How organisms get the energy to survive & reproduce

DO NOW:

Describe the difference between phototrophs and chemotrophs, as well as the difference between

autotrophs and heterotrophs.

Bioenergetics:

Bioenergetics: the study of energy flowing through and between living systems.

Areas of StudyPhotosynthesisRespiration

AerobicAnaerobic

ThermodynamicsAlgaeHuman Energy Use

Unit 2: Bioenergetics

2nd Law of Thermodynamics:In a closed system, entropy (disorder)

increasesSo how do living things remain so organized,

and in fact increase the organization in and around themselves?ENERGY. Living things use energy to prevent

entropy from destroying them.Living things are “negative entropy machines”

Entropy

Entropy and Energy

ORDER

Chaos

Energy Released(ΔG < 0)

Energy Required(ΔG > 0)

SpontaneousNonspontaneous

Photosynthesis & Respiration

C6H12O6

+ 6 o2

ATP Energy Produced

Light Energy Required

6 Co2 + 6 H2O

Photosynthesis

Respiration

Order vs. Chaos

ATP Energy Produced

Light Energy Required

Photosynthesis

Respiration

Photosynthesis : the process by which plants and other photoautotrophs store the energy of light as chemical energy in carbohydrates.

(Cellular) Respiration: the process by which animals and other chemotrophic organisms transform chemical energy stored in carbohydrates (or other sources) into available energy (ATP).

Critical Definitions

Make a connection:ΔG = ΔH – TΔS

Remember: Gibbs Free Energy always decreases in spontaneous reactions.

In other words, when ΔG is negative, reactions happen without the input of work.

Gibbs Free energy change when breaking down glucose = -2870 kJ/mol

Chemistry II Students…

Reducing carbon (adding more H to it) requires energy (i.e. photosynthesis)

Oxidizing carbon (adding more O to it) releases energy (i.e. combustion)

Redox Reactions

Photosynthesis Respiration

Requires energy Releases energyCarbon is reduced

Carbon is oxidized

Entropy decreases Entropy increasesΔ G > 0 Δ G < 0phototrophs Chemotrophs

Bioenergetic Chemistry

Along with bioenergetics, we will also study the true

algae:

unicellular Eukaryotic photoautotrophs.

Organisms

Chlorophyta: green algae

Phaeophyceae: Brown algae

Rhodophyta: Red Algae

Human Ecology & Energy Use

Human Energy Use

Consequences

2 key definitions today: photosynthesis & respiration

4 major sections to the unit:PhotosynthesisCellular RespirationAlgaeHuman Energy Use

In Conclusion