Answer:
Sometimes molecules cannot move through the cell membrane on their own. These molecules need special transport proteins to help them move across the membrane. Facilitated diffusion is the diffusion of substances with the help of transport proteins in the plasma membrane. These special proteins are called channel proteins or carrier proteins, and they are attached to the cell membrane. In fact, they go through the cell membrane, from the inside of the cell to the outside. Facilitated diffusion is used for molecules that cannot diffuse rapidly through cell membranes on their own, even when the molecules are moving from high to low concentration areas. An example is the sugar plants and animals use for energy, called glucose. Even though facilitated diffusion involves transport proteins, it is still passive transport because the solute is moving down the concentration gradient so it does not require the use of cellular energy.
Answer:
After 48 hours amount left = 6.25 g
Explanation:
Given data:
Half life of potassium = 12 hours
Total mass = 100 g
Mass left after 48 hours = ?
Solution:
Number of half lives passed:
Number of half lives = Time elapsed / half life
Number of half lives = 48 hours/ 12 hours
Number of half lives = 4
At time zero = 100 g
At first half life = 100 g/ 2 = 50 g
At 2nd half life = 50 g/2 = 25 g
At 3rd half life = 25 g/2 = 12.5g
At 4th half life = 12.5 g/2 = 6.25 g
Adenosine triphosphate (ATP)
Our muscles are attached to our skeleton to help us move. If we had no skeleton then our muscles would hang limply, making it harder for us to move.
