Energy Production Flashcards
What is cell metabolised defined as?
The highly integrated network of chemical reactions that occur within cells
What does the network of chemical reactions involved in cell metabolism consist of?
A number of distinct chemical pathways (metabolic pathways) which link together
Do the metabolic pathways occur in all cells?
Some do, whilst others are confined to cells with specific functions
What is produced from cell metabolism of nutrients?
- Energy for cell function and synthesis of cell components
- Building block molecules
- Organic precursor molecules
- Biosynthetic reducing power
In what form is energy produced by cell metabolism?
ATP
What are the building block molecules produced by cell metabolism used for?
Synthesis of cell components needed for growth, maintenance, repair and division of the cell
What are the organic precursor molecules produced by cell metabolism used for?
To allow the inter-conversion of building block molecules
Give an example of an organic precursor molecule produced by cell metabolism
Acetyl-CoA
What is the biosynthetic reducing power produced by cell metabolism used in?
The synthesis of cell components
What molecule holds biosynthetic reducing power?
NADPH
What sources provide cells nutrients?
- Diet
- Synthesis in the body tissue
- Release from storage
What can happen to cell nutrients after being metabolised?
- Degradation to release energy
- Synthesis of cell components
- Storage
In what tissues can nutrients be degraded to release energy?
All
In what tissues can nutrients be used to synthesise cell components?
All tissues except RBCs
In what tissues can nutrients be metabolised to storage?
- Liver
- Adipose tissue
- Skeletal muscle
What is catabolism?
The breakdown of larger molecules into smaller ones
What is anabolism?
Where smaller molecules are built up into larger ones
How are catabolism and anabolism involved in cell metabolism?
Cell metabolism consists of pathways in which the overall reaction is catabolism linked to anabolism
Are catabolism pathways oxidative or reductive?
Oxidative
What is meant by catabolic pathways being oxidative?
They release H+ ions (reducing power)
What do catabolic pathways release?
- Large amounts of free energy
- Intermediary metabolites
Are anabolic pathways oxidative or reductive?
Reductive
What is meant by anabolic pathways being reductive?
They use H+ ions
What do anabolic pathways do?
Use the intermediary metabolites and energy (ATP) produced by catabolism to drive the synthesis of important cell components
What happens if energy intake from food is insufficient for cells function?
The body utilises energy stores to keep the supply of energy continuous
What does metabolism couple?
The energy released from exergonic reactions to the energy required by endergonic reactions
What is required in the coupling of exergonic reactions and endergonic reactions in metabolism?
An intermediate process - the ADP/ATP cycle
What is an exergonic reaction?
One that is energy releasing
Is the Gibbs Free Energy positive or negative in exergonic reactions?
Negative
Give three examples of phosphorylated compounds
- Phosphonenolpyruvate
- Creatine phosphate
- ATP
Why do many phosphorylated compounds have a high energy of hydrolysis?
Because the phosphate-phosphate bond is a high energy bond
What is the free energy change of ATP + H2O -> ADP + Pi?
-31 kJ/mol
GIve an example of a cell type that might need to increase metabolic activity very quickly
Muscle
What is required in cell types that need to increase metabolic activity very quickly?
A reserve of high energy stores that can be used immediately
What is used as a high energy store in cells that need to increase metabolic activity very quickly?
Creatine phosphate
Give the reaction whereby creatine phosphate produces energy quickly
Creatine phosphate + ADP <–> Creatine + ATP
What catalyses the reaction of interconversion between creatine and creatine phosphate?
Creatine kinase
What happens to creatine and creatine phosphate when ATP concentration is high?
The reaction towards creatine phosphate is favoured
What are oxidative reactions?
When electrons are removed
In biological terms, what are oxidative reactions?
Removal of hydrogen atoms (H+ and e-)
What happens to the removal hydrogen atoms in biological oxidative reactions?
They immediately react with something else
What is the result of the hydrogen atoms removed in biological oxidative reactions immediately reacting with something else?
It makes the whole reaction a redox reaction
What happens when fuel molecules are oxidised in catabolism?
Hydrogen atoms are transferred to carrier molecules
What do the hydrogen carrier molecules carry?
Reducing power
What kind of molecules are hydrogen carriers?
Complex molecules that contain components from B vitamins
How are hydrogen carriers reduced?
By the addition of two H atoms (H+ and e-)
What happens to the H+ on carrier molecules in solution?
It dissociates
Does the total number of oxidised and reduced carriers vary?
No, it is constant
Give three hydrogen carriers
- NAD
- NADP
- FAD
What is the oxidised form of NAD?
NAD+
What is the reduced form of NAD?
NADH + H+
What is the oxidised form of NADP?
NADP+
What is the reduced form of NADP?
NADPH + H+
What is the oxidised form of FAD?
FAD
What is the reduced form of FAD?
FAD2H
When are catabolic pathways generally activated?
When the concentration of ATP falls, and concentrations of ADP/AMP increase
When do anabolic pathways tend to be activated?
When the concentration of ATP rises
Why is ATP known as a high energy signal?
Because it signals that the cell has adequate energy levels for its immediate needs
Other than ATP, what else are high energy signals?
- NADH
- NADPH
- FAD2H
Why are NADH, NADPH, and FAD2H high energy signals?
Because high concentrations of these molecules mean reducing power is available for anabolism
What molecules are low-energy signals?
- ADP and AMP
- NAD+
- NADP+
- FAD
