Week Four- Energy and enzymes Flashcards
What is the first law of thermodynamics?
Energy cannot be created or destroyed bit simply changed from one form to another without being depleted.
What is food?
Chemical potential energy
What are the two major fuels stored in the body?
Glycogen and triacylglycerol
Where is glycogen stored?
Liver, muscle and water
Where is triacylglycerol stored?
Adipose tissue
What does the total energy of a system relate to?
Potential and kinetic energy.
How is chemical energy stored?
Bonds of compounds and molecules
What are exergonic reactions?
- Release energy
- Energy is ‘freed up’ to the surroundings for biological work
What are endergonic reactions?
- Energy is absorbed
- Typically coupled to the energy released form an exergonic reaction
What do endergonic reaction enable?
- Building bodily structures, ATP or substance transportation
- Increases in potential energy.
What is the second law of thermodynamics?
All of the potential energy in a system degrades to the unusable form of kinetic or heat energy.
What type of reaction is the breakdown of food?
Exergonic
Give an example of mechanical work within the body
Muscle contraction
Convert chemical to mechanical energy
What type of work do all cell perform?
Chemical work (maintenance and growth)
What is transport work?
Active transport
Low to high concentration
Essential for muscle contraction
How is a calorie measured?
increase 1g of water by 1°C
How is a Kilogram calories measured?
Increase 1kg of water by 1°C
What is a joule?
The energy expended when 1 newton of force move a distance of 1m
How is energy in food measured?
Bomb calorimeters measure the gross energy value of macronurientst
What are Atwater general factors?
4 kCal/g dietary carbohydrate
4 kCal/g dietary protein
9 kCal/g dietary lipid
7 kCal/g dietary alcohol
What is the coefficient of digestibility?
efficiency of the digestive processes to extract the
potential energy yield within food (digested and absorbed)
What is an enzyme?
A specific protein catalyst that accelerate the forward and reverse rates of chemical reactions without being consumed or changed in the reaction
What do enzymes do?
Increase the speed of reaction and lower the energy of activation for a reaction to take place.
Is the energy released the same when an enzyme is involved?
Yes
Are enzymes adapted to a specific pH?
Yes
What can extreme pH do to an enzyme?
Permanently change enzyme structure
What do small changes in pH do to enzymes?
Reduce enzyme activity by modifying biding between enzyme and substrate.
What does an increase in temperature do to the rate of chemical reactions?
Increase it
What happens when the temperature is above 50°C?
Thermal denature and reaction rates fall
What is the optimal temperature range for humans?
30-40°C
What are coenzymes and what do they do?
They are organic substances which assist with the work of enzymes.
They are also temporary carriers
What do coenzymes help facilitate?
enzyme binding with substrate
What can effect the rate of chemical reaction?
- Substrate concentration
- pH and temperature
- Enzyme concentration and location
What are reversible reactions also known as?
Equilibrium reactions
