Nucleic Acids

What are the components of an RNA nucleotide

• Ribose pentose sugar

• Phosphate group

• Nitrogen containing base

What is the function of RNA?

• Copy and transfer the genetic code from DNA in the nucleus to the ribosomes

• Some DNA is also combined with proteins to create ribosomes

What are the 3 types of RNA

• mRNA (messenger RNA)

• tRNA (transfer RNA)

• rRNA (ribosomal RNA)

What is the role of mRNA?

• Created in the nucleus and then leaves to carry a copy of the genetic code of one gene to a ribosome in the cytoplasm

• Copy of a gene from DNA

Why is mRNA needed?

• DNA is too large to leave the nucleus

• mRNA is much shorter so it can leave the nucleus

• DNA would be at risk of being damaged by enzymes and being destroyed permanently if it left the nucleus

• mRNA is short lived so by the time enzymes break it down, it will have carried out its function

What is a codon?

A sequence of 3 bases which codes for a specific amino acid

What is the role of tRNA?

1. Attaches to one of the 20 amino acids which is specific to its amino acid attachment site

2. Has 3 bases (anticodon) which are complementary to 3 bases (codon) on mRNA

3. Transfers the amino acid to the ribosomes to create a polypeptide chain

What is the role of rRNA?

Combines with proteins to make ribosomes

What are the two key differences between DNA and RNA monomers?

• DNA contains thymine, whereas RNA contains uracil instead

• DNA contains pentose sugar Deoxyribose, whereas RNA contains pentose sugar Ribose.

What are the two key differences between DNA and RNA polymers?

• DNA is much larger

  • DNA contains approximately 23000 genes (the entire genome)

  • RNA is much shorter, having the length of one gene

• DNA is double stranded, whereas RNA is single stranded