Term
| proteins are links between __ and __ |
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Definition
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Term
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Definition
| the process by which dna directs protein synthesis, includes two stages: transcription and translation |
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Term
| two stages of gene expression |
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Definition
| transcription and translation |
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Term
| who suggested that genes dictate phenotypes through enzymes that catalyze specific chemical rxns? |
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Term
| who developed one gene one enyzyme hypo with x rayed moldy bread? |
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| __ is teh intermediate between genes and protins for which they code |
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Definition
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Term
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Definition
| the synthesis of rna under the direction of dna |
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| (mRNA) produced by transctiption |
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Term
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Definition
| synthesis of a polypeptide, which occurs under the direction of mRNA |
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Definition
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| modification of rna transcripts including splicing out of introns, joining together of exons, and alteration of the 5' and 3' ends |
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Definition
| initial transcript from any gene |
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Term
| central dogma is the concept that cells are goverened by a cellular chain of command: what is it? |
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Definition
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Term
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Definition
| set of three nucleoutide long "words" that specify the amino acids for polypeptide chains |
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Term
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Definition
| the dna strand that produces the pattern, or template, for orderin gthe sequence of nucleotides in an RNA transcript |
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Definition
| a three nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code |
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Definition
| on an mrna, the triplet grouping of ribonuleotides used by the translation machinery during polypeptide synthesis |
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Definition
| enzyme that links ribonucleuotides into a growing rna chain during transcription |
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Term
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Definition
| dna sequence where rna polymerase attaches. a specific nucleotide sequence in dna that binds rna polymerase, positioning it to start transribing rna at the appropriate place |
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Term
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Definition
| 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 detache from the dna |
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Term
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Definition
| a region of dna that is transcribed into an rna molecule |
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Term
| three stages of transcription |
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Definition
| initiation, elongation, and termination |
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Term
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Definition
| mediate the binding of rna polymerase and the initiation of transcription |
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Term
| transcription initiation complex |
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Definition
| the completed assembly of transcription factors and rna polymerase bound to a promoter |
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Term
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Definition
| dna sequence in eukaryotic promoters crucial in forming the transctiption initiation complex |
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Term
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Definition
| a modified form of guanine nucleotide added onto the nucleotide at the 5' end of a pre-mrna molecule |
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Term
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Definition
| a sequence of 50 to 250 adenine nucleotides added onto the 3' end of a pre-mrna molecule |
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Term
| what are the functions of the modifications made by the 5' cap or poly a tail |
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Definition
- they facilitate the export of mRNA
- they protect m RNA from hydrolytic enzymes
- they help ribosomes attach to the 5' end
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Term
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Definition
| long stretes of nucleotides that lie btween coding regions, noncoding regions or intervening sequenes |
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Term
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Definition
| regions of nucleotides that are eventually expressed and are usually translated into amino acid sequences |
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Term
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Definition
| removes introns and joins exons, creating an m RNA molecule with a continuous coding sequence |
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Term
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Definition
| consist of a variety of proteins and several small nuclear ribonucleoproteins (snRNPs) that recognize splice sites |
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Term
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Definition
| catalytic RNA molecules that functions as enzymes and can splice rna |
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Term
| what three properties of rna enable it to function as an enzyme |
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Definition
- it can form a three dimensional structure because of its ability to base pair with itself
- some bases in rna contain functional groups
- rna may hydrogen bond with other nucleic acid molecules
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Term
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Definition
| a type of eukaryotic gene regulation at rna processing level in which different mrna molecules are produced from the same primary transcript, depending on which rna segments are treated as exons and which as introns |
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Term
| proteins often have modular achitecture consisting of discrete regions called __ |
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Definition
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Term
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Definition
| helps a cell translate m rna message into protein |
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Term
| why aren't the molecules of t rna identical? |
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Definition
each carries a specific amino acid on one end
each has an anticodon on the other end |
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Term
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Definition
| a nucleotide triplet at one end of a trna molecule that recognizes a particular complementary codon on an mrna molecule |
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Term
| accurate translation requires two steps what are they? |
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Definition
