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

(A) synthesis of small RNA polymers by ribozymes

(B) formation of molecular aggregates with selectively permeable membranes

(C) formation of protocells that use DNA to direct the polymerization of amino acids

(D) abiotic synthesis of organic molecules.

Short Answer

Expert verified
  1. The statement “synthesis of small RNA polymers by ribozymes” isfalse.

  2. The statement “formation of molecular aggregates with selectively permeable membranes” isfalse.

  3. The statement “formation of protocells that use DNA to direct the polymerization of amino acids” is true.

  4. The statement “abiotic synthesis of organic molecules” is false.

Step by step solution

01

Origin of life

A complex process led to the creation of the Earth. Its surface has changed dramatically over millions of years. The planet has been active since it began accumulating gas and dust during its accretionary phase. This ultimately led to the origin of life on Earth.

02

Explanation of option (A)

In low yield, enhanced polymerase ribozyme can produce aptamers, ribozymes, and even tRNAs. The polymerase may replicate nucleic acids as part of an RNA-catalyzed PCR, multiplying tiny RNA templates 10,000-fold.

Thus, the synthesis of small RNA polymers by ribozyme is a discovered process.

Therefore, the given statement is false.

03

Explanation of option (B)

There has long been an understanding that cellular signaling pathways are regulated by cellular clustering in the plasma membrane. Recent breakthroughs in microscopy, including super-resolution, have made it possible to observe nanoscale molecular clusters in plasma membranes.

Thus, molecules aggregation with the selectively permeable membrane is a possible technique.

Therefore, the given statement is false.

04

Explanation of option (C)

The polymerization of amino acids is a complex biological process that requires numerous proteins and cofactors to work together at different sites in the cell. Despite specific technological achievements in creating synthetic protocells, the synthesis of amino acids directly from DNA has yet to be achieved.

Thus, polymerization of amino acids has not been possible till now.

Therefore, the given statement is true.

05

Explanation of option (D)

Nonliving elements are said to have given rise to life. The formation of biological molecules, such as amino acids, simple sugars, and simple oligomers of these substances, is attributed to the interaction between heat, UV radiation, and other factors on primordial gases.

Thus, abiotic synthesis of organic molecules is also a possible process.

Therefore, the given statement is false.

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Most popular questions from this chapter

Herbivory (plant eating) has evolved repeatedly in insects, typically from meat-eating or detritus-feeding ancestors (detritus is dead organic matter). Moths and butterflies, for example, eat plants, whereas their “sister group” (the insect group to which they are most closely related), the caddisflies, feed on animals, fungi, or detritus. As illustrated in the following phylogenetic tree, the combined moth/butterfly and caddisfly group shares a common ancestor with flies and fleas. Like caddisflies, flies and fleas are thought to have evolved from ancestors that did not eat plants. There are 140,000 species of moths and butterflies and 7,000 species of caddisflies. State a hypothesis about the impact of herbivory on adaptive radiations in insects. How could this hypothesis be tested?

Calculate the mean (average) persistence times for species with planktonic larvae and species with nonplanktonic larvae.

What factors promote adaptive radiations?

Count the number of new species that form in each group beginning at 60 mya (the first three species in each group were present around 64 mya, the first time period sampled, so we don’t know when those species first appear in the fossil record).

You can estimate quantitative data (fairly precisely) from a graph. The first step is to obtain a conversion factor by measuring along an axis that has a scale. In this case, 25 million years (my; from 60 to 35 million years ago (mya) on the x-axis) is represented by a distance of 7.0 cm. This yields a conversion factor (a ratio) of 25 my/7.0 cm = 3.6 my/cm. To estimate the time period represented by a horizontal bar on this graph, measure the length of that bar in centimeters and multiply that measurement by the conversion factor, 3.6 my/cm. For example, a bar that measures 1.1 cm on the graph represents a persistence time of 1.1 cm * 3.6 my/cm = 4 million years.

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