Structures of RNA Flashcards
How is the coded information on the DNA in the nucleus transferred into the cytoplasm where it is translated into proteins?
Sections of DNA are transcribed onto a single-stranded molecule called ribonucleic acid.
What is the role of mRNA?
Transfers the DNA code from the nucleus to the cytoplasm.
How is mRNA suited to its function?
mRNA is small enough to leave the nucleus through nuclear pores and to enter the cytoplasm, where the coded information that it contains is used to determine the sequence of amino acids in the proteins that are synthesised there.
What is a codon?
Refers to the sequence of three bases on mRNA that codes for a single amino acid.
What is a Genome?
The complete set of genes in a cell, including those in mitochondria and/or chloroplasts.
What are the components of a nucleotide of RNA?
- Pentose sugar ribose
- Organic base (A, G, C, U)
- Phosphate group
What are the two types of RNA that are important in protein synthesis?
- messenger RNA (mRNA)
- transfer RNA (tRNA)
What is mRNA?
A long strand arranged in a single helix. The base sequence of mRNA is determined by the sequences of bases on a length of DNA in a process called transcription. mRNA leaves the nucleus via pores in the nuclear envelope and associates with ribosomes and acts as a template for protein synthesis.
How is mRNA’s structure suited to its function?
Possesses information in the form of codons which determine the amino acid sequence of the specific polypeptide that will be made.
What is tRNA?
Relatively small molecule made up of around 80 nucleotides. Single-stranded, folded up into a clover-leaf shape. One end of chain extends beyond the other, this is where the amino acid can easily attach on the tRNA molecule. There are many types of tRNA, each of which binding to a specific amino acid. At the opposite end of the molecule is a sequence of three organic bases, known as the anticodon. There are as many tRNA molecules as there are coding triplets.
What is the difference in the organic bases in RNA to DNA?
Thymine is always replaced by Uracil.
What do the anticodons do during protein synthesis?
An anticodon pairs with the three complimentary organic bases that make up a codon on mRNA. The tRNA structure is structurally suited to its role of lining up amino acids on the mRNA template during protein synthesis.
