RBSE Class 9 Science Chapter 5: Concept of Life Important Textbook Questions and Solutions

Concept of Life Class 9 Science Chapter 5 deals with different theories of the origin of life, our solar system, different types of planets, an invention of new planets of Earth, etc. By studying this chapter, students will understand what’s the difference between living and nonliving things, how our solar system works, why Earth is an ideal planet for life existence and many more interesting facts. We come across both living and nonliving things in our day-to-day life. At times, it is easy to differentiate between the two, but sometimes it is difficult.

RBSE Science Class 9 Chapter 5: Concept of Life important textbook questions and solutions provided in this article are solved precisely after doing extensive research related to each question. These RBSE Solutions for Class 9 Chapter 5 will guide students to grasp the right way to answer questions in their exam. We have compiled all the questions and answers provided in the Class 9 science textbook.

RBSE Class 9 Science Chapter 5: Objective Textbook Questions and Solutions

Q1. Besides Earth, on which planet of our Solar System is life possible ?

(A) Mercury

(B) Jupiter

(C) Venus

(D) Mars

Answer: D

Q2. Which is not a characteristic feature of living beings ?

(A) Reproduction

(B) Evolution

(C) Growth

(D) All options are wrong

Answer: D

Q3. According to Oparin’s theory, Origin of life has been divided into how many stages?

(A) 5

(B) 6

(C) 7

(D) 8

Answer: C

Q4. Who propounded the theory of biogenesis ?

(A) Oparin

(B) Francisco Redi

(C) Von Helmont

(D) Liebig

Answer: B

Q5. Name of the earth-like planet discovered on 17 April 2014 is :

(A) Kepler 186 f

(B) Kepler 452 a

(C) Kepler 186 g

(D) Kepler 452 b

Answer: A

Q6. In the solar system which is the nearest celestial body to the earth.

(A) Sun

(B) Moon

(C) Venus

(D) Jupiter

Answer: B

Q7. Which famous Russian bio-chemist, proposed a hypothesis regarding origin of life?

(A) A.I. Oparin

(B) Francisco Redi

(C) Von Helmont

(D) Liebig

Answer: A

Q8. Which planet is considered as the hottest planet in the solar system?

(A) Sun

(B) Moon

(C) Mercury

(D) Jupiter

Answer: C

Q9. Which British scientist got the Bharatiya Citizenship?

(A) A.I. Oparin

(B) Francisco Redi

(C) Von Helmont

(D) JBS Haldane

Answer: D

Q10. When was the first spacecraft sent to the planet Mars?

(A) 1950

(B) 1960

(C) 1980

(D) 1970

Answer: B

Q11. Among the following which is the major component of the planet Mars

(A) Carbon dioxide

(B) Oxygen

(C) Nitrogen

(D) Water vapour

Answer: A

Q12. In which planet life is not possible because of lack of both water and atmosphere.

(A) Sun

(B) Jupiter

(C) Mercury

(D) Moon

Answer: D

Q13. A planet similar to earth was found and was referred to as the Earth’s

(A) Cousin

(B) Big Older Cousin

(C) Big Cousin

(D) Big Son

Answer: B

Q14. According to the present view, what is the basis of life.

(A) Effect of Sunlight

(B) God’s Grace

(C) Food

(D) None of the above

Answer: D

Q15. In which year Mars Orbiter Mission (MOM), of Bharat, recorded success

(A) 2014

(B) 2015

(C) 2016

(D) 2017

Answer: A

Q16. During the initial phase the entire universe was in the form

(A) Line

(B) Space

(C) Dot

(D) Blank

Answer: C

Q17. Which one of the following is not related to the origin of life

(A) Urey

(B) Aristotle

(C) Wallace

(D) Haldane

Answer: C

Q18. Coacervates are clusters of

(A) Sugar

(B) Fats

(C) Sugar and Fats

(D) Proteins

Answer: D

Q19. The hypothesis of Oparin’s was experimentally proved by

(A) Redi’s experiment

(B) Miller’s experiment

(C) Pasteur’s experiment

(D) All the above

Answer: B

Q20. Initially, which of the following was considered responsible for the origin of life on Earth.

(A) God

(B) Spontaneous origin

(C) Cosmic panspermic

(D) Coincidental origin

Answer: A

Q21. In which year famous Russian bio-chemist, A.I.Oparin proposed a hypothesis regarding the origin of life.

