BIOL 1000 Lecture Notes - Lecture 13: Ribosomal Rna, Peptide, Transfer Rna
7/2/18
BIOL 1000- LECTURE 11- GENETICS
1.1 THE GENETIC CODE DICTATES HOW CODONS ARE TRANSLATED INTO AMINO
ACIDS:
•The genetic code is the set of rules that dictates the amino acid translations of each of the
mRNA nucleotide triplets.
•Nearly all organisms use an identical genetic code to convert the mRNA codons transcribed
from a gene to the amino acid sequence of a polypeptide.
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7/2/18
•In the nucleus, the DNA helix unzips (unwinds) and RNA nucleotides line up and RNA poly-
merase joins them along one strand of the DNA as it follows the following rules:
I. A specific nucleotide sequence called a promoter acts as a binding site for RNA polymerase
and determines where transcription starts.
II. RNA polymerase adds RNA nucleotides until it reached a sequence of DNA bases called the
terminator, which signals the end of the gene.
1.2 EUKARYOTIC RNA IS PROCESSED BEFORE LEAVING THE NUCLEUS AS mRNA:
•The kind of RNA that encodes amino acid sequences is called messenger RNA (mRNA) be-
cause it conveys genetic messages from DNA to the translation machinery of the cell.
•Translation takes place in the cytoplasm as follows:
I. A ribosome attached to the mRNA and translates its message into a specific polypeptide, aid-
ed by transfer RNA (tRNA).
III. Each tRNA is a folded molecule bearing a base triplet called an anticodon on one end and a
specific amino acid attachment site at the other end.
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7/2/18
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Document Summary
1. 1 the genetic code dictates how codons are translated into amino. 7/2/18: a specific nucleotide sequence called a promoter acts as a binding site for rna polymerase and determines where transcription starts. Rna polymerase adds rna nucleotides until it reached a sequence of dna bases called the terminator, which signals the end of the gene. Each trna is a folded molecule bearing a base triplet called an anticodon on one end and a specific amino acid attachment site at the other end. 7/2/18: translation can be divided into the same three phases as transcription which are. 7/2/18: the overall process by which genetic information flows from genes to proteins, from genotype to phenotype is gene expression, gene regulation the turning on and off of genes can help organisms respond to environmental. 7/2/18 a string of bead like nucleosomes: dna packing tends to block gene expression by preventing access of transcription proteins to.