Structure of RNA Flashcards
Why is RNA needed in our body?
DNA is found in the nucleus but the synthesis of proteins takes place in the cytoplasm so RNA comes in, where it translates parts of the DNA sequence and transfer it into the cytoplasm.
What does mRNA do?
It transfers the DNA code from the nucleus to the cytoplasm, acts as a type of messenger.
Why is mRNA used to transfer the DNA code?
mRNA is small enough to leave the nucleus through the nuclear pores and enters the cytoplasm.
What is a codon and what’s the difference between a codon and triplet?
Codon refers to the sequence of 3 bases on mRNA that codes for a single amino acid.
Condon is used in terms of mRNA bases and triplets refers to normal DNA bases.
What is a genome?
Complete set of genes in a cell, including those in the mitochondria or chloroplast.
What is proteome?
The full set of proteins produced by the genome.
This is sometimes be called the complete proteome, in this case, the proteome refers to the proteins produced by a given type of cell under a certain condition.
What is RNA?
RNA is a polymer made up of repeating mononucleotide sub-units.
What is the structure of an RNA?
- Pentose sugar ribose.
- Organic bases - Adenine, Guanine, Cytosine or Uracil.
- A phosphate group.
What are the 2 types of RNA that are important for protein synthesis?
- mRNA
- tRNA
What is mRNA?
- Consists of thousands of mononucleotides.
- Long strand that is arranged in a single helix.
- The base sequence of mRNA is determined by the sequence of bases on the section of DNA in a process called transcription.
What happens when mRNA has formed from the DNA sequence?
Once formed, mRNA leaves the nucleus by pores on the nuclear envelope and enters the cytoplasm where it associates with the ribosomes.
It acts as a template for protein synthesis.
Its structure is suited for its function as it contains the information in the form of codons. The sequence of codons determines the amino acid sequence for a specific polypeptide.
What is tRNA?
- It’s fairly small and made up of about 80 nucleotides.
- It single-stranded chain folded into a clover-leaf shape, with one end extending beyond the other.
- The extension part allows an amino acid to be easily attached.
- There are many types of tRNA, each binds to a specific amino acid.
- At the opposite end, there is a sequence of 3 other organic bases - anticodon and the anticodon is also specific to an amino acid.
- As the genetic code is degenerate, there must be as many tRNA molecules as coding triplets.
What are the base pairings in RNA?
- Guanine with cytosine.
- Adenine with uracil - which replaces thymine.
What’s does the tRNA do during protein synthesis?
An anticodon pairs with the 3 complementary organic bases which make up the codon on mRNA. tRNA with end chain for amino acid attachment and anticodon is suitable for its role of lining up amino acids on the mRNA template during protein synthesis.
