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Terms : Hide Images
| 670557839 | gene expression | the process by which DNA directs the synthesis of proteins, or RNAs in some cases | |
| 670557840 | In eukaryotic cells, transcription cannot begin until... | several transcription factors have bound to the promoter | |
| 670557841 | The anticodon of a particular tRNA molecule is | complementary to the corresponding mRNA codon. | |
| 670557842 | 5′-CTTCGGGAA-3′ | Using Figure 17.5, identify a 5′ → 3′ sequence of nucleotides in the DNA template strand for an mRNA coding for the polypeptide sequence Phe-Pro-Lys. |  |
| 670557843 | B | Which of these is a tRNA? |  |
| 670557844 | What enzyme catalyzes the attachment of an amino acid to tRNA? | aminoacyl-tRNA synthetase | |
| 670557845 | The tRNA anticodon, GAC, is complementary to the mRNA codon with the sequence _____. | CUG | |
| 670557846 | The initiator tRNA attaches at the ribosome's _____ site. | P | |
| 670557847 | Who formulated the one gene-one enzyme hypothesis? | Beadle and Tatum | |
| 670557848 | Genetic information of eukaryotic cells is transferred from the nucleus to the cytoplasm in the form of _____. | RNA | |
| 670557849 | 5' cap | A modified form of guanine nucleotide added onto the nucleotide at the 5' end of a pre-mRNA molecule | |
| 670557850 | Archibald Garrod | the first to suggest that genes dictate phenotypes through enzymes that catalyze specific chemical reactions in the cell | |
| 670557851 | "inborn errors of metabolism" | a term coined by Archibald Garrod, refferring to an inheirted disease reflecting a person's inability to make a particular enzyme | |
| 670557852 | Tatum and Beadle | American genetists that coined the "one gene-one enzyme" hypothesis from their various experiments | |
| 670557853 | Tatum/Beadle experiment | ... | |
| 670557854 | one gene-one enzyme hypothesis | the function of a gene is to dictate the production of a specific enzyme | |
| 670557855 | one gene-one polypeptide | ... | |
| 670557856 | inaccuracy of "one gene-one polypeptide" | 1) many eukaryotic genes can code for a set of closely related polypeptides in a process called alternative splicing 2) quite a few genes code for RNA moleucles that have important functions in cells even though they are never translated into protein | |
| 670557857 | RNA vs DNA | 1) ribose instead of deoxyribose as a sugar 2) uracil not thymine 3) ACCU 4) usually single stranded | |
| 670557858 | transcription | the synthesis of RNA using DNA as a template | |
| 670557859 | messenger RNA (mRNA) | the carrier of information from DNA to the cell's protein-synthesizing machinery | |
| 670557860 | translation | the synthesis of a polypeptide under the directions of mRNA | |
| 670557861 | ribosomes | the site of translation | |
| 670557862 | difference of genetic information flow between bacteria and eukaryotes? | 1) DNA is not segregated from ribosomes and the other protein synthesizing equipment, since there is no nucleus in bacteria | |
| 670557863 | The lack of segregation of DNA in bacteria results in... | simultaneous translation and transcription | |
| 670557864 | primary transcript | ... | |
| 670557865 | central dogma of Francis Crick | ... | |
| 670557866 | bacterial transcription/translation | In a bacterial cell, which lacks a nucleus, mRNA produced by transcription is immeadiately translated without additional processing. |  |
| 670557867 | eukaryotic translation/transcription | The nucleus of a eukaryotic cell provides a seperate compartment for transcription. The original transcript, called pre-mRNA, is processed in various ways before leaving the nucleus as mRNA. |  |
| 670557868 | triplet code | A set of three-nucleotide-long words that specify the amino acids for polypeptide chains | |
| 670557869 | template strand | the DNA strand that provides the pattern for ordering the sequence of nucleotides in an RNA transcript | |
| 670557870 | For each gene, one DNA strand functions as a template for transcription. The base-pairing rules for DNA synthesis also guide transcription, but uracil (U) takes the place of thymine (T) in RNA. During translation, the mRNA is read as a sequence of base triplets, called codons. Each codon specifies an amino acid to be added to the growing polypeptide chain. The mRNA is read in the 5'-3' direction. | triplet code |  |
| 670557871 | Marshall Nirenberg | deciphered the first codon by translating poly-U into a peptide for phenylalanine | |
| 670557872 | redundancy of the genetic code | Codons that are synonyms for a particular amino acid differ onlt in the third base of the triplet. | |
| 670557873 | reading frame | on an mRNA, the triplet grouping of ribonucleotides used by the translation machinery during polypeptide synthesis | |
| 670557874 | universiality of genetic code | DNA is a language shared by all living things that must have been operating very early in the history of life. | |
| 670557875 | exceptions to the universiality of the genetic code | 1) translation systhems in which a few codons differ 2) slight variations in genetic coder and in organelles 3) stop codons can be translated into one of two amino acids not found in most organisms | |
| 670557876 | RNA polymerase | the enzyme that pries apart the 2 DNA strands and joins the RNA nucleotides as they base-pair along the DNA template | |
| 670557877 | promoter | a specific nucleotide sequence in DNA that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place | |
| 670557878 | 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 moleucle and detach from the DNA | |
| 670557879 | transcription unit | a region of DNA that is transcribed into an RNA molecule | |
| 670557880 | stages of transcription | 1) initiation 2) elongation 3) termination | |
| 670557881 | initiation | After RNA polymerase binds to the promoter, the DNA strands unwind, and the polymerase initiates RNA synthesis at the start point on the template strand. |  |
| 670557882 | elongation | The polymerase moves downstream, unwinding the DNA and elongating the RNA transcript 5'-3'. In the wake of transcription, the DNA strands reform a double helix. |  |
| 670557883 | termination | Eventually, the RNA transcript is released, and the polymerase detaches from the DNA. |  |
| 670557884 | transcription factor | a regulatory protein that binds to DNA and affects transcription of specific genes | |
| 670557885 | transcription initiation complex | the completes assembly of transcription factors and RNA polymerase bound to a promoter |  |
| 670557886 | RNA processing | modification of RNA transcripts including splicing out introns, joining together of exons, and alteration of the 5' and 3' ends |
