Bio Test 4 Flashcards
Nucleotide added to a growing DNA strand
Nucleoside Triphosphate
What catalyzes elongation?
DNA Polymerases
What is the rate of elongation (bacteria)?
500 nucleotides/s
What is the rate of elongation (humans)?
50 nucleotides/s
How long is one DNA strand?
3 billion base pairs
dNTP
Deoxiribonucleoside triphosphate
What prevents DNA from reannealing/stabilizes DNA?
Single Strand Binding Proteins (SSBs)
Enzyme that removes primers and replaces it with the corresponding nucleotides
DNA Polymerase 1
Enzyme that connects the DNA fragments
DNA Ligase
Strand that goes away from fork
Lagging
Strand that goes toward the fork
Leading
- “Nicks” (makes a small cut out of) 1 strand of DNA and repairs it; corrects “overwinding”
- Breaks, swivels, and rejoins DNA strands
DNA Topoisomerase
In which direction does a DNA strand elongate?
5’ to 3’
To cut out and replace damaged stretches of DNA
Nucleotide Excision Repair (NER)
Two thymines have an extra bond
Thymine Dimer
Repairing incorrect, deleted, or misincorporated bases that occur during replication process, removes a chunk and starts over
Mismatch Repair
What is the name for mRNA before being processed? (Eukaryote)
Pre-mRNA, Primary Transcript
What is the name for mRNA after being processed? (Eukaryote)
Mature RNA
Processing DNA (connect exons, get rid of introns)
Splicing
Ribosyme
RNA molecules that are enzymes
Spliceosome
Protein and catalytic RNA complex that catalyzes the splicing process
Promoter
DNA sequence that RNA Polymerase attaches to
Terminator
Sequence that signals end of transcription
What part of the DNA is transcribed in RNA transcription?
Transcription Unit
Poly-A tail
200 adenines at 3’ end found in eukaryotic mRNA
Affinity Chromotography
Chromotography for extracting mRNA (column full of T extracts the mRNA which has the poly-A tail)
Initiation
- Small unit attaches to promoter
- tRNA attaches to codon
- Large subunit attaches
Elongation
- Codon recognition (w/ anticodons on tRNA)
- Peptide bond formation (between amino acids that the tRNAs carry, forms a chain)
- Translocation (tRNA naked detaches)
Anticodon
Part of tRNA that has the complimentary RNA sequence to the DNA strand sequence
Release factor
Binds to stop codon, ribosomal subunits separate and end translation (termination)
Polyribosome
Multiple ribosomes reading and translating to make lots of proteins
Proprotein
Protein that must be cut to become functional
Prokaryote transcription & translation are…
At the same time and in the same place
Reading frame
Reads one codon at a time
Silent Mutation
No change to protein (the nucleotide sequences result in the same amino acid)
Missense Mutation
Wrong amino acid due to different nucleotide sequence (codon)
Nonsense Mutation
Leads to an early stop codon
Read Through
A mutation on a stop codon, which changes the codon and prevents the translation from ending (reads through the poly-A tail)
Frameshift Mutation
Insertion or deletion of a nucleotide
Point Mutation
Mutation at a single nucleotide
Fillial
Generations after parent:
P → F1 → F2
Genes expressed 24/7 are called…
Constitutive/Housekeeping Genes
Genes expressed only in the presence of a stimulus
Induced Genes
Genes that are turned off in the presence of a stimulus
Repressible Genes
Protease
Protein hydrolysis enzyme
Operon
Coordinated unit of gene expression
Regulatory Gene
Produces repressors that can interact with the operator
Promoter
Where RNA polymerase bonds to
Operator
on/off switch
Structural Gene
Genes that are translated
Inactive Repression
Repressor cannot bind to operator
