Tutor profile: Soshawn B.
When building spaceships, NASA must consider what will happen to gases as they expand, in order to determine what pressure the various parts of the shuttle must be able to withstand. You have been hired as a consultant for NASA. How do you go about helping them determine how much pressure the fuel apparatus will need to withstand?
If we consider only gases being produced by fuel burn off and treat these gases as ideal gases then the behavior of the gas can be modeled using the ideal gas law PV = nRT where n is the amount of gas expected and R is the ideal gas constant. P is the pressure of the gas. The volume, V, of the gas tank and space ship components remains constant throughout the mission but the temperature, T, fluctuates. If we know approximately the temperature on the International Space Station and the temperature when entering and leaving earth's atmosphere and the fluctuations in between then we can estimate how much pressure will be exerted by our gases at different points on out mission, and then definitely build and test our spaceship to be able to withstand pressure in excess of these values! Safety first!
What is the function of superoxide dismutase in the cell?
Superoxide dismutase is an antioxidant! Aerobic cells release reactive oxygen species such as superoxide, hydrogen peroxide and oxygen as a natural part of cellular processes. It's totally normal, but accumulation of too many reactive oxygen species causes damage to DNA, proteins and other components of the cell, just because these cellular byproducts can be so reactive. The job of antioxidants such as superoxide dismutase is to keep these reactive species in check by either reacting with them to create something harmless, such as water, or to grab them up and take them away (scavenging). Superoxide dismutase removes superoxide from cells, like a clean up crew.
Explain the difference between mitosis and meiosis.
In both processes, a cell splits to form two new cells but the processes are differentiated fundamentally by the new cells that they create. Mitosis creates two identical cells that have the same composition as the parent cell, while meiosis creates two daughter cells that contain half the chromosomes of the parent cell. One good way to remember the difference is by remembering that miTosis creates Twins. The original cell and the new cell are literally TWINS, mi-T-osis!
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