| Transferring the coded information | - Synthesis of proteins takes place in cytoplasm
- Coded information on DNA in nucleus is transferred to cytoplasm, then translated into proteins |
| How is the information on DNA transferred to cytoplasm | - Sections of the DNA code are transcribed onto single-stranded RNA |
| Codon | - Sequence of 3 bases on mRNA that codes for a single amino acid |
| Anticodon | - Sequence of 3 nucleotides on tRNA that bond to a complementary sequence on mRNA |
| Genome | - The complete set of genes in the cell |
| Proteome | - Range of proteins produced by genome
- Proteins produced by certain cells or tissues under certain conditions |
| Different types of RNA | - Messenger RNA (mRNA)
- Transfer RNA (tRNA) |
| Function of messenger RNA (mRNA) | - Transfers DNA code from nucleus to the cytoplasm
- Small enough to leave nucleus through the nuclear pores + to enter cytoplasm |
| Detailed role of mRNA | - Small enough to leave nucleus through the nuclear pores + to enter cytoplasm
- Associates with ribosomes
- Acts as template for protein synthesis |
| Messenger RNA (mRNA) structure | - Made of 1000s of mononucleotides
- Long strand
- Single helix
- Base sequence of mRNA is determined by sequence of bases on a length of DNA in transcription |
| How mRNA suited for its function | - Possesses information in form of codons, 3 bases complementary to triplet on DNA
- Sequence of codons determines sequence of amino acid to make specific polypeptide |
| Function of transfer RNA (tRNA) | - Helps decode mRNA sequence into a protein
- Genetic code is degenerate so must be equal amount of molecules as coding triplets
- But each tRNA is specific to 1 amino acid + anticodon that is specific to that amino acid |
| Detailed role of tRNA | - Opposite end of tRNA molecule is an anticodon
- Anticodon bonds to complementary sequence on mRNA |
| Transfer RNA (tRNA) structure | - Relatively small molecule
- Made up of around 80 nucleotides
- Single-stranded chain folded into clover leaf shape
- One end extending beyond the other
- So amino acid can easily attach |
| How tRNA is suited for its function | - End chain for attaching amino acids + anticodon bonds to complementary sequence on mRNA
- So can line up amino acids on mRNA template during protein synthesis |
| mRNA (comparing structure of mRNA and the structure of tRNA) | - Single polynucleotide chain
- Larger
- Single-helix
- Ribose
- Less stable |
| tRNA (comparing the structure of mRNA and the structure of tRNA) | - Single polynucleotide chain
- Smaller
- Clover-shaped
- Ribose
- More stable |
