Immediate System

Question 1

break down what we need from energy to survive and their amounts

Answer 1

RMR - 60-75%

TEF - 10%

PA - 15-30%

Question 2

• During exercise, demand for ATP increases up to …-fold compared to rest
• ATP … does not change appreciably

Question: If [ATP] does not change much during exercise, how does the muscle cell “know” to activate pathways to resynthesize ATP?

ATP only goes down when you do 250% of your VO2

… … is a signal to increase ATP resynthesis

Signals to match ATP demand with ATP synthesis

• […]
  Metabolites
• […], […], […], […]
  Mitochondrial reduction/oxidation state
• […] / […]

Answer 2

• During exercise, demand for ATP increases up to 100-fold compared to rest
• ATP concentration does not change appreciably

Question: If [ATP] does not change much during exercise, how does the muscle cell “know” to activate pathways to resynthesize ATP?

ATP only goes down when you do 250% of your VO2

Increase in ADP, AMP, and Pi is a signal to increase ATP resynthesis

Signals to match ATP demand with ATP synthesis

• [Ca 2+ ]
  Metabolites
• [ADP], [AMP], [Pi], [H +]
  Mitochondrial reduction/oxidation state
• [NAD+] / [NADH]

NAD+ increase ATP turnover.
You have many Canada Post machines in the station, they are empty and ready to deliver. Post office is behind, they should increase workload

Question 3

Sources of ATP
… / phosphagen / alactic
* … and p…

Glycolytic / lactic
* Glycogenolysis and …
* … production

… / aerobic
* … (…)
* … phosphorylation

WHAT IS THE MOST POWERFUL
WHAT IS THE LARGEST CAPACITY
WHAT IS THE LONGEST

Answer 3

Sources of ATP
Immediate / phosphagen / alactic
* Adenosine triphosphate and phosphocreatine

Glycolytic / lactic
* Glycogenolysis and glycolysis
* Lactate production

Oxidative / aerobic
* Different sources (carbohydrate, lipid, protein, lactate)
* Oxidative phosphorylation

IMMEDIATE
OXIDATIVE
OXIDATIVE

Question 4

Immediate system

S…

S…
* … + ADP + H + → ATP + …

A…
* … + … → …

ATPase
A…P → …

Answer 4

Immediate system

Stored ATP

Stored Phosphocreatine
* PCr + ADP + H + → ATP + Cr

ADENALYTE KINASE
* ADP + ADP → ATP + AMP

ATPase
ATP → ADP + Pi + H +

Question 5

Catalyzes this reaction: …
* … + ADP + H+ → … + Cr

… line of defense; … buffer
* We have ~… mmol/kg dry muscle (ATP)
* We have ~… mmol/kg dry muscle (PCr)
* More PCr is to maintain the …

EXAMMMMMM
CK is activated by:
* Increase in […]
* Decrease in […]

PCr transfers a …

The PCr breakdown releases … kcal/per mole
This energy is … than that seen in the breakdown of the …

Answer 5

Creatine kinase

• PCr + ADP + H+ → ATP + Cr

First line of defense; ATP buffer. Fastest and most effective
* We have ~90 mmol/kg dry muscle (PCr)
* We have ~25 mmol/kg dry muscle (ATP)
* More PCr is to maintain the homeostasis of ATP

Activated by:
* Increase in [ADP]
* Decrease in [ATP]

PCr transfers a phosphate to ADP to form ATP

The PCr breakdown releases 10.3 kcal/per mole
This energy is more than that seen in the breakdown of the ATP
but the same of ADP to AMP

Question 6

Adenylate kinase ADK - what do we think?

• … + … → …
• …

Quantitatively … source of ATP during exercise
* Occurs during …
* Removes adenine nucleotides from pool
* … recovery time

Answer 6

Adenylate kinase ADK - we dont like it because that AMP doesnt go to ATP, it transforms into toxic ammonia and is removed

• ADP + ADP → ATP + AMP
• AMP + H + → IMP + NH4+

Quantitatively insignificant source of ATP during exercise
* Occurs during VERY high-intensity exercise
* Removes adenine nucleotides from pool
* Increases recovery time

Question 7

• ATP-PCr system can act in … but …

During the first few second of exercise:
* … is maintained but … decreases

At exhaustion:
* … and …
* At exhaustion: the decline in ATP and PCr prevents further …
* A combination of stored ATP and PCr can sustain the muscles’ energy for ~ … Beyond that time, other energy systems should be activated.

Answer 7

• ATP-PCr system can act in the presence of oxygen but does not need oxygen

During the first few second of exercise:
* ATP is maintained but PCr decreases

At exhaustion:
* Both ATP and PCr decrease
* At exhaustion: the decline in ATP and PCr prevents further muscle contractions
* A combination of stored ATP and PCr can sustain the muscles’ energy for ~ 3 to 15 s. Beyond that time, other energy systems should be activated.

Question 8

 Rate Limiting Enzyme (RLE): enzymes contributing to the control of the …
 RLE is usually located in an …
 The activity is RLE depends on the accumulation of substrate further down the pathway

when you have lots and lots of ATP, it decreases the rate of production

Answer 8

 Rate Limiting Enzyme (RLE): enzymes contributing to the control of the rate of a reaction
 RLE is usually located in an early step of a pathway
 The activity is RLE depends on accumulation of substrate further down the pathway

Question 9

Summary

Muscle cells …
* … changes to […] during exercise
* ATP … matches ATP …

Skeletal muscle stores …
* A … high-intensity exercise

Signals related to muscle contraction (not [ATP] itself) “turn on” pathways to generate ATP (e.g., … reaction)
* Immediate system provides rapid but limited supply of ATP

Answer 9

Summary

Muscle cells defend [ATP]
* Minimal changes to [ATP] during exercise
* ATP synthesis matches ATP demand

Skeletal muscle stores very little ATP
* A few seconds of high-intensity exercise

Signals related to muscle contraction (not [ATP] itself) “turn on” pathways to generate ATP (e.g., creatine kinase reaction)
* Immediate system provides rapid but limited supply of ATP