Respiration Flashcards
(40 cards)
Why does respiration occur?
To produce ATP for energy
Required in metabolic processes and for the organism to survive
Give examples of biological processes where ATP is required
Active Transport Endocytosis Exocytosis Protein synthesis DNA Replication Cell division Movement Anabolic and Catabolic reactions
Describe the structure of ATP
Pentose sugar (Ribose)
Adenine base
3 phosphates joined to sugar by phosphodiester bond
Describe the process of Glycolysis
Phosphorylation of Glucose to Hexose biphosphate
Lysis of Hexose biphosphate to Triose phosphate
Oxidation of Triose phosphate to Pyruvate
What are the 4 stages of aerobic respiration?
Glycolysis
Link Reaction
Krebs Cycle
Oxidative Phosphorylation
What are the products of Glycolysis?
2 ATP (4 were made by 2 were used at start)
2 reduced NAD (NADH)
2 Pyruvate
In What organelle does respiration occur?
Mitochondrion
Outline the key structures in the mitochondria
Double membrane (inter-membrane space)
Matrix
Cristae
ATP Synthase channels
What does the matrix contain?
Enzymes NAD and FAD molecules Oxaloacetate mitochondrial DNA mitochondrial ribosomes
Why is the inner membrane folded into cristae?
To provide a large surface area for the electron carriers and ATP synthase enzymes
Where does the link reaction occur?
Mitochondrial matrix
What enzyme catalyses the link reaction?
Pyruvate dehydrogenase
What is the main products of the link reaction?
Acetyl CoA and NADH
What is the bi-product of the Link reaction
CO2
How many molecules of each product are formed per 1 molecule of pyruvate in the link reaction?
1 Acetyl CoA
1 NADH
1 CO2
Where does the Krebs cycle occur?
Mitochondrial matrix
What is substrate-level phosphorylation?
the formation of ATP from ADP by donation of a phosphate from a substrate.
Low yield of ATP
Outline the main stages of the Krebs cycle
Acetyl (2C) group released from Acetyl CoA and combines with Oxaloacetate (4C) to form Citrate (6C)
2 stages of oxidative (aka dehydrogenation) decarboxylation occur forming a 4C compound releasing 2CO2 and 2 NADH
4C compound further dehydrogenated releasing FADH
4C compound is rearranged by isomerase enzymes and dehydrogenated (releasing NADH) to form oxaloacetate
What is the Krebs cycle designed to make lots of?
NADH (reduced NAD)
Outline the process by which energy is produced from the ETC
NADH releases a H atom, this then splits into H+ and e-
H+ accumulate in the matrix
e- picked up by a carrier protein which causes it to become reduced and pass it on to the next carrier protein in the chain (series of redox reactions)
at the end of the chain:
4H+ + 4e- + O2 = 2H2O
How is the energy released from the ETC used to create ATP?
the energy released is used to actively transport the H+ from the matrix into the inter-membrane (IM) space
H+ accumulate in IM space (as the membrane is impermeable to H+) forming an electrochemical gradient.
H+ move back through protein channels coupled to ATP Synthase enzymes
Causes a conformational change in ATP Synthase driving the production of ATP
Where does oxidative phosphorylation occur?
Cristae
Why will the process of oxidative phosphorylation not occur in anaerobic conditions?
No O2 as final acceptor of ETC Build up of e- in the matrix Electrochemical gradient doesn't form ATP Synthase isn't activated No ATP produced
Why must NADH be reoxidised for respiration to continue?
Because it is needed for the link reaction and Krebs cycle to occur
