<span>The first enzyme is reverse transcriptase. The concept of
reverse transcription was much unknown at first. A reverse transcriptase is an enzyme used to
generate complementary DNA (cDNA) from an RNA template, a process termed
reverse transcription. It is mainly associated with retroviruses. As it
contradicted the central dogma of molecular biology, which states that DNA is
convert into RNA, which is then translated into proteins.</span>
Answer:
E. All of the above
Explanation:
In cardiac contractile cells there is rapid depolarization, then a plateau phase and repolarization.
when an action potential stimulates the cell, voltage-gated channels open quickly commencing the positive-feedback mechanism of depolarization. This in turn raises the membrane potential to approximately +30 mV, and this closes the sodium channels. Next comes the plateau phase, where membrane potential declines relatively slowly due to the opening of the slow Ca2+ channels, allowing Ca2+ to enter the cell while few K+ channels are open, leading to K+ to exit. Once the membrane potential reaches approximately zero, the Ca2+ channels close and K+ channels open, allowing the exit of K+. The repolarization lasts approximately for a while and here is when the membrane potential drops until it reaches resting levels once more and repeats the cycle.
Answer:
hello Prokaryotes are unicellular organisms that lack organelles or other internal membrane-bound structures. Therefore, they do not have a nucleus, but, instead, generally have a single chromosome: a piece of circular, double-stranded DNA located in an area of the cell called the nucleoid.
The concentration of water differ by placing the cell in hypotonic, hypertonic or isotonic solution.
Hypertonic solution:
If a cell is placed in a hypertonic soluton, water will leave the cell, and the cell will shrink.
Isotonic solution:
The relative concentration of solute and water are equal on both sides of membrane.
Hypotonic solution:
If cell is placed in a hypotonic solution, water will enter the cell and cell would swell.
Answer:
Chlorhexidine
Explanation:
Chlorhexidine is a guanide compound containing the two chlorine molecules attached to the two phenolic rings (two 4-chlorophenyl rings) and two biguanide group.
The chlorhexidine is used as an antiseptic (antibacterial) as the positive charge of molecule interacts with the negatively charged batteries membrane and disrupts the structure of bacteria.
This molecule then enters the cell and cause intracellular leakage and leads to the death of the cell.
Thus, Chlorhexidine is the correct answer.
