BRAINCAKETranscription Factors
Every cell in an organism contains the same genes, but only some of them are expressed. One way eukaryotic cells control which genes are transcribed is by using transcription factors.
A transcription factor is a protein that binds to a specific DNA base sequence and controls the transcription of a gene. Each transcription factor has a DNA-binding site with a shape that is complementary to a particular base sequence, usually in the promoter region just upstream of the target gene.
In eukaryotes, transcription of target genes can be stimulated or inhibited when specific transcription factors move from the cytoplasm into the nucleus. Transcription factors are made by ribosomes in the cytoplasm and enter the nucleus through nuclear pores to reach the DNA.
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Key terms in this lesson
- hormone
- A chemical messenger, secreted by an endocrine gland directly into the blood, that travels to target cells bearing complementary receptors and brings about a response.
More in Control of Gene Expression
- Pluripotent, Multipotent and Unipotent Stem Cells
- Stem Cells in Mature Plants
- Induced Pluripotent Stem Cells
- Stem Cells in Treating Disease
- Oestrogen and the Initiation of Transcription
- RNA Interference (siRNA and miRNA)
- Epigenetics
- DNA Methylation
All 18 lessons in Control of Gene Expression · All AQA A-level Biology topics