-- Except in some viruses, DNA serves as the genetic material in all living organisms on Earth.
-- According to the Watson-Crick model, DNA exists in the form of a right-handed double helix.
-- The strands of the double helix are antiparallel and held together by hydrogen bonding between complementary nitrogenous bases.
-- The structure of DNA provides the means of storing and expressing genetic information.
-- RNA has many similarities to DNA but exists mostly as a single-stranded molecule.
-- In some viruses, RNA serves as the genetic material.
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| 237393388 | What are the four characteristics a Genetic Material Must Exhibit? | Replication, storage of information, expression of information, and variation by mutation. | |
| 237393389 | One of the characteristics a Genetic Material is Replication, what does this mean? | Once the genetic material of cells replicates and is doubled in amount, it must then be partitioned equally—through mitosis—into daughter cells. The genetic material is also replicated during the formation of gametes, but is partitioned so that each cell gets only one-half of the original amount of genetic material—the process of meiosis. | |
| 237402486 | What is central dogma of molecular genetics? | DNA makes RNA, which makes proteins. | |
| 237402487 | At what wavelength λ is UV light most mutagenic on DNA and RNA? | UV light is most mutagenic at the wavelength λ of 260 nanometers (nm), and both DNA and RNA absorb UV light most strongly at 260 nm. | |
| 237410735 | What are retroviruses? | These are the retroviruses, which replicate in an unusual way. Their RNA serves as a template for the synthesis of the complementary DNA molecule. The process, reverse transcription, occurs under the direction of an RNA-dependent DNA polymerase enzyme called reverse transcriptase. This DNA intermediate can be incorporated into the genome of the host cell, and when the host DNA is transcribed, copies of the original retroviral RNA chromosomes are produced. Retroviruses include the human immunodeficiency virus (HIV), which causes AIDS, as well as the RNA tumor viruses. | |
| 237410736 | DNA stands for? | Deoxyribonucleic acid | |
| 237410737 | RNA stands for? | Ribonucleic acids | |
| 237410738 | Nucleotides structural units consist of three essential components? | a nitrogenous base, a pentose sugar (a 5-carbon sugar), and a phosphate group. | |
| 237410739 | two kinds of nitrogenous bases? | the nine-member double-ring purines and the six-member single-ring pyrimidines. | |
| 237410740 | The two purines are? | The two purines are adenine and guanine, abbreviated A and G. | |
| 237410741 | The three pyrimidines are? | The three pyrimidines are cytosine, thymine, and uracil, abbreviated C, T, and U. | |
| 237410742 | Nitrogenous bases in RNA? | Both DNA and RNA contain A, C, and G, but only DNA contains the base T and only RNA contains the base U. | |
| 237410743 | Ribonucleic acids (RNA) contain -------- sugar? | ribose sugar. | |
| 237417604 | deoxyribonucleic acids (DNA) contain ----- sugar? | deoxyribose sugar. | |
| 237417605 | The linkage between two mononucleotides consists of ? | The linkage between two mononucleotides consists of a phosphate group linked to two sugars. It is called a phosphodiester bond. | |
| 237417606 | Number of hydrogen bonds between A and T? | Two | |
| 237417607 | Number of hydrogen bonds between G and C? | Three | |
| 237421324 | Different forms of DNA? | Right-handed double helix: A-,B- (most common), C-,D-, E-, P- left-handed double helix: Z-DNA | |
| 237429470 | Difference between RNA and DNA molecules? | Although RNA also has nucleotides linked into polynucleotide chains, the sugar ribose replaces deoxyribose, and the nitrogenous base uracil replaces thymine. Another important difference is that most RNA is single stranded, although there are two important exceptions. First, RNA molecules sometimes fold back on themselves to form double-stranded regions of complementary base pairs. Second, some animal viruses that have RNA as their genetic material contain double-stranded helices. | |
| 237429471 | Three major classes ofcellular RNA molecules? | ribosomal RNA (rRNA), messenger RNA (mRNA), and transfer RNA (tRNA). | |
| 237429472 | ribosomal RNA (rRNA) | The RNA molecules that are the structural components of the ribosomal subunits. In prokaryotes, these are the 16S, 23S, and 5S molecules; in eukaryotes, they are the 18S, 28S, and 5S molecules. S stands for Svedberg coefficient --based on sedimentation. | |
| 237429473 | messenger RNA (mRNA) | An RNA molecule transcribed from DNA and translated into the amino acid sequence of a polypeptide. | |
| 237429474 | transfer RNA (tRNA) | A small ribonucleic acid molecule playing an essential role in translation. tRNAs contain: (1) a three-base segment (anticodon) that recognizes a codon in mRNA; (2) a binding site for the specific amino acid corresponding to the anticodon; and (3) recognition sites for interaction with ribosomes and with the enzyme that links the tRNA to its specific amino acid. | |
| 237429475 | Svedberg coefficient (S) | Sedimentation behavior depends on a molecule's density, mass, and shape, and its measure is called the Svedberg coefficient (S). | |
| 237429476 | telomerase RNA | The enzyme that adds short, tandemly repeated DNA sequences to the ends of eukaryotic chromosomes. | |
| 237429477 | small nuclear RNA (snRNA) | Abundant species of small RNA molecules ranging in size from 90 to 400 nucleotides that in association with proteins form RNP particles known as snRNPs or snurps. Located in the nucleoplasm, snRNAs have been implicated in the processing of pre-mRNA and may have a range of cleavage and ligation functions. | |
| 237429478 | antisense RNA | An RNA molecule (synthesized in vivo or synthetic) with a ribonucleotide sequence that is complementary to part of an mRNA molecule. | |
| 237429480 | microRNA (miRNA) | Single-stranded RNA molecules approximately 20-23 nucleotides in length that regulate gene expression by participating in the degradation of mRNA. | |
| 237429482 | short interfering RNA (siRNA) | Small interfering RNA (siRNA), sometimes known as short interfering RNA or silencing RNA, is a class of double-stranded RNA molecules, 20-25 nucleotides in length, that play a variety of roles in biology. The most notable role of siRNA is its involvement in the RNA interference (RNAi) pathway, where it interferes with the expression of a specific gene. |
