Heart rate is controlled by the two branches of the autonomic (involuntary) nervous system. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate. The parasympathetic nervous system (PNS) releases the hormone acetylcholine to slow the heart rate. Such factors as stress, caffeine, and excitement may temporarily accelerate your heart rate, while meditating or taking slow, deep breaths may help to slow your heart rate.
The statement 'interactions of the hydrophobic and hydrophilic amino acids help to anchor the protein in the membrane' explains why protein folding is critical. This process is fundamental for the function of transmembrane proteins.
Protein folding refers to the process by which a polypeptide (i.e., a protein) adopts its final tridimensional 3D shape (conformation).
In a protein, some amino acids contain hydrophilic R groups, whereas other amino acids contain hydrophobic R groups.
During protein folding, hydrophobic amino acids are arranged so they can interact with the long chains of the fatty acids in the internal region of the lipid bilayer, whereas hydrophilic amino acids are arranged so they interact with water on the surface of the cell membrane.
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The answer is Living things have all evolved from a common ancestor.
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Answer:
a. The operon is under positive control
a.) Loss of enzyme synthesis results from loss of regulatory R gene product which is regulated in the presence of Tis ophane for transcription. Absence of (Tis), transcription is positively controlled by regulatory Rprotein
b.) The proposed model reveals Tis / B complex prevents Tis enzymes from undergoing transcription through the RB operator by binding to the B region
the role of the R protein is
-decrease affinity of Tis / B complex to B region of RB
-bind to the R region on RB
- change the conformation of B region
- yield decreased affinity of Tis / B complex when R gene is lacking preventing transcription in the process
Effects of the RB mutations is that R protein will not bind to Tis / B complex to reduce transcription
