DNA and RNA - Biochemistry

The helix-turn-helix motif has two helices at a particular angle, with one of them, the recognition helix, fitting into a major groove. Zinc fingers have sheets and helices held together via zinc complexes. Beta sheets have hydrogen bonds along their strand backbones. The helix-loop-helix motif has one helix folded and packed against another. In the leucine zipper, two helices are coiled up to where they are "unzipped" to form a Y.

The backbone of DNA is made up of alternating phosphate groups and sugar groups, linked together via phosphodiester bonds. The nitrogenous bases jut off of the backbone and form bonds with nitrogenous bases on other strands of DNA to become double stranded. A nucleotide consists of a sugar, nitrogenous base, and one or more phosphate groups.

The anticodon is a part of tRNA that is capable of finding its complementary codon on mRNA. This allows the tRNA to carry its specific amino acid to a ribosome when necessary in the production of proteins.

The clover-like structure of tRNA is held together by hydrogen bonds between nitrogenous bases of the molecule. Without them, this tertiary structure would not be possible.

In RNA the four bases are: adenine, uracil, guanine, and cytosine. The bases in DNA are similar, except uracil is replaced with thymine. In RNA, adenine will always pair with uracil, and guanine will always pair with cytosine. Remember, a purine (adenine, guanine) will always pair with a pyrimidine (cytosine, uracil or thymine).

The glycosidic bonds of B DNA are in the anti conformation. This means that the nucleotide and sugar are on opposite sides of the N-glycosidic bond.

The function of snRNA is to participate in the splicing of RNA exons. Micro RNA binds to complementary mRNA to inhibit translation. Small interfering RNA binds to mRNA to facilitate its degradation. mRNA functions as a template for protein synthesis. Transfer RNA (tRNA) carries amino acids to the ribosome during translation.

The function of snRNA is to participate in the splicing of RNA exons. Micro RNA binds to complementary mRNA to inhibit translation. Small interfering RNA binds to mRNA to facilitate its degradation. mRNA functions as a template for protein synthesis. Transfer RNA (tRNA) carries amino acids to the ribosome during translation.

The TATA box and/or the Hogness box are regions on DNA that function as promoter sites. RNA polymerase scans DNA for these regions and when it sees one, it recognizes that it should begin transcription of the following gene.

Primase is an enzyme used in the replication of DNA. DNA polymerase synthesizes DNA in a 5' to 3' direction, so it needs a free 3' end to begin its replication from. The primase constructs an RNA substrate with a free 3' end, that binds complementary to the unwound and single-stranded DNA template that is about to be replicated.

After DNA Polymerase 1 replaces the RNA primers with DNA. DNA ligase then comes along and uses an ATP for energy as it connects the 3' and 5' ends of the DNA gap, completing the replication of the template strand.

A codon is a set of three nucleic acids on the messenger RNA that codes for an amino acid. The start codon is AUG. In this strand, AUG is the first codon, the second is UUA, and the third is GCG.

tRNA carries the anticodon. tRNA is a transfer ribonucleic acid; it is a type of RNA molecule that decodes the mRNA sequence to form a protein. The anticodon is the part of the tRNA structure that complements the mRNA codon, dictating the identity of the amino acid carried by the tRNA and required to build the proper polypeptide chain.

The presence of an group on the 2’ carbon if ribose does indeed make any phosphodiester bonds at this site subject to hydrolysis. RNA can sometimes form double-helices, such as in tRNA. mRNA is constantly being degraded in the cytoplasm, and so it has a very short half-life relative to the life of the cell. RNA’s hairpin turn structures are composed of only one molecule which has doubled back on itself, rather than two separate molecules.

B DNA has a wide and deep major groove and a narrow and deep minor groove. All other statements regarding B DNA are true.

The correct order is base pair, nucleotide, nucleosome ("bead on a string"), solenoid, radial loop, chromosome. A solenoid is created by the packing of DNA with multiple nucleosomes, and a radial loop is compacted even further in chromatin.

Recall that guanine and cytosine form three hydrogen bonds to one another in DNA, while adenine and thymine only form two hydrogen bonds to one another. This means that DNA strands with higher concentrations of guanine and cytosine will be more stable, and thus require greater energy to break apart. In this case, since DNA-2 required more energy (higher temperature) to denature, it has a higher concentration of guanine and cytosine.

The promoter region is a short segment of DNA that is recognized and bound to by RNA polymerase prior to transcription. The promoter region is usually upstream of the operator and will not be transcribed into mRNA.

DNA's sugar is deoxyribose, which involves the lack of a hydroxyl group on the second cabon. RNA's sugar is ribose. DNA and RNA is found in both prokaryotes and eukaryotes and both contain phosphate and neither contain sulfur.