4.1: Metabolism overview

Question 1

Phototrophs vs Chemotrophs

Answer 1

2 ways organisms harvest energy.
Phototrophs: Use energy of sunlight to break down molecules into sugars
Chemotrophs: Ingests other organisms/organic molecules to gain energy directly.

Question 2

Autotrophs vs Heterotrophs

Answer 2

2 ways organisms get their carbon
Autotrophs: Converts CO2 (inorganic carbon) into glucose (organic carbon). “Self-feeders”
Heterotrophs: Obtain carbon from organic molecules synthesized by other organisms. “Other-feeders”.

Question 3

Catabolism vs Anabolism

Answer 3

Set of chemical reactions that BREAK DOWN molecules into smaller units - produces ATP
Set of chemical reactions that BUILD molecules from smaller units - requires energy (ATP)

Question 4

What is chemical energy? Relate bond strength to chemical energy

Answer 4

Form of potential energy held in the chemical bonds between pairs of atoms in a molecule
Stronger the bond, less energy required to hold the bonds together = little chemical energy, works the opposite for weak bonds.

Question 5

Gibbs free energy (G). What is ΔG ?

Answer 5

The amount of energy available to do work
G of product - G of reactants. Positive ΔG indicates net input of energy is required. Negative ΔG indicates energy is released and available to do work.

Question 6

Exergonic vs Endergonic reaction? Which is spontaneous?

Answer 6

Exergonic: Reactions with negative ΔG, releases energy = spontaneous.
Endergonic: Reactions with positive ΔG, requires energy = non-spontaneous.

Question 7

What in enthalpy? What is entropy? How does this relate to G?

Answer 7

Enthalpy (H): Total amount energy in a compound.
Entropy (S): Amount of intrinsic disorder in a compound.
G = H - TS or ΔG = ΔH -TΔS
S is multiplied by T (temperature) because temperature influences the degree of disorder.