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
Outline the roles of NAD and FAD in aerobic respiration.
Coenzymes;
Help / for dehydrogenation;
Carry / transfer hydrogens / H;
To ETC / inner mitochondrial membrane / cristae
How does inhibition of transfer of electrons in the electron transport chain of the mitochondrion affect ATP synthesis in the mitochondrion?
No energy release from electron transfer / ETC;
No chemiosmosis;
No protons pumped to intermembrane space;
No proton gradient;
No protons move through ATP synthase;
No ATP synthesised
Describe the effect on Calvin cycle when there is an increase. In concentration of rubisco.
More carbon fixation;
More GP produced;
More TP produced;
More regeneration of RuBP;
More Calvin cycle
Intermediate products of the Calvin cycle are needed to produce organic molecules for use by the cell.
Describe how these organic molecules are used by cells.
Glucose for respiration;
Starch for storage;
Cellulose to make cell walls;
Sucrose for translocation;
Lipid to make membranes OR Lipid for storage OR fatty acids to make acetyl CoA;
Amino acids to make proteins / enzymes;
Proteins for growth / repair
Describe the properties of ATP that make it suitable for its role as the universal energy currency.
Water soluble;
So easily transported around the cell;
ATP loses Pi;
Hydrolysed by ATPase / ATP is stable molecule;
To release energy immediately;
Can be recycled / regenerated
Suggest why ATP is needed for protein synthesis.
Unwinding DNA;
Activating RNA nucleotides;
Peptide bond formation / joining amino acids;
Movement of mRNA from nucleus / moving ribosomes along mRNA
Suggest and explain why cardiac muscle cells have mitochondria with very large numbers of cristae.
More cristae results in more ETC / ATP synthase / carrier proteins OR more cristae results in more oxidative phosphorylation / chemisosmosis / ATP synthesis;
Because cardiac muscle must undergo continuous contractions
