Question 80
Explain the three pathways of the breakdown in living organisms.

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Solution

During cellular respiration, glucose is converted into pyruvate in the cytoplasm. Then pyruvate is converted into pyruvic acid. The breakdown of pyruvic acid takes place in mitochondria.
$G l u c o s e (6 C) (I n c y t o p l a s m) - ----------- \to 2 P y r u v i c a c i d (3 C) + E n e r g y .$
The molecules formed after breakdown depends on the type of cellular respiration inside the cell viz. aerobic respiration and anaerobic respiration.
1. Aerobic respiration happens in the presence of oxygen. The pyruvic acid is converted into carbon dioxide, water, and ATP is released at the end of this process.
$P y r u v i c a c i d (O_{2} p r e s e n t) - -------- \to C a r b o n d i o x i d e + w a t e r + e n e r g y (i n m i t o c h o n d r i a)$ .
Anaerobic Respiration happens in the absence of oxygen. This process is also known as fermentation. The pyruvic acid is either converted into ethyl alcohol or lactic acid.
2. In microbes like yeast or bacteria ethyl alcohol is usually formed during anaerobic respiration.
$P y r u v i c a c i d (O_{2} a b s e n t) - ------- \to E t h a n o l + C O_{2} + E n e r g y . (I n y e a s t c e l l)$ .
3. Lactic acid is formed in some microbes as well as in the muscle cells of humans during intense exercise.
$P y r u v i c a c i d (O_{2} a b s e n t) - -------- \to L a c t i c a c i d . (I n m u s c l e c e l l s) .$
$molecule)Pyruvate+Energy\overset{Glucose}{(6-carbon~molecule)} \xrightarrow{In~cytoplasm} \overset{Pyruvate}{(3-carbon~molecule)}+Energy$
$\xrightarrow{In~yeast(lack~of~oxygen)} Ethyl~alcohol+carbon~dioxide+Ener$

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Cellular Respiration

Standard X Biology

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Question 80 Explain the three pathways of the breakdown in living organisms.

Question 80
Explain the three pathways of the breakdown in living organisms.