed the theory of 'Natural Selection'?(iv) Name the organism used as an example to explain 'Industrial Melanisum'.(v) Give two examples of vestigial organs in humans.

Accepted Answer

(i) Picture A → Neanderthal man, Picture B → Australopithecus.(ii) Two characteristic features of each are:Neanderthal man — Height 160 cm, semi erect stooping posture, Cranial capacity 1450 cm3Australopithecus — 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:Vermiform AppendixWisdom tooth

Question 9

Question 6(a)In Mendel's experiments, tall pea plants (T) are dominant over dwarf pea plants (t). [5](i) What is the phenotype and genotype of the F1 generation if a homozygous tall plant is crossed with a homozygous dwarf plant?(ii) Draw a Punnett square board to show the gametes and offspring when both the parents are heterozygous for tallness.(iii) What is the Phenotypic ratio and genotypic ratio of the above cross in (ii)?(iv) State Mendel's Law of Dominance.(v) What is a Dihybrid Cross?

Accepted Answer

(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: TtTTTTttTttt(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.

Question 10

Question 6(b)Given below is a diagram representing a stage during the mitotic cell division. Study the diagram and answer the following questions : [5](i) Identify the stage by giving a suitable reason.(ii) Is it a plant or an animal cell? Give a reason to support your answer.(iii) Draw a neat, labelled diagram of the stage which follows the one shown in the diagram.(iv) How many chromosomes will each daughter cell have after the completion of the above division ?(v) Name the four nitrogenous bases.

Accepted Answer

(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:AdenineGuanineCytosineThymine

Question 11

Question 7(a)Answer the following questions briefly : [5](i) How are the cytons and axons placed in the brain and the spinal cord ?(ii) Which part of the human ear gives 'Dynamic balance' and 'Static balance' to the body ?(iii) Explain how the human eye adapts itself to bright light and dim light.(iv) What is Parthenocarpy ? Give one example.(v) Mention any two objectives of 'Swachh Bharat Abhiyan'.

Accepted Answer

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

Question 12

Question 7(b)The diagram given below represents a system in the human body. Study the diagram and answer the following questions: [5](i) Identify the system.(ii) Label the parts marked 5 and 6.(iii) Name the two hormones secreted by 1.(iv) Mention the number and the name of the part involved in fertilization and implantation from the above diagram.(v) Mention the surgical methods of contraception in :Human males.Human females.

Accepted Answer

(i) Human female reproductive system.(ii) Parts marked 5 and 6:5 → Oviducal funnel6 → Cervix(iii) Oestrogen, Progesterone(iv) Fertilisation – 2, (Oviduct/Fallopian tube)      Implantation – 3 (Uterus)(v) The surgical methods of contraception are mentioned below:Human males — VasectomyHuman females — Tubectomy

Solved 2019 Question Paper ICSE Class 10 Biology

Section I 40 Marks

Section Ii 40 Marks