- a correct match between a trna and an amino acid, done by the enzyme aminoacyl - trna synthetase
- a correct match between the trna anticodon and an m rna codon
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Term
| aminoacyl trna synthetase |
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Definition
| an enzyme that joins each amino acid to the appropriate trna |
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Term
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Definition
| flexible pairing at the third base of a codon. allows some tRNAs to bind to more than one codon |
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Term
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Definition
| (rRNA) the most abundant type of RNA, which together with proteins makes up ribosomes |
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Term
| a ribosome has three binding sites for tRNA. what are they? |
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Definition
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Term
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Definition
| holds the tRNA that carries teh growing polypeptide chain |
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Term
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Definition
| holds the tRNA that carries the next amino acid to be added to the chain |
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Term
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Definition
| the exit site, where discharged tRNAs leave the ribosome |
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Term
| three stages of translation. all three stages require __ |
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Definition
| initiation, elongation, termination; require protein factors that aid in the tranlation process |
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Term
| the initiation stage of translation brings what things together? |
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Definition
| an mRNA, a tRNA with the first amino acid, and the two ribosomal subunits |
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Term
| what happens during the elongation stage of translation? |
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Definition
| amino acids are added one by one to the preceding amino acid |
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Term
| translation can be divided into three stages initiation, elongation and termination. all three stages require protein "facrors" that aid in the translation process. what are these three factors? |
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Definition
- codon recognition
- peptide bond formation
- translocation
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Term
| when does termination occur? |
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Definition
| when a stop codon in the mRNA reaches the A site of the ribosome |
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Term
| the A site accpets a protein called a __ __ during termination of translation |
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Definition
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Term
| what does the release factor do? |
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Definition
| causes the addition of a water molecule instead of an amino acid. this rxn releases the polypeptide and the translation assembly then comes apart |
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Term
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Definition
| a number of ribosomes can translate a single mRNA simultaneously, forming a polyribosome or polysome |
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Term
| post translation modification |
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Definition
| modifications made after translation. |
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Term
| what do free/bound ribosomes do? |
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Definition
- free ribosomes mostly synthesize proteins that function in the cytosol
- bound ribosomes make proteins of teh endomembrane system and proteins that are secreted from the cell
- both are identical and can switch from free to bound and vice versa
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Term
| where does polypeptide synthesis begin |
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Definition
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Term
| what event causes synthesis to not finish in the cytosol? |
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Definition
| when a polypeptide signals the ribosome to attach to the ER |
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Term
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Definition
| marks polypeptides destined for the ER or for secretion |
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Term
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Definition
| Signal recognition particle, binds to signal peptide and brings the signal peptide with its ribosome to the ER |
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Term
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Definition
| changes in the genetic material of a cell or virus |
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Term
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Definition
| chemical changes in th just one base pair of a gene |
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Term
| two general categories of point mutations within a gene |
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Definition
- base-pair substitutions
- base-pair insertions or deletions
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Term
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Definition
| replaces one nucleo tide and its partner with another pair of nucleotides |
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Term
| why dont silent mutations have any effect on the amino acid? |
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Definition
| because of the redundancy in the genetic code |
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Term
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Definition
| mutations that still codes for an amino acid, but not necessarily the right amino acid |
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Term
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Definition
| mutations that change an amino acid codon into a stop codon, nearly always leading to a nonfucitonal protein |
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Term
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Definition
| + or - of nucleotide pairs in a gene causing disastrous efects on the reulting protein |
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Term
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Definition
| alternate reading frame produced by the insertion or deletion of nucleotides |
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Term
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Definition
| physicla or chemical agents that cause mutations |
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Term
| a gene is considered to be |
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Definition
- a discrete unit of inheritance
- a region of specific nucleotide sequence in a chromosome
- a sequence that codes for a specific polypeptide chain
in summary, a gene is defined as a region of dna that can be expressed to produce a final functional product, either a polypeptide or an RNA molecule |
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Term
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Definition
| small nuclear ribonucleoproteins |
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Term
| name the three stop codons |
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Definition
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Term
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Definition
| monkey king, siren, arctic/antarctic AFGP, morpheus, sphinx, sonic the hedgehog |
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