Nucleic Acids & RNA review

Both DNA and RNA _____. A) are information-containing molecules B) show primary, secondary, tertiary, and quaternary structure C) are highly reactive catalysts in cells D) naturally occur as a double helix

A

Compare proteins to nucleic acids. Which of the following is true? A) Both have primary and secondary structure. B) Both contain sulfur. C) Both take on structural roles in the cell. D) Both have monomers, which contain phosphorus.

A

DNA double helices are soluble in water but insoluble in alcohol. How do these physical properties reflect the chemical structure of the DNA molecule? A) The charged phosphate groups and sugars of DNA are hydrophilic. B) The purine and pyrimidine bases are hydrophilic. C) The 5 prime to 3 prime polarity of DNA makes it soluble in water but not in alcohol. D) The charged R-groups of DNA are hydrophilic.

A

DNA is the main hereditary material of all life. However, DNA lacks one important characteristic for the first forms of life. Why have researchers rejected the idea that DNA was found in the first life form? A) It does not function as a catalyst. B) It is not stable enough to have withstood early Earth's harsh atmosphere. C) DNA only has four types of bases. Therefore, DNA cannot adapt and evolve. D) The type of sugar found in DNA is too complicated to have been present early in Earth's history.

A

Nucleic acids are polymers made up of which of the following monomers? A) nucleotides B) sugars C) amino acids D) nitrogenous bases

A

When nucleotides polymerize to form a nucleic acid _____. A) a covalent bond forms between the sugar of one nucleotide and the phosphate of a second B) a hydrogen bond forms between the sugar of one nucleotide and the phosphate of a second C) covalent bonds form between the bases of two nucleotides D) hydrogen bonds form between the bases of two nucleotides

A

Why is it that RNA can catalyze reactions but DNA cannot? A) The sugar of RNA is much more reactive than the sugar of DNA. B) The bases of RNA are much more reactive than the bases of DNA. C) The phosphate groups of RNA are much more reactive than the phosphate groups of DNA. D) The primary structure of RNA is fundamentally different than the primary structure of DNA.

A

A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of _____. A) 120 adenine and 120 uracil molecules B) 120 thymine and 120 adenine molecules C) 120 cytosine and 120 thymine molecules D) 120 adenine and 120 cytosine molecules E) 120 guanine and 120 thymine molecules

B

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes? A) The two strands of the double helix would separate. B) The phosphodiester linkages of the polynucleotide backbone would be broken. C) The purines would be separated from the deoxyribose sugars. D) The pyrimidines would be separated from the deoxyribose sugars. E) All bases would be separated from the deoxyribose sugars.

B

One of the primary functions of RNA molecules is to _____. A) transmit genetic information to offspring B) function in the synthesis of proteins C) make a copy of itself, thus ensuring genetic continuity D) act as a pattern or blueprint to form DNA E) form the genes of higher organisms

B

What is the difference between a ribonucleotide and a deoxyribonucleotide? A) Ribonucleotides contain a phosphate group. B) Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit. C) Ribonucleotides contain a sugar with five carbon atoms. D) Ribonucleotides have a hydrogen atom on the 1 carbon of their sugar subunit.

B

What is the structural feature that allows DNA to replicate? A) sugar-phosphate backbone B) complementary pairing of the nitrogenous bases C) disulfide bonding (bridging) of the two helixes D) twisting of the molecule to form an α-helix E) three-component structure of the nucleotides

B

Which of the following are purine nitrogenous bases? A) cytosine and guanine B) guanine and adenine C) adenine and thymine D) thymine and uracil E) uracil and cytosine

B

Which of the following are pyrimidine nitrogenous bases? A) guanine and adenine B) cytosine and uracil C) thymine and guanine D) ribose and deoxyribose E) adenine and thymine

B

Which of the following statements about the 5' end of a polynucleotide strand of RNA is correct? A) The end has a hydroxyl group attached to the number 5 carbon of ribose. B) The end has a phosphate group attached to the number 5 carbon of ribose. C) The end has phosphate attached to the number 5 carbon of the nitrogenous base. D) The end has a carboxyl group attached to the number 5 carbon of ribose. E) The end is the fifth position on one of the nitrogenous bases.

