Answer:
Explanation:
Similar to a guard at the outside of a club, deciding who should be allowed in and who to keep out, the cell membrane is semi-permeable, regulating the movement of substances in and out of the cell with the help of protein channels.
The cell membrane is a double layer of lipids (fats) and proteins that surround a cell and separates the cytoplasm/ organelles from its surrounding environment.
A deficiency in the diet of the element Iodine [I] can lead to goiter. This is why in the U.S. we placed more of it in all table salt ("iodized salt").
In active transport particles move by making use of energy in the form of ATP.
<u>Explanation:</u>
Unlike in passive transport particles have to move against the concentration gradient in active transport. Thus particles require energy to do so and this energy is in the form of ATP. Osmosis and simple diffusion are examples of passive transport where substances move from a region of high concentration to a region of low concentration.
This movement is down the concentration gradient. In active transport particles move from a region of low concentration to a region of high concentration which is against the concentration gradient. Active transport is of two types.
In the first type called primary active transport energy is directly used in the form of ATP. In the second type called secondary active transport an electrochemical gradient created by ATP is used to facilitate the transport.
They use different genetic codes
1). secondary; physical and thermal and radiological
2). primary; chemical radiological
3). secondary; physical and biological
