$A$ huge amount of starch is deposited in potato tubers due to:

Where does glycerol enter the respiratory pathway?

Choose the incorrect sentence$(s)$ regarding the amphibolic pathway.
$(1)$ Carbohydrates are generally used as substrates for respiration.
$(2)$ Fatty acids can first be degraded into acetyl $CoA$,which enters the respiratory pathway.
$(3)$ In the case of proteins,they are first broken down into amino acids,which are later converted into pyruvic acid and enter the respiratory pathway.
$(4)$ The respiratory pathway is involved in both anabolism and catabolism.
$(5)$ Glycerol would enter the pathway after being converted to $PGAL$.

Given below are two statements:
Statement $I$ - $A$ stepwise release of chemical bond energy facilitates the utilization of a relatively higher proportion of that energy in $ATP$ synthesis.
Statement $II$ - Due to stepwise oxidation of respiratory substrate,the same pathway may be used for synthesis of another biomolecule.
In light of above statements,select the correct answer from the options given below.

How many substrate-level $ATP$ molecules are formed if one molecule of amino acid is oxidized via the amphibolic pathway?

Proteins act as respiratory substrates only when: