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29 Cards in this Set
- Front
- Back
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What is the goal of DNA replication?
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To make an exact copy of DNA double helix so both daughter cells will have identical genetic information after the cell divides
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_______ transcription --> _______ translation --> _______
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DNA
RNA polypeptide |
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What are some differences between DNA and RNA?
a. strands b. sugar c. bases |
a. double single
b. deoxyribose ribose c. thymine uracil |
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What is the goal of transcription?
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To make a copy of a particular segment (gene sequence) of DNA
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What are the players of transcription?
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DNA section to be transcrbied
RNA nucleotides RNA polymerase |
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What are the three stages of transcription?
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Initiation
Elongation Termination |
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What is the initiation for transcription?
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Segement to be trascribed
Promoter region = "start" located |
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What is the elongation for transcription?
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RNA nucleotides bind to the bases of one of the DNA strands (other DNA can be ignored), RNA polymerase joins up the RNA nucleotides
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What is the termination for transcirption?
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Termination sequence on DNA strand is reached, mRNA strand is released
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What is the goal of translation?
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Translate the original DNA segment (via mRNA) and assemble the polypeptide
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What are the players of translation?
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mRNA, tRNA, ribosomes, release factor protein
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What is the initiation for translation?
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mRNA attaches to small ribosome unit, "start" codon on mRNA read by a tRNA carring the amino acid "met" methionine
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Elongation for translation?
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tRNA in middle spot of large ribosome unit holds onto chain
new tRNA enters reads the mRNA codon peptide bond formation between new amino acid & rest of the change transfer of chain to new tRNA translocation = old tRNA leaves "new" tRNA moves to middle spot |
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Termination for translation?
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release factor protein binds to "stop" codon on mRNA
tRNA holding amino acid chain releases the chain and leaves the ribosome mRNA retaches from small unit of ribosome |
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Templates for transcription (tc) and translation (tl)
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tc = DNA
tl = mRNA |
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Location for tc and tl
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tc = nucleus
tl = ribosome (in cytoplasm or on rough ER) |
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Molecules involved for tc and tl
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tc = DNA & RNA nucleotides
tl = mRNA, tRNA, amino acids, ribosomes, release factor protein |
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Enzymes involved for tc and tl
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tc = RNA polymerase
tl = none |
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Control start & stop for tc and tl
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tc = promoter region "start here" & terminator region "stop here"
tl = "start" codon = AUG 1 of 3 "stop" codons: UAA, UAG, UGA |
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Product for tc and tl
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tc = single strand of mRNA
tl = polypeptide chain |
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Bfore mRNA gets translated, it needs to be processed. How does this happen? What gets added and what gets removed?
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Cap: 5' end; sequence of phospahte groups that adds stability and helps to bind ribosome
Tail: 3' end; sequence of A-bases that adds stability and helps mRNA leave nucleus Introns: intervening sequences that get removed by spliceosomes (make loops, enzyme snips them off, joins exons together) |
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What are introns?
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Introns are DNA segments found between the exons (protein-coding segments of a gene)
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Why are introns present?
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Evolutionary leftovers - maybe ease of reshuffling into useful new combos
Alternative splicing - different mRNA's produced from same gene, depending on which segments treated as introns/exons |
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What are point mutations?
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Mutations in which as single base-pair gets inserted/deleted/substituted
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Original segment of DNA: T-A-C-T-T-C-A-A-A-C-C-G-A-T-T
What is the complimentary mRNA sequence for the original DNA segment? |
A-U-G-A-A-G-U-U-U-G-G-C-U-A-A
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A-U-G-A-A-G-U-U-U-G-G-U-U-A-A
determine the type of mutation that has occured (base-pair insertion/deletion/substitution), and what the resulting problem is? |
base-pair substitution; nothing happens--same as a.a. coded form
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A-U-G-A-A-G-U-U-U-A-G-C-U-A-A
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base-pair substitution; because substitution at start of codon, different a.a. inserted
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A-U-G-U-A-A-G-U-U-U-G-G-C-U-A-A
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base insertion; frameshift so now there's a stop codon just after the start codon
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A-U-G-A-A-G-U-G-G-C-U-A-A
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base deletion; frameshift such that all codons after the deletion are wrong = wrong a.a.'s inserted
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