7.1 - Energy for exercise Flashcards
What is glycolysis
breakdown of glucose
What is ATP
only usable form of energy for muscular contraction
What enzyme breaks ATP down
ATPase
What type of reaction is the break down of ATP
exothermic
What is left when ATP is broken down
ADP and a signle phosphate
What is left when ATP is broken down
ADP and a single phosphate
Where is ATP stored
muscle cell
Why does ATP have to constantly be resynthesized
as ATP- exhausted quickly so to continue exercising- ATP needs to be resynthesised
what reaction occurs to resynthesise ATP
endothermic reaction
Breakdown of ATP equation and reaction type
ADP + P + energy
(exothermic reaction)
Resynthesis of ATP equation and reaction type
ADP + P + energy
(endothermic reaction)
Name the 3 energy systems that provide energy for ATP resynthesis
-ATP-PC system
-glycolytic system
-aerobic system
When does the ATP-PC system kick in
very high-intensity activity
after the first 2 seconds of intense activity depletes original ATP stores
Explain why the ATP-PC system kicks in and what happens
ATP levels fall dramatically and ADP and P levels rise
triggers release of creatine kinase
What is creatine kinase
enzyme which catalyses the breakdown of phosphocreatine
What is creatine phosphate made up of (PC)
creatine with a high energy phosphate bond
-stored in muscle cells
Explain how and where the creatine phosphate (PC) is broken down
-what does it do when broken down
broken down anaerobically in sarcoplasm
–> releases energy for ATP resynthesis
ATP-PC SYSTEM
-type of reaction
-fuel used
-specific site of reaction
-controlling enzyme
-ATP yield
-by products
-intensity
-duration of system
anaerobic
PC (phosphocreatine)
sarcoplasm
creatine kinase
1 ATP
no by products
very high intensity
2-10 secs
What is a coupled reaction
where products of one reaction are used in another
What are the advantages of the ATP-PC system
- no delay of oxygen
- PC readily available in the muscle cell
-simple and rapid breakdown of PC
What are the weaknesses of the ATP-PC system
- low ATP yield
- small PC stores
-> rapid fatigue
When does the glycolytic system kick in
high intensity activity after first ten seconds of intense activity exhausts PC stores and ATP levels fall
Name the 2 specific stages in the ATP-PC system
(atpase)
ATP ———> ADP + P + energy (EXOthermic)
Energy + P + ADP -> ATP (ENDOthermic)
coupled reaction: breakdown of ATP releases energy which can be used to resynthesise ATP
Explain how the ATP system kicks in in the glycolytic system
ADP and P levels rise again and trigger release of phosphofructokinase (PFK)
What is phosphofructokinase
enzyme which catalyses the breakdown of glucose (glycolysis)
What occurs if glucose levels fall in glycolytic system
- glycogen phosphorylase (GPP) is released, converting glycogen into glucose to maintain its concentration in the blood stream
What is glycogen phosphorylase (GPP)
enzyme which catalyses breakdown of stored glycogen
What is the process of the breakdown of glucose in the absence of oxygen
anaerobic glycolysis
What does anaerobic glycolysis produce
pyruvic acid
What happens when at high intensity exercise and energy extraction from pyruvic acid cant continue
- lactate dehydrogenase (LDH) is released
What is lactate dehydrogenase (LDH)
enzyme which catalyses conversion of pyruvic acid into lactic acid
How does muscle fatigue occur in glycolytic system
anaerobic glycolysis frees only about 5% of potential energy
lactic acid levels rise
PH in muscle cells decreases -> inhibits enzymes
prevents further breakdown of fuel and ATP resynthesis causing muscle fatigue
What is the point where blood lactate levels significantly rise
OBLA
Give the equation for the breakdown of glucose in the glycolytic system
glucose –> pyruvic acid + energy
Give the equation for lactic acid production in the glycolytic system
Pyruvic acid –> lactic acid
Give the equation for the resythnthesis of ATP in the glycolytic system
energy + 2P + 2ADP —> 2ATP
Give the equation for the breakdown of ATP in the glycolytic system
ATP —> ADP + P + energy from muscular contraction
When does the aerobic system kick in
low-moderate intensity activity
Name the three stages in the aerobic system
- aerobic glycolysis
- kerbs cycle
- electron transport chain
What does aerobic glycolysis in the sarcoplasm do
converts glucose into pyruvic acid with enzyme PFK catalysing the reaction
Meaning of aerobic glycolysis
releases enough energy to resynthesise two moles of ATP
What occurs when converting glycogen into glucose in aerobic glycolysis
maintains process for extended periods of time, oxygen is now in sufficient supply, pyruvic acid is no longer converted into lactic acid. Link reaction occurs catalysed by coenzyme A (produces acetyl CoA), allows access to mitochondria
Describe what occurs in the Krebs cycle
- acetyl CoA combines with oxaloacetic acid -> citric acid,
this is oxidised through reactions.
