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.
NUCLEAR FUSION, hope it helps
Well, put simply, biology is the study of life. Everything living is organic (everything living decomposes). Biologists study living things which have organic chemistry.
Answer:
The average trait value changed in one direction.(In this case, larger size)
Explanation:
In evolution a natural selection can be disruptive, directional or stabilizing
In stabilizing no extreme trait is favored hence provides intermediate values .
Disruptive selection both extreme traits are favored over the intermediate trait.
Directional, the enviroment will favor the survival of one trait hence a change in direction either towards the left or the right.
In the case of swallow cliff mortality, selection favored the larger size.
Hi!
The ancestral finch founded a new population on one of the Hawaiian Islands. Due to the founder effect , allele frequencies of the first small population on one of the islands could have differed from their continental goldfinch-like ancestors. The process of natural selection resulted in adaptation and evolution of the island population into a new species over time. Some of the birds crossed to some of the other islands where they were geographically isolated and evolved into more species occupying different niches.
In terms of population genetics, founder effect is when there is a loss of genetic diversity as a result of the establishment of a new population by a relatively few individuals. Following such an establishment, natural selection is the process which results in the genes of the fittest individuals of the population being selected over generations. This process ultimately results in evolution, and over time may give rise to new species. Geographical isolation is the physical separation of a population from another owing to geographical changes in the terrain or area. If two populations of the same species are geographically isolated, there is a great chance over time they may evolve into two different species.
Hope this helps!
