State and briefly explain the functions of the enzymes involved in DNA replication?
Helicase: Unwinds DNA helix. Primase: releases RNA primer. DNA polymerase- adds complementary nucleotides. DNA ligase- creates phosphodiester bonds.
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Briefly describe the process of DNA replication?
1. Helicase unwinds helix 2. Primase releases an RNA primer 3. DNA polymerase reads from 3' to 5' and adds nucleotides 4. Okazaki fragments are produces in the lagging strand 5. DNA ligase synthesises in 5' to 3' 6. Terminator sequence is recognised
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Describe the results of the Meselsohn and Stahl experiment?
F1 Gen: 1 heavy + 1 light. F2 Gen: 1 light + 1 hybrid
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What does the Meselsohn and Stahl experiment prove?
That DNA is Semi-Conservative.
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What is a Primer?
Short single strand of DNA/RNA that helps the addition of nucleotides to the sequence.
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Describe the initiation stage of Transcription?
RNA pol and TF bind to specific start sequence-> DNA unwinds
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Describe the elongation of Transcription?
RNA pol moves and synthesises antiparallel RNA stand
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Describe the Termination stage of Transcription?
RNA pol reaches end->RNA pol and RNA released-> DNA duplex reforms
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What are the sense and antisense strand?
sense: DNA coding strand (5' to 3') Antisense: DNA template strand (3' to 5')
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What is splicing?
The process in which introns are removed
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What are RNA transcripts modified by?
3'-poly-A-tail and 5'- cap
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What is the function of the 3'-poly-A-tail?
Carries out polyadenylation. This helps stables the RNA molecule removing the original RNA 3' end.
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What is the function of the 5'-cap?
Protects from degradation .
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What may alternative splicing patterns result in?
- Alternative proteins, Introduction of new stop codons, altered reading frames, proteins with different modules of regulatory elements.
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Other cards in this set
Card 2
Front
Briefly describe the process of DNA replication?
Back
1. Helicase unwinds helix 2. Primase releases an RNA primer 3. DNA polymerase reads from 3' to 5' and adds nucleotides 4. Okazaki fragments are produces in the lagging strand 5. DNA ligase synthesises in 5' to 3' 6. Terminator sequence is recognised
Card 3
Front
Describe the results of the Meselsohn and Stahl experiment?
Back
Card 4
Front
What does the Meselsohn and Stahl experiment prove?
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