CO2, hydrogen and enough energy to resynthesise 2 moles of ATP are released. Occurs in matrix of mitochondria
GLYCOLYTIC SYSTEM
-type of reaction
-fuel used
-specific site of reaction
-controlling enzyme
-ATP yield
-by products
-intensity
-duration of system
-anaerobic reaction
-glycogen/ glucose
-sarcoplasm
-GPP, PFK, LDH
-2 ATP
-lactic acid
-high intensity
-10-180 secs
What are the 3 strengths of the glycolytic system
-no delay for oxygen- anaerobic
-fast fuel breakdown for ATP resynthesis
-provides energy for high-intesnity actvities
What are the 2 weakness of the glycolytic system
-relatively low ATP yield
-fatiguing by-product
Meaning of the krebs cycle
2nd stage of aerobic system producing energy to resynthesise 2 ATP in mitochondrial matrix
Meaning of anaerobic glycolysis
partial breakdown of glucose into pyruvic acid
Meaning of electron transport chain
3rd stage of aerobic system producing energy to resynthesise 34 ATP in mitochondrial cristae
What is ATP made up of
-1 adenosine molecule
-3 phosphate groups
What occurs in terms of ATP to create muscle contraction
-ADENOSINE-PHOSPHATE-PHOSPHATE->PHOSPHATE
-bond in between last two phopshate groups (one with arrow) is where energy is stored
-this bond is broken down by ATPase
-this releases energy -> muscle contraction
Give an example of a coupled reaction
energy from exothermic reaction is used in endothermic reaction
How is the resynthesis of ATP achieved
-achived by 3 energy systems:
-ATP/ PC
-glycoltyic
-aerobic glycolysis
-
How is ATP resynthesised using the ATP-PC system
-CREATINE- ENERGY- PHOPSHATE
-enzyme creatine kinase breaks bond between creatine & phosphate- releasing energy
-energy released reconnects free phosphate to adenosine diphosphate to resynthesise ATP
-ADENOSINE- PHOSPHATE- PHOSPHATE- ENERGY- PHOSPHATE
What is the energy continuum
contribution of each energy system to overall energy production
What is intermittent exercise
activity where the intensity alternates, either during interval training between work & relief intervals or during a game with breaks of play
Give an example of intermittent exercise
rugby player who is required to alternate between various modes of activity; standing, walking, running, jumping
ATP-PC SYSTEM
-type of reaction
-site of reaction
-food fuel used
-controlling enzyme
-ATP yield
-specific stages
-by-products
-intensity of activity
-duration of system
-aerobic (with oxygen)
-sarcoplasm
-glycogen
-GPP, PFK, lipase, co-enzyme A
-1 mole of glycogen yields 38 mole of ATP (1:38)
-aerobic glycolysis, krebs cycle, electron transport chain
-co2, h2o
-low/moderate intensity
-3 mins +
What energy system is present duing high intensity activites lasting <10 secs
-ATP-PC system is predominant
What energy system is present duing high intensity activites lasting 10 secs to 3 mins
glycolytic system is predominant
What energy system is present duing low-moderate intensity activites lasting >3 mins
aerobic system is predominant
What is threshold
when an athletes predominant energy production moves from one energy system to another
-e.g. netballer uses atp-pc system to receive ball on centre pass, but uses glycoltyic system when man marking
Explain what happens in the ATP-PC system during very high intensity exercise
-atp levels fall
-adp & p levels rise
-triggers release of creatine kinase (breaks down PC in sarcoplasm)
-for every mole of PC broke down, 1 mole of ATP is resynthesised
-this forms a coupled reaction
Explain what happens in the glycolytic system during high intensity exercise
after first 10 secs of intense activity -> PC & ATP levels fall
-triggers release or phosphofructokinase (PFK) -> catalyses next avaliable
fuel: glucose
-if glucose levels fall (GPP) breaksdown storedglycogen -> converting it into glucose
-breakdown of glucose in absence of oxygen -> anaerobic glycolysis -> productuon of pyruvic acid
-at high intensity oxygen is not avaliable to continue energy extraction -> LDH is released
-LDH converts pyruvic acid into lactic acid
Explain what happens in the aerobic system duriny low to moderate exercise
aerobic glycolysis in sarcoplasm converts glucose -> pyruvic acid (PFK catlalyses reaction)
-converting glycogen into glucose by GPP maintains this process for long periods of time
-oxygen is in sufficient supply -> pyrivic acid doesnt convert into lactic acid
-goes through link reaction catalysed by coenzyme A -> acetyl coA
krebs cycle
-acetyl coA combines with oxloacetic acid -> citric acid
Give the coupled reaction of PC breakdown and ATP resynthesis within the ATP-PC system
PC ——————-> P + C + energy
creatine kinase
(EXOTHERMIC reaction)
ADP + P + energy —–> ATP
(ENDOTHERMIC REACTION)
Explain the reaction that occurs in the glycolytic system
glycogen—> glucose –> pyruvic acid —> lactic acid
GPP PFK LDH
Explain the reaction that occurs in the aerobic system
glycogen—> glucose –> pyruvic acid—–> acetyl coA
GPP PFK
—> citric acid —>krebs cycle —> electron transport chain
