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45 Cards in this Set
- Front
- Back
What kind of bonds between nitrogenous bases in DNA? |
Hydrogen |
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What does DNA contain? |
Instructions for making proteins |
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DNA replication |
Parent strands unwind and two new daughter strands are built |
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Base pairing rules |
A with T, C with G |
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Helicase |
Unzips DNA molecule |
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Single-stranded binding proteins |
Keeps 2 parent strands apart after helicase unzips them |
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Topoisomerase |
Unwinds double helix, prevents twisting ahead of replication fork |
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Primase |
RNA primers, need this to start process |
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DNA Polymerase (III & I) |
III: replaces RNA nucleotides w/ DNA nucleotides to the 3' end I: cleans up RNA primer |
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Leading Strand |
moves toward replication fork, only one primer |
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Lagging Strand |
away from fork, multiple primers |
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Leading Strand Steps |
1 set of RNA primase makes primer, polymerase III adds DNA nucleotides, polymerase I cleans up RNA primer |
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Lagging Strand Steps |
Multiple RNA primases make primer, making gaps between primases. Okazaki fragments fill in gaps by polymerase III, DNA ligase acts as glue for okazaki fragments, Polymerase I cleans up RNA primer. |
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Nucleotides excision repair |
Nuclease cuts out damaged DNA |
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Mutations |
Change in DNA sequence |
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Telomeres |
DNA sequencing at the end of eukaryotic chromosomes |
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Telomerase |
Enzyme that lengthens the telomeres in gamete making cells so that DNA is not missing |
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Chromatin |
Complex of DNA and protein; found in the nucleus of eukaryotic cells |
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Euchromatin |
Loosely packed chromatin, actively transcribed genes are present. |
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Heterochromatin |
Telomere and centromere regions. Tightly packed chromatin, no transcription. |
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Histones |
Proteins around which DNA is wrapped thus condensing the chromosome structure |
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Mismatch repair |
The cellular process that uses special enzymes to fix incorrectly paired nucleotides |
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Nucleosome |
Bead like structure consisting of DNA wrapped around histone proteins |
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What phase is DNA replicated in the cell cycle? |
S phase |
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Protein Synthesis occurs in how many stages? |
2: Transcription and Translation |
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Transcription |
Making of mRNA from DNA sequences |
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Translation |
Creating polypeptide chains with mRNA instruction, occurs in ribosome |
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Codon |
Codes for specific amino acid, groups of 3 |
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What are the three stages of transcription? |
Initiation, Elongation, Termination |
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Initiation in Transcription |
Promoter region: the site where RNA polymerase attaches, RNA polymerase: adds RNA nucleotides, Transcription factors: bind RNA polymerase to promoter region |
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Elongation in Transcription |
RNA chain is made |
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Before translation |
eukaryotes must convert pre-mRNA to mRNA, 2 protective structures in pre-mRNA: Poly a tail (3’ end) & Cap (5’ end) |
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Initiation in Translation |
Small ribosomes attach to mRNA |
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Anticodon |
Identical to template strand |
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Codon |
Identical to non template strand |
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Elongation in translation |
P site: does initial accepting of tRNA, A site: holds tRNA/accepts new codons |
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Termination in translation |
E site: tRNA exits |
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tRNA |
transfer RNA, specific amino acid on one end and anticodon on other end |
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RNA splicing |
removing introns, expression exons |
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mRNA |
messenger RNA, specifies structure of protein |
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Acetylation of histones |
Adding an acetyl group (CHCO3), makes chromatin less compact and transcription can occur. |
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Deacetylation of histones |
Removing an acetyl group (CHCO3), makes chromatin more compact and transcription is prevented. |
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DNA methylation |
The presence of methyl groups on DNA bases (usually cytosine). Typicallyprevents transcription. |
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Histone charge |
Positive tails attracted to negative DNA, reducing transcription |
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What happens if transcription does not occur? |
Proteins will not be made/expressed |