Question 1

Which experiment is depicted in the first image, and what was its significance in the study of the origin of life?

Accepted Answer

The Miller-Urey experiment; it showed that organic molecules could be synthesized abiotically under early Earth conditions.

Question 2

According to the study materials, which of the following best describes the four stages hypothesized for the origin of life on Earth?

Accepted Answer

Abiotic synthesis of small organic molecules, joining into macromolecules, packaging into protocells, origin of self-replicating molecules

Question 3

What evidence supports the hypothesis that meteorites contributed to the origin of life on Earth?

Accepted Answer

Fragments of the Murchison meteorite contain amino acids, lipids, simple sugars, and nitrogenous bases.

Question 4

Which property is NOT exhibited by protocells, as described in the study materials?

Accepted Answer

Photosynthesis

Question 5

Why is RNA considered a likely candidate for the first genetic material?

Accepted Answer

RNA can act as a catalyst and self-replicate, as shown by ribozymes.

Question 6

Which of the following environments is considered most suitable for the origin of life, according to the study materials?

Accepted Answer

Alkaline vents with high pH (9–11) and warm water (40–90ºC)

Question 7

What is the significance of montmorillonite clay in the formation of protocells?

Accepted Answer

It increases the rate of vesicle formation and helps organic molecules attach and be absorbed.

Question 8

The structures shown in the third image are best described as:

Accepted Answer

Stromatolites, which are layered rocks formed by the activities of prokaryotes and represent some of the oldest fossils.

Question 9

Which of the following statements about the Miller-Urey experiment is correct?

Accepted Answer

It simulated a reducing atmosphere and produced amino acids and other organic molecules.

Question 10

Which process is illustrated by the spontaneous formation of vesicles from lipids in water?

Accepted Answer

Packaging of molecules into protocells

Question 11

Which of the following best explains why double-stranded DNA eventually replaced RNA as the genetic material?

Accepted Answer

DNA is more chemically stable and can be replicated more accurately than RNA.

Question 12

Which of the following is a real-world application of the concept of ribozymes?

Accepted Answer

Ribozymes are used as catalysts in laboratory experiments to replicate RNA sequences.

Question 13

Which of the following equations best represents the chemical reaction for the formation of water vapor from hydrogen and oxygen, a process relevant to early Earth conditions?

Accepted Answer

$$2H_2 + O_2$ \rightarrow 2H_2O$$

Question 14

Which of the following statements about the earliest evidence of life is correct?

Accepted Answer

Stromatolites, formed by prokaryotes, are the oldest large-scale fossils found on Earth.

Question 15

Which scenario best illustrates the concept of natural selection acting on protocells?

Accepted Answer

Protocells that could replicate RNA more efficiently outcompeted others and became more common over generations.

Question 16

Which of the following is NOT a plausible source of organic molecules on early Earth, according to the study materials?

Accepted Answer

Photosynthesis by plants

Question 17

Which of the following best describes the role of vesicles in the origin of life?

Accepted Answer

They provided a compartment for maintaining an internal environment different from the surroundings.

Question 18

Which of the following statements about the early Earth's atmosphere is supported by the study materials?

Accepted Answer

It contained water vapor, nitrogen, carbon dioxide, methane, ammonia, and hydrogen.

Question 19

Which of the following best explains why organic compounds are unstable near black smoker vents?

Accepted Answer

The extreme heat (300–400ºC) causes organic molecules to break down.

Question 20

Which of the following is a multi-step process that could have occurred on early Earth, leading to the formation of the first cells?

Accepted Answer

Abiotic synthesis of RNA monomers $$\rightarrow$$ formation of RNA polymers on hot surfaces $$\rightarrow$$ encapsulation in vesicles $$\rightarrow$$ self-replication of RNA

The History of Life on Earth: Origin and Early Evidence

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