Answer:
Cellular membranes or plasma membranes has many functions. Some of these include regulation of cellular transport, and responding to cellular signals or hormones.
<h2>Cellular Transport</h2>
The plasma membrane is made up of the <u>phospholipid bilayer with embedded transmembrane proteins</u>. This makes the cell membrane <u>semi-permeable</u>. Movements of substances depend on the composition of the molecules e.g. glucose and amino acids, as needed by the pancreatic cells. These are larger and uncharged molecules and can't pass freely through the membrane so they utilize the transmembrane proteins via attaching to carrier proteins. This is called <em>passive transport</em>. On the other hand, in <em>active transport</em>, <u>ATP is used</u> to transfer molecules, like Hydrogen, from a low to high electrochemical gradient.
Other kinds of cellular transport are:
- Osmosis and diffusion
- Endocytosis
- Exocytosis
<h2>Cellular Signalling</h2>
The cell membrane is able to signal other neighboring cells by utilizing complex proteins. These proteins may take form as receptors or markers.
<h3>Membrane Receptors</h3>
They act as receivers of extracellular signals and spark intracellular processes. These receive signals from hormones, growth factors, etc.
<h3>
Membrane Markers </h3>
These allow the cells to identify each other and respond if this cell is needs further development as in organ development, or a foreign body to the system.
Kinases. Kinases add phosphate to molecules, and the modification can serve as a "switch" to turn events in the cell on or off. CDKs or cyclin dependent kinases regulate the cell cycle.
Answer:
Classification is a systematic ordering of the object of research, in this case, ecosystems at the earth's surface or, in other words: landscape units as 'holons'. As for general principles of classification, we can learn a lot from the best-known classification, the taxonomical classification of species.
Explanation:
