C1.2 Cell Respiration Flashcards
Describe the structure of ATP.
A nucleotide composed of adenine, ribose and three phosphates
Outline properties of ATP that make it suitable for the use as an energy currency within cells.
High energy bonds
Unstable bonds between phosphates and releases energy when broker
Outline example cellular processes that require use of ATP.
Active transport across membranes
Anabolism
Movement of the whole cell
Movement of components within the cell
Describe the ATP-ADP cycle, including the relative amount of energy and the roles of hydrolysis and phosphorylation.
The hydrolysis from ATP to ADP releases an inorganic phosphate used as activation energy for metabolic reactions
Energy is then required to go from ADP and P to ATP through condensation. Cellular respiration provides the energy
State why heat is generated during the ATP-ADP cycle.
Due to inneficiencies in cellular respiration and metabolic reactions
Define cellular respiration.
the controlled release of ATP energy from organic compounds within cells
Distinguish between cellular respiration and gas exchange.
Gas exchange is the exchange of CO2 and oxygen in living cells and tissues whereas cellular respiration is the release of ATP energy from organic compounds within cells
List common substrates of cellular respiration.
Glucose
Fatty Acids
List reasons why cellular respiration must be continuously performed by all cells.
Sustaining metabolic and biochemical processes.
Maintenance of cellular homeostasis.
Fueling growth, repair, and reproduction.
Compare and contrast anaerobic fermentation and aerobic respiration.
Aerobic and Anaerobic :
Occur in cells
Glucose as initial substrate
Enzymes to catalyse reaction pathways
Produces ATP
Aerobic
Oxygen is required
High yield (+36ATP)
CO2 and water are waste products
Most of the process occurs in mitochondria
Anaerobic
Oxygen isn’t used
Low yield (+2ATP)
Lactate
Occurs in cytoplasm (not mitochondria)
List three approaches for determining the rate of cellular respiration.
Measuring volume gas produced by yeast
Measuring change in oxygen concentration using ocygen probes
Measuring the change in CO2 concentration using CO2 probes
Outline oxidation and reduction reactions in terms of movement of hydrogen and electrons.
Oxidation results in removal of hydrogen and loss of electrons
Reduction results in addition of hydrogen and gain of electrons
Define “electron carrier.”
a molecule or protein capable of accepting and donating electrons during metabolic reactions or electron transport processes
State the name of the electron carrier molecule used in cellular respiration.
NAD
Outline the formation of reduced NAD (=NADH + H+) during glycolysis.
NAD removes two electrons and hydrogen from substrates at various stages of respiration. When NAD gains electrons and hydrogen from a substrate it forms reduced NAD
State the formula for the glycolysis reaction.
C6H12O6+6O2=6O2+6H2O
State that glycolysis occurs in both anaerobic and aerobic respiration.
Glycolysis occurs in both anaerobic and aerobic respiration
State the location of the glycolysis reaction in a cell.
Cytoplasm of the cell
State that glycolysis is an example of a metabolic pathway catalyzed by enzymes.
Glycolisis is an example of a metabolic pathway
Outline the glycolysis reaction, including phosphorylation of glucose, lysis, oxidation and ATP formation.
Phosphorylation of Glucose, two ATPs are hydrolysed bond to glucose formin Hexose Bisphosphate
Hexose Bisphosphate breaks apart into 2 triose phosphates
NAD is converted to reduced NAD as it takes electrons from the triose phosphates resulting in them being oxidized.
ADP+Pi turns to ATP as each carbon compound is converted to pyruvate
Glucose converts to pyruvate
- State the net yield of ATP and reduced NAD produced in glycolysis.
2 ATP and 2 reduced NAD
State why NAD must be regenerated in anaerobic respiration.
Because glycolysis requires a constant supply of NAD
State the condition in which humans would perform anaerobic respiration.
When oxygen isn’t present in human cell
Compare anaerobic respiration in yeasts and humans.
Yeast produces ethanol and CO2
Humans produce lactic acid
Outline the process of regenerating NAD and production of lactate in humans during anaerobic respiration.
Pyruvate is converted to lactate by oxidizing reduced NAD to NAD
Outline the process of regenerating NAD and production of ethanol in yeast during anaerobic respiration.
Pyruvate is converted to ethanol and carbon through oxidizing reduced NAD to NAD
Outline how anaerobic respiration in yeast is used in brewing and baking.
CO2 produced by yeast during anaerobic respiration causes the dough to rise
Yeast produces ethanol in the brewing process
Summarize the reactants and products of the link reaction.
