RNA and DNA are both types of nucleic acids; therefore, both molecules are made from nucleotide monomers. Recall that a nucleotide contains a phosphate group, a pentose sugar, and a nitrogenous base. The biggest difference between an RNA nucleotide and a DNA nucleotide is the type of pentose sugar. DNA, or deoxyribonucleic acid, contains deoxyribose sugar whereas RNA, or ribonucleic acid, contains ribose sugar. A ribose sugar contains a hydroxyl group on its 2’ carbon whereas the deoxyribose sugar contains a hydrogen; therefore, the RNA pentose sugar has an extra hydroxyl group.

RNA molecules do contain the nitrogenous base uracil in place of thymine; however, bases are not part of the RNA or DNA backbone structure. The backbone only consists of the phosphate groups and the pentose sugars.

Given the backbone of DNA, with the phosphate group attached to the deoxyribose via a phosphodiester bond, DNA is negatively charged. For this reason, histones - the proteins around which DNA molecules are wrapped in eukaryotes - have lots of positively charged amino acids on their DNA-binding sites. This produces a strong attractive force between DNA and histones.

The backbone of DNA consists of a phosphate group and a deoxyribose. These two components are therefore connected by a phosphodiester bond. The nucleotides are not included in the backbone. Instead, they make up the "rungs" of the double helical structure of DNA, which are hydrogen bonded to the bases of the complementary antiparallel strand. 

The two strands of DNA are actually connected by hydrogen bonds (H-bonds) between the nitrogenous bases. There are 2 hydrogen bonds between adenine and thymine, and 3 hydrogen bonds between cytosine and guanine. All other statements are true.

DNA is the hereditary material found in virtually all organisms; however, some viruses use RNA. DNA consists of several components. It has a phosphate-sugar (deoxyribose) backbone and is composed of two strands made from purine-pyrimidine hydrogen bonds in a double helix confirmation. The purines associated with DNA include adenine and guanine and the pyrimidines include cytosine and thymine. Adenine bonds with thymine and cytosine bonds with guanine. 

All of the responses are correct except that eukaryotic DNA is found in the nucleus, cytoplasm, and ribosomes. In eukaryotes, DNA is only found in the nucleus, mitochondria, and only sometimes free floating in the cytoplasm. DNA is not found in ribosomes. RNA on the other hand, is found in the nucleus, cytoplasm, and ribosomes. Note that since prokaryotes lack membrane-bound organelles, their DNA is free-floating in the cytoplasm.

Watson and Crick are credited with discovering the DNA double helix and built a model that explains the shape of DNA. Rosalind Franklin was the crystallographer who found the structure of DNA, but it was Watson and Crick who looked at this scan and realized the shape of DNA. Since Watson and Crick's shunning of Franklin from the discovery, the topic has become a point of controversy. Franklin had died by the time Watson and Crick were awarded the Nobel Prize for their work.

It is important to know that Watson and Crick are credited for the discovery of DNA structure, but selecting Franklin for the question is acceptable.

DNA is an organic compound that is made up of repeating subunits call nucleotides. Each DNA nucleotide is composed of three parts: a deoxyribose sugar molecule, a phosphate group, and a nitrogen-containing base. Phosphate groups are formed by a phosphorus atom bonded to four oxygen atoms. The deoxyribose sugar and the phosphate group are identical in all DNA nucleotides and form the backbone of the DNA. There are four possible nitrogenous bases: adenine, guanine, cytosine, and thymine. In double-stranded DNA, adenine pairs with thymine and guanine with cytosine via hydrogen bonding to create the DNA helix.

During transcription, uracil is added to RNA to complement adenine. DNA does not contain ribose sugar or uracil, but RNA does.

The double-helix structure of DNA was discovered by James Watson and Francis Crick, as well as Rosalind Franklin. They published an article titled "Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid" that described the three-dimensional structure of DNA.

Linus Pauling was the first scientist to propose a helical structure for DNA; however, he proposed that DNA was a triple helix. His work regarding DNA structure heavily influenced Watson and Crick who won the Nobel Prize for their model of DNA.

The double-helix is the three dimensional structure of a DNA molecule. This structure arises due to the interaction (hydrogen bonding of base pairs) between the two strands of a DNA molecule. A double-helix can occur in any double-stranded molecule; therefore, a double-stranded RNA molecule can also form a double-helix if there is proper base pairing between the strands.

The base pairing in the double-helix involves hydrogen bonds, a type of noncovalent bond or intermolecular force. Since it is a noncovalent bond, hydrogen bonds between bases can be broken down by adding energy in the form of heat. Recall that the DNA backbone contains a series of pentose sugars that have a phosphate group attached to their 5' carbon. These pentose sugars in the DNA backbone are held together by covalent bonds called phosphodiester bonds; therefore, the DNA backbone is held together by covalent bonds.

One of the characteristics of double-helix is the presence of the major groove and the minor groove. The major groove is the region of the double-helix where the distance between the two DNA strands is largest. The minor groove, on the other hand, is the region of double-helix where the distance between the two strands is smallest.