ATP & Energetics Flashcards
What is metabolism?
A set of biochemical reactions that are required to sustain life.
Foods are broken down via catabolic pathways to make cellular building blocks which then synthesize macromolecules
From the breakdown of foods during metabolism what is happening?
Energy is being generated
Energy is then used to synthesize macromolecules
What is energy
The capacity to do work
eg:
-mechanical, chemical
What is energy transduction?
A process by which living organism:
- collects and stores energy
- releases stored energy to do work
What do we need to make energy?
mitochondria
fuel (food: carbs, fats)
Helpers: O2(wo this, the cells without be able to generate the energy needed for biochemical needs), enzymes,
What are the products during the process of making energy?
ATP
What are the waste products during the process of making energy?
CO2, water
What is ATP?
The energy currency of the cell.
How much ATP do we synthesize
> 60kg daily
What is cellular reparation?
Process in which sugars (glucose) are converted into usable energy (ATP)
Sugar + Oxygen –> CO2 + water + energy (stored in the form of ATP)
Explain the ATP-ADP cycle
When ATP is used, ADP is generated
O2 + energy from food + O2 + Pi –> ATP
ATP used for cellular work (biosynthesis of macromolecules, muscle contraction, active ion transport, thermogenesis) and a Pi is extracted
Why the ATP energy system is used?
quick and renewable
produces a rapid turnover of ATP
highly efficient
rapidly responds to energy demands
Hydrolysis of ATP
-Water required to spilt phosphate bond to get energy
-The terminal phosphate (high energy gamma phosphate) bond is hydrolyzed.
- Thermostable: does not hydrolyze spontaneously
- Energy is released from ATP when the terminal phosphate bond is broken
- This release of energy comes from the chemical change to a state lower free energy, not from the P-bonds themselves
- Pi can be transferred to another molecule
- release of 1 phosphate group and formation if 1 ADP
very slow unless there is a catalyze available
Where does the energy in ATP hydrolysis comes from?
Release from the chemical change to a state of lower free energy, not from the phosphate bonds themselves
What do the different Gibbs free energy values mean?
- delta G = 0. means body is at equilibrium, inert
- delta G -, exergonic, favorable, the driving force is in the forward direction, releases energy
- delta G +, endergonic, meaning the driving force is in the reversible direction, requires energy, usually ATP
How does ATP work?
As a coupled reaction = 2 half reactions
eg: Glucose + Pi –> G-6-P + H2O delta G = +3.3
ATP + H2O –> ADP + Pi delta G = -7.3
Glucose + ATP –> G-6-P + ADP delta G = -4.0
ATP is not the highest energy compound. Why use ATP rather than other phosphorylated compounds?
It and the other nucleotide triphosphates are stable
It is quick and renewable (unlike the others)
Hydrolysis is slow and enzymatically catalyzed
riboflavin
Vitamin used as a food coloring
Where is more ATP generatied? TCA or ETC
ETC
TCA has little ATP
The high energy phosphate bond in ATP is located in which of the following groups
- Adenine and phosphate
- Ribose and phosphate
- Ribose and adenine
- Two phosphate groups
Remember the gamma phosphate
Where does the energy needed to drive the biochemical reactions come from?
The food we eat.
The larger foods are broken down into smaller molecules from which energy is extracted.
Joules to calorie conversion
1J = 1/4 calorie
1 calorie is needed to raise the temperature of water by 1 degree C
How is ATP used in transport?
Helps take molecules across the cell membrane against a concentration gradient.
How is ATP used in transport in the stomach?
H+/K+ ATPase (proton pump; acidified the stomach)
ATP provides the energy to maintain pH levels low
How is ATP used in transport in the heart/neurons?
Na+/K+ pump
ATP provides the energy to maintain Na+ levels low inside the cells
Needed for heart contractions and synaptic transmission in neurons
What are mechanisms for synthesizing ATP?
- Substrate level phosphorylation
-Direct transfer: ADP + Pi –> ATP
Glycolysis and TCA cycle - Oxidative phosphorylation (~90% of ATP is generated)
- indirect transfer: energy in the form of e- is passed to electron carries and used indirectly to form ATP
“ETC:
3, Photophosphorylation
occurs in plants
What are the cofactors needed for ATP synthesis?
NAD+ - coenzyme.
vitamin needed: niacin
carrier of e-
FAD - prosthetic group. vitamin needed: riboflavin
carrier of e-
Coenzyme A - coenzyme
vitamin needed: pantothenic acid
carrier of acyl groups
How does Coenzyme A work as a cofactor
It has a reactive thiol group at its end terminus which binds to the acyl group. When hydrolyzed, it releases energy
What are the stages in cellular respiration
Glycolysis - makes few ATP
TCA cycle - provides the energy to make alot of ATP, doesn’t generate much ATP
ETC - generates the most ATP
Total oxygen consumption takes place where?
mitochondria
