<span>Cell membrane needs to allow and exit the materials that enter the cell because the cell needs nutrients and these nutrients are converted into molecules that aid in many cellular activities like repair, divide and form structures and biomolecules.
Also to excrete wastes and other harmful materials for the cell.
This continues because the cell wants to attain homeostasis.
Homeostasis is the state where the internal and external part of the body maintains and establishes balance and equilibrium. This is achieved through cellular processes in the body, the integumentary system regulates the body temperature, the hypothalamus –hunger and thirst of the individual and other interrelated organ systems that make the body healthy and in the state of equilibrium. Now, when diseases or disorders appear they disrupt the organ systems in the body thus, causing imbalance state –high fever, inability to focus and etc.<span>
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This type of asexual reproduction is called apomixis.
Apoximis is reproduction by special generative tissues without fertilization. It includes parthenogenesis in animals, in which the new individuals develop from unfertilized egg, and apogamy in certain plants in which the generative tissues may be the sporophyte or the gametophyte.
Yes, all polypeptides have tertiary structures. All proteins have primary, secondary and tertiary structures. However, quaternary structures only arise when a protein is made up of two or more polypeptide chains. Hope this answers the question. Have a nice day.
The answer is signal transduction. It is also known as cell signaling. It is the transmission of molecular signals beginning from a cell's exterior to its interior. Signals got by cells must be transferred efficiently into the cell to make certain a suitable response. This step is started by the cell-surface receptors.