Introduce to Metabolism & Cellular Energy

What kind of system are you?

Living things are open system

First Law of Thermodynamics

Energy cannot be created or destroyed but can only change form or be transform from one object to another

Entropy

Measure of disorder or Reduces the amount of usable energy available to do work

Second Law of Thermodynamics

Energy transfer increases the entropy of the universe

Is any energy transfer is completely efficient?

No, some energy is lost as heat

Internal Organization

Cells → Tissues → Organs → Organ Systems → Entire body

High degree of organization of living things is maintained by

Constant input of Energy

Energy

Capacity to caused change

Potential Energy

Energy that matter possesses because of its position, structure 

Is chemical energy is potential energy?

Yes because its available for release in a chemical reaction

Kinetic Energy

Energy associated with motion

Why is Thermal energy is kinetic energy?

Because it associated with random movement of atoms or molecules

Metabolism

All the chemical reactions that are required to maintain cells

Catabolic

Breaking bonds between molecules (Hydrolysis)

Anabolic

Forming bonds between molecules (Dehydration Synthesis)

Metabolic Pathway

Begins with a specific molecule and ends with a product

Gibb’s Free Energy (G)

A measure of the amount of usable energy of a system

Exergonic Energy

Chemical reactions that released energy

Endergonic Energy

Chemical reactions that require input of energy

Spontaneously

Occuring naturally

Exergonic Reaction

G < 0

Endergonic Reaction

G > 0

Energy Coupling

Cells store chemical energy in biological molecules, digest it and harvest the energy for cellular work

Organisms couple:

Exergonic Reactions with Endergonic Reactions

Full name of ATP

Adenosine Triphosphate

ATP meaning

Energy currency of the cell

Short term energy-storing molecule

ATP

Long term energy-storing molecule

Lipid

ATP Structure

• Ribose Sugar (Pentose Sugar)

• Adenine (Nitrogenous base)

• Tri - phosphate group (3)AT

ATP Function

Releases energy when the bonds between the 2nd and 3rd groups are broken, forming ADP (Adenosine Diphosphate) and Inorganic Phosphate

Pi

Inorganic Phosphate and no carbon

Explain the ATP/ADP Cycle

Rechargeable Energy

Phosphorylation meaning

• Kinase enzymes transfer phosphate groups from one molecule to another

• Phosphatases remove phosphate group from proteins

What does Inorganic phosphate caused when it binds to another molecule?

Because it’s unstable, it causing a conformational change and becomes unstable

Conformational change

Change form, shape to new function

Phosphorylation is

Essential for controlling the activation of proteins involved in various cell functions