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30 Cards in this Set
- Front
- Back
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What is the symbol equation for aerobic respirarion |
6O2 + C6H12O6 --> 6CO2 + 6H2O + 32ATP |
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Describe respiration |
A series of oxidation reactions Transfers energy from glucose and oxygen into ATP Some energy is lost as heat |
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Labled mitochondria |
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How to measure respiration rate |
With a respirometer |
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What is respiratory rate |
The rate at which an organism convets glucose into co2 and water. It can be calculated by measuring an organisms rate of oxygen consumption |
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What does a resppirometer measure |
The change in gas volume in a closed system |
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What is used to absorb the carbon dioxide |
Potassium hydroxide or soda lime. This means any changes in volume is from the oxygen consumption. |
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What are the 4 stages of respiration |
Glycolysis Link reaction Krebs cycle Electron transport chain |
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What are the 3 main co enzymes in respiration |
NADH FADH Coenzyme A |
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Describe glycoysis |
-sugar spliting - in the cytoplasm -1 glucose oxidised to release 2 pyruvate - no oxygen required -2 ATPs used at this stage - 4 ATPs made plus 2 NADH - Net Yield is 2 ATP and 2 NADH from each glucose - part of aerobic and anaerobic respiration -phosphorylation of glucose to glucose phosphate, using ATP-production of triose phosphate-oxidation of triose phosphate to pyruvate with a net gain of ATP and reduced NAD. |
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Describe the link reaction |
- links glycolysis to the krebs cycle - Occurs in the matrix - pyruvate enters the mitochondria by active transport - pyurate undergos decarboxylation producing acetate and co2 -ACetate picked up by Co enzyme A forming acetyIcoenzyme -acetylcoenzyme A reacts with a four-carbon molecule, releasing coenzyme A and producing a six-carbon molecule that enters the Krebs cycle - occurs twice for every glucose as 2 pyruvate made - no ATP made but 2 NADH made per glucose |
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describe the krebs cycle |
- occurs in the matrix - only occurs in aerobic - a series of redox reactions -electrons are stripped from acetate creating large numbers of co enzymes - 1 cycle produces . 1 atp . 3NADH .1 FADH .2CO2 |
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Describe substrate and oxidative phosphorylation |
- substrate phosphorylation is the production of ATP -occurs in glycolysis and krebs cycle - ATP made using an electron transport chain called oxidative phosphorylation. |
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Describe the electron transport chain |
-a series of proteins arranged on the cristae - electrons are delivered to them by NADH and FADH - electrons pass along the chain from 1 protein to the next - each electron transfer is oxidation /reduction that releases energy - energy is used to make ATP - by products are low energy electrons and protons that combine with oxygen to make water. - oxygen is known as the final proton /electron acceptor. |
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What is chemiosmosis |
Using a chemical gradient established by electron movement to generate ATP. |
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What is the evidence for chemiosmosis |
- The proton gradient across the inner membrane can be measured as there is PH gradient - Isolated ATP syntgase enzymes can produce ATP using a proton gradient even if no electron transport is occurring - Chemicals that block the electron transport chain inhibt the formation of a proton gradient and prevent ATP synthesis. |
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What are some respiratory substrates |
Glucose Glycerol Fatty acids Amino acids |
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Describe the effciency of aerobic respiration |
- some protons leak across the mitochondrial membrane so not all are avaliable for chemiosmosis - some ATP is used up moving pyruvate into the mitochondria by active transport - some ATP is used up moving hydrogen from reduced NAD made during glycolysis into the mitochondria - some energy is lost as heat. This heat helps maintain a suitable body temperature for emzyme conrolled reactions |
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what is the deffinition of cellular respiration |
the breakdown of complex organic molecules to release energy in the form of ATP |
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describe anaerobic respiration |
-not as efficient as aerobic - glycolysis is the only stage which occurs in the cyoplasm -pyruvate is converted into lactic acid or lactate rather than entering the link reaction - plants and microorganisms convert their pyruvate into ethanol and CO2 -these reductions of pyruvate require NADH |
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how many ATPs are produced in anaerobic respiration |
2 ATP efficiency is 2% lactic acid may be converted into pyruvate by the liver. this can then enter the kerbs cycle |
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what happens without oxygen |
-oxygen is the final electron acceptor in oxidative phosphorylation -when absent all other stages of respiration except from glycolysis stop - the reduced NAD produced during glycolysis must be reoxidised so that glycolysis can continue -this increases the chance of the organism surviving under tempoary adverse conditions |
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what reoxidation pathways are used for reducedd NAD in eukaryotic cells |
animal cells use lactate fermentation fungi and some plant tissue use ethanol frmentation |
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describe lactate fermation |
-pyruvat acts as a hydrogen acceptor -it accepts H atoms from reduced NAD -the oxidised NAD is now able to pick up more H atoms during glycolysis -this means that glycolysis can continue to produce ATP to allow the cells to function -particularly important in muscle contraction |
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dscribe pyruvate to lactate |
-the enzyme lactte dehydrogenase removes H atoms from the reduced NAD reduces the pyruvate to lactate |
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what happens to the lactate |
-lactate carried in the blood from the muscles to the liver -when oxygen is available lactate can be converted back to pyruvate and enter the mitochondria for the link reaction and the krebs cycle -or it is converted to glucose/ glycogen -not the build up of lactate that causes fatigue but the reduction in PH which reduces enzyme activity in muscles |
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describe what happens to lactate in the muscles |
-if lactate is not removed quickly it will build up in the muscles -snce it is acidic it cn affect the functioning of enzyms by altering PH -this lads to muscle fatigue -blood contains buffers such as haemogloin that cna accept H ions and keep the PH constat |
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describe ethanol fermentation in yeast cells |
-yeast is a facultative anaerobe so can live without oxyge id necessary -pyruvate is decarboxylated by the enzyme pyruvate decarboxylase and becomes ethanal -ethanal acceps hydrogen atoms from reduced NAD and forms ethanol -this is catalysed by ethanol dehydrogenase -the NAD returns to the glyolysis pathway to accept more H atoms |
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what hapens in yeast cells |
-each pyruvate is decarboxylalted and bcomes ethanal -thisis catalysed by pyruvate decarboxylase which isnt present in animals -ethanal accepts H atoms from reduced NAD whih becomes oxidised -ehanal is reduced to ethanol - the reoxidised NAD can now accept more hydrogen atoms from glucose during glycolysis |
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describe the pasteur effect |
-discoveed in 1857 by louis pasteur -found that aerating yeasted broth caused the yeast cell goeth to increase while the rate of fermentation decreased -oxygen slows the rate of fermention -as aerobic respiration produces more ATP -ATP inhibts the enzyme which catalyses fructose-6-phosphate forming fructose 1,6-bisphosphate in glycolysis -respiration slows down |
