Cell surface or membrane is made of phospholipid bilayer with embedded proteins and sugars. Cell membrane acts as a barrier between cell and its external environment but it is also responsible for the communication with other cells and transport of molecules inside and outside the cell. It is selectively permeable to ions and molecules (some of them pass through the membrane easily, while others require transport proteins or channels). There are 4 ways of molecule transport:
1. Diffusion – no energy required
2. Facilitated transport – transport proteins included
3. Active and co-transport – energy required
4. Vesicle transport (exocytosis and endocytosis)
Microvilli are extensions of cell membrane that increase its surface for diffusion.
Different types of cell junctions have a different influence on the membrane transport. For example, tight junctions are a barrier and the molecules are unable to pass through.
Answer:
D
Explanation:
The digestive system foes all those functions
I wrote a paragraph summing the importance of Carbon a while back, see if it helps find your answer. :)
Carbon is an element on the periodic table with the symbol C, and the atomic number 6. There are many reasons that carbon is vital to life on earth, not only to humans but to plants as well. First of all, humans are made of eighteen percent carbon. It is not only found in humans, it is also found in every organism currently known, including plants in a technological way. To plants, carbon flows inside of their cells. They need it to create glucose which then works as food. To humans, it's used in many science sets. It is used in a vast array of compounds including gasoline. Gasoline is what keeps motors around the world running, and it's made up of hydrocarbons with at least 5 carbon atoms each. It also aids the greenhouse effect, keeping the earth warm and habitable by human beings.
Answer:
If oxygen supply is depleted the muscle cells will respire anaerobically and release lactic acid and energy.
The accumulation of lactic acid , results in a pain in the muscles of the athlete.
Explanation:
If you compare them, Denver has a much colder climate.
