8.3.1 Transcription Factors

• What are transcription factors?

  Proteins regulating gene expression
• What effect do repressor transcription factors have on transcription rate?

  Decrease the rate
• The activation or repression domain of a transcription factor determines whether it activates or represses gene expression.
• Transcription factors bind to either promoter or enhancer sequences using their DNA-binding domain
• Match the structural component of a transcription factor with its function:

  DNA-binding domain ↔️ Attaches to specific DNA sequences

  Activation or repression domain ↔️ Determines whether to activate or repress

  Ligand-binding domain ↔️ Interacts with specific molecules
• Transcription factors can respond to environmental cues to regulate gene expression.

  True
• Transcription factors influence gene expression by acting as either activators or repressors
• Repressors reduce transcription by blocking the binding of RNA polymerase.


  True
• Activator transcription factors bind to enhancer sequences
• Transcription factors consist of several key structural components
• Where do transcription factors bind to regulate gene expression?

  Promoter or enhancer sequences
• Which structural feature is found in leucine zipper transcription factors?

  Leucine zipper dimerization domain
• What does the lac activator bind to in the lac operon?

  Enhancer
• What type of DNA sequence do activator transcription factors bind to?

  Enhancer sequences
• What is the primary function of the DNA-binding domain in a transcription factor?

  Attaches to specific DNA sequences
• The complex structure of transcription factors enables them to precisely regulate gene expression.


  True
• Activator transcription factors enhance transcription by recruiting RNA polymerase.


  True
• Which type of transcription factor binding directly regulates the transcription rate?

  Promoter sequence binding
• What type of transcription factor binds hormones and translocates to the nucleus?

  Steroid hormone receptors
• What do repressor transcription factors bind to in order to decrease transcription?

  Promoter sequences
• How do activators increase transcription?

  Recruit RNA polymerase
• What is the primary function of transcription factors?

  Control gene expression
• Transcription factors regulate both transcription and translation.

  True
• Match the structural component of transcription factors with its function:

  DNA-binding domain ↔️ Attaches to DNA sequences

  Ligand-binding domain ↔️ Interacts with specific molecules
• Match the type of transcription factor with its structural feature:

  Zinc-finger transcription factors ↔️ Zinc-finger motifs

  Steroid hormone receptors ↔️ Ligand-binding domain
• The lac repressor in E. coli binds to the lac operon promoter
• Transcription factors regulate gene expression by binding to DNA
• The Lac repressor in E. coli is an example of a repressor transcription factor.

  True
• What structural domain allows transcription factors to form dimers?

  Dimerization domain
• Where are promoter sequences typically located in relation to genes?

  Near the start of genes
• What enables transcription factors to precisely regulate gene expression based on cellular needs?

  Their complex structure
• Zinc-finger transcription factors contain motifs that bind to DNA
• Steps in the mechanism of activator transcription factors

  1️⃣ Bind to enhancer sequences

  2️⃣ Recruit RNA polymerase

  3️⃣ Increase transcription rate
• Transcription factors play crucial roles in gene expression by controlling the transcription of specific genes
• Match the role of transcription factors with their function:

  Activator ↔️ Enhances transcription

  Repressor ↔️ Reduces transcription
• Where do repressor transcription factors bind on DNA?

  Promoter sequences
• What is the function of the DNA-binding domain in transcription factors?

  Attaches to DNA sequences
• Promoter sequences are located near the start of genes
• Transcription factors act as either activators or repressors in gene expression.


  True
• The p53 transcription factor is a tumor suppressor in humans.


  True