The question is incomplete. The complete question is:
Question: Why do organisms without oxygen need to convert pyruvate to lactate?
A) because pyruvate is toxic to the cells
B) in order to regenerate NAD+
C) in order to use lactate in the citric acid cycle
D) because lactate is needed to produce ATP
Answer:
B) in order to regenerate NAD+
Explanation:
Kreb's cycle and electron transport chain (ETC) are the aerobic stages of cellular respiration. ETC regenerates NAD+ and FAD+ by oxidation of NADH and FADH2 produced during glycolysis and Kreb's cycle. Here, oxygen serves as the terminal electron acceptor.
Glycolytic reactions use NAD+ as an electron acceptor and produce NADH. Therefore, a constant supply of NAD+ is required to sustain glycolysis. In absence of oxygen, ETC cannot occur and organisms convert pyruvate into lactate. Pyruvate is reduced in lactate and NADH serves as the electron donor. Thereby, lactate fermentation regenerates NAD+ to continue the process of glycolysis.
Answer:
The correct answer will be option-A
Explanation:
The practice of marriage is practised in every culture which is associated with the union of the boy and a girl to which they are committed to spending a life-long relationship.
The studies on the preferences shown by the woman who has to get married have to look for the boys who are career-oriented which could provide a good earning to feed them and their family and fond of children to establish a family which will help develop the stronger relationship between them.
The girls ignored the attractiveness feature of their spouses as in a long term relationship attractiveness does not matter because of the feeling of love and strong bond between them.
Thus, option-A is the correct answer.
The right answer is E. Sodium (with 140mmol/L)
Sodium is the most important element in the blood and extracellular liquids of the body.The needs of an adult subject are of the order of 1 to 2 g of sodium per day. The normal diet is much richer than our actual needs, about 4g, so it can largely compensate for the needs of an athlete or a runner.
Losses are majoritarly by feces and sweat. The kidney is able to reabsorb almost all the sodium that is filtered: urinary losses can be tiny.