| 1118078556 | Structure and the role Nucleotides play | Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. They serve as sources of chemical energy, participate in cellular signaling, and are incorporated into important cofactors of enzymatic reactions | |
| 1118078557 | Purines and Pyrimidines | Purines and pyrimidines make up the two groups of nitrogenous bases, including the two groups of nucleotide bases. Two of the four deoxyribonucleotides and two of the four ribonucleotides, the respective building blocks of DNA and RNA, are purines. The purines are Adenine and Guanine; the pyrimidines are Thymine, Cytosine, and Uracil | |
| 1118078558 | How do we know that DNA is the transformation material? | There were three major studies that confirmed that DNA was indeed the genetic information. It all began with Frederick Griffith. Griffith studied two strains of bacteria, a virulent, or disease causing form, and a non-virulent, or non-disease causing form. His research found that two seemingly harmless strains of bacteria were deadly due to transformation, a process in which bacteria takes up foreign DNA. The second study was by Oswald Avery. Avery wanted to identify the substance that made the non-virulent bacteria become virulent. To do this he modified Griffith's experiment and used protein and DNA destroying enzymes to help him identify that DNA was the genetic material. Lastly, Alfred Hershey and Martha Chase confirmed that DNA is indeed the genetic material. They did this by radioactively labeling the protein coat and DNA in viruses. They found that only the radioactively labeled DNA was passed along to the new viruses, thus confirming that DNA, not protein, was the genetic material. | |
| 1118078559 | Chargaff's rules | The first rule holds that a double-stranded DNA molecule globally has percentage base pair equality: %A = %T and %G = %C.[6] The rigorous validation of the rule constitutes the basis of Watson-Crick pairs in the DNA double helix. The second of Chargaff's rules (or "Chargaff's second parity rule") is that the composition of DNA varies from one species to another; in particular in the relative amounts of A, G, T, and C bases. Such evidence of molecular diversity, which had been presumed absent from DNA, made DNA a more credible candidate for the genetic material than protein | |
| 1118078560 | Know the Parts of a Nucleotide and the Watson-Crick DNA model | A nucleotide is composed of a nucleobase (nitrogenous base) and a five-carbon sugar (either ribose or 2'-deoxyribose), and one to three phosphate groups. Together, the nucleobase and sugar comprise a nucleoside. The phosphate groups form bonds with either the 2, 3, or 5-carbon of the sugar, with the 5-carbon site most common. Cyclic nucleotides form when the phosphate group is bound to two of the sugar's hydroxyl groups.[1] Ribonucleotides are nucleotides where the sugar is ribose, and deoxyribonucleotides contain the sugar deoxyribose. Nucleotides can contain either a purine or pyrimidine base | |
| 1118078561 | DNA replication-how it occurs | 1) an enzyme called Helicase separates the DNA strands2) DNA polymerase adds complementary nucleotides to the separated strand of DNA3) the DNA polymerase enzyme finishes adding nucleotides and there are two identical DNA molecules. It ALWAYS replicates in the 5' to 3' direction. | |
| 1118078562 | mRNA transcription | In chromosomes, DNA acts as a template for the synthesis of RNA in a process called transcription. In most mammalian cells, only 1% of the DNA sequence is copied into a functional RNA (mRNA). Only one part of the DNA is transcribed to produce nuclear RNA, and only a minor portion of the nuclear RNA survives the RNA processing steps. One of the most important stages in RNA processing isRNA splicing. In many genes, the DNA sequence coding for proteins, or "exons", may be interrupted by stretches of non-coding DNA, called "introns". In the cell nucleus, the DNA that includes all the exons and introns of the gene is first transcribed into a complementary RNA copy called "nuclear RNA," or nRNA. In a second step, introns are removed from nRNA by a process called RNA splicing. The edited sequence is called "messenger RNA," or mRNA. | |
| 1118078563 | RNA polymerase | RNA polymerase (RNAP or RNApol) is an enzyme that produces RNA. In cells, RNAP is needed for constructing RNA chains from DNA genes as templates (transcription) | |
| 1118078564 | Translation- Initiation | 1. Initiation * The small subunit of the ribosome binds to a site "upstream" (on the 5' side) of the start of the message. * It proceeds downstream (5' -> 3') until it encounters the start codon AUG. (The region between the cap and the AUG is known as the 5'-untranslated region [5'-UTR].) * Here it is joined by the large subunit and a special initiator tRNA. * The initiator tRNA binds to the P site (shown in pink) on the ribosome. * In eukaryotes, initiator tRNA carries methionine (Met). (Bacteria use a modified methionine designated fMet.) | |
| 1118078565 | Translation-Elongation | 2. Elongation * An aminoacyl-tRNA (a tRNA covalently bound to its amino acid) able to base pair with the next codon on the mRNA arrives at the A site (green) associated with: o an elongation factor (called EF-Tu in bacteria) o GTP (the source of the needed energy) * The preceding amino acid (Met at the start of translation) is covalently linked to the incoming amino acid with a peptide bond (shown in red). * The initiator tRNA is released from the P site. * The ribosome moves one codon downstream. * This shifts the more recently-arrived tRNA, with its attached peptide, to the P site and opens the A site for the arrival of a new aminoacyl-tRNA. * This last step is promoted by another protein elongation factor (called EF-G in bacteria) and the energy of another molecule of GTP. | |
