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:
They can move about freely.
They can reproduce.
They can respond to internal stimulus.
Answer:
<em>Cellular Respiration</em>
Inputs Outputs
sugar + oxygen ⇒ carbon dioxide + water + energy
<em>Photosynthesis</em>
Inputs Outputs
carbon dioxide + water + light ⇒ oxygen + sugar
Explanation:
Head foot and visceral mass
Most of the mollusks species are gastropods. The body of the mollusk is made of shell and fleshy part. The fleshy part is divide into foot and visceral mass. Foot is a distinct feature of mollusk. They use it mainly for locomotion. The visceral mass involves the organs for circulation, digestion and other important processes in living organism. The visceral mass has two external flaps of tissue called as the mantle. It secretes calcerous shell and encloses a mantle cavity.
