1) Why does the addition of dideoxynucleotides to the DNA sequencing reaction cause DNA synthesis to stop after the modified nucleotide is added? A)Because once a modified nucleotide is incorporated into the DNA, there is no free 5'OH group to attach the next nucleotide being added.
B)Because once a modified nucleotide is incorporated into the DNA, there is no free 3'PO4-group to attach the next nucleotide being added.
C)Because once a modified nucleotide is incorporated into the DNA, there is no free 3'OH group to attach the next nucleotide being added.
D)Because once a modified nucleotide is incorporated into the DNA, there is no free 5'PO4-group to attach the next nucleotide being added.

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.