Answer: 43 x 10^6 CFU.
Explanation:
Plate count is a method used to determine the number of viable microorganisms in a sample. When the bacterial concentration is high, serial dilutions are carried out in a 1:10 sequence. <u>Then, the dilutions are successive dilutions keeping the dilution factor constant at each step</u>. Small aliquots of these dilutions are seeded in medium contained in a Petri dish where the bacteria grow forming colonies. Then the plates are incubated and colonies develop both within the agar and on the surface.
If the concentration of the seeded aliquot is too high, the bacteria will grow too much and it will not be possible to distinguish the colonies. <u>However, if the concentration is very low, the number of colony forming units (CFU) may be very low and thus can be counted</u>.
Colony forming units are calculated:
CFU = Number of colonies / (volume seeded on the plate * dilution).
The dilution is 10^-6, the number of colonies counted is 43, and usually the volume plated is 0.1 mL, so we replace that in the equation:
CFU= 43 / (0.1 mL * 10^-6)
CFU= 43000000 = 43 x 10^6
Most of the primary productivity in the ocean is by microscopic creatures.
The answer is 10 O2, it should de 13 O2.
To know if a reaction is well balanced between the reactants and the products, you have to calculate the number of atoms of each element on both sides of the reaction and to check if they are equal.
*For carbon, on both sides, there are 8 carbon atoms.
*For hydrogen, on both sides there are 20 hydrogen atoms.
*For oxygen, there are 20 oxygen atoms in the reagents and 26 in the products, so it is necessary to increase the number of oxygen in the reactants (without touching the others). For this we put 13 O2 in the reactants instead of 10, to have 26 oxygen atoms on each side.
