Energy systems

what are the different forms energy can come in?

• chemical energy

• electrical energy

• potential energy

• kinetic energy

what is chemical energy?

found in foods; released during chemical reactions

what is electrical energy?

 energy is stored and released by charged particles, human body uses electrical energy to pass impulse through the nervous system to cause muscle contractions

what is potential energy?

this energy stored within an object due to its position e.g. energy stored in the muscle tissues

what is kinetic energy?

 energy that causes the movement of an object

what provides us with energy?

Food provides us with energy but we have to break it down in order to release ATP

what is ATP made up of?

• 1 adenosine molecule

• 3 phosphate molecules

how is ATP broken down to release energy?

• to release energy that is held in the bonds between the 3 phosphate molecules in ATP, one of these bonds must be broken.

• chemical reaction is catalyzed by ATPase, which splits the bond between the 3 phosphate molecules  to produce ADP, 1 phosphate molecule and energy.

• This is a chemical reaction

how long does ATP last?

2-3 secs

why do we have to resynthesise ATP?

• we don’t have an endless supply

• need it for energy in the future

how is ATP resynthesized and what type of reaction is it?

• resynthesized by using energy to from a bond between a phosphate molecule and ADP

• endothermic reaction

what are the 3 energy systems?

• ATP-PC system

• Glycolytic system

• Aerobic system

what does the ATP-PC system resynthesise ATP from?

resynthesizes ATP from breakdown of phosphocreatine

what does the glycolytic system resynthesise ATP from?

resynthesizes ATP from the breakdown of glycogen

what does the aerobic system resynthesise ATP from?

resynthesis ATP from the breakdown of glycogen

what type of reaction is the ATP-PC system using (aerobic or anaerobic)?

anaerobic

what type of reaction is the glycolytic system using (aerobic or anaerobic)?

anaerobic or aerobic

what type of reaction is the aerobic system using (aerobic or anaerobic)?

aerobic

what is the chemical used in the ATP-PC system?

phosphocreatine

what is the chemical used in the glycolytic system?

glucose/glycogen

what is the chemical used in the aerobic system?

glucose/glycogen and fat

what is the site of reaction for the ATP-PC system?

cytoplasm

what is the site of reaction for the glycolytic system?

cytoplasm

what is the site of reaction for the aerobic system?

mitochondria

what is the controlling enzyme for the ATP-PC system?

Creatine kinase

what is the controlling enzyme for the glycolytic system?

• Phosphofructokinase (PFK) - main one

• Glycogen phosphorylase

what is the controlling enzyme for the aerobic system?

• Acetyl Coenzyme A

• PFK

• GPP

• lipase (if fats used)

what is the ATP yield for the ATP-PC system?

1 ATP

what is the ATP yield for the glycolytic system?

2 ATP

what is the ATP yield for the aerobic system?

38 ATP

what are the by products after using the ATP-PC system?

none

what are the by products after using the glycolytic system?

• NaDH

• lactic acid

what are the by products after using the aerobic system?

• carbon dioxide

• water

how long does the ATP-PC system last?

up to 10 seconds

how long does the glycolytic system last?

2-3 mins

how long does the aerobic system last?

forever

what intensity does the ATP-PC system work in?

highest intensity (explosive)

what intensity does the glycolytic system work in?

very high intensity

what intensity does the system work in?

low/moderate intensity

what happens when there the exercise is high intensity? (in terms of by products)

• high intensity = no oxygen

• pyruvic acid converted to lactic acid by lactate dehydrogenase

explain the sequence of how energy systems run through during exercise

what does the enzyme phosphofructokinase (PKF) do in the glycolytic system?

• as ADP + P levels rise PFK is released which catalyses the breakdown of glucose in the blood

what happens in the glycolytic system if the glucose levels are low?

• glycogen (stored glucose in the muscle cells) is broken down by an enzyme called glycogen phosphorylase (GPP) to retain the concentration of glucose back in the blood

what happens in the glycolytic system (anaerobic)?

• converts glucose into pyruvic acid

• one mole of glucose produces 2 moles of ATP and produces a by-product called NADH

• energy is unable to be continually extracted from pyruvic acid so an enzyme lactate dehydrogenase (LDH) is released converting pyruvic acid into lactic acid

what happens as lactic acid accumulates when using the glycolytic system anaerobically?

• it inhibits enzyme activity from earlier processes, slowing the rate of ATP resynthesis, leading to fatigue and OBLA

what happens if oxygen is available in the glycolytic system?

• in the final stage pyruvic acid is converted to acetyl CoA instead of lactic acid

• this then enters the Krebs cycle of the aerobic energy system

when all stages are combined how many molecules of ATP are produced from the aerobic system? (and how many per each stage)

• 2 ATP from aerobic glycolysis

• 2 ATP from krebs cycle

• 34 ATP from electron transport chain

TOTAL: 38 ATP

which is the most effective energy system?

aerobic system

how many molecules of acetyl CoA does glycolysis produce per one molecule of glucose?

produces 2 acetyl CoA per 1 glucose

where does the krebs cycle occur?

the matrix of the mitochondria

what happens during the krebs cycle?

• hydrogen is released and accepted by the hydrogen carried NAD and FAD

• ATP is resynthesized

what does the krebs cycle produce per glucose molecule?

• 4 CO2

• 2 reduced FAD

• 6 reduced NAD

• 2 ATP

what happens the hydrogen produces in the krebs cycle?

• transported by NAD and FAD to the electron transport chain

what happens at the electron transport chain?

• hydrogen is split into ions and electrons

• ions are transferred over the inner membrane of the mitochondria

• electrons pass through a series of reactions which release energy and produce H20

• the energy is used to resynthesise 34 ATP from ADP

why may some sports want to save glycogen stores? how is this done?

• some sports like football and rugby may want to save glycogen stores for explosive moment as glycogen can be used for aerobic and anaerobic exercise

• may use fats as a fuel for aerobic system during lower intensity exercise

• enzyme lipase is released to breakdown fats into free fatty acids and glycerol where the free fatty acids can be converted to acetyl CoA and enter the krebs cycle

how is energy production during exercise determined?

determined by the duration and intensity of the exercise

explain the graph

• ATP - PC - provides energy during maximum intensity exercise for a short duration (up to 10 secs) e.g. a power lifter

• glycolytic - provides energy during high intensity exercise for an intermediate period of time (2-3 mins) e.g. 200m sprinters

• aerobic - provides energy during low intensity exercise which lasts for an extended period of time (3+ mins) e.g. marathon runners

what will those with a high anaerobic fitness be able to do?

• exercise at high intensity for longer, due to greater stores of PC and an improved ability to handle lactic acid

what will those with high aerobic fitness be able to do?

• will be able to support a greater intensity of exercise before relying on anaerobic glycolysis for energy