| 1118078566 | Translation-Termination | # The end of translation occurs when the ribosome reaches one or more STOP codons (UAA, UAG, UGA). (The nucleotides from this point to the poly(A) tail make up the 3'-untranslated region [3'-UTR] of the mRNA.) # There are no tRNA molecules with anticodons for STOP codons. (With a few special exceptions: link to mitochondrial genes and to nonstandard amino acids.) # However, protein release factors recognize these codons when they arrive at the A site. # Binding of these proteins —along with a molecule of GTP — releases the polypeptide from the ribosome. # The ribosome splits into its subunits, which can later be reassembled for another round of protein synthesis | |
| 1118078567 | Lac operon | The lac operon is an operon required for the transport and metabolism of lactose in Escherichia coli and some other enteric bacteria. It consists of three adjacent structural genes, a promoter, a terminator, and an operator. The lac operon is regulated by several factors including the availability of glucose and of lactose.In its natural environment, lac operon is a complex mechanism to digest lactose efficiently. The cell can use lactose as an energy source, but it must produce the enzyme β-galactosidase to digest it into glucose. It would be inefficient to produce enzymes when there is no lactose available, or if there is a more readily-available energy source available (e.g. glucose). The lac operon uses a two-part control mechanism to ensure that the cell expends energy producing β-galactosidase, galactose permease and transacetylase only when necessary. It achieves this with the lac repressor, which halts production in the absence of lactose, and the Catabolite activator protein (CAP), which assists in production in the absence of glucose. This dual control mechanism causes the sequential utilization of glucose and lactose in two distinct growth phases, known as diauxie. Similar diauxic growth patterns have been observed in bacterial growth on mixtures of other sugars as well, such as glucose and xylose or glucose and arabinose, etc. The genetic control mechanisms underlying such diauxic growth patterns are known as xyl operon and ara operon, etc. | |
| 1118078568 | Okazaki fragments | a relatively short fragment of DNA (with an RNA primer at the 5' terminus) created on the lagging strand during DNA replication. The lengths of Okazaki fragments are between 1,000 to 2,000 nucleotides long in E. coli and are generally between 100 to 200 nucleotides long in eukaryotes. n dealing with the synthesis of complementary DNA strands the nascent leading strand always reads 3' to 5'. Its antiparallel complement strand, the nascent lagging strand reads from 5' to 3'. Because the original strands of DNA are antiparallel, and only one continuous new strand can be synthesised at the 3' end of the leading strand due to the intrinsic 5'-3' polarity of DNA polymerases, the other strand must grow discontinuously in the opposite direction. Regarding the lagging strand, the result of this strand's discontinuous replication is the production of a series of short sections of DNA called Okazaki fragments. | |
| 1118078569 | Mutation | hanges to the nucleotide sequence of the genetic material of an organism. Can be caused by | |
| 1118078570 | Genes specify A enzymes and then a polypeptide. Why? Which is better? | Who knows what this means? I am pretty sure I've never heard of it | |
| 1118078571 | 3 steps of translation | Chain initiation, chain elongation, chain termination | |
| 1118078572 | RNA types- be able to read AAATTT and what mRNA and tRNA does it give | mRNA UUUAAA and tRNA AAAUUU (opposite) | |
| 1118078573 | Nucleic Acid | A nucleic acid is a macromolecule composed of chains of monomeric nucleotides. In biochemistry these molecules carry genetic information or form structures within cells. The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleic acids are universal in living things, as they are found in all cells and viruses. | |
| 1118078574 | DNA | Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. | |
| 1118078575 | RNA | Ribonucleic acid (RNA) is a type of molecule that consists of a long chain of nucleotide units. Each nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate. RNA is very similar to DNA, but differs in a few important structural details: in the cell, RNA is usually single-stranded, while DNA is usually double-stranded; RNA nucleotides contain ribose while DNA contains deoxyribose (a type of ribose that lacks one oxygen atom); and RNA has the base uracil rather than thymine that is present in DNA. | |
| 1118078576 | bacterophage | A bacteriophage is any one of a number of viruses that infect bacteria. The term is commonly used in its shortened form, phage. Typically, bacteriophages consist of an outer protein capsid enclosing genetic material. The genetic material can be ssRNA, dsRNA, ssDNA, or dsDNA ('ss-' or 'ds-' prefix denotes single strand or double strand) between 5,000 and 500,000 nucleotides long with either circular or linear arrangement. Bacteriophages are much smaller than the bacteria they destroy - usually between 20 and 200 nm in size. | |
