Transcription Regulation
What do we call transcription factors that upregulate (or activate) transcription of a gene? What do we call transcription factors that downregulate a gene?
Activators and repressors
What is the term for tightly packed DNA that is typically inaccessible to RNA polymerase?
Heterochromatin
What are the three types of cytoskeletal filaments/elements in order of most stable to least stable?
Intermediate Filaments, Actin Filaments, Microtubules
What are the 4 main types of cell signaling?
Endocrine, paracrine, neuronal, and contact dependent.
What DNA sequences do activators bind to?
Enhancers
What type of post-translational protein modification to histones silences genes?
Histone deacetylation
Which cytoskeletal element is most abundant in the cell cortex?
Actin Filaments
Between protein, peptide, fatty acid, and amino acid, which type of signaling molecule will most readily diffuse through the cell membrane?
Fatty acid
What DNA sequences do repressors bind to?
Silencers
What type of chemical modification to DNA can be used to silence genes by recruiting histones? What about activating them?
DNA methylation & DNA demethylation
What are the 4 types of intermediate filaments? What kind of animal cells are each found in?
The four types of intermediate filaments are:
1. Keratin Filaments: Found in epithelial cells.
2. Vimentin Filaments: Present in connective tissue cells, muscle cells, and glial cells.
3. Neurofilaments: Found in nerve cells (neurons).
4. Nuclear Lamins: Located in the nucleus of animal cells.
What is the difference between indirect and direct signal transduction?
In direct signal transduction, receptors can translocate to the nucleus, requiring few secondary messengers, while indirect signal transduction involves multiple secondary messengers, making it a slower process.
Prokaryotes tend to have clusters of genes that are related in function and regulated by a single operator, what do we call these clusters?
Operons
When an embryo first develops, each cell has the potential to turn into any type of cell in the body. We call these totipotent stem cells.
Various potential stem cell types.
What is the difference between desmosomes and hemidesmosomes?
Desmosomes form links between epithelial cells, holding them tightly together, while hemidesmosomes form links between epithelial cells and the basal membrane, anchoring cells to the basement membrane.
Which type of signal transduction is used by the Notch receptor?
Direct.
What is miRNA and its function in gene regulation? Is its activity exerted before transcription or after transcription?
miRNA = micro RNA; micro RNA silences genes by targeting mRNA transcripts for destruction or simply block ribosomes from attaching. This means their activity is exerted after transcription but before translation.
Researchers are able to create pluripotent stem cells from differentiated cells or multipotent stem cells. They do this by adding transcription factors that help maintain pluripotency, including Oct4, Sox2, KLF4, and L-Myc (seen below). Keeping gene regulation in mind, can you come up with some possible mechanisms for how these 4 transcription factors might regulate gene transcription in a way that helps maintain pluripotency?
Oct4, Sox2, KLF4, and L-Myc are transcription factors that regulate gene expression to maintain pluripotency in stem cells. They do this by activating genes associated with pluripotency and silencing genes associated with differentiation. Each factor binds to specific DNA sequences and collaborates with other regulatory proteins to control the expression of target genes.
What filament type is associated with amyotrophic lateral sclerosis?
Neurofilament
What kind of cell signaling occurs between the neurons?
Neuronal