1.3 RNA and Transcription Flashcards
Structure of RNA
- single stranded molecule
* composed of RNA nucleotides
Where RNA molecules are found
- nucleus
* cytoplasm
Composition of RNA nucleotide
- phosphate
- ribose sugar
- RNA bases
The four RNA bases
Adenine, Uracil, Cytosine and Guanine
RNA Base pairings
Adenine and Uracil
Cytosine and Guanine
The bonds that exist between the RNA bases
Weak hydrogen bonds
The bonds that exist between the ribose sugar and the phosphate group
Strong sugar phosphate bonds
Three different types of RNA and their functions
- mRNA- messenger RNA, carries the genetic code from the DNA in the nucleus to the ribosome
- rRNA- ribosomal RNA, along with proteins forms the ribosome
- tRNA- transfer RNA carries a specific amino acid to a ribosome
What the instructions for protein synthesis are coded in
The order of bases on DNA
The building blocks of proteins
Amino acids
The number of different amino acids that exist naturally within cells
Twenty
A sequence of three bases on the DNA
Triplet
Another term for triplet code
Sequence of bases coding for proteins
Requirements for transcription
- DNA to act as a template for the new RNA molecule
- RNA polymerase
- ATP for energy
- Free RNA nucleotides (Adenine, Uracil, Cytosine and Guanine)
Where transcription takes place
The nucleus
Complementary pairings between the DNA and mRNA molecule
A - U
T - A
C - G
G - C
Describe transcription
mRNA carrying a code for a protein from DNA in the nucleus to the ribosome
Group of three bases on the mRNA strand
Codon
What the primary mRNA strand contains
Introns and exons
Definition of intron
Non coding region of the gene
Definition of exon
Coding region of the gene
Definition of splicing
The introns in the primary transcript are removed during transcription
What forms the mature mRNA transcript
The exons not removed by splicing
Where splicing takes place
The nucleus
What each triplet on the mRNA strand codes for
One specific amino acid
The two processes resulting in different proteins being expressed from one gene
- Alternative RNA splicing
* Post translation modification
Definition of alternative RNA splicing
Different RNA molecules being produced during RNA splicing as sometimes exons are removed along with the introns next to them
