DNA -> RNA -> Protein
What are the three steps in gene expression?
Transcription, RNA processing, Translation
What protein helps switch genes ON?
Activator protein
What tissue type has tight junctions?
Epithelial tissue
What two traits define cancer cells?
Uncontrolled proliferation and the ability to invade other tissues
What’s the main role of a stem cell?
To self-renew and differentiate into specialized cell types
What does RNA polymerase do?
It synthesizes RNA by reading the DNA template strand
Name two ways eukaryotic gene expression is regulated post-transcriptionally
RNA splicing and microRNA regulation
What protein connects epithelial cells to the basal lamina?
Integrins, through hemidesmosomes.
What’s the difference between a proto-oncogene and an oncogene?
Proto-oncogenes are normal genes, oncogenes are mutated versions that promote cancer
What are induced pluripotent stem cells (iPSCs)?
Adult cells reprogrammed back into a pluripotent state
How do stop codons end translation?
They are recognized by release factors that signal the ribosome to stop translation and release the polypeptide
What is epigenetic memory in a cell?
Mechanisms like DNA methylation and histone modifications that help cells maintain identity through cell division
What are the three components of connective tissue?
Ground substance, fibers (like collagen), and cells (like fibroblasts)
What are tumor suppressor genes?
Genes that normally inhibit cell division. their loss leads to uncontrolled growth
What role do transcription regulators play in differentiation?
They control gene expression to determine a cell’s fate
What is a codon and where is it found? Provide me with the start Codon (s) and the stop Codon (s)
A codon is a three-nucleotide sequence in mRNA that codes for an amino acid. Start is AUG. Stop are UAA, UAG, UGA.
Describe how cortisol affects gene expression in liver cells
Cortisol binds receptors that act as transcription regulators, increasing transcription of specific genes
What is the extracellular matrix made of?
Polysaccharides, and proteins (like collagen and fibronectin)
what term refers to the spread of cancer cells from the original site to other parts of the body.
Metastasizes
What happens if a master transcription regulator is artificially expressed in a wrong body part?
It can trigger development of an inappropriate organ (like an eye on a fly’s leg)
Define the "reading frame" in mRNA translation
It’s the set of triplets (codons) in mRNA that determines how the sequence is read into amino acids
What is the role of enhancers and silencers in eukaryotic gene regulation?
Enhancers are DNA sequences that increase transcription when bound by activators. Silencers decrease transcription when bound by repressors. Both can act from far distances by looping the DNA.
are desmosomes and hemidesmosomes the same?explain
No because desmosomes connect cells to each other, while hemidesmosomes connect cells to the basal lamina
How do oncogenes and tumor suppressor genes work together to influence cancer development?
Oncogenes promote cell division and survival when activated, while tumor suppressor genes prevent uncontrolled growth. Mutations in both can lead to unregulated proliferation and cancer.
What is the difference between multipotent and pluripotent stem cells? Give one example of each.
Pluripotent stem cells can become almost any cell type in the body (embryonic stem cells), while multipotent stem cells can only become a limited range of cells within a certain tissue (hematopoietic stem cells in bone marrow).