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:
White petal color is a recessive trait.
Explanation:
Further explanation is posted as an attached file due to technical difficulties.
Answer:
<h3>A) Enzymes are highly specific protein catalysts</h3>
Explanation:
- Enzymes are highly specific protein catalysts i.e. it react with only that substrate for which it has been made.
- Enzymes have an active site by which it binds to substrate at that specific site.
- Enzymes lowers the activation energy required for completion of a chemical reaction. As a result rate of the reaction increases.
- Enzymes never participate in a chemical reaction rather they are obtained back in its original form on the completion of the reaction.