8.3 Structures of ribonucleic acid Flashcards
What is a codon
The sequence of three bases on mRNA that codes for a single amino acid
What is the genome
The complete set of genes in a cell, including those in mitochondria and chloroplasts
What is the proteome
The full range of proteins produced by the genome
Describe the structure of RNA
A polymer made up of repeating mononucleotide sub-units. It forms a single strand in which each nucleotide is made up of
- The pentose sugar ribose
- One of the organic bases Adenine, Uracil, Cytosine, Guanine
- A phosphate group
What are the two types of RNA that are important in protein synthesis
- mRNA
2. tRNA
Describe mRNA
- Single polynucleotide chain
- Smaller than DNA, larger than tRNA
- Single helix molecule
- Pentose sugar = Ribose
- A,U,C,G
- Manufactured in nucleus, found throughout cell
- Quantity varies from cell to cell with level of metabolic activity
- Less stable than DNA and mRNA. Easily broken down
Describe tRNA
- Single polynucleotide chain
- Smaller than mRNA and DNA
- Clover shaped molecule
- Pentose = Ribose
- A,U,C,G
- Manufactured in nucleus, found throughout cell
- Quantity varies from cell to cell with level of metabolic activity
- More stable than mRNA less stable than DNA
What does mRNA do once formed
Leaves the nucleus via nuclear pores in the nuclear envelop and enters the cytoplasm, where it associates with ribosomes. There it acts as a template for protein synthesis.
Why is mRNA’s structure suited to its function
Because it possesses information in the form of codons. This sequence of codons determines the amino acid sequence of a specific polypeptide
What does tRNA have
An anticodon that is specific to an amino acid
