Eukaryotic Gene Regulation Flashcards

Flashcards about Eukaryotic Gene Regulation

What is one of the big questions regarding the control of the eukaryotic genome?

How are genes turned on and off in eukaryotes?

What is another one of the big questions regarding the control of the eukaryotic genome?

How do cells with the same genes differentiate to perform completely different, specialized functions?

What is the final big question regarding the control of the eukaryotic genome?

How have new genes evolved?

What are the characteristics of a prokaryote genome?

Small size of genome, circular molecule of naked DNA, most of DNA codes for protein or RNA, small amount of non-coding DNA

What are the characteristics of a eukaryote genome?

Much greater size of genome, DNA packaged in chromatin fibers, cell specialization, most of DNA does not code for protein or RNA

What are the points of control in gene expression from gene to functional protein?

Unpacking DNA, transcription, mRNA processing, mRNA degradation, translation, protein processing, protein degradation

What is specialization in gene expression?

Each cell of a multicellular eukaryote expresses only a small fraction of its genes.

In terms of gene expression, what is development?

Some gene expression must be controlled on a long-term basis for cellular differentiation & specialization during development.

How do cells respond to the organism's needs in terms of gene expression?

Cells of multicellular organisms must continually turn certain genes on & off in response to signals from their external & internal environment.

What are nucleosomes ('beads on a string') in DNA packing?

Histone proteins have high proportion of positively charged amino acids (arginine & lysine); bind tightly to negatively charged DNA

What is DNA methylation?

attachment of methyl groups (–CH3) to DNA bases (cytosine) after DNA is synthesized

What is histone acetylation?

Attachment of acetyl groups (–COCH3) to certain amino acids of histone proteins.

What is heterochromatin?

Highly compact, not transcribed, found in regions of few genes

What is euchromatin?

Loosely packed in loops of 30nm fibers, transcribed, found in regions of many genes

What are enhancer DNA sequences?

Distant control sequences

What are activator proteins?

Bind to enhancer sequence & stimulates gene transcription.

What are silencer proteins?

Bind to enhancer sequence & block gene transcription.

What happens in alternative RNA splicing?

Variable processing of exons creates a family of proteins

What is the regulation of mRNA degradation?

Life span of mRNA determines pattern of protein synthesis.

What is protein processing?

Folding, cleaving, adding sugar groups, targeting for transport

What is protein degradation?

Ubiquitin tagging & proteosome degradation

What are proto-oncogenes?

Normal cellular genes code for proteins that stimulate normal cell growth & division.

What are oncogenes?

Mutations that alter proto-oncogenes cause them to become cancer-causing genes.

What is the role of the p53 gene ('Guardian of the Genome')?

After DNA damage is detected, p53 initiates: DNA repair, growth arrest, and apoptosis

What defect in the X chromosome causes Fragile X syndrome?

Mutation of FMR1 gene causing many repeats of CGG triplet in promoter region

What is Huntington's Disease?

Rare autosomal dominant degenerative neurological disease with the mutation on chromosome 4 with CAG repeats

What is the significance of Alu elements within interspersed repetitive DNA?

Alu is an example of a "jumping gene" – a transposon DNA sequence that "reproduces" by copying itself & inserting into new chromosome locations.

What are retrotransposons?

Transposable elements that move within a genome by means of RNA intermediate, transcript of the retrotransposon DNA.