Gene Regulation and Expression

Front

Gene Expression Noun

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[jeen ik-spresh-un]

Back

Gene Expression

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The process by which information from a gene is used to synthesize a functional product, such as a protein.

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Example: This diagram shows how information in a gene (DNA) is used to create a protein through the processes of transcription and translation.

Front

Operon Noun

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[op-er-on]

Back

Operon

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A cluster of genes found in prokaryotes that are regulated together and transcribed as a single messenger RNA molecule.

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Example: An operon is a group of genes on a bacterial chromosome that are controlled together, transcribed into a single mRNA, and then translated into multiple proteins.

Front

Promoter Noun

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[pruh-moh-ter]

Back

Promoter

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A specific DNA sequence where RNA polymerase binds to initiate the process of transcription for a particular gene.

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Example: This diagram shows a promoter as a specific starting region (red) on a DNA strand where the enzyme RNA polymerase attaches to begin making an RNA copy.

Front

Operator Noun

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[op-er-ay-ter]

Back

Operator

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A short DNA region where a repressor protein can bind, preventing the transcription of genes within an operon.

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Example: This cartoon shows a repressor protein sitting on the operator section of DNA, acting as a roadblock to stop gene expression.

Front

Repressor Noun

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[ri-pres-er]

Back

Repressor

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A DNA-binding protein that inhibits gene expression by binding to an operator and blocking RNA polymerase from transcribing genes.

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Example: This diagram shows a repressor protein binding to DNA, which acts like a roadblock to stop the RNA polymerase from making a gene's message.

Front

TATA box Noun

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[tah-tah boks]

Back

TATA box

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A DNA sequence in the promoter region of eukaryotic genes that helps position RNA polymerase for transcription initiation.

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Example: This diagram shows that the TATA box is a specific DNA sequence in the nucleus that acts as a signal, telling the enzyme RNA polymerase where to begin transcribing a gene.

Front

Transcription Factor Noun

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[tran-skrip-shun fak-ter]

Back

Transcription Factor

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A protein that binds to specific DNA sequences, thereby controlling the rate of transcription from DNA to messenger RNA.

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Example: A transcription factor, like an activator protein, binds to a specific site on DNA, helping to turn a gene 'on' by starting the transcription process.

Front

Enhancer Noun

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[en-han-ser]

Back

Enhancer

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A short region of DNA that can be bound by proteins to increase the likelihood of a particular gene's transcription.

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Example: This diagram shows how a distant DNA section called an enhancer loops over to bind with proteins, helping to activate a specific gene.

Front

Differentiation Noun

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[dif-er-en-shee-ay-shun]

Back

Differentiation

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The process where a less specialized cell becomes a more specialized cell type to form various tissues and organs.

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Example: This diagram shows how general-purpose stem cells undergo differentiation to become many different types of specialized cells, like nerve, muscle, or blood cells.

Front

Homeotic Gene Noun

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[hoh-mee-ot-ik jeen]

Back

Homeotic Gene

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A master control gene that regulates the development and identity of anatomical structures in specific parts of an organism.

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Example: This diagram shows that homeotic (Hox) genes are arranged on a chromosome in the same order as the body parts they control in a fly.