Unit 6.1-6.3 Energy, metabolism, and thermodynamic laws

Describe and name the two types of metabolic pathways

1. Anabolic: Use energy to assemble complex molecules

2. Catabolic: Release energy to break complex molecules

Bioenergetics definition

Concept of energy flow through living things, energy for life on Earth comes from the sun

Photosynthesis is what type of reaction? Why?

Anabolic rxn: plant takes in a bunch of molecules & energy from sun

What type of reaction is cellular respiration? Why

Catabolic rxn: Animal/human breaks down molecules from plant, use energy in form of ATP

List and describe the three major energy types

• potential energy: stored energy

• kinetic energy: energy of movement

• thermal energy: heat

What is chemical energy and what are some examples of chemical energy in the cell?

• a form of potential energy

• represented by bonds between atoms

• can be released to surroundings when bond breaks

• Ex: Energy of chem/electrochem gradients across plasma membrane (Energy stored in BONDS key thing)

What is gibb’s free energy

How we quantity the energy that releases from one rxn to another rxn/ how we study the amount of energy exchanged in a metabolic reaction

Gibbs free energy equation

Delta G = Delta H -T(Delta S)

Free energy = total energy (enthalpy) - (temp x entropy)

S = amount of energy lost to entropy

G = change in free energy

What does a negative delta G mean?

It means the reaction releases energy/ rxn’s products have less free energy than the reactants, exergonic rxn: energy exiting the system, spontaneous

• decrease in potential energy

• Decrease in the amount of free energy available

What does a positive delta G mean?

It is a chem rxn that requires energy, products have more free energy than the reactants, products are energy storing molecules: energonic

• non-spontaneous

• Energy into the system

• Increase potential energy and increase amount of free energy available

Is photosynthesis endergonic or exergonic?

Endergonic, energy from the sun is taken into the system (plants) increasing the amount of available free energy, it is not spontaneous

How are open and closed systems different?

Open: Energy & matter transfer between system and surroundings

Closed: only energy transfer happens between system and surroundings

Are biological organisms an example of open or closed system

Open! Matter (food) enters, feces exit & energy is transferred

What is the first law of thermodynamics

Energy cannot be created or destroyed it can only be transferred or transformed

What is the second law of thermodynamics?

Entropy (randomness/disorder) Of an isolated system can only increase or remain constant

• due to inefficiency with every transfer or transformation some energy is converted to an unusuable form (heat)

Do living organism have an increased or decreased entropy, why?

Decreased entropy because they are highly ordered