energy systems

the bodt must use one of three energy systems to produce the energy which is required to resynthesise ATP from ADP + Pi

• ATP-PC system

• Glycolytic system

• Aerobic system

ATP-PC system

• resynthesises ATP from breakdown of phosphocreatine

glycolytic system

• resynthesises atp from the breakdown of glycogen

aerobic system

• resynthesises ATP from the breakdown of glycogen, glucose and free fatty acids

site of reaction in ATP-PC

• cytoplasm of a muscle cell

what chemical does it use

• produces energy by breaking down phosphocreatine

• the energy and phosphate molecule released from the breakdown of PC are then used to resynthesise 1 ATP and 1 ADP

what is the enzyme used in the ATP-PC system

• creatine kinase

is the ATP-PC system aerobic or anaerobic

• anaerobic system

• therefore supplies energy for actions such as sprinting

ATP yield from the ATP-PC system

• 1 ATP molecule

time frame from ATP-PC system

• up to 10 secs of exercise

• due to limited stores of PC in the body

by products of ATP-PC system

• no by products

what is the ATP-PC system used for

• used to provide energy very quickly, as PC is readily available and doesn’t require oxygen to be delivered

process of ATP-PC system

• system kicks in after high intensity exercise after 1st 2 secs depletes original stores of ATP

• ATP levels fall dramatically and ADP + PI levels increase

• triggers the release of creatine kinase which triggers the breakdown of the immediately available fuel phosphocreatine (PC)

• PC is made up of creatine with a high energy phosphate bond and is stored in muscle cells

• bond is broken which releases energy for ATP synthesis

• every one mol of PC broken down, one mol of ATP is resynthesized

when does the glycolytic system kick in

• used to produce energy once the PC stores have been used up when performing anaerobically

where does the glycolytic system take place

• in the cytoplasm of a muscle cell

what type of reaction is the glycolytic system

• anaerobic

• (if it has oxygen it goes to aerobic)

what is the chemical used in the glycolytic energy system

• glucose in the blood

• or glycogen

what is the controlling enzyme for glycolytic system

• as ADP + Pi levels rise, an enzyme is released which catalyses the breakdwon of glucose in the blood

• phosphofructokinase (PFK)

what happens if glucose levels in blood are low

• glycogen (stored glucose in muscle cells) is broken down by an enzyme

• glycogen phosphorylase (GPP)

• to retaain concentration of glucose back in blood

what happens in glycolytic system if there is no oxygen available

• glucose is used as a fuel and broken down to continue the resynthesis of ATP in the cytoplasm

• a process called anaerobic glycolysis

ATP yield from glycolytic system

• 2 ATP molecules

actual products from glycolytic system

• glucose is converted into pyruvic acid

• 2 ATP mols

• NADH is by-product

by products from glycolytic system

• NADH

• lactic acid

duration of glycolytic system

• 2-3 mins

process of glycolytic system

• kicks in during high intensity activity after first 10 secs exhausts the PC stores and ATP levels fall- ADP + P levels will increase again

• this triggers the release of PFK-catalyses the breakdown of glucose

• if low glucose- GPP catalyses the breakdown of stored glycogen

• anaerobic glycolysis results in production of pyruvic acid

• one molecule of glucose= 2 ATP produced

consequences of glycolytic system peaking at 1 min at falling at 3

• at high intensity, oxygen is not available to continue the energy extraction from pyruvic acid

• lactate dehydrogenase is released

• this is a enzyme which catalyses the conversion of pyruvic acid into lactic acid which accumulates and slows ATP synthesis

problems with anaerobic glycolysis

• frees only 5% of potential energy held in glucose molecule

• lactic levels rising= pH decrease and acidity increases

• this inhibits enzyme activity preventing further breakdown of fuel and ATP resynthesis, causing local muscular fatigue

• point at which blood lactate levels significantly rise is known as OBLA

what occurs in the glycolytic system if oxygen is available

• the final stage of glycolic energy system will involve pyruvic acid being converted to acetyl CoA (instead of lactic acid)

• this will enter krebs cycle of aerobic system

what type of reaction is the aerobic system

• aerobic

what chemicals are used in aerobic system

• glucose

• glycogen

• triglycerides/ fats

site of aerobic system

• mitochondria

• specifically cytoplasm, matrix and cristae

controlling enzyme for aerobic system

• GPP

• PFK

• acetyl coenzyme A

• lipase

ATP yield from aerobic system

• 2 ATP from aerobic glycolysis

• 2 ATP from krebs cycle

• 34 ATP from electron transport train

• 38 overall

by products of aerobic system

• carbon dioxide

• water

what are the 3 stages in the aerobic system

1. aerobic glycolysis

2. krebs cycle

3. electron transport chain

aerobic glycolysis

• in cytoplasm converts glucose into pyruvic acid with the enzyme PFK

• releases enough energy to resynthesise two moles of atp

• converting glycogen into glucose (by GPP) maintains this process for extended periods of time

• oxygen is now in sufficient supply, the pyruvic acid is no longer converted into lactic acid

• goes through link reaction catalysed by coenzyme A which produces acetyl CoA

krebs cycle

• acetyl CoA combines with oxaloacetic acid to from citric acid which is oxidised through a cycle of reaction

• co2, hydrogen and enough energy to resynthesise 2 mols of ATP are released

• occurs in the matrix of mitochondria

electron transport chain

• 3rd stage of aerobic system producing enough energy to resynthesise 34 ATP in the mitochondrial cristae

aerobic system and FFAs

• glycogen stores can fuel the system for a long time

• triglycerides or fats can also be metabolised as free fatty acids (FFAs) which provide a huge potential fuel store

• on the release of lipase- responsible for breaking down fats and triglycerides- they are converted into ffas and glycerol.

• ffas converted to acetyl coa and follow the same path through krebs and etc and pyruvic acid

total number of ATP released in aerobic system

• 2 from aerobic glycolysis

• 2 from krebs

• 34 from electron transport chain