Tutor profile: Michelle C.

Why do so many people call the mitochondria the "power-house" of the cell?

Ah very good! The mitochondria is often referred to as the "power-house' of the cell because it is where ATP is synthesized. ATP stands for adenosine triphosphate and is an essential fuel for all functioning. Because the mitochondria creates ATP an important fuel (power) for the cell, many people refer to the mitochondria as the "power-house" of the cell.

How do I distinguish the humerus from the femur? Can you compare and contrast them?

Great question! They do look quite similar. There are a few key way to distinguish between the two. The femur is the largest bone in the body, has a larger head with a neck whereas the humerus has a smaller head and no neck. The femur has a "linea aspera" which in latin means "hard line" and it is a pronounced ridge on the bone and the vastus rectus muscle attached to it. The humerus has a similar protrusion that is called the deltoid process. This process is smaller than the linea aspera, and is where the deltoid attaches to the humerus

Why are their two houses in congress?

The congress of the United States of America was developed to best represent the people of the union. The House of Representatives is composed of a representatives from each state and the number from each state is determined by the population of the state. The senate is composed of two senators from each state. The different set-up of the two houses ensures proportional and at the same time equal representation of each state.