Exam 4: Nucleic Acids and the Origin of Life

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

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 _______.

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?

_______ are sequences of DNA that are transcribed into RNA.

If there is an exposed purine during DNA replication,

The second hot chemistry experiment of Miller and Urey included several gasses that were not included in the first experiment.What is assumed to have been the source of these gasses on early Earth?

Refer to the table below showing the percent overlap in genomic sequences between species pairs. Which two species are most closely evolutionarily related, and which two are most distantly related?

DNA utilizes the bases guanine, cytosine, thymine, and adenine.In RNA, _______ is replaced by _______.

In the rise of life, several steps have been proposed, beginning with the formation of building-block monomers from simple molecules.The next step involved polymerization of monomers to form more complex polymers.Polymerization reactions were likely facilitated by conditions that increased the concentrations of monomers.But this step may never have resulted in the emergence of living cells without the formation of a(n) _______ that enclosed reacting molecules within a protocell, separating them from the surrounding environment.The protocell would have protected the molecules and facilitated their interactions in ways that could never have been achieved by clay surfaces or evaporating pools of water.

Which statement concerning protocells made in a laboratory is true?

Which molecules were produced by Miller and Urey in their initial experiment to simulate conditions in the early Earth atmosphere?

Which statement about amphipathic fatty acids is true?

Five statements about modern cells are given.Which statement is consistent with the claim that catalysts were likely important during the earliest history of life when the first cells were emerging?

Which statement about DNA or RNA is true?

Which statement correctly describes a difference between DNA and RNA?

Which occurs in a pyrimidine, but not in a purine?

In water, fatty acid molecules will self-organize into a sphere in which the hydrophilic ends point outward to interact with the aqueous environment, and the fatty acid tails point inward.What occurs when this sphere surrounds an inner core of water?

Refer to the figure below showing an RNA polynucleotide increasing the rate of its own replication process. This is an example of how RNA could have functioned as a(n) _______ in the formation of long-chain polymers during the prebiotic period of early Earth.

Refer to the figure showing a single-stranded RNA molecule. Which statement is true?

Refer to the table below listing protein enzymes found in modern cells.The half-lives of the chemical reactions catalyzed by these enzymes within cells are on the order of seconds to milliseconds or less.The half-lives of these same chemical reactions in the absence of their enzymes are listed in the table.The half-life of a chemical reaction is the time it takes for half of the reactants to be converted to products, so you can use these data to compare the rates of catalyzed reactions to their noncatalyzed counterparts. Can these data be used to justify the need for catalysts in the origin of life? Explain.