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31 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Semiconservative replication |
2 DNA strands unzip, each a template for complementary nucleotides to form new strands -> 2 identical chromosomes |
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Topoisomerase |
A replication enzyme that relaxes DNA supercoiling |
Replication enzyme |
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Helicase |
A replication enzyme which disrupts hydrogen bonds between bases -> unzips DNA |
Replication enzyme |
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DNA primase |
A replication enzyme that forms short RNA primer -> initiates binding of DNA polymerase to parent strands |
Replication enzyme |
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DNA polymerase |
Dimeric structure (2 copies) each binds a parent strand, travels towards 5' end of each parent strand -> nucleotides added to 3' end of daughter strands -parent strands antiparallel -> linked polymerases want to go in opposite directions |
Antiparallel |
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Leading strand |
DNA strand which is synthesized continuously |
DNA replication |
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Lagging strand |
The strand synthesized in Okazaki fragments, 200-2k base pairs separated by 50 bp gaps |
DNA Replication |
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Ligase |
Replication enzyme that fills 50 bp gap between Okazaki fragments -> another DNA polymerase replaces RNA primer with DNA nucleotides |
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Telomeres |
Numerous at ends of eukaryotic chromosomes One lost from ends of chromosome with each replication (terminal RNA primer shops new strand from teaching last nucleotides) When last telomere is lost, more replication causes chromosome damage (aging) |
Prevents damage to coding regions |
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Centromere |
Area of a eukaryotic chromosome with repeating base
The gal sister chromatids remain connected at the centromere until disjunction in meiosis or mitosis |
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Okazaki Fragments |
Associated with lagging strand of DNA replication Much short in eukaryotes because of differences in polymerases |
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Transcription (What are its steps?) |
DNA to RNA Has 3 steps: initiation, elongation and termination |
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Translation |
RNA to amino acid sequence of proteins |
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Operon |
Adjacent genes expressed together |
Transcription |
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Initiation |
Transcription factors bind to the promoter site (TATA box) at start of gene -- both eukaryotes and prokaryotes
Eukaryotes only: RNA polymerase then binds to a protein initiation factor to be activated |
Transcription |
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Initiation |
Transcription factors bind to the promoter site (TATA box) at start of gene -- both eukaryotes and prokaryotes
Eukaryotes only: RNA polymerase then binds to a protein initiation factor to be activated |
Transcription |
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TATA Box |
The promoter site at the start of a gene that transcription factors bind to during initiation both eukaryotes and prokaryotes have this |
Transcription |
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Elongation |
Helicase unwinds gene from nucleosome (histones) and unzips -- both eukaryotes and prokaryotes In eukaryotes only, RNA polymerase disrupts hydrogen bonds between base pairs >> travels down coding strand towards 5' end >> ribonucleotides added to 3' 4!: of growing mRNA transcript complementary to DNA template |
Transcription |
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Termination |
-Eukaryotic step ONLY RNA polymerase reaches terminator A-poly sequence -Releases primary mRNA transcript |
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Symporter |
Secondary active transport that couples the energy of a molecule going down its gradient to move another against it (both in same direction) E.g., the sodium/glucose transporter which couples the transport of the two molecules to move glucose against its concentration gradient |
Nephrons take advantage of Na gradient to transport glucose
Transport across a cell membrane |
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Antiporter |
Secondary active transport where a molecule uses its gradient to move another molecule (moving in different directions)
Sodium goes down concentration gradient and glucose is going against it |
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Amphipathic |
Both hydrophobic and hydrophilic environments |
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Fenestrations |
Small windows, as seen in nephrons which allow for the easy passage of small molecules over the membrane |
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Phagocytosis |
Captures foreign pathogens and releases noxious substances inside vesicles to neutralize the invaders |
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Leak Channel |
Passive transport (requiring no energy) of certain ions, like K+, across cell membrane |
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Primary active transport |
Uses energy/ATP directly |
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Secondary active transport |
Uses gradient set up using energy |
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Intercalated disks |
Permits the passage of ions between cells, allowing an action potential to spread very rapidly to produce a coordinated contraction in muscle cells |
Cardiac muscle cells |
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Receptor tyrosine kinases |
Integral membrane proteins that relay a "message" from the extracellular side of the cell to the intercellular side of the cell. Upon activation, RTKs dime rise and phosphorylase tyrosine residues on each other's tails. |
Enzyme-linked receptors |
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Codon |
-"Words" in DNA/RNA "language" -translated into amino acids, the protein language -3 nucleotides long, there are 64 possible codons |
The genetic code |
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Start codon |
-TAC: DNA template strand -AUG: mRNA transcript |
The genetic code |
