BioL107
Terms
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- transformation
- kill the pathogenic bacteria with heat and then mix the cell remains with lving bacteria of the nanpathogenic strain, some of the lving cells become pathogenic.
- bacteriophages/phages
- bacteria-eaters, viruses that infect bacteria.
- DNA Polymerases
- Elongation of new DNA at a replication fork is catalyzed by enzymes.
- mismatch repair
- cells use special enzymes to fix incorrectly paired nucleotides.
- nucleotide excision repair
- the enzymes involved in filling the gap are a DNA plymerase and ligase. DAN repair of this type is called nucleotide excision repair.
- transcription
- the synthesis of RNA under the direction of DNA.
- translation
- the actual synthesis of a polypeptide, which occurs under the direction of mRNA. the cell must translate the base sequence of an mRNA molecule into the amino acid sequence of a polypeptide.
- mRNA
- protein-coding genes, it carries a genetic message from the DNA to the protein-synthesizing machinery of the cell.
- template strand
- during transcription, the gene determineds the sequence of bases along the length of an mRNA molecule. for each gene, only one of the two DNA strands is transcribed.
- the triplet code
- for each gene, one DNA strand functions as a template for transcription. the base-pairing rules for DNA synthesis also guide transcription, but U takes the place of T in RNA. during the transcription, the mRNA is read as a sequence of base triplets, called codons. each codon specifies an amino acid to be added to the growing polypeptide chain. the mRNA is read in the 5'-> 3' direction.
- transcription-initiation
- after RNA polymerase binds to the promoter, the DNA strands unwind, and the polymerase initiates RNA synthesis at the start point on the template strand.
- transcription-Elongation
- the polymerase moves downstream, unwinding the DNA and elongating the RNA transcript 5'->3'. in the wake of transcription, the DNA strands reform a double helix.
- transcription-termination
- eventually, the RNA transcript is released, and the polymerase detaches from the DNA.
- replication fork
- a replication fork is a Y-shaped region where the new strands of DNS are elongating.
- Helicase
- unwinds parental double helix at replication forks
- single-strand binding protein
- binds to and stablizes single-stranded DNA until it can be used as a template
- topoisomerase
- corrects 'overwinding' ahead of replication forks by breaking, swiveling, and rejoning DNA strands.