Respiration Flashcards
Respiration definition
Process, which occurs in living cells, that releases energy stored in organic molecules such as glucose for ATP production
Respiration equation
6O2 + C6H12O6 -> 6H2O + 6CO2 + 38ATP
(Photosynthesise equation reversed)
Metabolism definition
Sum of all chemical process in organisms
Catabolism
Reactions breaking things down
Anabolism
Type of mechanism which breaks complex chemicals into smaller simpler ones
Anaerobic meaning
Without oxygen
Aerobic meaning
With oxygen
What is glucose RQ
1
What is RQ
Respiratory quotient
When different respiratory substances are used the ratios CO2 given out to O2 taken in
4 stages of respiration
1) Glycolysis
2) Link reaction
3) Krebs cycle
4) Electron transport chain
Where does glycolysis take place
Cytoplasm
What is glycolysis doing
Splitting glucose to be able to fit into mitochondria
What are the 2 stages in glycolysis
1) Phosphorylation
2) Oxidation
Phosphorylation process
1) Glucose is phosphorylated by adding 2 phosphates from 2 molecules of ATP
2) Hexose biphosphate is split using hydrolysis
3) 2 TP molecules created
Why do we add 2 phosphates
To raise the activation energy of glucose
Summary using word equation of phosphorylation
C6H12O6 + ATP -> Hexose phosphate -> Hexose biphosphate -> [hydrolysis] -> 2 TP
Overall what are we doing to the glucose in phosphorylation
Glucose + ATP twice
Then hydrolysed to enter oxidation stage
Describe the oxidation process
1) 2x Triose phosphates are oxidised to produce pyruvate
2) Hydrogen removed is transferred to NAD to form NADH
3) Net gain of 4 ATP molecules, using 2
What does glycolysis produce (products)
2 ATP
2 NADH
2 Pyruvate
What does the link reaction depend on
O2 availability
Describe the process of the link reaction
1) Pyruvate enter mitochondria matrix via active transport
2) Pyruvate is oxidised to acetate. CO2 is released and loses 2 hydrogens
3) Acetate combines with coenzyme A making acetyl-coenzyme A
How many types does the link reaction happen before entering krebs cycle
2 process happen so
2 acetyl coenzyme A enter, 2 products come out
2CO2 released
2NADPH produces
The link reaction equation
2 pyruvate + 2 NAD + 2 CoA -> 2CO2 + 2NADH + 2 acetyl coA
What enters the krebs cycle
Acetyl coenzyme A
What does the krebs cycle produce PER ONE GLUCOSE MOLECULE
4CO2
2ATP
6 NADH
2 FADH
1 CoA
What are the hydrogen atoms produced in the krebs cycle used for
To reduce NAD and FAD. 3NAD produced, 1 FADH per cycle
Describe the process of The Krebs Cycle
1) acetyl coA reacts with 4C producing citrate
2) coA released to be used in link reaction
3) citrate is decarboxylated and dehydrogenated to lose CO2 and Hydrogen
4) Hydrogen used to reduce NAD
5) This is repeated again
6) substrate level phosphorylation occurs producing ATP
7) Two more dehydrogenation reactions producing a FADH and NADH
8) Oxaloacetate is regenerated
Can the Krebs cycle occur without oxygen
No
What does the electron transfer chain do
Makes ATP from NADH and FADH
How many ATP molecues do 1 FADH and 1 NADH makes
1 FADH = 2ATP
1NADH = 3 ATP
What are the steps in the electron transfer chain
1) H atoms from krebs are donated from NADH and FADH
2) H atoms split into protons and electrons
3) Electrons enter electron transport chain, pass along chain through series of oxidation-reduction reactions, releasing a bit of energy each time
4) This energy pumps H+ ions from matrix into the inter-membrane space forming a concentration gradient
5) The H+ ions diffuse back into the matrix through ATP synthase enzyme turning ADP + Pi -> ATP
6) Oxygen is the final electron accepts, combing protons and electrons for form water
What happens to the oxygen at the end of respiration
Each O2 atom picks up 2 protons and 2 electrons to produce water
What is the equation for the use of oxygen in respiration
O2 + 4e- + 4H+ -> 2H2O
What would happen if there was no oxygen
there would be no where for electrons to go at the end of the electron transfer chain
NADH and FADH could not get rid of their electrons and everything would stop
Which cycles reduce NAD
Glycolysis
Krebs
Which cycle produces ATP
Glycolysis
Krebs
Which cycle requires ATP
Glycolysis
When does anaerobic respiration occur in
Glycolysis
Fermentation
What does anaerobic respiration convert
Glucose -> lactice acid
Pyruvate’s involvement in anaerobic respiration
Convert pyruvate into lactate using NADPH by oxidising NAD
NAD available again to accept electrons and protons so glycolysis continues
What happens if NAD is not regenerated in anaerobic respiration
Glycolysis stops because there would be no oxidised NAD available to accept electrons and protons
Anaerobic respiration equation
Pyruvate + NADH -> Lactate + NAD
Process of anaerobic respiration
(Glycolysis)
