DNA 1.4- Gene expression Flashcards
What causes Gene regulation?
DNA methylation and Histone modification. Both cause changes in the coiling of DNA around histones
What factors control the phenotypic expression of genes?
Factors controlling transcription and translation, including transcription factors and the environment.
Define transcription factors and describe their function.
Transcription factors activate the transcription of specific genes by binding to the gene’s promoter sequence. Activator proteins increase the rate of transcription, while repressor proteins inhibit it.
What is a gene? Provide an example of its function.
A gene is a section of DNA containing information for a specific function, such as coding for a protein.
Define gene expression and explain its significance
Gene expression refers to the process where different combinations of genes are expressed and repressed.
How is cellular differentiation associated with tissue growth and development controlled?
Cellular differentiation associated with tissue growth and development is controlled by gene expression, where specific genes are activated or repressed to guide the specialization of cells.
Describe the process of cellular differentiation and provide examples.
Cellular differentiation occurs as genes are switched on and off due to processes such as methylation. Examples include the differentiation of stem cells into nerve cells and muscle cells.
How does DNA methylation alter gene expression?
DNA methylation is when methyl groups are added to the DNA molecule. This can alter the attachment of proteins to the DNA. Methylation changes the activity of a DNA segment without changing the sequence. DNA methylation typically acts to repress gene transcription.
How does the coiling of DNA around histone proteins effect gene expression?
A tighter wrap of the DNA around a histone protein will restrict the ability for gene expression. A loosely wrapped section of DNA will be more likely to be expressed.
What is phenotypic expression
Phenotypic expression relates to physical, biochemical, and physiological characteristics.
do epigenetic changes change DNA sequence?
No, but they do affect gene expression. It determines if genes are “on or off”
How do epigenetic modifications in genes control cell division, such as changes in DNA methylation lead to cancer?
Epigenetic modifications in genes that control cell division can cause cells to divide uncontrollably, leading to cancer.
Summarise the difference between an unmethylated and methylated gene.
Gene is switched on if unmethylated, and DNA is loosely packed around histones. This means the gene is active and expressed. Gene is off when methylated and DNA is tightly packed. Gene is silent and not expressed.
