Single Recognition Particle (SRP) RNA is necessary for the targeting of proteins to the prokaryotic plasma membrane or to the eukaryotic endoplasmic reticulum membrane. Its job is to bind to the signal peptide of the membrane or secretory proteins coming from the ribosome at which time it forms a ribosome-nascent chain (RNC)-SRP complex.
SRP plays an important role in understsnding bacterial physiology, emphasizing the importance of proper membrane protein biogenesis, and demonstrates the ability of time-resolved quantitative proteomic analysis to provide new biological insights.
Answer:
It occurs in organisms because an organism with a beneficial trait/mutation have a higher chnace of surviving compared to organisms that do not. So the organsims that do survive pass on their genes to the next generation, and the bext generation will pass on those genes to the generation after and so on. But all the organisms that do not possess a beneficial trait/mutations will not survive, therefore they cannot reproduce and pass on those genes to their offspring. This means that most of the population will posses that trait/mutation.
Example: Spotted moths camouflage with bark so they are seen by predators and eaten. Black moths are easily seen by predators and are eaten. Spotted moths then pass on their genes to the next generation of moths.
Answer:
The correct answer is option E. "None of A-D is false; all are true statements".
Explanation:
The standard plate count involve different considerations including the ones listed:
A. It utilizes a standard dilution procedure called serial dilution. Most of the time culture plates have thousands of cells growing in it, it is necessary to use a standard dilution in order to make the counting feasible.
B. It measures both live and dead cells in the liquid sample. The standard plate count procedure uses a dye such as crystal violet to differentiate among live and dead cells. Both should be counted and the percentage of viability should be reported as well.
C. A countable plate in the procedure is one having 30 to 300 CFUs on it. Between 30 to 300 CFU is considered a countable plate since less than 30 will be make errors in dilution to be considerable and more than 300 is difficult to count and tend to form cell aggregates.
D. It is a viable count method to quantitate cell density of a liquid sample. This is true as long as the cells in the liquid sample are able to growth in a standard plate as well, since the cells must adhere to the counting device in order to perform the procedure.
