Term
| What are telomeres? What happens to them over time |
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Definition
| Series of short nucleotide sequences repeated at the end of Eukaryotic chromosomes. Can be likened to the plastic tip on a shoelace. As cells replicate their chromosomes lose 30 to 200 bp per division. |
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Term
| Why can't DNA polymerase copy the tip of a DNA strand with a 3' overhang |
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Definition
| There is no place for upstream primer to be made |
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Term
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Definition
| An enzyme that attaches many copies of DNA repeat sequences to the ends of chromosomes. Function reduces as organism ages. |
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Term
| Why is it that cancers have high levels of telomerase? |
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Definition
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Term
| Chromosomes are composed of what? |
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Definition
| Chromatic, a DNA protein complex. |
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Term
| What are the 3 levels of DNA compaction? |
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Definition
| DNA wrapping, 30-nm fiber, |
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Term
| What happens during the first step of DNA compaction? |
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Definition
| DNA wrapping: DNA is wrapped around histones to form nucleosomes. Shortens length of DNA molecule 7 fold |
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Term
| During DNA wrapping, DNA is wrapped around what to form what? By what factor does it shorten the length of a DNA molecule? |
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Definition
| histones, nucleosome, 7-fold |
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Term
| What happens during the second step of DNA compaction? |
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Definition
| Current model suggests DNA folds into a 3D zigzag of nucleosomes 30 nm wide. Shortens length of DNA 7 fold (again). |
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Term
| What happens during the third step of DNA compaction? |
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Definition
| Radial Loop Domains: the 30 nm fibers interact with the nuclear matrix. Each chromosome if located in discrete territory however the level of compaction is not uniform. |
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Term
| What is the difference between heterochromatin and Euchromatin? |
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Definition
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Term
| What is the function/result of Helicase? |
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Definition
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Term
| What is the function/result of Photo repair? |
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Definition
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Term
| What is the function/result of Single-stranded binding proteins? |
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Definition
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Term
| What is the function/result of DNA polymerase III? |
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Definition
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Term
| What is the function/result of Mutation? |
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Definition
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Term
| What is the function/result of RNA primer? |
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Definition
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Term
| What is the function/result of Lagging strand? |
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Definition
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Term
| What is the function/result of Telomerase? |
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Definition
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Term
| What is the function/result of Okazaki? |
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Definition
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Term
| What is the function/result of Excision repait? |
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Definition
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Term
| What is the function/result of DNA ligase? |
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Definition
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Term
| What is the function/result of Gyrase? |
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Definition
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Term
| What is the function/result of Leading strand? |
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Definition
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Term
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Definition
| A segment of DNA that is functional. It specifies the arrangement of amino acids that will make a functional product. |
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Term
| What do most genes encode? |
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Definition
| Information about how to make a polypeptide: a 'structural' gene |
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Term
| What does the "One-gene, one-polypeptide" hypothesis describe? |
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Definition
| One gene codes for one polypeptide |
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Term
| What "is the link between genotype and phenotype" |
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Definition
| Proteins (link between what two things?) |
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Term
| What in a gene encodes for the sequence of amino acids in a protein? |
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Definition
| the sequence of bases (A,T,G,C) |
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Term
| What does the sequence of amino acids in a protein do? |
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Definition
| Gives the protein the function, gives structure to an organism |
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Term
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Definition
| The nucleus so that it can be protected |
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Term
| Where are proteins made? What makes them? |
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Definition
| in the rER (ribosomal endoplasmic reticulum), proteins are made by ribosomes. |
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Term
| How does the cell "know" to make proteins if the proteins are made outside the nucleus while the DNA is inside? |
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Definition
| Transcription creates mRNA which leaves the nucleus and carries the info to the ribosomes. |
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Term
| What are the 3 classes of RNA and what function do all three share? |
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Definition
