Tag: theories of the origin of life

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Multiple choice biology concept of life theories of the origin of life origin of life the origin of cells and cell division

When did life originate on earth?

  1. 2 billion years ago

  2. 3.5 billion years ago

  3. 1 billion years ago

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The origin of life on earth a scientific problem which is not yet solved. There are plenty of ideas but few clear facts.

It is generally agreed that all life today evolved by common from a single primitive lifeform. It is not known how this early form came about, but scientists think it was a natural process which took place perhaps 3,900 million years ago. 

So, the correct answer is "3.5 billion years ago".

Multiple choice biology concept of life theories of the origin of life origin of life the origin of cells and cell division

At the times of origin of life, the structure temperature of earth was :

  1. $100^o C $
  2. $50-60^o C $
  3. $85-40^o C $
  4. $10-15^o C $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Scientific consensus regarding the early Earth's environment suggests that the temperature was significantly lower than the boiling point of water, often estimated in the range of 50 to 60 degrees Celsius, which allowed for the formation of organic compounds.

Multiple choice biology concept of life theories of the origin of life origin of life the origin of cells and cell division

Atmosphere of earth just before the origin of life consisted of  ___________________.

  1. Water vapours, $CH _4 , NH _3 $ and Oxygen
  2. $ CH _4 , NH _3 $ and $CH _4$
  3. $ CO _2 , NH _3 , H _2 $ and water vapours
  4. $ CH _4 , O _3 , O _2 $ and water vapours
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Oparin-Haldane hypothesis suggests that the primitive atmosphere was reducing, containing methane, ammonia, hydrogen, and water vapor. Carbon dioxide is sometimes included in models of the early atmosphere.

Multiple choice biology concept of life theories of the origin of life origin of life the origin of cells and cell division

Which was absent/ least abundant in the atmosphere at the time of origin of life ?

  1. $NH _3$
  2. $H _2$
  3. $O _2$
  4. $CH _4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The early Earth's atmosphere was a reducing atmosphere. Free oxygen (O2) was absent or present in only trace amounts because it would have oxidized the organic molecules necessary for the origin of life.

Multiple choice biology concept of life theories of the origin of life origin of life the origin of cells and cell division

Following are the two statements about the origin of the life :
(a) The earliest organisms that appeared on the earth were nongreen and presumably anaerobic.
(b) The first autotrophic organisms were the chemoautotrophic that never released oxygen. 
Of the above statements which one of the following options is correct?

  1. Both (a) and (b) are false.

  2. (a) is correct but (b) is false.

  3. (b) is correct but (a) is false.

  4. Both (a) and (b) are correct.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The first organisms were indeed anaerobic heterotrophs that lived in a reducing environment. The first autotrophs were chemoautotrophs, which derived energy from inorganic chemical reactions without releasing oxygen.

Multiple choice biology concept of life theories of the origin of life origin of life the origin of cells and cell division

Prctobiogenesis occurred :

  1. 1.2 billion years ago

  2. 2.0 billion years ago

  3. 2.5 billion years ago

  4. More than 3.5 billion years ago
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Biopoiesis (not 'Prctobiogenesis' - appears to be a typo) occurred more than 3.5 billion years ago, coinciding with the oldest known fossil evidence of life in rocks dated to approximately 3.5-3.8 billion years old. This places the origin of life in the Archean Eon.