Respiration Flashcards
Where does glycolysis take place?
Cytoplasm
What is the purpose of respiration?
Release ATP
Is oxygen needed for glycolysis?
No
Glycolysis is the first series of reactions in both anaerobic and aerobic respiration.
Name the chemical made when glucose is phosphorylated.
Glucose –> glucose phosphate
How is triose phosphate made during glycolysis?
Glucose is phosphorylated to form glucose phosphate using ATP
Glucose phosphate is hydrolysed to form 2 molecules of triose phosphate
Describe what happens to triose phosphate in glycolysis.
Triose phosphate -> pyruvate + ATP + NADH
Triose phosphate is oxidised to form pyruvate.
In anaerobic reparation what is pyruvate converted into?
In animals - Lactate
In plants and yeast - Ethanol and carbon dioxide.
What happens to NADH when pyruvate is converted into lactate?
Oxidised to regenerate NAD.
This allows glycolysis to continue
Give 3 differences between aerobic and anaerobic respiration.
Aerobic releases more ATP than anaerobic.
Aerobic produces carbon dioxide and water whereas anaerobic produces lactate or ethanol + carbon dioxide.
Aerobic requires oxygen whereas anaerobic does not require oxygen.
Which type of transport is used to get pyruvate into the mitochondria?
Active transport.
Which organelle is responsible for aerobic respiration
Mitochondria
Where precisely does Krebs’ cycle and the link reaction take place?
Matrix of mitochondria.
Where precisely does the electron transport chain and oxidative phosphorylation take place.
Inner membrane of mitochondria.
How is acetate made from pyruvate?
Pyruvate is oxidised / NADH is made.
What is the name of the coenzyme that carries acetate.
Coenzyme A
Name the process used to make ATP in Krebs’ cycle.
Substrate level phosphorylation.
Name the particles transported into the intermembrane space during electron transport chain.
Protons or H+ ions
Name the enzyme used to make ATP.
ATP synthetase
How is energy provided to transport the protons/H+ into the intermembrane space?
Electrons lose energy as they travel along the electron transport chain. This energy is used to actively transport the protons into the intermembrane space.
Name the four main stages of aerobic respiration
Glycolysis
Link reaction
Krebs cycle
Oxidative phosphorylation
Outline the stages of glycolysis
Glucose is phosphorylated to glucose phosphate using 2 ATP
Glucose phosphate is hydrolysed into 2 molecules of triose phosphate.
Each triose phosphate is oxidised to make pyruvate releasing NADH and ATP
What are the products of glycolysis?
2 x Pyruvate
2 x ATP (net)
2 x NADH
Describe what happens in the link reaction.
Pyruvate is oxidised and decarboxylated
To form acetyl
NADH is produced
Carbon dioxide is released
Acetyl is attached to Coenzyme A
Name the co enzymes involved in aerobic respiration
NAD
FAD
Coenzyme A
What is a coenzyme?
A non-protein molecule which is needed for an enzyme to work
Where does oxidative phopshorylation occur?
Cristae (inner membrane) of mitochondria
Describe the process of oxidative phosphorylation within the mitochondria
NADH/FADH release electrons
Electron pass along electron transfer chain
Energy released caused protons to be pumped into the intermembrane space creating a electrochemcial gradient
Protons/H+ diffuse through ATP synthase
ATP is made from ADP and Pi
Electrons form ETC move to oxygen (terminal electron acceptor)
Why is oxygen needed for aerobic respiration?
Final electron acceptor
H+ and electron transport change would stop
NAD and FAD could not be reformed
Other stages of respiration would stop
The energy not harvested during the electron transport chain is lost as …
Heat
The mitochondria of metabolically active cells have more densely packed cristae. How does this help these cells?
Greater surface area of inner membrane provides more space for electron transport proteins and enzymes. Increases rate of oxidative phosphorylation
What is the benefit of an electron transport chain rather than a single reaction?
Energy released in a more gradual way.
Minimises energy wasted as heat.
Which reaction is the only source of ATP in anaerobic conditions?
Glycolysis
Can glucose cross the mitochondrial membrane?
No
Glycolysis used to break it down to pyruvate which is then transported across the membrane.
What is the equation for anaerobic respiration in plants and microorganisms?
Pyruvate + NADH –> Ethanol + CO2 + NAD
What is the equation for anaerobic respiration in animals?
Pyruvate + NADH –> Lactate + NAD
How does pyruvate enter the mitochondria?
Active transport
Describe what happens in the Krebs cycle
Acetyl added to a 4C molecule to form a 6C molecule
Decarboxylation released 2 X CO2
NAD and FAD are reduced
ATP produced by substrate level phosphorylation
Name 2 types of molecule that can e used as alternative respiratory substrates
Amino acids from proteins
Glycerol and fatty acids from lipids
How can lipids be used an a respiratory substrate?
Lipid –> glycerol + fatty acids
Glycerol is phosphorylated to form triose phosphate
Fatty acids converted into acetyl
How can amino acids be used an a respiratory substrate?
Amino aid is deaminated to form:
3C compounds converted to pyruvate
4C/5C compounds form intermediates in Krebs cycle
Name the stages of respiration that produce ATP by substrate level phosphorylation
Glycolysis
Krebs cycle
What is the advantage of producing ethanol/lactate during anaerobic respiration?
Converts NADH back into NAD so glycolysis can continue.
What is the disadvantage of producing ethanol during anaerobic respiration?
Ethanol is a poison causing cells to die
Ethanol dissolves cell membranes.
What is the disadvantage of producing lactate during anaerobic respiration?
Acidic so decreases pH
Results in muscle fatigue
How many membranes does pyruvate need to pass through to enter the matrix of the mitochondria
2
