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25 Cards in this Set
- Front
- Back
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What is transcription?
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Process of transferring genetic information from DNA to mRNA
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How is RNA different than DNA?
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RNA has Ribose instead of deoxyribose, only one strand, and Uracil instead of Thymine.
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What is Uracil?
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Nitrogenous base only found in RNA it is a pyrimidine that bonds with Adenine.
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What is mRNA?
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Messenger Ribonucleic Acid
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What does mRNA do?
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When ever the cell needs a protein a copy of the DNA is made, that copy is mRNA and is used as a template for the protein.
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Why is mRNA important?
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If there is no mRNA then there is no way for the genetic information to get from the DNA to the ribosome.
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What enzymes are needed for transcription?
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Only RNA polymerase, but it does require helper proteins too.
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Where does transcription happen?
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In Eukaryotes: in the nucleus
In Prokaryotes: in the cytoplasm. |
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What is the first step of transcription called?
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Pre-initiation
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What happens during pre-initiation?
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Co-factors and RNA polymerase unwind the DNA to make an initiation bubble.
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What is the difference between the sense strand and the antisense strand?
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The anti-sense strand is the one copied and runs 3' to 5'
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What is the second step in transcription called?
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Initiation
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What happens during initiation?
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Transcription factors help the RNA polymerase attach to the correct spot on the DNA.
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What are transcription factors?
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Proteins that help the RNA polymerase bind to the DNA molecule.
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What is the third step of transcription called?
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Promoter Clearance
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What happens during promoter clearance?
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RNA polymerase needs help clearing the promoter region of the DNA, so promoter proteins help it get started.
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What happens to RNA polymerase if it doesn't get help from the promoter proteins?
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It will fall off the DNA and not make mRNA.
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What is the 4th step of transcription?
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Elongation
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What happens during elongation?
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Polymerase zooms down the antisense strand putting the correct nucleotides in order, making a long mRNA strand.
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What happens when the RNA polymerase encounters an Adenine nucleotide?
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It puts the nitrogenous base, Uracil into the sequence.
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What is the fifth step of transcription?
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Termination
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What happens during termination?
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When RNA polymerase reads a stop sequence of nucleotides on the DNA it cuts the mRNA loose. The mRNA goes to the ribosome.
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What are nuclear pores?
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Small tunnels through both membranes around the nucleus, they allow some molecules like mRNA through.
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What stage of the cell cycle does transcription occur?
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Interphase
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During which phase of Interphase does transcription primarily occur?
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G1
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