Lecture 6 - Bioenergetics 1 Flashcards
what are substrates and list the diferent types
fuel sources from which we make energy (ATP)
- > these are comprised of three groups
1. carbohydrates
2. Fats
3. proteins
bioenergetics
the conversion of substrates into energy
- > this process occurs at the cellular level
metabolism
the chemical processes that happen in the body to convert food to energy
1 calorie (cal)
is the heat energy required to raise 1g of water from 14.5 to 15.5
cal vs kcal vs Calorie
1000 cal = 1 kcal = 1 Calorie
substrates are made up of which 4 elements
- > carbon
- > hydrogen
- > oxygen
- > nitrogen (only in proteins)
where is energy from chemical bonds in food stored?
in a high energy compound called ATP
when are substrates consumed
Resting
- > 50% carbs 50% fats
Exercise (short term)
- > more carbs
Exercise (long)
- > carbs and fats, proteins only consumed for energy in dire situations
characteristics of carbs
all carbs are converted to glucose
- > 4.1 kcal/g (2500 kcal stored in body)
- > extra glucose is stored as glycogen in the liver and muscles
- > glycogen converted to glucose when needed to make ATP
characteristics of fat
- > very efficient substrate with efficient storage capabilities
- > 9.4 kcal/g (70000+ kcal stored in bogy)
where are carbs and fats stored
*know general trends*
characteristics of protein
- > used as substrate only during starvation (converted into glucose)
- > 4.1 kcal/g
- > converted into Free Fatty Acids through lipogenesis which is used for energy storage and cellular energy
how are fats, carbs and proteins used for energy production
what controls the rate of energy production
substrate availability
- > more available substrate yields higher pathway activity; this is known as the Mass Action Effect
enzyme activity
- > enzymes act as chemical catalysts in specific steps of metabolism (they do not start chemical reactions, they lower the activation energy of a reaction, see picture)
how do enzymes change the activation energy
- > specific enzymes are required for each step of the biochemical pathway
- > more enzyme activity = more product
rate limiting enzymes
- > slows the overall reaction, prevents runaway reaction
- > limits available enzymes required to start one of the early steps in the biochemical pathway
characteristics of ATP-PCr systems
- > anaerobic, substrate level metabolism
- > ATP yield: 1 mol ATP/1 mol Phosphocreatine
- > lasts 3-15sec
PCr + creatine kinASE - > Creatine + Pi + energy
