Transcription+Translation Flashcards
transposons
can be copied and inserted elsewhere in the genome
this is why they account for a large percentage of the repeated DNA sequences
lateral gene transfer
genetic information is transferred from one species to another
very common in prokaryotes
Sources of new genes
gene duplication
Gene duplication causes
often caused by mistakes in crossing over repeated elements
What does gene duplication result in?
gene ‘families’
Gene family
genes with similar sequences and often similar functions
Example of a gene family
hemoglobin groups
have different genes for oxygen carrying during different points in development
B-globin
How do transposons work?
- RNA polymerase makes mRNA of whole transposon
- LINE mRNA leaves the nucleus to be translated
- mRNA returns to nucleus
- Reverse transcriptase converts mRNA to LINE cDNA
- Integrase cuts the chromosomal DNA and inserts the LINE cDNA
What does integrase do?
cuts the chromosomal DNA in order for the LINE cDNA to be inserted
Where does LINE DNA originate from?
part of the chromosomal DNA sequence
Initiation of transcription in prokaryotes
sigma proteins bind to RNA polymerase and promoter sequences on DNA to bring them together
Promoter
sequence of genes
How do prokaryotes control gene transcription?
there are different sigma proteins that express different genes depending on what is needed
Elongation of transcription in prokaryotes
RNA polymerase moves in 5’ to 3’ direction to synthesize mRNA
What is the advantage of using RNA polymerase?
there is no need for a primer