Tau is a microtubule-associated protein that plays a key role in the development of certain brain disorders. to analyze tau expression, mouse brain extracts are made at different developmental stages, separated on an sds-page gel, and analyzed by western blot with antibodies recognizing only mouse tau protein. if the results at the right represent tau’s normal expression pattern, the two different size protein products could result from:
1. transcription of tau dna in different directions.
2. translation of tau mrnas of different sizes.
3. expression of two different genes.
4. different chemical modifications of tau protein.

The dna in a cell’s nucleus encodes proteins that are eventually targeted to every membrane and compartment in the cell, as well as proteins that are targeted for secretion from the cell. for example, consider these two proteins: phosphofructokinase (pfk) is an enzyme that functions in the cytoplasm during glycolysis. insulin, a protein that regulates blood sugar levels, is secreted from specialized pancreatic cells. assume that you can track the cellular locations of these two proteins from the time that translation is complete until the proteins reach their final destinations.for each protein, identify its targeting pathway: the sequence of cellular locations in which the protein is found from when translation is complete until it reaches its final (functional) destination. (note that if an organelle is listed in a pathway, the location implied is inside the organelle, not in the membrane that surrounds the organelle.)

What are some natural processes that represent physical and chemical changes?

Plz quick a natural resource that is replaceable through a cycle in nature or sustainable practice is called a? the subject is science