Introduction to metabolism: anabolism and catabolism

What is metabolism?

Metabolism is the set of processes that take energy in different forms, break it down into fundamental components, and then build it up in useful ways for energy, structure, growth, reproduction, and response to the environment.

What are the two main processes of metabolism?

Catabolism, which breaks down substances into building blocks for energy or structure, and anabolism, which rebuilds those building blocks into useful molecules.

What is catabolism?

Catabolism is the breaking down of molecules to release energy or obtain building blocks for cellular processes.

What is anabolism?

Anabolism is the process of rebuilding molecules from smaller components into structures that are useful for the organism.

What analogy is used to explain catabolism and anabolism?

The analogy of breaking down a Lego structure into pieces (without destroying them) to rebuild a new structure demonstrates catabolism (breaking down) and anabolism (building up).

Where does the energy for life primarily originate?

The energy primarily comes from the sun, which powers most life on Earth, though some organisms can obtain energy from sources like hydrothermal vents.

How are the heavier elements in living organisms formed?

Heavier elements such as carbon and oxygen are formed through fusion reactions in stars, including both existing stars and dead stars that contributed materials billions of years ago.

How does photosynthesis relate to metabolism?

Photosynthesis allows plants to use energy from sunlight to fix carbon from carbon dioxide into solid molecules like glucose, which can then be used to build other molecules.

What are the primary inputs required for photosynthesis?

Carbon dioxide (CO2), water (H2O), and sunlight energy.

How do plants convert carbon dioxide into glucose?

Plants form chemical bonds between carbon atoms and other atoms, converting gaseous CO2 into glucose and other carbohydrates like starch and cellulose.

How do other organisms obtain energy from plants?

Animals and other organisms consume plants, catabolize their molecules into building blocks, and use those blocks to build structures and generate energy for their own metabolism.

What types of macromolecules are broken down and rebuilt in metabolism?

Carbohydrates (simple sugars and polysaccharides), lipids (fatty acids and cholesterol), and proteins (amino acids).

Why is ATP considered the “molecular currency” of energy?

ATP stores usable energy in its three phosphate groups, particularly in the bond of the last phosphate, which can be released to power life processes including metabolism.

What is the structure of ATP?

ATP consists of ribose (a sugar), adenine (a nitrogenous base), and three phosphate groups attached in a chain, forming high-energy phosphoanhydride bonds.

How can ATP be related to RNA and DNA?

ATP contains ribose, adenine, and phosphate groups, which are components that can also be used to construct RNA and DNA molecules.

How does the transcript connect metabolism to the universe?

The energy and elements used in metabolism ultimately originate from fusion reactions in stars, connecting biological processes to cosmic events billions of years ago