Genes and Protein Synthesis (A-level Biology)
Genes and Protein Synthesis
DNA and Genes
Recap
- A chromosome consists of lots of DNA molecules.
- A DNA molecule has lots of genes.
- A gene has lots of base pairs.
Coding and Non-Coding DNA
Some parts of DNA codes for proteins, whilst others don’t:
- Coding sequences: regions of the DNA which encode for a particular protein or functional RNAs, such as ribosomal RNA (rRNA) and transfer RNA (tRNA).
- Non-coding sequences: regions of the DNA which do not encode for anything. These regions usually are regulatory regions of DNA, protective regions of DNA (e.g., telomeres), or simply junk DNA.
Genes
A gene is a specific sequence of DNA bases which codes for a particular protein or functional RNA. Genes are made of coding DNA sequences.
- Each gene has a unique base sequence of DNA. Remember that DNA is made up of four nucleotides, each with a unique base that is either adenine, thymine, guanine, or cytosine. The order of these bases is unique to each gene.
- Each gene codes for a unique protein or functional RNA. Different genes have different DNA base sequences, which means that they code for different things. Most genes code for proteins, but a few code for functional RNA.
Forming Genes and Proteins
The Genome and The Proteome
The genome of a cell is the complete set of genes in the cell.
The proteome of a cell is the full range of proteins that the cell can produce.
The genes the cell has determines the proteins it can make, so the genome and proteome are closely linked.
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