Question 1

In which characteristic are living cells and protocells alike?

Accepted Answer

Both living cells and protocells have membranes that create a distinct internal environment, separating it from the external surroundings. This is fundamental for maintaining the necessary conditions for various biochemical processes.

Question 2

Refer to the figure below.  Information transfer in a cell begins with DNA and proceeds to RNA through process A.RNA then proceeds through process B to produce polypeptides.Process A is called _______.

Accepted Answer

The answer of Refer to the figure below.  Information...

Question 3

What vital role in the evolution of life was performed by fatty acids?

Accepted Answer

Fatty acids formed a boundary between the external and internal environments, leading to the development of cell membranes, which played a vital role in the evolution of life.

Question 4

Which model represents a structure that was likely a key intermediate in the evolution of life on Earth?

Accepted Answer

The answer of Which model represents a structure that was...

Question 5

Refer to the figures below representing nitrogenous bases found in the structures of RNA and DNA.  The bases that can be grouped into the pyrimidines are shown in figures _______.

Accepted Answer

The answer of Refer to the figures below representing nitrogenous...

Question 6

Refer to the figure below.  What belongs in the empty box?

Accepted Answer

The answer of Refer to the figure below.  What...

Question 7

Which characteristic of living cells is also a characteristic of protocells?

Accepted Answer

The answer of Which characteristic of living cells is also...

Question 8

A scientist has isolated a strand of DNA from a fungus and plans to characterize its properties.She has made a list of these properties in the table below.  If the scientist wants to explore the evolutionary relationship between this fungus and another organism, she should use the _______ property of the DNA strand to carry out her analysis.

Accepted Answer

The answer of A scientist has isolated a strand of...

Question 9

Which is a characteristic of protocells?

Accepted Answer

One of the defining characteristics of protocells is that they have a distinct inner environment compared to their exterior environment. This separation allows for the possibility of metabolic reactions and other cellular processes to occur within the protocell.

Answer: D
 Self-reproduction has been observed in some protocell models, which is a key characteristic of living organisms. This ability to produce offspring could be a crucial step in the eventual evolution of more complex life forms.

Question 10

Scientists have generated protocells under lab conditions using different combinations of fatty acids.They have found that branched but not straight-chain fatty acids allow nucleotides to pass into protocells from the surrounding environment.Why is this an important finding in the study of the evolution of life?

Accepted Answer

The finding that branched fatty acids allow nucleotides to pass into protocells from the environment suggests that even primitive cells could take up molecules from the environment to support their internal reactions. This is important in understanding how early life forms survived and evolved in an environment that lacked complex organic compounds.

Answer: B
 The discovery that different types of fatty acids can form protocells with different membrane compositions suggests that primitive cells may have developed with diverse membrane structures, which could have contributed to the evolution and diversification of early life forms.

Question 11

To test the idea of spontaneous generation, Francesco Redi used three jars containing meat, as represented by the figure below.  Suppose Pasteur had set up jars of sterile broth in the same way that Redi set up jars of meat to show that microorganisms do not arise spontaneously.In this case, two jars would serve as the controls and jar number _______ would differ from the controls, as both air and microorganisms would be excluded from entering the environment.

Accepted Answer

The answer of To test the idea of spontaneous generation,...

Question 12

J.William Schopf examined Australian sedimentary rocks that first formed 3.5 billion years ago and observed chains and clumps that resembled modern cyanobacteria.What evidence in the sediments and fossils indicated that these were remains of living organisms?

Accepted Answer

The ratio of carbon isotopes in the structures is a strong indicator of photosynthesis, which is a biological process, suggesting that these were remains of living organisms.

Question 13

Which statement about amphipathic fatty acids is true?

Accepted Answer

Amphipathic fatty acids have a polar and hydrophilic head and a nonpolar and hydrophobic tail. The polarity of the head allows it to interact with water, while the nonpolarity of the tail keeps it away from water.

Question 14

In 2011, microfossil structures were found in sandstone about 3.4 billion years old and 20 miles from the site of J.William Schopf's discovery.What was distinctive about these microfossils was that they were

Accepted Answer

Microfossils found in 3.4 billion-year-old sandstone were distinctive because they were from cells that used sulfur, rather than oxygen, in reactions that released chemical energy. This suggests an early form of life that thrived in an anaerobic environment.

Question 15

When J.William Schopf observed chains and clumps that resembled modern cyanobacteria in Australian sedimentary rocks, he concluded that these were remains of living organisms because

Accepted Answer

The structures had internal substructures characteristic of living systems, which is a key indicator of biological origin, distinguishing them from non-biological mineral formations.

Question 16

When fatty acid molecules are in water, they can self-organize into a bilayer (double layer) that surrounds an inner core of water.Where "middle" refers to the middle of the bilayer between the outer and inner layers of fatty acids, which of the following statements is correct?

Accepted Answer

In a bilayer, the polar (hydrophilic) heads of the fatty acids face the aqueous environments, both outside and inside, while the non-polar (hydrophobic) tails face each other in the middle of the bilayer.

Question 17

What is the significance of the specific ratio of carbon isotopes (¹³C:¹²C) in microfossils found in Australian sediments that are 3.5 billion years old?

Accepted Answer

The specific ratio of carbon isotopes found in microfossils from Australian sediments that are 3.5 billion years old indicates that photosynthesis had occurred in the region at that time. This is because photosynthesis produces a distinctive ratio of carbon isotopes, with a higher concentration of the lighter isotope carbon-12. Therefore, option A is correct. The other options are incorrect as they do not relate to the actual significance of the specific carbon isotope ratio in microfossils.

Question 18

Which statement about fatty acids is true?

Accepted Answer

The answer of Which statement about fatty acids is true?
...

Question 19

Which statement concerning protocells made in a laboratory is true?

Accepted Answer

Protocells made in a laboratory require external nucleotides for the replication of nucleic acids inside them, as they do not have the capability to synthesize nucleotides on their own.

Question 20

Suppose scientists develop a protocell with a membrane that allows all molecules to enter or leave the protocell via diffusion.Will this serve the function of a cell membrane?

Accepted Answer

A key function of a cell membrane is to maintain a distinct internal environment by selectively allowing substances to pass through, which a membrane allowing all molecules to enter or leave cannot achieve.

Quiz 4: Nucleic Acids and the Origin of Life