(A) 1921

(B) 1924

(C) 1925

(D) 1926

Answer: 1924

Q22. The initial environment of earth was of reducing nature because of excess of

(A) Carbon Dioxide

(B) Nitrogen

(C) Hydrogen

(D) None of the above

Answer: C

Q23. Gases like CO2 and N2 were formed by reaction of free oxygen and

(A) Carbon Dioxide

(B) Nitrogen

(C) Hydrogen

(D) Methane and Ammonia

Answer: D

Q24. The biggest mountain of the solar family is on which planet.

(A) Mars

(B) Moon

(C) Mercury

(D) Jupiter

Answer: A

Q25. When was 186f (Kepler-186f) discovered

(A) 17 April 2014

(B) 16 April 2014

(C) 20 April 2014

(D) 21 April 2014

Answer: A

Q26. After Kepler-452b which planet has been discovered resembling Earth.

(A) Kepler – 170f

(B) Kepler – 186f

(C) Kepler – 190f

(D) Kepler – 140f

Answer: B

RBSE Class 9 Science Chapter 5: Short Answer Type Questions and Solutions

Q27. Name the scientist who negated the theory of spontaneous generation.

Answer: Louis Pasteur negated the theory of spontaneous generation

Q28. Which are the two planets similar to earth?

Answer: The two planets similar to earth are

  • Kepler – 452b
  • Kepler – 186f

Q29. Which scientist propounded the Cosmozoic theory?

Answer: Ritcher propounded the Cosmozoic theory

Q30. After Earth, on which planet life may exist.

Answer: Mars is the only planet of our solar system on which life may exist.

Q31.Which is the nearest celestial body to the Earth?

Answer: In the solar system Moon is the nearest celestial body to the earth. In Moon, life is not possible because of the lack of water and atmosphere.

Q32. What were the views of Louis Pasteur?

Answer: According to Louis Pasteur, life originated only from pre-existing life.

Q33. Which scientist conducted an experiment to explain the origin of life.

Answer: Stanley Miller conducted an experiment to explain the origin of life.

Q34: Who proposed the Theory of Biogenesis and rejected spontaneous generation?

Answer: Francesco Redi proposed biogenesis and rejected spontaneous generation.

Q35. In our solar system, in which planet life is not at all possible.

Answer: Mercury is too hot because of its nearness to the Sun, hence life is not possible on it.

Q36. Which nation in the world to register success in the first effort of Mars mission and that too at a considerably low cost.

Answer: India is the first nation which successfully recorded Mars mission in 2014 at considerably low cost.

RBSE Class 9 Science Chapter 5: Short Answer Type Questions and Solutions

Q37. Explain the differences between living and nonliving with the help of examples.

Answer: The differences between living and nonliving are as follows:

  • Living beings exhibit development and growth. Animals grow upto a particular age but in plants growth is a lifelong process, whereas there is no development and growth exhibited in non-living things.
  • Cells are present in living beings. A definite organisation of tissues and organs are present whereas in non-living things there is no cellular organisation.
  • In living beings respiration occurs. In living beings energy is obtained by oxidation of organic substances. This process is known as Respiration whereas in non-living things respiration does not take place.
  • In living beings metabolism takes place. Both catabolism and anabolism occur whereas in non-living things metabolism does not occur.

Q38. Give an illustrated account of the Miller’s experiment.

Answer: In 1954, a scientist from Chicago, Stanley Miller, reproduced the conditions prevalent on primitive earth, i.e. 3 to 4 trillion years ago, to explain the origin of life. Miller boiled a mixture of methane, ammonia and hydrogen together along with water in his apparatus. The vapours formed were condensed. Thus mixtures of various gases were formed by their mutual reaction. After one week, he observed a red coloured substance in the flask. Chemical analysis revealed the presence of various organic substances like alanine, glycine, glycerine etc. From this experiment it was inferred that life originated on earth in a similar manner.

RBSE Class 9 Chapter 5: Concept of Life Important Textbook Questions and Solutions - 38

Q39. Describe biogenesis.

Answer: Biogenesis means the origin of life is only possible from the organisms. He rejected the concept of spontaneous generation. He took flesh of fish, snake etc and boiled it to kill all the organisms present on it. Then these flesh pieces were placed in different jars. After that, the first jar was left open, the second was covered with a cork and the third was covered with a fine muslin gauze. After a few days, flies and maggots appeared in the first jar. In the second jar there were no flies or maggots and in the third jar flies laid eggs on the gauze. The larvae developed in the third jar only if any egg could pass through the gauze. So, in conclusion Pasteur inferred that organisms could originate from other organisms only.

