A. It makes the ecosystem more diverse
The cell membrane is also called selectively permeable membrane for the sole reason being it is selective in nature.
It forms a physical barrier and as a barrier between the cell and the external environment as it allows only selected necessary molecules to pass through it and at the same time prevents entry of unwanted / unnecessary substances.
It also regulates the entry and exit of molecules into and out of the cell.
The cell membrane permits the entry of vital molecules like
<span>water, oxygen, amino acids and glucose into the cell as they are crucial for various life processes and at the same time metabolic waste products are expelled through the cell membrane.</span>
The placenta is the interface between the maternal and embryo's blood, and allows for the exchange of nutrients, including oxygen and carbon dioxide exchange, but prevents certain drugs and chemicals from reaching the embryo. Its a bit like a security guard that only lets certain things though to the baby.
Answer:
- Only some molecules move from a higher concentration to a lower concentration.
Explanation:
Selective permeability of the membrane means that membrane regulates which molecules (ions, substances) and how much of them can pass through it. Permeabilty of the membrane is determinated by its structure (hydrophobic heads and hydrophilic tails, cholesterol), temperature
The simplest form of transport through membrane is diffusion, passive transport of the molecule down its concentration gradient 9from higher to lower concentration). Some molecules can move down their concentration gradients directly, some have to pass through membrane proteins in a process called facilitated diffusion while others require energy and use active transport.
You can also find photosynthesis, the carbon cycle, the water cycle and others
