BIOL 201 Lecture Notes - Lecture 24: Sarcoma, Shmoo, Grb2
Document Summary
Cellular responses can be either short term or long term. Long term: time frames are less critical & decision is all or nothing; decisions need to be made correctly but there"s more time to make those decisions. Amplification of the signal is a result of multi-step activations. One molecule activates multiple other molecules, and so on. This serves a different role for long term signals compared to short term signals. Long-term signals lead to changes in gene expression. Cell surface receptors respond to certain signals/ligands which triggers activation/phosphorylation of dna in the nucleus through a series of protein activation and this triggers transcription/expression of certain genes. Growth factor discovery from extract of a chunk from the chicken embryonic nerve tissue & put into a dish which would then sprout branches. Placed a piece of a mouse tumour into the dish with the embryonic tissue. Wanted to know if the factor was a nucleic acid or a protein.