RBSE Class 9 Chapter 5: Concept of Life Important Textbook Questions and Solutions - 39

Q40. Why is Earth considered as the most ideal planet for the origin of life?

Answer: The earth is the only habitable planet in our solar system. Life exists on earth due to several optimal conditions like the presence of atmosphere and water and the right distance away from the sun. The earth appears bluish green from outer space as light from the landmass and water bodies gets reflected. Earth has only one natural satellite: the Moon. The earth’s axis of rotation is tilted which causes seasonal variations.

RBSE Class 9 Science Chapter 5: Essay Type Questions and Solutions

Q41. Name the various hypothesis regarding the origin of life. Explain any one of them.

Answer: The various hypotheses regarding the origin of life are

  • Spontaneous Generation (Abiogenesis)
  • Cosmozoic Theory (Theory of Panspermia)
  • Theory of Biogenesis
  • Oparin Theory

Cosmozoic Theory

This theory was supported by Liebig, Calvin and Arrhenius and Crick, a French and Leslie Orgel. According to this theory the first organism reached earth from some unknown planet of the universe, in the form of showers of minute spores and evolved in the favourable environment of the earth which led to the origin of life. However, this theory was not accepted by many scientists because no organism could reach earth from the universe in living condition.

Q42. Explain the Oparin theory of origin of life.

Answer: The famous Russian bio-chemist, A.I. Oparin proposed a hypothesis regarding the origin of life, in 1924, on the basis of his studies. According to this hypothesis only carbonic compounds were present on primordial earth which were present in dissolved condition in the oceanic waters. The entire process of the origin of life was divided by Oparin in seven stages:

First stage: According to scientists, the age of earth is 5-6 billion years. It originated from a mass of hot cosmic dust and gases that was moving rapidly in the universe. Various

planets were formed by the division of this massive block. Earth was one of them. The temperature of the primitive earth was 5000-6000ºC. The hydrogen, carbon and oxygen molecules were present in it in abundance. Their mutual reactions resulted in the formation of compounds like water, ammonia and methane. Over a period of time the temperature of the earth reduced, as a result these compounds started solidifying and liquefying and clouds were formed. Gaseous ammonia and methane started accumulating in seawater through the rain waters. Some minerals also reached the oceans along with river waters. Finally, the first organism originated by the chemical synthesis of these compounds.

Second stage: The initial environment of earth was of reducing nature because of excess of

hydrogen. After billions of years, when the earth temperature reduced, simple hydrocarbons started forming by the condensation of methane. These simple organic molecules formed complex organic molecules like sugars, glycerine, fatty acids amino acids, pyrimidines, purines, etc. The earth crust was hardened because of solidification of many compounds. Thus, Lithosphere was formed.

Third stage: Various organic compounds like sugars, glycerine, amino acids, fatty acids, purines and pyrimidines formed by chemical synthesis, started boiling in the water bodies, just like soup. This resulted in their mutual combination forming complex organic molecules like carbohydrates, fats, proteins and nucleic acids, which laid the basis of origin of life.

Fourth stage: Nucleoproteins and other macro molecules were formed by the mutual reactions of carbohydrates, fats, proteins and nucleic acids. Certain specific nucleoproteins had the capability of replication because of which, replication was made possible. Replication resulted in an increase in the amount of nucleoproteins and this led to competition. New nucleoproteins were formed by mutation some existing nucleoproteins. In this way, the process of evolution of nucleoproteins was established.

Fifth stage: During this stage, the first cell evolved. With the reduction of nutrients available in the sea water, competition between nucleoproteins started. The sticky nature of the new formed mutated nucleoproteins resulted in formation of their aggregates. They remained in such groups and got a regular supply of nutrients.

Sixth stage: During this stage, evolution started on the basis of nourishment methods in primitive organisms. Parasitic, saprophytic, chemo-tropic and phototrophic organisms evolved.

Seventh stage: The amount of usable oxygen in the environment started increasing with the gradual increase in number of photosynthetic organisms. Gases like CO2 and N2 were formed by reaction of free oxygen with methane and ammonia. It was because of these processes that the primitive atmosphere converted into the present day atmosphere.

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