Question

Which of the following statements about metabolism are true?

1) Catabolism is the process in which complex substances are broken down, yielding a net output of energy.
2) Metabolism is an integrated system in which many of the same reactions participate in degradative (catabolic) and biosynthetic (anabolic) pathways.
3) Anabolism involves the synthesis of polymeric biomolecules and complex lipids from monomers such as fatty acids and nucleotides.
4) All organisms derive raw materials and energy from organic molecules, such as glucose.

Answer 1

The true statements are:

1) Catabolism is the process in which complex substances are broken down, yielding a net output of energy.

Catabolism reactions break down macromolecules (lipids, proteins, nucleic acids and sugar) into smaller units that can be used for further reactions, for energy, for the synthesis of new polymer molecules or be simple waste products.

2) Metabolism is an integrated system in which many of the same reactions participate in degradative (catabolic) and biosynthetic (anabolic) pathways.

Metabolism combine all chemical reactions of an organism. Functions of metabolism include: providing energy form food molecules, synthesis of building blocks of the cell, elimination of the waste products.

3) Anabolism involves the synthesis of polymeric biomolecules and complex lipids from monomers such as fatty acids and nucleotides.

Anabolic reactions are opposite of those in catabolism: these reactions require energy (endergonic processes) for the synthesis of necessary molecules for the cells. That energy is the product of catabolic reactions.