| mRNA (messenger RNA), rRNA (ribosomal RNA), and tRNA (transfer RNA). All three are involved in making proteins from the DNA instructions |
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Term
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Definition
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Term
| Through what process does DNA create RNA? What process does RNA create proteins? |
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Definition
| Transcription, Translation |
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Term
| What is Transcription? Where does this occur? |
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Definition
| Information contained in a gene is copied to mRNA. Only 1 strand of DNA is used to copy the message to mRNA template strand. From the DNA template a complimentary mRNA is made. This occurs in the nucleus (DNA cannot leave the nucleus) |
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Term
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Definition
| Information carried by mRNA is made into a protein by tRNA and rRNA |
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Term
| What are the 3 steps of transcription? |
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Definition
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Term
| What happens during Initiation stage of transcription? |
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Definition
| RNA synthesis begins with RNA polymerase binding at the promoter region of the gene. Results in DNA strands separating to form an 'open complex' |
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Term
| Where does RNA polymerase bind and what does it do? |
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Definition
| Promoter region of the gene, this allows the sigma factor to bind to both the RNA polymerase and to the promoter. This results in the DNA strands separating to form an open complex. |
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Term
| What happens during Elongation stage of transcription? |
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Definition
| RNA polymerase travels along the template strand making the mRNA |
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Term
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Definition
| RNA polymerase travels along a template strand of DNA and uses free RNA nucleotides |
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Term
| Initiation results in what two complementary things. |
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Definition
| a template strand and a coding strand of DNA |
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Term
| What happens during the Termination stage of transcription? |
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Definition
| RNA polymerase encounters a 'termination signal' aka a specific combination of AUGC which tells the RNA polymerase that the sequence is over. |
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Term
| What is the difference between Eukaryotic and Prokaryotic transcription? |
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Definition
| Each step has more proteins. There are 3 types of RNA polymerase. RNA polymerase requires 5 general transcription factors to initiate transcription |
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Term
| What are the 3 types of RNA polymerase found in Eukaryotic transcription and what are their functions? |
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Definition
| RNA polymerase II transcribes mRNA, RNA polymerase I and III transcribes nonstructural genes for rRNA and tRNA |
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Term
| What must happen to enable the transcript (mRNA) to leave the nucleus? What else does this serve to do? |
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Definition
| a Poly A tail is added to the 3' end and a cap is added to the 5' end. This tells the ribosome where to attach and promotes longevity in cytosol. |
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Term
| What are the two ends of DNA and RNA denoted? |
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Definition
| each has a 3' and a 5' end. The DNA template strand reads 3' to 5' and the RNA transcript is 5' to 3' (mirrors the DNA) |
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Term
| What are introns? What happens to them? |
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Definition
| Unexpressed regions of DNA which are removed during splicing by the spliceosome. (During mRNA processing) |
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Term
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Definition
| The expressed regions of a region which remain after splicing. |
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Term
| What happens immediately before mRNA processing? What are the 3 basic stages of mRNA processing? |
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Definition
| Transcription creates pre-mRNA. Capping > Splicing > Tailing results in mature mRNA. |
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Term
| What is the function of Spliceosomes? What are they made of? |
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Definition
| removes introns precisely. Composed of snRNPs (small nuclear RNA). |
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Term
| Which two types of RNA are self splicing? |
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Definition
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Term
| What is the function of a ribozyme? |
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Definition
| RNA molecule that catalyzes a chemical reaction |
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Term
| What happens after transcription? |
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Definition
| mRNA binds to ribosomes, codons of mRNA are "translated" to amino acids to make proteins |
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Term
| What is the difference between DNA bases and RNA bases? |
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Definition
| T is substituted by a U in RNA |
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Term
| How many of these (codon translated compounds) are in proteins? |
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Definition
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Term
| How many bases sequence each amino acid? Where is it usually written? |
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Definition
| A 3 base sequence: Triplet Code- In the sequence of the mRNA molecule. |
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Term
| Each 3 base sequence is called a? |
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Definition
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Term
| mRNA is made up of how many of these 3 base sequences? |
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Definition
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Term
| How many start and stop codons are there? |
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Definition
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Term
| Can more than one codon code the same amino acid? |
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Definition
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Term
| Do all mutations alter proteins and why? |
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Definition
| No. More than one amino acid can be coded for by different codons. |
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Term
| What is rRNA? Where is is synthesized? Where are it's products made and sent to? |
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Definition
| makes up ribosomes and other proteins. Synthesized in nucleolus. Proteins made in cytosol and sent to the nucleus. |
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Term
| How many subunits make up rRNA |
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Definition
| 2: a large and small subunit |
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Term
| What does the small subunit of rRNA do? |
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Definition
| recognizes and binds mRNA |
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Term
| What does the large subunit of rRNA do? |
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Definition
| synthesizes proteins and binds to tRNA |
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Term
| What is tRNA? Where does it work? |
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Definition
| binds to free amino acids in cytoplasm and brings them to the ribosome. Puts the amino acids into growing protein chains following mRNA instructions. |
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Term
| Why are there many types of tRNA? |
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Definition
| each tRNA is for a different codon which has a complimentary anti-codon. (each for one codon) |
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Term
| What 3 things do all types of tRNA have in common? |
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Definition
| cloverleaf structure, a complimentary anti-codon, and an acceptor stem for amino acid binding |
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Term
| What is the function of Aminoacyl-tRNA synthetase? |
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Definition
| catalyzes the attachment of amino acids to tRNA (one for each of the 20 different amino acids). |
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Term
| What are the 3 possible results of Aminoacyl-tRNA synthetase reactions? |
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Definition
| tRNA with amino acid attached, charged tRNA, or aminoacyl tRNA |
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Term
| What has been referred to as "the second genetic code?" |
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Definition
| The ability of aminoacyl-tRNA synthetase to recognize appropriate tRNA |
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Term
| What are the 3 steps of Translation? |
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Definition
| Initiation, Elongation, Termination |
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Term
| What happens during the Initiation stage of Translation (3 things)? What does it require? |
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Definition
| Start codon on mRNA signals where to begin, small subunit binds to mRNA and moves along until start codon is encountered. At the start codon, tRNA binds to the first binding site on the large subunit. Requires energy (GTP) and initiation factors. |
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Term
| What happens at the beginning of the Elongation stage of Translation? |
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Definition
| Aminoacyl tRNA brings a new amino acid to the A site |
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Term
| During the Elongation stage of Translation, what allows binding to occur? |
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Definition
| codon/anti-codon recognition, polypeptide chain formation, movement of the ribosome towards the 3' end of the mRNA (by one codon) |
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Term
| Elongation factors do what to bind tRNA to A site during the Elongation stage of Translation? |
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Definition
| hydrolyze GTP to provide energy |
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Term
| What is in the P site? When is it important? |
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Definition
| Peptidyl tRNA, during the Elongation stage of Translation |
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Term
| What is in the A site? When is it important? |
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Definition
| Aminoacyl tRNA, during the Elongation stage of Translation |
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Term
| During the Elongation stage of Translation, what happens to the A site? |
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Definition
| Amino acid is brought and a peptide bond is formed between the amino acid and the growing polypeptide chain. |
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Term
| Where does the polypeptide chain of the Elongation stage of translation come from? What reaction occurs? |
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Definition
| removed from the tRNA in the P site and transferred to the A site during a peptidyl transfer reaction. |
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Term
| What catalyzes the peptide bond formation during Elongation stage of translation? |
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Definition
| rRNA catalyzes (ribosome is a ribozyme) |
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Term
| During the Elongation stage of Translation, movement or translocation of the ribosome towards the 3' end of the mRNA causes what? |
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Definition
| shifts tRNAs at the P and A sites to the E and P sites putting the next codon at the A site. Uncharged tRNA exits from the E spot |
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Term
| What is the E site? When is it important? |
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Definition
| the site from which uncharged tRNA exits during the Elongation stage of Translation |
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Term
| What happens during the Termination stage of Translation? |
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Definition
| A stop codon is found at the A site |
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Term
| What are the 3 stop codons? |
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Definition
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Term
| To what is the completed polypeptide chain attached at the beginning of the Termination stage of Translation? |
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Definition
| attached to a tRNA in the P site and the stop codon in the A site |
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Term
| What happens to the completed polypeptide chain (and associated compounds) during the Termination stage of Translation? (3 things) |
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Definition
| 1) Release factor binds to the stop codon at the A site. 2) The bond between polypeptide and tRNA hydrolyzed to release polypeptide. 3) Ribosomal subunits and release factors disassociate |
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