5.2.2 Respiration Flashcards
Aerobic respiration in both plant and animal cells ultimatley depends on photosyntheis. Explain this dependence
Oxygen is required for aerobic respiration, oxygen in the cell and the atmopshere is generated as an output of photosynthesis
Glucose produced in photosynthesis is the substrate for cellular respiration in plants
Plant matter eaten by animals provides the glucose for cellular respiration
Explain what happens in the body during first stage of aerobic respiration
1)Glucose phosphorylated by adding 2 phosphates to form 2 ATP molecules - 2 ATP hydrolysed to 2 ADP and Pi
2) forms 1 hexose bisphosphate and 2 ADP, hexose bisphopshate unstable and split into 2 TP (3C)
3) 2 TP oxidised to form 2 pyruvate, loss of H+ ions are accepted by 2 NAD(coenzymes) , forming 2 reduced NAD
5) conversion of TP to pyruvate produces 4 ATP in total by substrate level phosphorylation
Net gain 2 ATP in glycolysis
What is substrate level phosphorylation
Phosphate group is transfered from the TP to ADP
Where does the link reaction take place in the cell
Matrix of the mitochondrion
Explain the link reaction
Pyruvate is actively transported across mitochondrial membrane into matrix
Pyruvate undergoes decarboxylation and oxidation (H atoms removed), forming acetate (2 C) - process is called oxidative decarboxylation, removed H accepted by NAD - reduced NAD , acetate combines W coA to form acetyl coA(2c)
State which coenzymes are involved in the Krebs cycle
NAD
FAD
both used to accept protons and electrons
State the number of ATP molecules that are made per turn of krebs cycle
1
Discuss how reduced NAD and FAD contribute to the transfer of energy using cheimosmostic theory
NADH and FADH approach the inner mitochondrial membrane where thye become oxidised upon the release of hydrogen atom. Hydrogen atoms then split inot protons and electrons, electrons enter the ETC. Move through ETC, undergo a series of oxidation reduction reactions which relese energy
Energy is used to pump the hydrogen ions/ protons across the inner mitochondrial membrane into the intermembrane space. Accumulation of protons in the inter membrane space creates a proton gradient, electrochemical gradient.
Protons move down gradient through ATP synthase channels.
Protons through the channle causes a conformational shape change within ATP synthase, resulting in ADP and P1 combining to synthesise ATP
Describe the pathway of anaeobic respiration
Occur in cytoplasm of the cells, occurs in tissue when demand for ATP is high and lack of O2
Uses glycolysis to prod. 2 molecules of ATP, 2 reduced NAD
Pyruvate is reduced to lactate /LA in the lactate fermentation pathway
Regenerates NAD, so glycolysis can occur
What are the implications of anaerobic respiration in mammals
lactate is acidic, can be toxic, lowers pH
To prevent: pyruvate is converted to glycogen in the liver OR is re oxidised
Describe what is meant by a respiratory substrate
Organic substance that can be oxidised by respiration releasing energy to make molecules of ATP
Explain how lipids can be used by human cells as a respiratory substrate
Lipids are hydrolysed to glycerol and fatty acids
Glycerol is then phosphorylated and converted into TP, can enter glycolysis
Fatty acid broken down into many 2 carbon fragments, converted into acetylcoA
Contain many hydrogen atoms, used to produce ATP in oxidative phosphorylation
Outline an experiment using a respirometer to investigate the effects of different temperature on the rate of respiration in woodlice
Set up the resporimeter with a sodium hydroxide soloution to absorb co2
Add glass beads of the same mass as the organisms to the same tube
Set up cappilary tube,syringe and test tubes and allow the set up to acclimitase and for the fluid to settle
Place organism in the test tube, measure the changed position of the fluid.
