Unit 1: Energy Production Flashcards
What is the role of ATP
ATP is an energy source used throughout the body. It provides the energy needed for cross bridge formation in muscle contraction.
Stored chemical energy
What is an absolute and what is a relative workload. Give examples
Absolute: known or assumed to be below an individual’s maximum and is constant for everyone
i.e. all class members exercise at 150 bpm
May be light for some and high for others
Relative: individualizes a workload for each person
A heart rate workload may be to ask each person to work at a heart rate of 60% of heart rate max
This may be 96 bpm for an older individual and 120 bpm for a younger individual
Name the 3 energy systems
- ATP – CP system (alactic system) POWER
- anaerobic glycolysis (lactic system) SPEED
- aerobic metabolism (oxidative phosphorylation) ENDURANCE
How many ATP does cellular respiration and glycolysis produce
38
Describe Cellular respiration and Glycolysis
Can use CHO, FFA and PRO as substrate. Has Acetyl COA as the central converting substance. Glycolysis is first step when using CHO. Glycolysis needs no O2, and has glucose transported via GLUT transporters (GLUT 1 at rest GLUT 4 at exercise). Glycolysis is mediated by enzymes that include:
- hexokinase
- PFK
- Pyruvate Kinase
- 1,6 Diphosphate
- O2 (inhibits glycolysis).
Now NAD needs to be converted to Acetyl COA (central conversion substance) with use of O2. If no O2 NAD goes to H+ to accept H+
Net gain of 3 ATP w glycolysis
Name the rate limiting enzymes in glycolysis
Hexokinase
PFK
Pyruvate Kinase
1,6 diphosphate
O2
What happens to hydrogen during CR/glycolysis with activity
- with moderate activity, hydrogen is oxidized at the same rate as production à pyruvate (+ H2O) (slow glycolysis – glucose)
- with intense activity, hydrogen production exceeds oxidation à lactate production from pyruvate (lactate dehydrogenase) (fast glycolysis – glycogen)
- therefore lactate accumulation signals high anaerobic metabolism
What does PFK do?
Breaks down glucose into pyruvate to produce ATP w no O2
What is the primary outcome of the krebs cycle
generating electrons in the form of H+ to pass NAD and FAD into respiratory chain
Role of NAD and FAD
Both transport hydrogen
reduce hydrogen when picking up and oxidize them
Summarize the krebs cycle
Does not use O2 but must be aerobic, occurs in mitochondrial matrix and gets 2 ATP
Explain ETC and Oxidative Phosphorlation
- A series of chemical reaction in the mitochondria that transfer electrons from the hydrogen atom carried NAD and FAD to oxygen
- Water is formed as a by-product
- The electrochemical energy released by the hydrogen ions is coupled to the formation of ATP from ADP and Pi via ATP synthase
How many ATP for one glucose in skelatal muscle
- 2 ATP from anaerobic glycolysis
- 2 ATP from Acetyl-CoA in the Krebs Cycle
- 26 ATP from ETS/OP
TOTAL 30 ATP (net)
Where is CHO stored in body
Blood glucose 5-7g
Intramuscular glycogen 300-400 g
Liver Glycogen 100g
Describe muscle vs liver glycogen
Muscle: Muscle cells lack enzyme glocise-6-phosphate, so intramuscular glycogen stores are destined for that muscle
Liver: Liver glycogen can be converted to glucose and used in blood for general use
Where are triglycerides available
Intramuscular fat stores 3000 kcal
Adipose tissue stores virtually unlimited
Describe fat mobilization/beta oxidation
The breakdown of TG into FFA is catalyzed by HSL. FFA that is transported in the blood is bound to albumin, then gets taken to acetyl COA. FFAs taken up by receptors on muscle cell then transported to mitochondrial matrix Whatever is converted into glycerol can enter the cytoplasm in some cells or be converted to glucose. beta oxidation is breaking down fat and enetring as Acetyl COA
How many ATP from fat
147 from one 18 carbon fat molecule
for each triglyceride 441
total 460 atp
Why cant we burn fats like CHO
need pyruvate to keep fat burn going - so, during exercise:
○ you can burn a combination of fat and CHO
○ you can burn only CHO (e.g. during high-intensity exercise)
○ but you can not burn only fat
○ therefore, carbohydrate sparing during exercise is important
What is hitting the wall and how does it happen
Its when you have glycogen depletion and occurs because of:
- prolonged exercise duration (e.g. marathon, triathlon, etc.)
- multiple repetitive bouts of extremely high intensity work
- consecutive days of training (especially with inadequate CHO diet)
- inadequate energy intake/dietary limit of carbohydrates
What is carb loading
When you load up on carbs before exercise
- CHO loading results in additional storage of glycogen in the muscle fibers that can be 2-3 times of normal
- This avoids hitting the wall
What can low CHO do to Energy metabolism
- If CHO is inadequate, oxaloacetate is converted to glucose to maintain brain and nervous system function
- oxaloacetate is necessary to Krebs
- Without oxaloacetate acetyl coA derived from fatty acids become metabolites called ketones
- Ketones can be used as fuel or if accumulate can disrupt acid-base balance
- During exercise aerobically trained individuals can use ketones more effectively than untrained individuals
cycle
What is keto and effect on exercise
Is a significant reduction in CHO intake. Promotes the use of ketones as fuel. low muscle glycogen availability promotes molecular changes that enhance training-derived endurance adaptations. body can reserve large amounts of energy in the form of fat
Describe protein metabolism
To be used a fuel must remove nitrogen
- Mostly undergo transamination – transfer of amino group from an amino acid to a keto acid
* Amino acid can enter into energy metabolism
- Keto acid forms alanine which undergoes gluconeogenesis containing amino group
Describe intramuscular cellular regulation
- When ATP is adequate there is no need to increase production – negative feedback.
- When muscle activity begins and ATP is broken down into ADP and P these by products stimulate production of ATP so muscle contraction can continue
Describe Extracelluar regulation of metabolism
- Regulation of blood glucose levels governed jointly by ANS and endocrine system
- When exercise begins, working muscles signal neurohormonal response from hypothalamus
- Hypothalamus stimulates anterior pituitary and SNS
- Norepinephrine and epinephrine are released and act directly on fuel sites
○ Increase in mobilization and utilization of FFA
○ Increase in breakdown of glycogen and increase in gluconeogenesis
○ Decrease in uptake of glucose into non working cells
