BRAINCAKENon-coding DNA
The human genome consists of 20-25,000 genes, making up about 25 of the human DNA. Large non-coding regions of DNA called introns are spliced from pre-mRNA in the nucleus before it leaves through the nuclear pores. The exons that are spliced together are then translated in the cytoplasm. Other non-coding regions of DNA are telomeres at the ends and centromeres with which chromosomes attach to the spindle during nuclear division.
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Key terms in this lesson
- intron
- A non-coding section of a gene or pre-mRNA molecule that is removed by splicing before translation.
- exon
- A coding section of a gene or pre-mRNA molecule that remains after splicing and is translated into protein.
More in Genetic Engineering and Biotechnology
- Gel Electrophoresis
- DNA Profiling
- The Polymerase Chain Reaction
- DNA Sequencing
- Automated Sequencing
- Pathogens, DNA Barcoding
- Genomics and Proteomics
- Recombinant DNA
All 17 lessons in Genetic Engineering and Biotechnology · All AQA A-level Biology topics