What biological processes need energy
Photosynthesis, active transport,DNA replication, cel division, protein synthesis
Animals- muscle contraction, active transport , DNA replication, cell division and protein synthesis
What is the difference between reduced NAD and NADP
Reduced NAD is the oxidises state used in cellular respiration
Reduced NADP is oxidised state used in photosynthesis
What are the products of the link reaction, per glucose molecule
2 acetyl coA
2 CO2
2 NADH
Explain the Krebs cycle
1) Acetyl group is released from acetyl CoA, coA returns to link reaction
2) acetyl group combines with oxaloacetate to form citrate (6C)- decarboxylation in the form of CO2, removed H atom accepted by NAD
4) 5C compound is decarboxylated and dehydrogenated to regenerate oxaloacetate- 1 C removed in the form of CO2,removed H atoms accepted by NAD and FAD, forming 1 FADH and 2 NADH
1 ATP formed by substrate level phosphorylation - direct transfer of a phosphate group from an intermediate compound to ADP
What are the products of the Krebs cycle, per glucose molecule
2 COA
2 Oxaloacetate
6 NADH- used in oxidative phosphorylation
2 FADH- used in oxidative phosphorylation
4 CO2 waste product
2 ATP
Explain the process of oxidative phosphorylation
Process where energy in electrons from NADH and FADH is used to make ATP
1) NADH and FADH are oxidised, releasing H atoms which split into H+ and electrons
2) electrons move along electron carriers in electron transport chain (ETC), releasing energy. ETC located on inner mitochondrial membrane - folded into Cristae, increases SA
3) energy used by electron carriers to actively pump H- from matrix to inter membrane space
4) H+ accumulates inter membrane space, creating electrochemical proton gradient
5) H+ moves down electrochemical gradient - facilitated diffusion back into matrix via ATP synthase
6) ATP synthase uses energy from movement of H+ to form ATP from ADP+ pi - chemiosmosis
7) electrons leaving ETC and H+ ions combine w O2 final electron acceptor to form water
How many number of ATP molecules per glucose
32
- 5 per NADH
- 5 per FADH
Outline the importance of coenzymes in respiration
Coenzymes required to transfer H+,electrons, functional groups between different molecules
Coenzymes required for redox reactions - reactions involve both oxidation and reduction -
Aerobic respiration - NAD,FAD,coenzymes A
Explain alcohol fermentation
1) glycolysis produces pyruvate
2) pyruvate is decarboxylated (loses CO2) to ethanal, catalysed by pyruvate decarboxylase
3) NADH from glycolysis is oxidised and transfers hydrogen to ethanal, forming ethanol
NAD is regenerated when NADH is oxidised
Why do respiratory substrates release different amount of ATP
Depends on hydrogen atoms per unit of mass
Why do lipids have an RQ less than 1
RQ- Co2 produced / o2 consumed
More o2 required to oxidise molecules
An RQ greater than 1 suggest anaerobic respiration being used
How can lipids and amino acids be used instead of glucose
Lipids - lipids hydrolysed to glycerol and fatty acids, glycerol converted to pyruvate then acetyl COA, enters Krebs cycle
Fatty acid converted to acetyl COA, beta oxidation, Krebs cycle
AA- proteins hydrolysed into AA,AA are deaminated (amine group removed) , converted to pyruvate then acetyl Coa
Describe how trachea of a mammal is different from insect trachea
Mammals just have one trachea/ insects have multiple tracheae
Mammals much larger diameter/ insect smaller diameter
Mammal trachea is longer/ individual insect tracheas shorter
Outline the difference between a spirometer and respirometer
Spirometer measures volume changes during breathing but a respirometer measures the change in volume of O2 or CO2
Suggest why, at each temperature, respirometer B contained some glass beads
To make the volume of peas the same,
Suggest how the student determined the quantity of glass beads to place in respirometer B at each temperature
Find difference in volume between soaked peas and dry peas, difference represents the volume of glass beads required, calculate volume of one bead to determine number of beads required
Suggest a reason for the difference in the rate of respiration between soaked and dry pea seeds
Reactions require aqueous medium, to take place in water, so enzymes can collide, soaked seeds need more energy
