Answer:
The correct answer is 3: "<em>High levels of Ca2+ are expected to be found </em><em>within the sarcoplasmic reticulum</em>".
Explanation:
Muscular contraction is a highly regulated process that depends on free calcium concentration in the cytoplasm. Amounts of cytoplasmic calcium are regulated by <u>sarcoplasmic reticulum</u> that functions as a storage of the ion.
When a nerve impulse reaches the membrane of a muscle fiber, through acetylcholine release, the membrane depolarizes producing the entrance of calcium from <u>extracellular space</u>. The impulse is transmitted along the membrane to the sarcoplasmic reticulum, from where calcium is released. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. The calcium channel in the sarcoplasmic reticulum controls the ion release, that activates and regulates muscle contraction, by increasing its cytoplasmic levels. When <em>calcium binds to the troponin C</em>, <em>the troponin T alters the tropomyosin by moving it and then unblocks the binding sites,</em> making possible the formation of <em>cross-bridges between actin and myosin filaments.</em> When myosin binds to the uncovered actin-binding sites, ATP is transformed into ADP and inorganic phosphate.
Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
Answer:
Promoter Strength
Explanation:
More than increasing mRNA stability, the promoter strength can be tuned to increase the gene expression by producing more quantities of the mRNA. The strength is based on efficient promoter recognition and rapid binding of the DNA polymerase.
hope it helps : )
I would say B so yea...hope ur day doing well
It must come into contact with a ribosome.
About the question:
You will find the chart in the attached files
Answer:
The strat codon is AUG
Explanation:
Genetic information for the aminoacids assembly during the protein synthesis is stored in short sequences of three nucleotides named <em>codons </em>in the mRNA. Each of the codons represents one of the 20 amino acids used to build the protein. The total number of possible codons is 64, from which 61 codify amino acids -more than one codon codify for the same amino acid-. One of these amino acids is also the start point of protein synthesis. And the left three codons are stopping translation points.
The codons indicating the initiation or stop points during the translation process are:
- The start codon AUG is the most common sequence used by eukaryotic cells and places near the 5´extreme of the molecule. However, other codons might be used as well. Prokaryote cells might use the codons GUG or UUG.
- The end codons are UAA, UAG, UGA.