The chemical activities of the cell. Cell Metabolism The chemical activities of the cell. Most conversations of metabolism are focused on “fast” or “slow” metabolisms …. the rate!

Anabolic Pathways “Anabolism” Pathways that consume energy, building complex molecules from smaller ones. Example: Photosynthesis

Catabolic Pathways “Catabolism” Pathways that break down complex molecules into smaller ones, releasing energy. Example: Respiration

Energy and ATP

Energy Gives the ability to do work. Most common forms of energy Kinetic: energy of motion Potential: stored energy Activation: energy required to start a reaction

Energy of action or motion. Kinetic Energy Energy of action or motion.

Stored energy or the capacity to do work. Potential Energy Stored energy or the capacity to do work.

Energy needed to convert potential energy into kinetic energy. Activation Energy Energy needed to convert potential energy into kinetic energy. Activation Energy Potential Energy

Why do cells need energy? To Do Work…….. The “work” cell’s need to do to stay alive is called the “Life functions”. The Life functions are: Grow Develop Reproduce Respond to Stimuli

1st Law of Thermodynamics Energy can be transferred and transformed, but it cannot be created or destroyed. Also known as the law of Conservation of Energy.

2nd Law of Thermodynamics Each energy transfer or transformation increases the entropy of the universe.

Entropy is a measure of disorder… Entropy is a measure of disorder…. In order to keep order you must apply energy.

How do living organisms overcome Entropy? Question? How do living organisms overcome Entropy? By using energy from the environment or external sources (e.g. food, light).

The portion of a system's energy that can perform work. Free Energy The portion of a system's energy that can perform work.

Free Energy G = H - TS G = free energy of a system H = total energy of a system T = temperature in oK (Kelvin) S = entropy of a system

Chemical Reactions Are the source of energy for living systems. Are based on free energy changes. Most energy lost is in the form of HEAT.

Reaction Types and Energy Exergonic: chemical reactions with a net release of free energy. Endergonic: chemical reactions that absorb free energy from the surroundings.

Exergonic/Endergonic

Exergonic - Respiration Endergonic - Photosynthesis Biological Examples Exergonic - Respiration Endergonic - Photosynthesis

All living cells use ATP as their energy source ATP is Adenosine Triphosphate Made of: - Adenine (nitrogenous base) - Ribose (pentose sugar) - 3 phosphate groupst

ATP 3 Phosphate Groups

The ATP Cycle ATP ADP + P + Energy

ATP in Cells A cell's ATP content is recycled every minute. Humans use close to their body weight in ATP daily. No ATP production equals quick death.

Adding a phosphate group to a molecule. Phosphorylation Adding a phosphate group to a molecule. The phosphate group adds “energy” to the molecule for chemical reactions.

ATP ATP energizes other molecules by transferring phosphate groups to them….. The process is called phosphorylation.

Phosphorylation

ATP is produced in the cytosol and the mitochondria. ATP Production ATP is produced in the cytosol and the mitochondria.