The flat Earth<span> model is an archaic conception of the Earth's shape as a plane or disk. </span>
Two examples of a base other than those could be, borax, and lye.
when an animal is thirsty, it responds by drinking water
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.
Answer:
1. The 2 bases forming each rung of the 'ladder' snap apart. This is caused by an enzyme that passes along the strands, 'unzipping' it
2. Spare nucleotides (in the nucleus of the cell) attach themselves to the 'broken rungs' to repair the break. Each repairing nucleotide is identical to the broken one
3. As each 'broken rung' is repaired, two 'ladders' form, that is 2 identical strands of DNA. The 'repairing' is really the process of replica
Explanation:
Hope this helps!
