Cancer & Genes
Cancer cells differ from normal cells because they bypass these regulatory mechanisms.
What are cell cycle checkpoints?
This phase of the cell cycle includes G1, S, and G2 and occupies about 90% of a cell’s life.
What is interphase?
These proteins fluctuate in concentration and regulate the timing of the cell cycle.
What are cyclins?
These nitrogenous bases are classified as pyrimidines.
What are thymine and cytosine?
This enzyme unwinds the DNA double helix during replication.
What is helicase?
A mutated proto-oncogene that is constantly active is called this type of gene.
What is an oncogene?
During this phase, DNA is replicated so that each daughter cell receives an identical copy.
What is S phase?
These enzymes require binding to cyclins to become active and when disrupted cells can progress unchecked through the cell cycle and contribute to tumorigenesis.
What are cyclin dependent kinases?
These three molecules combine to form a nucleotide.
What are phosphate, deoxyribose and a nitrogenous base?
DNA polymerase cannot initiate synthesis on its own, what is put in place to begin nucleotide addition.
What is RNA primer?
Explain why tumor suppressor genes are considered recessive at the cellular level.
What is both alleles must be mutated for the gene to lose function?
Explain one reason why cells may enter G₀ instead of continuing through the cell cycle.
What is cells are performing their normal functions and are not actively preparing to divide?
How does density-dependent inhibition helps maintain homeostasis in tissues.
What is density-dependent inhibition prevents cells from dividing when they are crowded, helping maintain proper tissue size and organization?
Describe the role of phosphodiester bonds in maintaining DNA structure.
What is phosphodiester bonds form the sugar-phosphate backbone, providing structural stability to the DNA molecule?
DNA polymerase synthesizes the new DNA strand in this direction by adding nucleotides during replication.
What is the 5′ → 3′ direction?
These extracellular signaling molecules bind to receptor tyrosine kinases and when their signaling is overactive there can be tumor formation.
What are growth factors (or aberrant growth factor signaling)?
Explain why spindle fiber attachment is essential for passing the M checkpoint.
What is to ensure chromosomes are aligned correctly so each daughter cell receives an identical set of chromosomes?
This checkpoint determines whether a cell has adequate nutrients, appropriate size, and intact DNA before committing to DNA replication.
What is the G1 checkpoint?
These nitrogenous bases have a double-ring structure and include adenine and guanine.
What are purines?
These short, discontinuously synthesized stretches of DNA are created on the lagging strand during replication and later joined by DNA ligase.
What are Okazaki fragments?
This molecule is the guardian of the genome and prevents cells with damaged DNA from dividing.
What is p53?
Predict the result if proteins holding sister chromatids together are not inactivated during anaphase.
What is sister chromatids would not separate, leading to daughter cells with abnormal chromosome numbers.
Failure at this checkpoint would most directly result in apoptosis if DNA damage from S phase is detected.
What is the G2 checkpoint?
This term describes the orientation of DNA strands running in opposite 5′ to 3′ directions, which is essential for complementary base pairing and replication.
What is antiparallel?
This model of DNA replication produces daughter molecules each containing one original (parental) strand and one newly synthesized strand.
What is semi‑conservative replication?