Cells and the Laws of Thermodynamics

Questions and Answers

The breakdown of organic molecules

The process of photosynthesis

The sun (correct)

Cellular respiration

Through the breakdown of ATP molecules

Through the process of oxidation (correct)

Through the formation of sugar molecules

Through the process of reduction

An increase in the amount of energy in the universe

A decrease in the amount of entropy in the universe

The creation of new organic molecules

The maintenance of a stable carbon cycle (correct)

As entropy increases, the movement of molecules increases Signup and view all the answers

Through the linking of smaller molecules to form macromolecules Signup and view all the answers

The sun Signup and view all the answers

Removal of electrons from an atom Signup and view all the answers

Towards disorder and entropy Signup and view all the answers

Photosynthesis Signup and view all the answers

Increase in entropy outside the cell Signup and view all the answers

Study Notes

The total amount of energy in the universe remains constant, and cells obey this law by converting energy from one form to another.
The ultimate source of energy for all life on Earth is the sun.

Plants obtain energy directly from sunlight through photosynthesis, storing it in chemical bonds of organic molecules.
Animals live on energy stored in chemical bonds of organic molecules by consuming plants or other animals that have eaten plants.
Energy is extracted from organic molecules by gradual oxidation, which involves adding oxygen atoms to a molecule.
Oxidation occurs in any reaction where electrons (e-) are transferred from one atom to another, essentially the removal of electrons.

Oxidation: adding O2 atoms to a molecule, or the removal of electrons from an atom.
Reduction: the reverse of oxidation, involving the addition of electrons to an atom.
Examples: photosynthesis (reduction of carbon dioxide to form glucose) and cellular respiration (oxidation of glucose to produce ATP).

Carbon in the atmosphere is constantly recycled: stored in glucose in plants, broken down by organisms, and sent back to the atmosphere.

Living things create order within themselves, but this requires energy and effort.
The universe tends towards disorder, known as entropy, where molecules move freely.
Cells maintain their structure by releasing enough energy into the surroundings, increasing the overall disorder of the environment.

Exergonic reactions: release energy, often involving oxidation events (e.g., cellular respiration).
Endergonic reactions: require energy, often involving reduction events (e.g., photosynthesis).