Reactants : NAD, Pyruvate, Co enzyme A, Acetyl
Product : Reduced NAD, Acetyl Coenzyme A
State that the link reaction occurs in the matrix of the mitochondrion.
The link reaction occurs in the matrix of the mitochondrion
Outline the link reaction with references to decarboxylation, oxidation and binding of CoA.
Decarboxylation of pyruvate : loss of CO2 to produce a 2 carbon acetyl group
Reduction of NAD : Pyruvate is oxidized as it loses electrons and hydrogen. NAD is reduced as it gains electrons and hydrogens
Formation of acetyl coenzyme A : acetyl group combines with coenzyme A to form acetyl coenzyme A.
State that the Krebs cycle occurs in the matrix of the mitochondrion.
Krebs cycle occurs in the matrix of the mitoochondrion
Outline the events of the Krebs cycle, referencing the formation of citrate from oxaloacetate, decarboxylation of citrate to reform oxaloacetate, formatting of CO2, formation of ATP and the oxidation reactions that form reduced NAD (=NAD + H+) and reduced FAD (=FADH2).
Oxaloacetate (4 carbon) combines with acetyl coA to form citrate (6C),
Citrate loses CO2 twice to form a 4 carbon compound.
Citrate is converted back to oxaloacetate through three intermediate compunds losing electrons and hydrogens to NAD to from reduced NAD, one carbon compound is oxidised and lsoes electrons and hydrogne to the elcetron carrier FAD producing reduced FAD
Each Kreb cycle provides enough energy to convert ADP and a phosphate to ATP through condensation reaction.
State that the reduced NAD and reduced FAD produced in the Krebs cycle carry electrons to the mitochondrial electron transport chain.
Reduced NAD and FAD produced in the krebs cycle carry electrons to mitochondrial electron transport chain
List the net products of one turn of the Krebs cycle.
NAD and FAD to Reduced NAD and FAD + 1 ATP
State that at the mitochondrial electron transport chain, reduced NAD (=NAD + H+) and reduced FAD (=FADH2) are oxidized with the transfer electrons to electron carrier proteins.
Reduced NAD and FAD are oxidized thanks to the mitochondrial electron chain transporting electrons to electron carrier proteins
List the reactions that generated the reduced NAD (=NAD + H+) and reduced FAD (=FADH2) used in the electron transport chain.
Isocitrate to α-ketoglutarate (NADPH)
α-ketoglutarate to succinyl-CoA(NADPH)
Describe how the movement of electrons through the electron transport chain is used to generate a proton gradient in the intermembrane space.
Movement of electrons provides energy for active transport of protons from the mitochondrial matrix into the intermembrane space
Define chemiosmosis.
The generation of ATP using kinetic energy as protons move trhough ATP synthase
Describe the structure ATP synthase.
A proton channel
Outline the formation of ATP by ATP synthesis, with reference to movement of protons and phosphorylation of ADP.
Protons pass trough ATP synthase from the high concentration in the intermembrane space to the low concentration in the matrix through facilitated diffusion. These protons provide energy to convert ADP and phosphate to ATP
Compare the total amount of ATP made from anaerobic and aerobic respiration.
Anaerobic 1 ATP
Aerobic 36 ATP
State that the formation of water in the matrix at the end of the electron transport chain helps to maintain the proton gradient between the intermembrane space and the matrix.
Formation of water in the matrix at the end of the electron transport chain helps maintain the proton gradient between the intermembrane spacce and the matrix
State that oxygen is the final electron acceptor in the electron transport chain.
Oxygen is the final electron acceptor in the electron transport chain
Explain why aerobic respiration will stop if oxygen is not present.
Because it requires oxygen as the final electron receptor
Compare the use of carbohydrates and lipids as respiratory substrates in aerobic and anaerobic respiration.
Lipids and carbohydrates
can be respired
(fatty acids not all lipids) can produce acetly coenzyme A
Carbohydrates
glycolisis and anaerobic respiration only occur with carbohydrates
Explain the greater energy yield of lipids compared to carbohydrates when used as respiratory substrates.
Lipids have a higher yield as the have less oxygen nand more oxidizable hydrogen and carboe
Outline the process by which lipids can be a substrate for respiration.
Lipolysis :break down into glycerol and fatty acids
Beta-oxidation : fatty acids break down into acetyl CoA through a series of oxidation reactions where each round generates NADH and FADH2
