Macro #1: Energy Sources Flashcards
How does our body store energy?
ATP
How is glucose stored?
As Glycogen
How are fatty acids stored?
As triglycerides
How are amino acids stored?
As proteins
Unit to measure energy
Calorie or kcal (kilocalorie)
Kcal
- How energy expenditure is expressed
- Heat required to raise the temperature of 1 kg of water by 1 C
Calorimetry
The measure of energy through how much heat a nutrient produces (steak may have more energy then a cheerio and therefore produce more heat/energy)
2 types of calorimetry
- Direct calorimetry
- Indirect calorimetry
Direct Calorimetry
Measures heat transfer through bomb calorimetry and determining energy content of nutrients
Indirect Calorimetry
Measures gas through a metabolic chamber or cart. Measures O2 consumed and CO2 produced, and estimates energy expenditure
Bomb calorimetry
Determines energy content of nutrients by the amount of heat produced during combustion of the nutrient
How does bomb calorimetry work?
- Put food in the chamber and fill it with oxygen
- Water surrounds the chamber
- You light the chamber and combust it
- Measure the heat produced during combustion of the nutrient to determine energy
Metabolic Chamber
A method used for indirect calorimetry where people are in a lab and scientists can see exactly what they eat, how much O2 they consume and how much CO2 they expel
Metabolic Cart
Measures O2 and CO2 by putting a mask over someones face while they do things
Respiratory Exchange Ratio (RER)
CO2 Produced / O2 consumed
What is the average RER at rest
0.75
Energy Metabolism
Chemical reactions that enable cells to store and use energy from nutrients
Basic concept of energy metabolism
Substrate goes into an enzyme to create a product. That product becomes the new substrate that can go into a different enzyme and create a new product
Three substrates our bodies prefer to use
- Phosphocreatine (PCr)
- Carbohydrates (glucose)
- Fat (fatty acids)
Phosphocreatine (PCr)
Produces ATP quickly but only produces small quantities (sprinting)
Carbohydrates (glucose)
Produces ATP at an average rate and produces average amounts of it
Fat (fatty acids)
Produces ATP at a slow speed but produces a lot of it
ATP creation BASIC
ATP is broken down when we require energy into ADP. That ADP receives 1 phosphate during phosphorylation to turn back into ATP
Locations of glucose in the body
Skeletal Muscle and the Liver
Locations of fat in our body
Visceral Fat: Around the abdomen/ main organs
Subcutaneous Fat: Under the skin
Intramuscular Fat: Between the muscles
Three energy systems
- Glycolytic
- Aerobic (oxidative phosphorylation)
- ATP-PCr
Glycolytic Energy System
Pathway that uses glucose (blood/liver) or glycogen (liver/muscle) to produce ATP
Glycogen
The polysaccharide of glucose
Glycolysis
The breakdown of carbohydrates (either glycogen stored
in the liver/muscle or glucose delivered in the blood) to
resynthesize ATP
How many ATP does glycolysis produce?
2-3 ATP
Glycogenesis
Glucose turning into its polymer glycogen
Glycogenolysis
Breaking glycogen into its monomer glucose
Where does glycolysis occur?
Cytoplasm of cells
Besides ATP, what are the other outcomes of glycolysis?
2 Pyruvate (Each has 3 carbons on it)
If there is no oxygen, what happens to the pyruvate?
Anaerobic Glycolysis: Pyruvate is converted into lactate. ATP resynthesis occurs at a faster rate but in little quantity. (Fast glycolysis)
If there is oxygen, what happens to the pyruvate?
Aerobic Glycolysis: Pyruvate can be sent to the mitochondria for oxidative phosphorylation. ATP synthesis occurs at a slower rate (Slow glycolysis)
Oxidative phosphorylation (aerobic system)
The transporting of electrons across the mitochondria to signals the pump which creates ATP
Substrates used in oxidative aerobic system
Carbohydrates and fats
Cellular Respiration Three Steps
- Glycolysis
- Krebs Cycle
- Electron transport chain (oxidative phosphorylation)
What happens between glycolysis and the krebs cycle
Pyruvate is brought to the mitochondria and converted into acetyl-CoA instead of lactate and then is placed into the start of the Krebs cycle
Krebs Cycle
Acetyl-CoA enters the cycle. Uses NAD+, FAD, and ADP to create ATP
Krebs Cycle outputs
2 ATP, FADH2, and NADH
Where does the Krebs Cycle occur?
Mitochondria
Beta-oxidation
The creation of Acetyl-CoA from fatty acids (occurs in mitochondria)
Electron Transport Chain
H+ ions are pumped up across the gradient which creates a concentration gradient
When the gradient becomes too much, ATP synthase is activated to create the ATP’s
How many ATP does oxidative phosphorylation create?
~24 ATP
Total amount of ATP created in the aerobic cellular respiration
36-38
Aerobic Lypolysis
Triglycerides are broken down into their monomers of fatty acids
Lipogenesis
Fatty acids combine into creating their polymer, triglycerides
What is produced when a triglyceride is broken down?
3 individual fatty acids and 1 glycerol molecule
Fatty acid length and ATP
Since most fatty acids are very large, they produce more energy in the form of ATP
How many ATP are created from oxidation phosphorylation from fat and beta-oxidation
100+
