DNA and RNA Structure - AP Biology

Watson and Crick were the two scientists who developed the model of DNA as a double helix in 1953.

Uracil in RNA bonds to adenine on the DNA template during transcription. These two nitrogenous bases form two hydrogen bonds.

Purines are adenine and guanine, while pyrimidines are cytosine, thymine, and uracil.

DNA and RNA share many characteristics. They are both composed of nucleotide monomers and are read in the 5'-to-3' direction. They also share the same complementary base pairs, except RNA uses uracil in place of thymine; both contain adenine.

RNA does not present in a double helix structure, and is typically single stranded.

Remember that mRNA is not a double helix like DNA; RNA is only one single strand of nucleotides. This means that we are unable to say that there are just as many cytosine bases as guanine bases, even though they would be able to form nucleotide pairs in DNA. For all we know, there could be zero cytosine bases! More information is needed before we can make a conclusion as to how many cytosine bases are in the RNA section.

The only correct statement here is the one regarding the types of sugar in the two molecules. RNA stands for "ribonucleic acid," which is a simple way to remember that it contains the sugar ribose. DNA, on the other hand, stands for "deoxyribonucleic acid." Its sugar is deoxyribose, which is identical to ribose except it is missing a hydroxyl (-OH) group on its second carbon. In total, RNA contains three hydroxyl groups, while DNA contains only two.

In RNA, uracil replaces thymine, not guanine. DNA is generally double-stranded and RNA is generally single-stranded (though both can exist in either form). Prokaryotes contain both DNA and RNA. Finally, DNA is transcribed to RNA in most biological organisms, but RNA can be reverse transcribed to DNA by the protein reverse transcriptase, which is found in some viruses.

Both DNA and RNA are polyanions. This is just a fancy way of saying that they are polymers of negatively charged molecules. The phosphate groups in the sugar-phosphate backbone account for this, as phosphate groups generally carry a charge of negative three.

DNA uses thymine and deoxyribose sugar, while RNA uses uracil and ribose sugar. While DNA is usually molded into a double-stranded helix, RNA is usually single-stranded, which allows for the binding of anticodons during translation.

RNA and DNA are very similar in composition, but differ in structure and function. DNA is used to code for genetic material, while RNA is used to generate protein products. Since DNA has a long-term goal of storing information and RNA has a short-term goal of increasing production, it makes sense that DNA is a permanent molecule and RNA is transient. Soon after translation, mRNA is degraded by ribonuclease (RNase). The transient nature of RNA is also linked to its stability. DNA must be very stable to avoid problems with gene storage. DNA is double-stranded to help enhance stability. In contrast, RNA can afford to be less stable and is easily degraded, partially due to its single-stranded structure.

Another key difference between DNA and RNA is the sugar component of the nucleic acid backbone. DNA uses deoxyribose, which lacks a hydroxyl (-OH) group on the 2' carbon. RNA uses ribose, in which this hydroxyl group is present on the 2' carbon.

DNA encodes information for the production of messenger RNA which then interacts with the cell's protein-synthesizing machinery to produce proteins. Ribosomes are the sites of polypeptide synthesis but are not coded for by RNA. The central dogma of biology is DNA RNA protein

Remember that the sugar for DNA is deoxyribose, and that for RNA is ribose. The nitrogenous bases adenine, guanine, and cytosine in DNA and RNA are the same. However, DNA which contains thymine and RNA that contains uracil. The structure of DNA is a double helix. There are three different structures of RNA: linear, clover-leaf, and globular. Also note that RNA is single stranded and DNA is double stranded

DNA is a macromolecule that has a double helical form. It has four nitrogenous base pairs (thymine, adenine, cytosine, and guanine) and a deoxyribose-phosphate backbone. The two strands of the helix are joined by hydrogen bonds. On the other hand, RNA molecules can be double-stranded (e.g. viruses) or single-stranded (e.g. mRNA), but RNA most commonly exists in a single-stranded form. RNA contains four base pairs (uracil, adenine, cytosine, and guanine) and a ribose sugar-phosphate backbone. Despite their differences, these molecules share one similarity: both DNA and RNA molecules can be found in the nucleus. DNA molecules reside solely within the nucleus. RNA is transcribed in the nucleus and, once targeted and post-transcriptionally modified, can leave via nuclear pores.

RNA molecules are most commonly found in a single stranded form (e.g. mRNA), but they can also be found in a double stranded form (e.g. viruses). It has four base pairs—uracil, adenine, guanine, and cytosine—and a ribose sugar-phosphate backbone. DNA molecules contin a deoxyribose sugar in their sugar-phosphate backbone; thus, this answer is incorrect.

Many types of RNA exist within cells, some are single stranded and others are double stranded. The following are among the types of single stranded RNA: mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA). Messenger or mRNA carries genetic information from DNA to ribosomes for protein synthesis. Transfer or tRNA carries amino acids to ribosomes that match with mRNA codons. Last, ribosomal or rRNA codes for ribosomes, which are necessary for protein synthesis. An example of a double stranded RNA molecule is viral RNA. Viral RNA is the genetic material of many viruses and has a structure of two complementary strands.

The genome is defined as the total genetic library of a cell. It is estimate that in humans, the genome codes for about 25,000 different genes.

Chromatin is the DNA-protein complex and is organized as a long, thin fiber. Chromosomes are densely-packed chromatin, wrapped around proteins called histones. The centromere is the region of a condensed chromosome that connects sister chromatids to each other, and is the site at which the spindle fibers attach during mitosis in order to move them about the cytoplasm.

In RNA, thymine is substituted by uracil. So adenine will bond to uracil instead of thymine when RNA interacts with DNA and when RNA folds with itself to make a 3-dimensional structure.

Uracil is a nitrogenous base that is only found in single-stranded RNA—it is not found in DNA. Thymine pairs with adenine in DNA, whereas in RNA, uracil pairs with adenine.

Uracil is the base pair that is used in ribonucleic acid (RNA) in the place of thymine. The other three bases adenine, guanine and cytosine are found in both DNA and RNA.

Uracil is only found in RNA under normal conditions. It replaces thymine, which is only found in DNA. Therefore, thymine, adenine, cytosine, and guanine are the bases found in DNA, and uracil, adenine, cytosine, and guanine are the bases found in RNA.

mRNA contains uracil instead of thymine, therefore your answer should not contain the base thymine. Remember, DNA is read in the 3' to 5' direction and the corresponding strand is created in the 5' to 3' direction. It is important to pay attention to polarity of the strands. Adenine pairs with thymine, and/or uracil. Guanine pairs with cytosine.