Nootan solutions for Biology [English] Class 12 ISC chapter 7 - Origin of Life [Latest edition]

Recent astronomical findings suggest that the earth’s early atmosphere may have contained ______.

With the origin of aerobic phototrophs the atmosphere of the earth became ______.

The scientist who gave the concept of spontaneous generation was ______.

Life originated about ______.

Through study of the geologic record, we know that the evolution of life has been profoundly influenced by ______.

______ was the first to obtain indirect evidence that organic molecules could have been formed on the early Earth.

An abundance of ______ was conspicuously absent from the Earth’s atmosphere 4 billion years ago.

Which of the following statements is false?

The big bang theory applies to the initial formation of ______.

The main explanation for the lack of a continuing abiotic origin of life on the Earth today is that ______.

Which of the following scientists are incorrectly paired with their theories or experiments?

Formation of microspheres, liposomes, and coacervates all require ______.

The first genes may have developed when ______.

In his laboratory apparatus, Stanley Miller synthesized ______.

Which of the following gases probably least abundant in the early atmosphere?

Which of the following steps has not yet been accomplished by scientists studying the origin of life?

Photoautotrophs use ______.

The first eukaryotic cells emerged during the ______.

Most of the history of life concerns the evolution of ______.

Which of the following statements is true?

Evolution of the DNA → RNA → protein system was a milestone because the protocell ______.

The significance of liposomes, phospholipid droplets, is that they show that ______.

Which of the following did Stanley Miller place in his experimental system to show that organic molecules could have arisen from inorganic molecules on the primitive Earth?

Which of the following gives a possible sequence of organic chemicals prior to the protocell?

Which of the following forms of energy is not one of those to have been involved in the production of large organic molecules in the primitive reducing atmosphere?

The term reducing atmosphere for the early Earth means that the atmosphere ______.

The first person who proposed that small organic molecules could have arisen by chemical evolution was ______.

Which of the following would have been most likely to develop only after the formation of a true cell?

Biological evolution differs from chemical evolution in that it would have been possible only after ______.

The synthesis of DNA or RNA from the organic soup would have been guided by the actions of enzymes in the ______.

The first autotrophs probably were ______ and produced ______.

Which of the following pairs of occurrence and date is not correct?

Which of the following did Stanley Miller place in his experimental system to show that organic molecules could have arisen from inorganic molecules on the primitive Earth?

Which of the following is not a place where polymers may have arisen?

Which of the following events did not occur during the Precambrian era?

The theory of spontaneous generation stated that ______.

Whose theory is not related with the origin of life?

Swan neck flask experiment of Louis Pasteur proves ______.

Primitive life was ______ in nature.

During chemical evolution, the small molecules that played a crucial role in the origin of life were ______, ______ and ______.

The most significant event in chemical evolution was the origin of ______ type of molecules.

The early atmosphere of the earth was a chemically ______ environment, whereas the present atmosphere is a chemically ______ environment. The event that changed the earth’s atmosphere from the first to the second type was the evolution of ______.

The first eukaryotic cell probably acquired energy from ______ cellular respiration.

State whether the following statement is true or false.

The present cellular forms of life evolved from molecular aggregates capable of self duplication by a slow process of sequential changes called organic evolution.

State whether the following statement is true or false.

The plausibility of Oparin’s theory depends greatly on the earth's being somewhat different than that it is now.

State whether the following statement is true or false.

Horowitz showed that the earliest organisms were probably heterotrophs.

State whether the following statement is true or false.

The term organic soup refers to the ancient oceans before life formed, in which organic molecules such as amino acids accumulated.

State whether the following statement is true or false.

Microspheres are structures made up of lipid and protein membranes with many of the properties of a cell, such as metabolic pathways.

Which gas was absent in the atmosphere in free form at the time of origin of life?

Name two main propositions of Oparin and Haldane.

Name the group of the earliest photosynthetic organisms that appeared during the origin of early life.

If you simulate conditions which existed in the atmosphere of the primitive earth in an experiment in laboratory, what products would you expect?

In what sequence did the following happen? living cell, oxidising atmosphere, autotrophy, heterotrophy, reducing atmosphere, first organic molecule.

Name the scientists from the following list who supplied evidence that supported the theory of spontaneous generation and those who supported biogenesis: Spallanzani, Needham, Pasteur, Fox, Miller, Oparin.

What are protobionts?

What is coacervate?

Can there be abiotic origin of lite on the earth today? Give reasons.

Name the scientist who disproved spontaneous generation theory.

Enumerate some important effects of oxygen on evolution.

Oparin-Haldane theory states that life originated on this earth through complex organic molecules formed as a result of a series of chemical reactions. Name any two sources which provided energy for these chemical reactions.

Tell the main characteristics of coacervates which remind us of bacteria and other simple unicellular organisms.

Tell the conditions of the Earth atmosphere conducive for the origin of life.

Which scientist used ‘spark discharge apparatus’ for his experiment?

What is the big bang theory?

List one evidence in support of the big bang theory.

What was the role of anaerobic chemoheterotrophs in evolution of life in primordial soup?

What was the role of anaerobic chemoautotrophs in evolution of life in primordial soup?

What was the role of anaerobic photoautotrophs in evolution of life in primordial soup?

What was the role of aerobic photoautotrophs in evolution of life in primordial soup?

What are the unique features of water that make it most suitable medium for the origin of life?

Describe the steps by which simple inorganic substances may have undergone chemical evolution to yield complex organic molecules that could eventually form living matter.

What was the composition of the primitive atmosphere that favoured abiotic origin of life on the earth?

Give an account of the Miller and Urey experiment on the origin of life.

Describe in brief the Oparin-Haldane theory of origin of life. How does meteorite favour this hypothesis?

Given below is a statement with two errors in it. Identify the errors and rewrite them correctly.

‘Stanley Miller and Harold C. Urey put the Darwin’s theory to an experimental test in the year 1935 by recreating in the laboratory the probable conditions on the primitive earth’.

Stanley Miller and Harold C. Urey performed an experiment by recreating in the laboratory the probable conditions of the atmosphere of the primitive Earth.

1. What was the purpose of the experiment?
2. In what forms was the energy supplied for the chemical reactions to occur?
3. For how long the experiment was run continuously?

Name the scientist who had used the set-up shown ahead. Write the purpose of the set-up and the conclusion, the scientist arrived at.

Who created coacervates artificially in laboratory for the first time? Enumerate their characteristics. What do they confirm about the origin of life?

Who were the two that conducted an experiment to synthesize organic molecules abiotically? How did they provide the probable conditions of the primitive earth in this experiment?

In 1953, S. L. Miller created primitive earth conditions in the laboratory and gave experimental evidence for origin of first form of life from pre-existing non-living organic molecules. In your opinion what primitive earth conditions he created.