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.
The correct answer among the choices listed above is option D. The connection between the mother and the embryo that provides the embryo with oxygen and nutrients and waste disposal is the placenta. Hope this answers your question. God Bless.
A. Chloroplasts are not found in both plants and animals cells
Answer:
Correct option is D.
Explanation:
Our nervous system contain cells which are known as neurons these cells help to send information from the spinal cord, and brain. From receptors sensory nervous receive stimuli, and then help in to transfer this information from cell to cell in the central nervous system.
These cells work by change in voltage potential which is present in plasma membrane. So, after the first channel opens, the movement of many types of ions (both inside and outside the cell) alters the distribution of charges near the second channel, causing it to open.
Carbon dioxide.
Happy studying ^-^
