Ch 17 Gene to Protein Flashcards
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| 253190893 | transcription | the synthesis of RNA using a DNA template | |
| 253190894 | translation | The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of "language" from nucleotides to amino acids | |
| 253190895 | RNA polymerase | unwinds DNA and adds nucleotides during transcription, based on complementary binding to nucleotides on a DNA template strand Binds with promoter region | |
| 256065232 | promoter | includes a TATA box, a nucleotide sequence containing TATA region where RNA polymerase attaches and initiates transcription | |
| 256065233 | transcription factors | proteins that allow RNA polymerase to bind | |
| 256066510 | terminator | in bacteria, a sequence of nucleotides in DNA that marks the end of a gene and signals RNA polymerase to release the newly made RNA molecule and detach from the DNA | |
| 256079128 | intron | noncoding segments of nucleic acid | |
| 256079129 | exons | regions that are expressed, usually by being translated into amino acid sequences | |
| 256079130 | spliceosome | cuts the premRNA, releasing the intron, splicing exons together | |
| 256079131 | mRNA | messenger RNA carries code for protein attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein | |
| 256079132 | tRNA | transfer RNA binds to one amino acid has one anticodon brings amino acids to mRNA in ribosomes | |
| 256079133 | rRNA | ribosomal RNA 2 rRNA subunits (large and small) and one protein that make one ribosome brings tRNA and mRNA together It has mRNA binding site It has tRNA binding site (P site, A site, E site) | |
| 256112228 | P site | holds the tRNA carrying the polypeptide chain | |
| 256112229 | A site | holds the tRNA carrying the next amino acid to be added to the chain | |
| 256112230 | E site | discharged tRNAs leave the ribosome from this site | |
| 256079134 | codon | code for amino acids carried my mRNA | |
| 256108998 | triplet code | 3 successive bases of mRNA specify the amino acids for polypeptide chains | |
| 256079135 | anticodon | a nucleotide triplet at one end of a tRNA molecule that base pairs with a particular complementary codon on an mRNA molecule | |
| 256110863 | wobble | flixibility in the base-pairing rules in which the nucleotide at the 5' end of a tRNA anticodon can form hydrogen bonds with more than one kind of base in the 3' end of a codon | |
| 256079136 | aminoacyl-tRNA synthetase | an enzyme that joins each amino acid to the appropriate tRNA | |
| 256091430 | transcriptional unit | the stretch of DNA that is transcribed into an RNA molecule | |
| 256177477 | polyribosome | many ribosomes on one mRNA strand | |
| 256087486 | two processes that link genes to proteins | Transcription and translation; transcription occurs nucleus translation occurs in the cytoplasm | |
| 256087487 | RNA difference from DNA | U replaces T ribose sugar single stranded leaves nucleus codes for protein | |
| 256091431 | initiation of transcription | Transcription factors recognize the TATA box and bind to promoter in DNA RNA polymerase binds to the promoter (helped by transcription factors) RNA polymerase unwinds the DNA and adds nucleotides complementary to the DNA template strand. | |
| 256096501 | elongation of transcription | RNA polymerase constructs RNA strand New RNA peels away from the template strand double helix reforms | |
| 256099727 | termination of transcription | RNA polymerase transcribes the polyadenylation signal (AAUAA) sequence from the DNA Transcription stops when proteins cut RNA strand from polymerase, releasing pre-mRNA | |
| 256103141 | RNA processing | modification of pre-mRNA 5' cap added poly A tail added The added ends are not translated into protein | |
| 256103142 | reason for RNA processing | The modified ends promote export of mRNA from the nucleus They help protect te mRNA from degradation. When mRNA reaches the cytoplasm, the modified ends facilitate ribosome attachment. | |
| 256105430 | RNA splicing | most of a transcription unit is noncoding RNA has introns and exons snRNPs and other proteins form a spliceosome snRNPs recognize the introns spliceosome cuts the pre-mRNA, releasing the introns and splicing the exons together | |
| 256105847 | alternative splicing | many polypeptides are made from one gene | |
| 256117254 | translation initiation | Small ribosomal subunit binds the mRNA and tRNA with anticodon MET Small subunit bound to tRNA binds to the 5' cap of the mRNA and then moves downstream along the mRNA until it reaches the matching start codon initiator tRNA hydrogen bonds to the start codon. Large ribosomal subunit joins the mRNA, tRNA, and small ribosomal subunit Hydrolysis of GTP provides energy for the assembly of the initation complex The initiator tRNA is in the P site | |
| 256127672 | translation elongation | amino acids are added one by one to the previous amino acid of the growing chain The anticodon of an incoming aminoacyl tRNA basepairs with the complementary mRNA codon in the A site. An rRNA molecule of the large ribosomal subunit catalyzes the formation of a peptide bond between the amino group of the new amino acid in the A site and the carboxyl end of the growing polypeptide in the P site. This step removes the polypeptide from the tRNA in the P site and attaches it to the amino acid on the tRNA in the A site. | |
| 256127673 | translation termination | Elongation continues until a stop codon in the mRNA reaches the A site of the ribosome Release factor binds to the stop codon in the A site Release factor causes the addition of a water molecule instead of an amino acid to the polypeptide chain. This reaction breaks (hydrolyzes) the bond between the completed polypeptide and the tRNA in the P site, releasing the polypeptide through the exit tunnel of the ribosome's large subunit. The two ribosomal subunits nd the other componets of the assembly dissociate | |
| 256177478 | post translation modification | protein folds and its aided by chaperonin polypeptides may be chemically modified or enzymatically spliced Polypeptide synthesis always begins in the cytosol as a free ribosome starts to translate an mRNA molecule and finish if it is a free ribosome | |
| 256177479 | polypeptide targeting | Polypeptide synthesis begins on a free ribosome in the cytosol. Polypeptide cues ribosome to attach to ER. Poly peptide destined for ER or secretion are marked by signal peptide. Signal peptide is recognized as it emerges from the ribosome and bound by a signal recognition particle (SRP). SRP brings the ribosome and binds to a receptor protein built into the ER membrane. SRP leaves and polypeptide synthesis continues in the ER. Polypeptide travels into ER lumen. Signal peptide is removed by an enzyme. Rest of the completed polypeptie leaves the ribosome and folds into its final conformation | |
| 256190898 | point mutation | change in just one base pair | |
| 256190899 | types of point mutations | substitution insertions or deletions (can be more than one nucleotides) | |
| 256190900 | substitution | one nucleotide replaced with another | |
| 256190901 | types of subtitution | silent missense nonsense | |
| 256190902 | silent mutation | no change in amino acid due to redundancy in codons | |
| 256190903 | missense mutation | one amino acid change changes protein structure and function May have little effect on protein | |
| 256190904 | nonsense | codon changed to stop short polypeptide | |
| 256190905 | time of insertion/deletion | frameshift mutation | |
| 256190906 | frameshift mutation | nucleotide numbers no longer mltiples of three all downstream codons incorrect |