Topic 8.1: Cell Respiration

Question 1

What are the characteristics of oxidation?(5)

Answer 1

addition of oxygen atoms; removal of hydrogen atoms; loss of electrons from a substance; results in many carbon and oxygen bonds; results in a compound with lower potential energy

Question 2

What are the characteristics of reduction?(5)

Answer 2

removal of oxygen atoms; addition of hydrogen atoms; addition of electrons to a substance; results in many carbon-hydrogen bonds; results in a compound with higher potential energy

Question 3

What are the parts of mitochondria?(9)

Answer 3

granules; ribosomes; cristae; intermembrane space; matrix; ATP synthase particles; inner membrane; outer membrane; DNA

Question 4

What is the process of glycolysis?(9)

Answer 4

begins with phosphorylation; 2PO₄ groups are added to a 6-carbon glucose (hexose) molecule to form Fructose-1, 6-Biphosphate; 2 ATP molecules provide the PO₄ and leave as ADP; step 2 is lysis; each Fructose-1, 6-Biphosphate splits to form 2 molecules of glyceraldegyde-3-phosphate (triose phosphate); step 3 is oxidation of G3P; 2 NAD⁺ electrons connect to and leave the 2 molecules of G3P and form two 3-carbon compounds carrying 2PO₄ groups each and the electrons leave as 2 NADH + H⁺; the last step is ATP formation; 4 molecules of ADP connect and leave the 2 3-carbon compounds which forms 2 pyruvate molecules and enzymes remove the 2 phosphate groups from the 2 3-carbon compounds and provide them to the ADP which leave as 4 ATP molecules

Question 5

How is the fate of pyruvate determined?

Answer 5

the fate of pyruvate is decided by the availability of oxygen

Question 6

What is the process of the link reaction?(5)

Answer 6

pyruvate passes from the cytosol to the inner mitochondrial matrix by active transport; decarboxylation and oxidation occur simultaneously hence why it is called oxidative decarboxylation; CoA combines with each molecule of pyruvate and CO₂ is released; an electron of NAD⁺ combines with each molecule of pyruvate and is released as NADH + H⁺; the result is a 2 carbon compound acetyl CoA

Question 7

What are the products of glycolysis from one glucose?(3)

Answer 7

net gain of 2 ATP; 2 NADH; 2 pyruvates

Question 8

What are the products Krebs Cycle from one glucose?(4)

Answer 8

2 ATP; 6 NADH; 2 FADH₂; 2CO₂

Question 9

What is oxidation phosphorylation/electron transport chain?(17)

Answer 9

The energy stored in NADH is used to generate a proton gradient across the inner membrane;The energy of the proton gradient is used to make ATP (phosphorylate);Co-enzymes NAD and FAD are reduced to NADH + H⁺ & FADH + H⁺; In the mitochondrial matrix electrons from NADH are transferred to Co-enzyme Q by NADH DEHYDROGENASE, energy is released; As a result the H+ ions ( protons) are transferred to the inter membrane space; Co Q carries the electrons to cytochrome bc1 complex, energy is released; Electrons are carried forward from cytochrome bc1 complex to cytochrome c, energy is released; As a result more and more H+ ions ( protons) are transferred to the inter membrane space; In the mitochondrial matrix electrons from FADH are transferred to Co Q, energy is released; As a result the H+ ions ( protons) are transferred to the inter membrane space; Co Q carries the electrons to cytochrome bc1 complex, energy is released; Electrons are carried forward from Cytochrome C to Cytochrome c oxidase, energy is released; As a result the more and more H+ ions ( protons) are transferred to the inter membrane space;Cytochrome c oxidase ultimately transfers electrons to Oxygen (terminal e^- acceptor) and water is formed as an end product; Transfer of protons to the inter membrane space develops a proton motive force across the membrane; Inner membrane is impermeable to protons so protons can pass through into the matrix is only through the ATP Synthase enzyme; Energy derived from the movement of these protons back into the inner matrix is used to synthesize ATP from ADP, This is oxidative phosphorylation

Question 10

What is respiration chemiosmosis?(6)

Answer 10

Involves an electron transport chain in the membrane s of the cristae; Energy is released when electrons are exchanged from 1 carrier to another; Released energy is used to actively pump hydrogen ions into the inter-membrane space; Hydrogen ions come from the matrix; H ions diffuse back into the matrix through the channels of ATP synthase; ATP synthase catalyses the oxidative phosphorylation of ADP to ATP