Glucose used two ways both resulting in lactate
1) Glycolysis process to produce pyruvate
2) 2NADH converted to 2 NAD and this cycle continues, releases 2x 2H atoms
3) 2x 2H atoms bind with pyruvate to form lactate
Production of ethanol in anaerobic respiration
Pyruvate loses a molecule of CO2 and accepts H from NADH to produce ethanol
Production of ethanol equation
Pyruvate + NADH -> ethanol + CO2 + NAD
Cycle to produce ethanol
1) Glucose to pyruvate using 2ADP -> 2ATP conversion and 2NAD to 2NADH back again cycle
2) Pyruvate takes up 2H atoms from NADH to make lactate
3) 2 acetyladehyde uses 2NAD to 2NADH cycle to form 2 ethanol
When does oxygen debt occur
In muscles when O2 is built up quicker than it is being supplied, forming oxygen debt
Reasons why anaerobic respiration important
- Oxygen debt occurs when O2 being used up quicker than it’s being supplied
- In absence of O2 glycolysis stops so NADH builds up
- Glycolysis continues if NADH converted into NAD
- This conversion happens when pyruvate takes up 2 H atoms from NADH to make lactate
- Lactate causes cramp fatigue in muscle that must be removed
- Can be oxidised back to pyruvate or taken to liver to be converted to glycogen
Describe how acetyl coenzyme A is formed
1) Oxidation of pyruvate and carbon dioxide released
2) Addition of coenzyme A
3) NADH is formed
Describe the roles of the coenzymes and carrier proteins in the synthesis of ATP
1) NAD/FAD are reduced
2)Electrons transferred in a series of redox reactions
3) Energy released as electrons passed on
4) Energy used to synthesise ATP from ADP and phosphate
5) Protons passed into intermembrane space
Equation for aerobic respiration
C6H12O6 + 6O2 -> 6CO2 + 6H2O
Describe what happens during phosphorylation
Two phosphates
combine with 6C glucose molecule
Two ATP molecules are used
Fructose biphosphate are formed
What happens during the oxidation of TP
Hydrogen is lost by TP
Hydrogen is picked up by coenzyme NAD
NADH is produced
State the process by which pyruvate moves through the membrane
Active transport
Because the movement of active transport requires ATP
State the role of coenzyme A in the link reaction
Coenzyme A combines with acetyl group to form acetyl CoA
Coenzyme A transports the acetyl group to the Krebs cycle
Define the Krebs cycle
The krebs cycle is a series of enzyme controlled reactions which occur in the matrix of the mitochondria, producing NADH, ATP, CO2 and FADH
How does temperature influence the rate of ATP production in respiration
Respiration consists of enzyme controlled reactions
So higher temperatures increase the rate of enzyme activity
When temperature is too high, enzymes become denatured AND ATP production stops
Suggest how a lack of cristae could lead to a decrease in ATP production
There is a smaller surface area of cristae
So fewer electron transport chains present
What is ATP synthase
Enzyme
Describe how these H+ ions move from the matrix to the inter-membranal space
Energy is released as electrons pass along electron transport chain
H+ ions use energy to move into the inter-membrane space
Carrier proteins are used as proton pumps
What are carrier proteins used for in chemiosmosis
Proton pumps
State two ways in which lactate could be metabolised by the body
Can be oxidised to produce pyruvate
Can be stored as glycogen
Identify the role of oxygen in the electron transport chian
Oxygen is the final electron acceptor of the electron transport chain
Oxygen combines with hydrogen and electrons to form H2O
Describe the mechanism by which ATP is formed in the mitochondria [6 marks]
Produced in the Krebs cycle
The krebs cycle produces NADH/FADH
Electrons are released from coenzymes NADH/FADH
Electrons pass along electron transport chain
Releasing energy each time
Allowing protons to move into intermembrane space
Protons diffuse back into the matrix via ATP synthase
Along the proton gradient
ATP forms from ADP + Pi
Oxygen is the final electron acceptor
Mitochondrial diseases in humans can cause their mitochondria to malfunction. Individuals that suffer from mitochondrial disease are only able to endure intense exercise for a short period of time. Explain why.
Mitochondria is the site of aerobic respiration
Mitochondria produces ATP required for muscle contraction during exercise
Explain why the solution used was isotonic
To prevent osmosis
So mitochondria do not burst
Describe and explain the effect of temperature has on the rate of CO2 released
The rate of CO2 release increases as temperature increases
BECAUSE
Enzyme activity increases so there is a higher rate of respiration and CO2 production
Explain why converting pyruvate to lactate allows the continued production of ATP by anaerobic respiration
NADH is reduced
So glycolysis continues