B

If 14C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled? A) phospholipids B) DNA C) RNA D) both DNA and RNA E) proteins

C

If a DNA sample were composed of 10% thymine, what would be the percentage of guanine? A) 10 B) 20 C) 40 D) 80 E) It is impossible to tell from the information given.

C

In the context of chemical evolution, DNA's structure is interesting because it suggests a possible copying mechanism. What about DNA's structure facilitates copying? A) It has the same number of purines and pyrimidines. B) The nitrogenous bases are located on the inside of the double helix. C) The strands of the double helix are complementary. D) DNA always goes from 5 prime to 3 prime.

C

Nucleic acids have a definite polarity, or directionality. Stated another way, one end of the molecule is different from the other end. How are these ends described? A) One end has a hydroxyl group on the 2 carbon; the other end has a hydrogen atom on the 2 carbon. B) One end contains a nitrogenous base; the other end lacks it. C) One end has an unlinked 3 carbon; the other end has an unlinked 5 carbon. D) One end has one phosphate group; the other end has two phosphate groups

C

Which of the following descriptions best fits the class of molecules known as nucleotides? A) a nitrogenous base and a phosphate group B) a nitrogenous base and a sugar C) a nitrogenous base, a phosphate group, and a sugar D) a phosphate group and an adenine or uracil E) a sugar and a purine or pyrimidine

C

Which of the following includes all of the pyrimidines found in RNA and DNA? A) cytosine and uracil B) cytosine and thymine C) cytosine, uracil, and thymine D) cytosine, uracil, and guanine

C

Which of the following is a difference between RNA and DNA? A) RNA is single-stranded and DNA is usually triple-stranded. B) DNA contains adenine and RNA does not. C) RNA has ribose sugar and DNA has deoxyribose sugar. D) RNA is made from nucleotide monomers and DNA is made from amino acid monomers.

C

Which of the following statements best summarizes the differences between DNA and RNA? A) DNA encodes hereditary information, whereas RNA does not. B) The bases in DNA contain sugars, whereas the bases in RNA do not contain sugar. C) DNA nucleotides contain a different sugar than RNA nucleotides. D) DNA contains the base uracil, whereas RNA contains the base thymine. E) The bases in DNA contain sulfur, whereas the bases in RNA do not contain sulfur.

C

RNA and proteins combine in cells to form structures called ribosomes. Ribosomes contain the active site for peptide bond formation. Based on their chemical structures, do you think protein or RNA molecules actually form the active site within the ribosome? A) protein, because RNA cannot catalyze reactions B) RNA, because proteins cannot catalyze a reaction that involves another protein C) proteins, because only proteins can catalyze a reaction that involves another protein D) It could be either, because both molecules have catalytic properties.

D

Some viruses consist only of a protein coat surrounding a nucleic acid core. If you wanted to radioactively label the nucleic acids separately from the protein, you would use radioactive _____. A) sulfur B) carbon C) nitrogen D) phosphorus

D

What feature of single nucleotides provides the energy needed for polymerization when nucleic acids are formed? A) their methyl groups B) their sugar groups C) their nitrogenous bases D) their phosphate groups

D

What is/are the variable structure(s) of a nucleotide? A) the phosphate group B) the sugar C) the base D) the sugar and the base

D

Which of the following best describes DNA's secondary structure? A) beta-pleated sheet B) double parallel helical strands C) turn-loop-turn D) double antiparallel helical strand

D

If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled? A) proteins B) cellulose C) amino acids D) nucleic acids E) glucose

E

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA _____. A) is a six-carbon sugar and the sugar in RNA is a five-carbon sugar B) can form a double-stranded molecule C) is an aldehyde sugar and the sugar in RNA is a keto sugar D) is in the α configuration and the sugar in RNA is in the β configuration E) contains one less oxygen atom

E

Which of the following did Watson and Crick already know when they were trying to determine the structure of DNA? The number of _____. A) purines is always larger than the number of pyrimidines B) pyrimidines is always larger than purines C) cytosines is always the same as adenines D) guanines is always the same as thymines E) purines is always the same as pyrimidines

E