Tutor profile: Eric M.
Subject: Natural Sciences
Describe what a wetland is, and what ecosystem services it provides.
A wetland is any area that is either permanently or seasonally saturated to the point where it becomes it's own unique ecosystem. They have been compared to sponges and kidneys. Like a sponge, a wetland slows down and soaks up water during periods of heavy rain, helping to reduce flooding and making a marshy area. This helps mediate the impact of droughts in the surrounding ecosystem. They have been compared to kidneys because the plants in the wetland filter out the water much like kidneys filter urine. Excess fertilizer runoff such as N,P,K, etc. will be utilized by the wetland plants and will not contribute to harmful algae blooms in the downstream body of water. Additionally, wetlands provide habitat for many different species of animals and plants, both aquatic as well as terrestrial. Their slow moving water and many hiding spots make wetlands an ideal nursery.
Subject: Environmental Science
Explain why energy on a home's electricity bill will have the units of kW/h and not just kW.
Kilowatts is a unit of energy that indicates how much energy you are using, but it does not tell you how long you're using it for. For an electric bill to make sense, you need to know how long you've been using a particular amount of energy. Compare a fire hose to a garden hose. A fire hose is capable of putting out much more water at any given time (kW), but if it's only turned on for a second, it will discharge much less water than a garden hose that has been trickling open for 3 days. In this case, the fire hose has a greater kW output, but a smaller amount of time. The garden hose has a very low kW output, but it was turned on for a very long time. Therefore, you need to know the amount of energy and the length of time that energy was used to understand your electricity bill.
Explain the role of adenosine di-phosphate (ADP) and adenosine tri-phosphate (ATP). What is their relationship during the energy cycle of a cell?
ATP is the energy currency of the cell. Bigger molecules such as glucose must first be broken down into ATP molecules that can then be used by the cell. It is similar to breaking down a $100 bill into 100 singles. Their relationship is that ADP is the "low energy" form of ATP. ADP has 2 phosphates attached to the adenosine, and ATP has 3. This extra phosphate allows more energy to be stored. When the cell needs energy, a phosphate bond is broken, releasing energy. The molecule of ATP is now a molecule of ADP. Another phosphate is attached by the cell which converts it back into a high energy ATP molecule. It's like a phone. It's fully charged after being plugged in all night (ATP). The phone is on during the day, using battery (cells breaking phosphate bonds to release energy). At the end of the day, the phone's battery is dead. (ADP). However, you can plug the phone into the wall (respiration) and "recharge" the battery (converting ADP into ATP)
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