Is carbon forms convalent bonds with other carbon atoms
<span>~Hello there!
Your question: Sam came home from school with a cold caused by a virus and his sister, Ana, caught it from him. Sam got well and went back to school. A few days before Ana got well, Sam came down with a cold again. Their mother said that Ana had given the cold back to Sam. How likely is it that their mother is correct, and what does it mean for Ana's chances of
getting sick again?
Your answer: Acquired immunity, he must have picked picked up a different disease virus so Ana can get sick again.
The answer is option A.
Hope this helps~
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Answer:
A. Many environments are not suitable for fossil formation.
Answer:
D) presence of transcription activators or repressors
Explanation:
The reason why this is not post-transcriptional regulation is that activators actually start the process of transcription by binding to specific sites. while on contrary when repressor binds it halt the process.
For example, there is a protein called CAP which in the presence of cAMP bind with promoter region and enhances the activity of RNA polymerase . While in the absence of cAMP it can not bind to promoter hence the transcription stooped.
Answer:
Ion channels are specialized proteins in the plasma membrane that provide a passageway through which charged ions can cross the plasma membrane down their electrochemical gradient.
Explanation:
Ion channels are molecular machines that serve as principal integrating and regulatory devices for controlling cellular excitability. Different types of ion channels have been described: channels that respond to mechanical, electrical (voltage-dependent ion channels), or chemical stimuli (ligand-gated ion channels); ion channels that are controlled by phosphorylation/dephosphorylation mechanisms; and ion channels that are dependent on G proteins. Most ion channels are of the voltage-dependent type and consist mainly of sodium (Na+), potassium (K+), and calcium (Ca2+) channels. Drugs can affect ion channel function directly by binding to the channel protein and altering its function or indirectly through G proteins and other intermediates. Lidocaine is a good example of a drug that directly affects voltage-gated Na+ channels by blocking the channel and thus Na+ entry into the cell.
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