Metabolism & ATP

Thermodynamics

The study of Heat Energy (“thermo”) and its properties (“dynamics”).

First Law of Thermodynamics (Also called the Principle of the Conservation of Energy.)--Energy cannot be created nor destroyed, only transferred or transformed.

Second Law of Thermodynamics--
1. Every Energy transfer increases the entropy (“disorder”) of the universe.
2. No work can be done because it is in a low state of order.

Making Sense of the 2nd Law

Entropy=disorder=less useful

Imagine your bedroom is usually a bit messy, with toys and clothes scattered around. That's pretty normal, right? Well, the Second Law of Thermodynamics is kind of like that, but for the whole universe!

This law says that everything in the universe naturally goes from being orderly to more messy, just like your bedroom. It's like if you tidy up your room, and then after playing, it becomes messy again. That messiness in science is called "entropy."

In more science-y terms, the law says that energy spreads out and becomes less useful over time. Like when you have a hot cup of cocoa, it cools down because its heat spreads into the air. The heat is energy, and when it spreads out, it gets less orderly, or more "messy."

So, the Second Law of Thermodynamics is a fancy way of saying that things naturally get more disordered and energy spreads out, like the messiness in your room or the heat from your cocoa!

Multiple Choice

A spontaneous reaction 

• occurs only when an enzyme or other catalyst is  present

• cannot occur outside of a living cell

• releases free energy when proceeding in the  forward direction

• is common in anabolic pathways

Multiple Choice

Anabolic pathways are and catabolic  pathways are .

• spontaneous, non-spontaneous 

• non-spontaneous, spontaneous

Multiple Choice

3 Which of the following correctly states the relationship  between anabolic and catabolic pathways?

• Degradation of organic molecules by anabolic  pathways provides energy for catabolic pathways.

• Energy from catabolic pathways drives the breakdown  of organic molecules in anabolic pathways.

• Anabolic pathways synthesize complex organic  molecules using energy from catabolic pathways.

• Catabolic pathways synthesize complex organic  molecules using energy from anabolic pathways.

Multiple Choice

In general, the hydrolysis of ATP drives cellular work by

• releasing free energy that can be coupled to other  reactions

• releasing heat

• acting as a catalyst

• lowering the free energy of the reaction 

Multiple Choice

What best characterizes the role of ATP in cellular  metabolism?

• The release of free energy during the hydrolysis of  ATP heats the surrounding environment.

• The free energy released by ATP hydrolysis may be  coupled to an anabolic process via the formation  of a phosphorylated intermediate

• It is catabolized to carbon dioxide and water