Energy conversion in the body Flashcards
What is energy
Capacity for work (W)
Energy
-unit
Joules (J)
Old unit:(cal)
Energy required to heat 1g of water by 1 degree C
What is power
Rate which work is performed or energy is transmitted
power
- unit
Watt (W)
First law of thermodynamics
- Energy cannot be created nor can it be destroyed - transferred from one form to another
Conservation of energy
- Ex. body transforms energy in food into heat
What happens to energy when it has appeared to be destroyed
- ‘quality’ changes
- energy diluted
- Energy can lose its abilities
Potential energy
Bound in a specific form
Kinetic energy
- Harnessing of potential energy
- Biosynthesis results from harnessing of potential energy
Exergonic
energy releasing process
Endergonic
Energy conserving process (absorbs energy)
Mechanical work
- Muscle contraction
- Cell division
Chemical work
Synthesis of molecules - i.e. fat
Transport work
- Diffusion
- Active transport (sodium/potassium pump)
Electrical work
- Transport of charged particles
- Action potentials in nerves and muscles
What does reaction rate depend on
- PH
- Temperature
- Availability of substrates
Hydrolysis reaction
- Catabolize complex organic molecules
How are chemical bonds split during hydrolysis
Adding H+ and OH
Biological example of hydrolysis
Digestion
Condensation reaction
reverse of hydrolysis
- peptide bonds
Oxydation
Loss of electrons
Reduction
Gain of electrons
Nutrients
Fuels for the body
Carb metabolism
Can happen under aerobic and anaerobic conditions
Protein and fat metabolism
require oxygen to be metabolised
- Need good oxygen supply to be effective
Biggest energy store
Fat - 79%, even more if person unhealthy
2nd largest energy store
Protein - 20%
3rd largest energy store
Carbs - 1%
most energy used comes from..
Carbs
Metabolic energy
Generated by oxidising different nutrient
Oxidation reaction
Combutions
aerobic glycolysis
body ‘burns’ glucose
Metabolic energy currencies
- NADH
- ATP
how is energy released in the cell
many single portions
Electron transport chain
- Transports electrons from high energy content (NADH) to low energy content
- Allows us to harvest enzyme into something we can use in the body
Controlled enzymatic reactions
Used to convert and transfer chemical energy of oxidation and make it utilizable for metabolism
Cellular redox reactions
underlie energy metabolism
NAD and FAD
oxidise food
What transports electrons
Carrier molecules
What are electrons passed to
Redox complexes
In electron transport what acts as the final electron acceptor
Oxygen
Reduction equivalents
- secondary energy currancy of the cell
- transport electrons
Where do reduction equivalents transport electrons
From the the nutrient to the final oxidising agents
Most important reduction equivalents
NAD+ (+2e) -> NADH + H+
FAD (+2e) -> FADH2
Oxidative phosphorylation
synthesises ATP
How does oxidative phosphorylation synthesise ATP
Transferring electrons from NADH & FADH2 to oxygen
How many ATP molecules can you get from 1 NADH molecule
3
Catabolic metabolism
Break down or oxidation of nutrients
- Releases energy
- Produces intermediates that are useful for metabolism
Anabolic metabolism
Produces new components i.e. fat, enzymes, hormones
- Consumes energy
- Requires different precursors
What is energy from catabolic metabolism used for
Anabolic metabolism
ATP
Adenosine triphosphate
- The energy currency
ATP
- Roles
- Powers all of cells energy-requiring processes
- Potential energy extracted from food
- Energy transferred to do work
Where is energy stored
In bonds of ATP
What is ATP hydrolysed by
Water
ATP Hydrolysis
- Outermost phosphate released
- Catalysed by ATPase
- Energy released
ATP levels
Low ATP levels in cells create sensitivity to ATP/ADP