| 1118078577 | Adenine | Adenine is a nucleobase (a purine derivative) with a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate (ATP) and the cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD), and protein synthesis, as a chemical component of DNA and RNA.[1] The shape of adenine is complementary to either thymine in DNA or uracil in RNA. | |
| 1118078578 | Guanine, | Guanine is one of the five main nucleobases found in the nucleic acids DNA and RNA. guanine is paired with cytosine. With the formula C5H5N5O, guanine is a derivative of purine, consisting of a fused pyrimidine-imidazole ring system with conjugated double bonds. | |
| 1118078579 | Thymine | Thymine is one of the four bases in the nucleic acid of DNA that make up the letters GCAT. Thymine (T) always pairs with adenine. Thymine is also known as 5-methyluracil, a pyrimidine nucleobase. As the name suggests, thymine may be derived by methylation of uracil at the 5th carbon. | |
| 1118078580 | Cytosine | Cytosine is one of the four main bases found in DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at position 2). The nucleoside of cytosine is cytidine. In Watson-Crick base pairing, it forms three hydrogen bonds with guanine. | |
| 1118078581 | Uracil | Uracil is a common and naturally occurring pyrimidine derivative. Found in RNA, it base pairs with adenine and is replaced by thymine in DNA translation | |
| 1118078582 | Helicase | Helicases are a class of enzymes vital to all living organisms. They are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands (i.e. DNA, RNA, or RNA-DNA hybrid) using energy derived from ATP hydrolysis | |
| 1118078583 | Replication Fork | The replication fork is a structure that forms within the nucleus during DNA replication. It is created by helicases, which break the hydrogen bonds holding the two DNA strands together. The resulting structure has two branching "prongs", each one made up of a single strand of DNA, that are called the leading and lagging strands. DNA polymerase creates new partners for the two strands by adding nucleotides. | |
| 1118078584 | DNA repair enzymes | DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome | |
| 1118078585 | One gene-one polypeptide hypothesis | The modern version of the one gene-one enzyme hypothesis. The one gene-one enzyme hypothesis is the idea that genes act through the production of enzymes, with each gene responsible for producing a single enzyme that in turn effects a single step in a metabolic pathway. | |
| 1118078586 | Central dogma | The central dogma of molecular biology deals with the detailed residue-by-residue transfer of sequential information. It states that information cannot be transferred back from protein to either protein or nucleic acid. In other words, 'once information gets into protein, it can't flow back to nucleic acid.' | |
| 1118078587 | Genetic code | he genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences) by living cells. The code defines a mapping between tri-nucleotide sequences, called codons, and amino acids. | |
| 1118078588 | Start Codon | AUG | |
| 1118078589 | Stop Codons | UAG, UGA, UAA | |
| 1118078590 | Promoter | n genetics, a promoter is a region of DNA that facilitates the transcription of a particular gene. Promoters are typically located near the genes they regulate, on the same strand and upstream (towards the 5' region of the sense strand). | |
| 1118078591 | Terminator | a section of genetic sequence that marks the end of gene or operon on genomic DNA for transcription. | |
| 1118078592 | Exon | An exon is a nucleic acid sequence that is represented in the mature form of an RNA molecule after a) portions of a precursor RNA, introns, have been removed by cis-splicing or b) two or more precursor RNA molecules have been ligated by trans-splicing. The mature RNA molecule can be a messenger RNA or a functional form of a non-coding RNA such as rRNA or tRNA. Depending on the context, exon can refer to the sequence in the DNA or its RNA transcript. | |
| 1118078593 | Intron | An intron is a DNA region within a gene that is not translated into protein. These non-coding sections are transcribed to precursor mRNA (pre-mRNA) and some other RNAs (such as long noncoding RNAs), and subsequently removed by a process called splicing during the processing to mature RNA. After intron splicing (ie. removal), the mRNA consists only of exon derived sequences, which are translated into a protein. | |
| 1118078594 | Spliceosomes | A spliceosome is a complex of specialized RNA and protein subunits that removes introns from a transcribed pre-mRNA (hnRNA) segment. This process is generally referred to as splicing. | |
| 1118078595 | Anticodon | An anticodon[1] is a unit made up of three nucleotides that correspond to the three bases of the codon on the mRNA. Each tRNA contains a specific anticodon triplet sequence that can base-pair to one or more codons for an amino acid. | |
| 1118078596 | Elongation factors | Elongation factors are a set of proteins that facilitate the events of translational elongation, the steps in protein synthesis from the formation of the first peptide bond to the formation of the last one. | |
| 1118078597 | Translocation | a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes. | |
