Chap.4

Although DNA is the main hereditary material in all life-forms, it lacks one important characteristic of being a candidate for the first life-form. Why have researchers rejected the idea that DNA was found the first life-form? Select one: a. Because it has only four different bases, it does not carry enough information; therefore, it cannot adapt and evolve. b. The type of sugar found in DNA is much too complicated to have been present early in Earth history. c. It is not stable enough to have withstood early Earth harsh atmosphere. d. It does not function as a catalyst.

The answer is: It does not function as a catalyst..

Which of the following is not a difference between RNA and DNA? Select one: a. One is made from nucleotide monomers and the other one is not. b. One contains uracil and the other does not. c. One is typically single stranded and the other is typically double stranded. d. One contains ribose sugar and the other contains deoxyribose sugar.

The answer is: One is made from nucleotide monomers and the other one is not..

What is the difference between a ribonucleotide and a deoxyribonucleotide? Select one: a. Ribonucleotides contain a phosphate group. b. Ribonucleotides have a hydrogen atom on the 1 carbon of their sugar subunit. c. Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit. d. Ribonucleotides contain a sugar with five carbon atoms.

The answer is: Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit..

All organisms have which of the following attributes? Select one: a. They can perform metabolism. b. They can reproduce. c. They can reproduce and they are composed of cells. d. They are composed of cells. e. They can reproduce, perform metabolism, and are composed of cells.

The answer is: They can reproduce, perform metabolism, and are composed of cells..

A nucleotide is made up of which of the following subunits? Select one: a. a 5-carbon sugar, an amino group, and an R-group b. a 5-carbon sugar, and a nitrogenous base c. a 5-carbon sugar, and a phosphate group d. a 5-carbon sugar, a phosphate group, and a nitrogenous base

The answer is: a 5-carbon sugar, a phosphate group, and a nitrogenous base.

What forms the backbone of a nucleic acid? Select one: a. purine and pyrimidine pairs, hydrogen-bonded to each other b. a chain of amino and carboxyl groups, linked via peptide bonds c. a chain of sugar and phosphate groups, linked through phosphodiester bonds d. a double helix of antiparallel strands

The answer is: a chain of sugar and phosphate groups, linked through phosphodiester bonds. In Mark 0 out of 1

Which of the following nitrogenous bases are purines? Select one: a. cytosine and thymine b. cytosine, uracil, and thymine c. adenine and guanine d. cytosine and uracil

The answer is: adenine and guanine.

Nucleic acids are polymers made up of which of the following monomers? Select one: a. sugars b. amino acids c. nucleotides d. nitrogenous bases

The answer is: nucleotides.

What is gel electrophoresis used for? Select one: a. to separate the two helices that make up the DNA double helix b. to separate macromolecules by size or charge c. to denature proteins for further analysis d. to identify the first self-replicating molecule that formed during chemical evolution

The answer is: to separate macromolecules by size or charge.

Which of the following nitrogenous bases is found in RNA, but not DNA? Select one: a. thymine b. guanine c. uracil d. adenine

The answer is: uracil.