5.7 Respiration Flashcards
Why do we need energy ?
Name 5
- active transport
- endo,exocytosis
- synthesis of large molecules
- movement
- activation of chemicals
- Dna replication
- cell division
All chemical reactions are either ……… or …… !
Define your terms
4
- Anabolic reactions ( small—>big)
- Catabolic reactions( big—>small)
ATP is …………. to form adp+pi
1
Hydrolysed
What’s the first stage of respiration ?
2
- Glycolysis (10 stage metabolic pathway that converts glucose to pyruvate )
Outline the glycolysis pathway ?
3
- Phosphorylation to Hexose bisphosphate
- splitting —> 2 x triose phosphate
- oxidation to pyruvate
Nad is synthesised from what ?
What can it do ?
2
- living cells from nicotinamide, adenine , 2 phosphoryl groups
- it can accept 2 hydrogens
How much ATP used in glycolysis ?
How much is made ?
Profit ?
- 2 ATP used
- 4 ATP made
- 2 profit
How much NAD is used ?
1
2NAD —> 2 reduced NAD
Products of Glycolysis ?
3
- 2ATP
- 2NADH
- 2x pyruvate
What are the 4 stages of aerobic respiration ?
4
- Glycolysis
- link reaction
- krebs cycle
- oxidative phosphorylation
Where does link reaction occur ?
1
Mitochondrial matrix
What enzyme is used in the link reaction and what does it do to the Pyruvate ?
4
- pyruvate Dehydrogenase
It decarboxylises and dehydrogenates the Pyruvate
( so it removes carbon by production of CO2)
And it also :
Removes hydrogen and This hydrogen reacts with NAD to produced NADH
What are the products of the link reaction ?
2
- Acetyl COA
- reduced NADH
Write the equation which summarises the link reaction ?
2
2 pyruvate + 2NAD + 2CoA —-> 2CO2+ 2 NADH + 2acetyl coA
Where does krebs cycle take place ?
1
- link reaction and Krebs cycle take place in MITOCHONDRIAL MATRIX
What’s the purpose of the Krebs cycle ?
2
To produce energy via a series of enzyme catalysed reactions
The acetyl group entering the Krebs cycle has how many carbons ?
1
-2
Outline the Krebs cycle briefly …
5 points in depth so 10 marks
1) acetyl group released from acetyl CoA combines with 4 carbon compound —-> 6 C compound
2) decarboxylated and dehydrogenated = 5 CARBON compound ( CO2 released and NADH)
3) decarboxylated and dehydrogenated =4 carbon compound ( CO2 and NADH released)
4) 4 carbon compound combines with CoA to produce SUCCINYL COA ( ATP IS PRODUCED HERE ! Substrate level phosphorylation )
4) then the 4 carbon compound is dehydrogenated to produce Another 4 carbon compound- FUMARATE ( FADH2 produced)
5) rearrangement occurs of the atoms in the 4 Carbon compound catalysed by ISOMERASE enzyme , the dehydrogenation and production of OXALOACETATE so cycle can continue
How many turns of the Krebs cycle produce glucose!
2
- two turns !
What’s oxidative phosphorylation?
2
- formation of ATP via the energy acquired via the electron transport chain in the presence of oxygen .
- last stage in aerobic respiration
Outline oxidative phosphorylation?
3
- reduced NAD and reduced FAD are reoxidised when they deliver H+ to e transport chain
- the Hydrogen spilts to Protons and electrons
- the protons go into the solution in the mitochondrial matrix
Where does glycolysis occur ?
1
Cytoplasm
what is the role of ATP within cells ?
3
- immediate source of energy
- provides 30j of energy
- phosphate can be removed in hydrolysis
- metabolic reactions : active transport …
- 30kj/mol energy provided
how do we calculate the respiratory quotient ?
1
-volume of CO2 produced /Volume of O2 consumed in the same time
whats anaerobic respiration ?
respiration in absence of oxygen
outline the ethanol fermentation pathway ? what uses this ?
fate of NAD
3
yeast
pyruvate (pyruvate decarboxylase )——–> ethanal ——–>(2NADH —>NAD) ethanol
REMEMBER : NAD can now be recycled for Glycolysis
outline the lactate fermentation pathway ? 3
mammals :
pyruvate —>(lactate dehydrogenase )(2reduced NADH–>NAD) Lactate
NAD can be recycled to Glycolysis which can produce ATP for a short amount of time (remember 2ATP yield)
where can NAD be reoxidised ? 1
cristae
why ids fermentation reversible in mammals - lactic acid but not for yeast = ethanol ?
3
- animals have lactic acid produced via lactate dehydrogenase , which can reverse the reaction
- Yeast has pyruvate –> Ethanal + CO2 –>Ethanol .The CO2 gas molecule is lost hence why it can’t form pyruvate again!
- Pyruvate decarboxylase enzyme can’t be reversed .
where does anaerobic respiration take place ? 1
-cytoplasm
