Bioenergetics And Cellular Respiration Flashcards
What is bioenergetics?
Energy production and use for cells, based on the laws of thermodynamics
What is the first law of thermodynamics ?
Energy is not lost or created, it is just converted from one form to another
What is the second law of thermodynamics ?
Every energy transfer increases the entropy of the universe
What do living organisms require constantly?
Energy input
What does ATP act as in a cell?
An energy reservoir
Anabolism
Energy to build things
Catabolism
Molecule breakdown releases energy
What is the Gibbs Free Energy formula?
ΔG = ΔH - TΔS
Exergonic reaction?
Where energy is released
Endergonic reaction?
When energy is required
What do enzymes do in a reaction?
Lower the activation energy (which is the energy required to kickstart a reaction)
Do enzymes change ΔG?
NO!
Enzymes are often inhibited by the end product in pathways, what is this called?
Negative feedback
When does ATP release energy?
When the outermost inorganic phosphate is cleaved off
Why is energy stored in the outermost Pi?
Because the negative charges repel each other.
How is ATP formed?
- Substrate level phosphorylation
- Oxidative phosphorylation (Chemiosmosis)
What is substrate level phosphorylation?
The transfer of a phosphate group to ADP
What is chemiosmosis?
The movement of ions down their electrochemical gradient across a semi-permeable membrane.
What is cellular respiration ?
A metabolic process with which an organism obtains energy by oxidising nutrients and releasing waste products.
What are the three stages of cellular respiration?
- Glycolysis
- Citric acid cycle
- Oxidative phosphorylation
Where does glycolysis take place, and what is glucose changed into?
The cytosol and
glucose -> pyruvate
Where does the citric acid cycle take place and what triggers it to start?
In the mitochondrion and it starts once pyruvate is made.
Does the citric acid cycle require oxygen?
No but pyruvate will not move to the citric acid cycle without oxygen.
What is the purpose of the citric acid cycle?
Creating more ATP and harvesting electrons
Where does oxidative phosphorylation take place?
In the mitochondrion
Does oxidative phosphorylation require oxygen
Yes!
What does cellular respiration release ?
CO2 and H2O
In glycolysis, in the energy investment phase: how much ATP is “invested”?
2 ATP is invested in the energy investment stage of glycolysis
In glycolysis, in the energy payoff stage: how much ATP is formed?
4 ATP are formed in the energy payoff phase
In glycolysis there is a net gain of ____ ATP per glucose molecule
In glycolysis there is a net gain of two ATP per glucose molecule
How many steps are there in glycolysis?
10!
