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
What happens to the food we eat when it is metabolised?
(Food stores as aa, triglycerides and glycogen)
They are converted into a compound know as ATP (universal energy compound)
When ATP is broken down energy is provided for cellular processes, such as digestion, nerve transmission and muscular contraction
What happens in the breakdown of ATP
to extract the energy from ATP the enzyme ATPase is released which stimulates the final high energy bond to be broken.
This exothermic contraction releases energy for muscular contraction and ADP
Breakdown of ATP equation and reaction type
ATP ->ADP + P + energy
(exothermic reaction)
What happens in the resynthesis of ATP
(Doesn’t last long only 2-3 seconds). e.g several seconds of sprinting.
To continue to exercise you need ATP to be resynthesised. Requires endothermic reaction, energy in surrounding area is absorb to rebuild a high energy bond between ADP and a single phosphate
Resynthesis of ATP equation and reaction type
ADP + P + energy->ATP
(endothermic reaction)
energy
ATPase
2/3
resynthesis
endothermic
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
e.g 60m and 100m
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