Flashcards in DNA, RNA, and Protein Conventions Deck (14):
Equivalent and Antiparallel
- Equivalent - no logical way to distinguish the two strands based on physical properties
- Antiparallel - the strands have an antiparallel arrangement
- 5' - 3' - strand on top
- 3' - 5'
Both Strands Can Contain Genes
- both strands can contain "genes" and be transcribed but in different directions.
- The top strand is the coding strand for gene 1. The bottom strand is the coding strand for gene 2.
- Often, when genome sequences are concerned, the sequence of only one strand is given.
The Two-Strand Convention
- The coding strand 5'-3' on the top
- the template strand 3'-5' on the bottom.
- has the same "sense" (direction and sequence) as the mRNA that it codes for.
- exception of U in RNA and deoxyT in DNA
- it is called the sense strand or the gene.
- the strand that basepairs with the incoming nucleotides that are connected by phosphodiester linkage to form RNA in the process of transcription.
- it is complementary to the mRNA
- It is also code the non-coding strand, or the anti-sense strand or non-sense strand.
- template is read 3'-5'.
- mRNA is synthesized 5'-3'.
- Therefore has the same "sense" as the gene or coding strand.
- mRNA read 5'-3'
- protein synthesized N-terminal - C-terminal
- using these conventions, gene, mRNA, and protein all have the same "sense"
Go from coding strand to mRNA
- without flipping
- just switch T's to U's
nucleic acids versus proteins
- nucleic acids have 5' to 3' ends
- proteins have amino and carboxy termini
The way usually seen
5' gene or coding strand 3'
3' template strand 5'
5' mRNA 3'
+H3N Protein COO-
- sequence of the cDNA same as gene.
- ALWAYS TALKS ABOUT SEQUENCE OF SECOND STRAND
- most time cDNA made double stranded so we can easily clone and sequence them
- reverse transcriptase requires polyDT as a primer
- RNA sensitive to high pH so remove and degrade with NaOH
- remove loop with single-stranded nucleotides