Category 1: DNA → RNA → Protein
What are the three steps in gene expression?
Transcription, RNA processing, Translation
What protein helps switch genes ON?
Activator proteins.
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
What’s an operon?
A cluster of bacterial genes transcribed as a single mRNA, controlled by a shared promoter and operator.
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 drive cancer.
What are induced pluripotent stem cells (iPSCs)?
Adult cells reprogrammed back into a pluripotent state.
What is a codon and where is it found?
A codon is a three-nucleotide sequence in mRNA that codes for an amino acid.
Name two ways eukaryotic gene expression is regulated post-transcriptionally.
RNA splicing and microRNA regulation.
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.
Define "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 epigenetic memory in a cell?
Mechanisms like DNA methylation and histone modifications that help cells maintain identity through cell division.
What is the extracellular matrix made of?
Polysaccharides (GAGs) and proteins (like collagen and fibronectin).
What does it mean when a cancer cell "metastasizes"?
It spreads from the original site to other parts of the body
Give an example of combinatorial control in gene regulation.
Using multiple transcription factors together to activate a gene only in specific conditions.
How do stop codons terminate translation?
They are recognized by release factors that signal the ribosome to stop translation and release the polypeptide.
Describe how cortisol affects gene expression in liver cells.
Cortisol binds receptors, which act as transcription regulators to increase the transcription of specific genes.
How do desmosomes and hemidesmosomes differ?
Desmosomes connect cells to each other; hemidesmosomes connect cells to the basal lamina.
Name one key pathway disrupted in most human cancers
The p53 pathway (others could include apoptosis, DNA repair, or growth signaling pathways).
What happens if a master transcription regulator is artificially expressed in a wrong body part?
It can trigger development of an inappropriate organ (e.g., an eye on a fly’s leg).