Absolute Drop Dead Last Chance Due Date for Late Lab Reports
Wednesday 12/17/08 6 pm
Professor Phillis's door
Log in as cureresp
password is blue2white
Post the URL of your maggot anatomy link here
This week I am asking you to come to lab in the morning to start your swarm plate experiments. It should take only a few minutes (see Lab 4 Handout Wk 2), but getting it going early is necessary to guarantee that the cells will be swarming by the afternoon.
I have loaded the protocol for this week's lab at the course website.
Two studies done by scientists at Schepens Eye Research Institute have established that stem cells, or undifferentiated cells, exist in every part of the brain, and not just the brainâ€™s regenerative tissue, and that they lie dormant. As in other parts of the body, stem cells need specific chemical messages to begin dividing and changing into their more specialized counterparts. In the brain, these stem cells are found to be â€œsleeping,â€ or dormant, in the presence of two chemical signals, ephrin-A2 and ephrin-A3.
Protein kinases are responsible for most of the cell singaling processes that occur within the cells of the human body. Within kinases are subsets, PKC-alpha, PKC-beta, and PKC-gamma. Kinases induce transduction by phosphorylating target proteins called substrates. Phosphorylation is the covalent bonding of a phosphate to one of the three amino acids with a free hydroxyl group, threonine, serine, and tyrosine. These phosphates are taken from ATP (adenosine triphosphate) by the kinase.
Kinases use a process called phosphorylation in order to target and activate other kinases eventually causing something to happen within a cell. Phosphorylation requires a phosphate group to be added to the kinase; this phosphate group is readily taken from an ATP molecule, which is created through processes such as cellular respiration.
Most phosphates are located throughout the body by way of ATP (adenosine triphosphate). ATP is avaliable in every cell and contains three phosphate groups. A kinase will take one phosphate group from ATP, making the previous ATP into ADP (adenosine diphosphate). It will take this phosphate and phosphorylate (or add a phosphate) to its target. The added phosphate will change the structure and therefore the function of the target.
The available phosphate groups in a cell are collectively called the â€œhigh-energy phosphate pool.â€ The phosphates are carried on weak, high-energy bonds by a few kinds of molecules: phosphagens in muscle cells, ATP and ADP, and other (?) nucleoside di- and triphosphates. ATP is generated in cellular respiration and glycolysis through â€œoxidative phosphorylation.â€ Phosphagens are molecules such as creatine and arginine that are phosphorylated by ATP, and then stored that way in muscle cells to allow for bursts of activity.