Answer: Some sticklebacks were stranded in lakes that were formed in the ice age
Answer:
C
Explanation:
abnormalities associated with developmental and reproductive systems
Answer:
<u>Passive transport</u>: It does not need any energy to occur. Happens in favor of an electrochemical gradient. Simple diffusion and facilitated diffusion are kinds of passive transport.
<u>Simple diffusion</u>: molecules freely moves through the membrane.
<u>Facilitated diffusion</u>: molecules are carried through the membrane by channel proteins or carrier proteins.
<u>Active transport</u> needs energy, which can be taken from the ATP molecule (<u>Primary active transport</u>) or from a membrane electrical potential (<u>Secondary active transport</u>).
Explanation:
- <u>Diffusion</u>: This is a pathway for some <em>small polar hydrophilic molecules</em> that can<em> freely move through the membrane</em>. Membrane´s permeability <em>depends</em> on the <em>size of the molecule</em>, the bigger the molecule is, the less capacity to cross the membrane it has. Diffusion is a very slow process and to be efficient requires short distances and <em>pronounced concentration gradients</em>. An example of diffusion is <em>osmosis</em> where water is the transported molecule.
- <u>Facilitated diffusion</u>: Refers to the transport of <em>hydrophilic molecules</em> that <em>are not able to freely cross the membrane</em>. <em>Channel protein</em> and many <em>carrier proteins</em> are in charge of this <em>passive transport</em>. If uncharged molecules need to be carried this process depends on <em>concentration gradients</em> and molecules are transported from a higher concentration side to a lower concentration side. If ions need to be transported this process depends on an <em>electrochemical gradient</em>. The <em>glucose</em> is an example of a hydrophilic protein that gets into the cell by facilitated diffusion.
<em>Simple diffusion</em> and <em>facilitated diffusion</em> are <u>passive transport</u> processes because the cell <u><em>does not need any energy</em></u> to make it happen.
- <u>Active transport</u> occurs <em>against the electrochemical gradient</em>, so <u><em>it does need energy to happen</em></u>. Molecules go from a high concentration side to a lower concentration side. This process is always in charge of <em>carrier proteins</em>. In <u>primary active transport</u> the <em>energy</em> needed <em>comes from</em> the <em>ATP</em> molecule. An example of primary active transport is the <em>Na-K bomb</em>. In <u>secondary active transport</u>, the<em> energy comes from</em> the <em>membrane electric potential</em>. Examples of secondary active transport are the carriage of <em>Na, K, Mg metallic ions</em>.
The exons of the pre -mRNA contain the protein -coding regions.
Pre mRNA is the first made mRNA transcript and requires undergo many post transcriptional modifications for the formation of a mature mRNA.
The exons are the regions of the pre-mRNA that are found in the mature RNA, after the splicing of introns takes place.
RNA splicing is the process in which the non-coding segments of the RNA, which are known as introns, are removed by the help of small nuclear ribonucleoproteins. These SnRNPs make the spliceosome, which catalyzes the process of splicing.
After the introns are removed by the splicing process, the exons are covalently joined, which forms the mature mRNA.
Learn more about mRNA from here:
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Answer:
the answer is 40c because i just took the test
Explanation:
