Respiration Flashcards
Explain why ATP is needed in the first part of glycolysis
To phosphorylate glucose;
Makes glucose less stable;
To make fructose biphosphate
Explain what happens to pyruvate in the link reaction in aerobic respiration.
Decarboxylated;
Dehydrogenated;
Acetyl / 2C joins coenzyme A to form acetyl coA
Describe the differences between the process of chemisosmosis in mitochondria and the process of chemiosmosis in chloroplasts
Mitochondria:
Oxidative phosphorylation
Inner mitochondrial membrane / cristae
Reduced NAD / reduced FAD give e- / H+
H+ diffuses into intermembrane space
oxygen is the final e- acceptor
Makes water
Chloroplasts:
Photophosphorylation
Thylakoid membrane
Photolysis / water / PS1 / chlorophyll give e- / H+
H+ diffuses into thylakoid space
NADP is the final e- acceptor
Makes reduced NADP
Describe the role of the inner mitochondrial membrane (crista) in chemiosmosis.
Electron transport chain;
Pumps protons to intermembrane space;
Forming electrochemical / proton gradient;
Protons diffuse to matrix;
Through ATP synthase;
ADP + Pi -> ATP;
Oxidative phosphorylation occurs
Describe how ATP is made by substrate-linked reactions.
ADP + Pi;
Forming ATP
State the role of acetyl coenzyme A in respiration.
Carrier of 2C / acetyl group to the Krebs cycle / oxaloacetate
Explain why lipids have higher energy value than carbohydrates.
More C-H bonds / more hydrogen;
Produces more reduced NAD;
More aerobic respiration / oxidative phosphorylation / chemiosmosis;
Produces more ATP per gram
Describe how the structure of a mitochondrion is related to its function.
Double membrane;
Inner membrane:
Cristae;
Large surface area;
Has ATP synthase;
Has carrier proteins;
Site of ETC / oxidative phosphorylation / chemiosmosis;
Intermembrane space:
Has high concentration of protons;
Accepts protons from ETC;
Proton gradient between intermembrane space and matrix;
ATP synthesis;
Matrix:
Contains enzymes;
Site of link reaction / Krebs cycle
Outer membrane:
Presence of carriers for pyruvate / reduced NAD
Describe respiration in anaerobic conditions in mammalian liver cells and describe how this differs in yeast cells.
Liver cells:
Only glycolysis occurs;
Pyruvate cannot enter mitochondrion / remains in cytoplasm;
Pyruvate becomes hydrogen acceptor / reduced;
By reduced NAD from glycolysis;
Lactate produced;
Lactate dehydrogenase;
Production of 4ATP;
Allows glycolysis to continue
Yeast cells:
Decarboxylation / CO2 removed;
Ethanal becomes hydrogen acceptor / reduced;
Two steps
State the two different ways in which phosphorylation reaction occurs in aerobic respiration.
Substrate-linked phosphorylation;
Chemisosmosis / oxidative phosphorylation
Describe and explain the role of the enzymes NAD and FAD in aerobic respiration.
Hydrogen carriers;
In glycolysis NAD becomes reduced;
So that triose phosphate becomes dehydrogenated;
In the link reaction NAD becomes reduced;
So that pruvate becomes dehydrogenated / for production of acetyl coenzyme A;
In the Krebs cycle both NAD and FAD become reduced;
To regenerate oxaloacetate;
Deliver H+ and e- to inner mitochondrial membrane / to cristae / to ETC / for oxidative phosphorylation / for chemiosmosis;
The enzyme pyruvate dehydrogenase catalyses the link reaction. Pyruvate dehydrogenase is inhibited when the ratio of acetyl coenzyme A to coenzyme A increases.
Control of rate of link reaction;
Allows build up of acetyl CoA to be used in the Krebs cycle;
Enzyme becomes active again when coenzyme A increases;
Allows more coenzyme A to enter the link reaction
Suggest the advantages of linking ATP transport to ADP transport across the inner membrane of the mitochondrion.
Constant supply of ADP;
So ATP can continue to be made / enough ATP can be made
Explain how Krebs cycle shows that glycolysis involves oxidation.
Triose phosphate dehydrogenated;
Reduced NAD made / released
Suggest 2 reasons why the actual net number of ATP molecules synthesised is less than the theoretical number.
ATP / energy used to transport pyruvate / reduced NAD / products of glycolysis into mitochondria;
Some protons leak from intermembrane space;
Some energy lost as heat;
Glucose may not be completely broken down / some intermediates are used in different metabolic processes;
Reduced NAD may be used for other metabolic reactions
