5.2.2- Respiration Flashcards
what is the need for cellular respiration
to release energy for cells, that is used as a temporary energy store (ATP)
what is ATP seen as, hint currency?
the universal energy currency
what are the 8 biological processes that cells use ATP for?
-active transport
-exocytosis
-endocytosis
-DNA replication
-protein synthesis
-polysaccharide synthesis
-cell division
-muscle contraction
what are the 4 key main features of a mitochondrion?
-outer membrane
-inner membrane/cristae
-matrix
-mitochondrial DNA
why is the cristae in mitochondrion folded?
to increase the surface area
where in a cell does glycolysis occur?
the cytoplasm
what is glycolysis?
the phosphorylation of glucose, energy is extracted from glucose with no oxygen needed
what are the two distinct phases in glycolysis?
-phosphorylation (phosphate added)
-dehydrogenation (pyruvate is formed, and ATP and reduced NAD are released)
what occurs in glycolysis?
-glucose
+2 ATP
= hexose biphosphate
-splits
= 2 triose phosphates
+ Pi to both
= 2 triose biophosphate
-4 ATP released
-2 reduced NAD released
= 2 pyruvates
what is the net primary productivity of glycolysis?
2 (start with 2, end with 4)
what is the link reaction?
when the pyruvate is oxidised to acetate
where does the link reaction occur?
the matrix of the mitochondria
what happens during the link reaction?
pyruvate
- carbon dioxide released
-reduced NAD released
= acetyl group + coenzyme A
= acetylcoenzymeA
what is the Krebs Cycle?
the Citric Acid Cycle, where 4 carbon citric acid is produced
it is when acetyl CoA combines with a oxoloacetate to make citrate, dehydrogenation and decarboxylation
where does the Kreb’s Cycle occur?
the matrix of the mitochondria
what does AcetylecoenzymeA combine with within the Krebs Cycle?
oxoloacetate
how many cycles occur for one glucose molecule?
2
what is oxidative phosphorylation?
the production of ATP using H atoms removed during glycolysis, link reaction and the Kreb’s Cycle
it involves oxidation-reduction reactions, as electrons from the H atoms are passed down a series of electron carriers, energy for making ATP is realised
what occurs during oxidative phosphorylation?
-high energy electrons are passed down the electron carriers, but they lose energy as they are passed down.
-energy released is used to allow H+ ions across the membrane via the electron carriers
-protons can only move back through the membrane across the ATP synthase
-this movement caused the bottom of the ATP synthase to spin and ADP and Pi attach to make ATP.
what does chemiosmosis mean?
the flow of H+ ions through ATP synthase during oxidative phosphorylation
where does oxidative phosphorylation occur?
across the cristae
what is anaerobic respiration?
the release of energy from substrates, in the absence of oxygen
what are the 3 coenzymes involved in aerobic respiration?
-NAD
-FAD
-coenzyme A
what is the role of NAD in aerobic respiration?
role in energy metabolism by accepting and donating electrons
what is the role of FAD in aerobic respiration?
an electron carrier, deceivers electrons to electron transport chain after being reduced in the Krebs Cycle
what is the role of Coenzyme A in aerobic respiration?
it is used to transfer aceyl groups
a reactant for reaction, it releases a molecule of CO2 and reduces NAD and FAD
what is the first step of aerobic respiration?
glycolysis, where 2 ATP, 2 reduced NAD and 2 pyruvate are produced per glucose
what is produced from pyruvate in animal cells during anaerobic respiration?
lactate
what occurs during anaerobic respiration in muscle cells?
-lactate fermentation
-pyruvate accepts H atoms from reduced NAD to form lactate
-lactate hydrogenase catalyses this reaction
-NAD is regenerated and is now available to accept more H atoms from glucose, allowing glycolysis to continue?
what is produced from pyruvate during anaerobic respiration of plant and microbe cells?
carbon dioxide and ethanol
what occurs during anaerobic respiration of yeast cells?
-alcohol fermentation
-pyruvate decarboxylase catalyses the removal of C02 from pyruvate to produce ethanal
-ethanal accepts the H atoms from reduced NAD forming ethanol
-ethanol dehydrogenase catalyses this reaction
-NAD is regenerated and is available to accept more H atoms from glucose, allowing glycolysis to continue.
what is the benefit of anaerobic respiration in muscles and yeast?
muscles= allows muscle contraction to continue
yeast= allows yeast cells to continue growing
what is a respiratory substrate?
any organic substance that can be used for respiration
what are the 3 types of respiratory substrate?
-carbohydrates
-proteins
-lipids
what do different respiratory substrates yield?
they yield different amounts of ATP and so they have different energy content
why do respiratory substrates have different energy content?
because they each have different proportions of H atoms per gram
-the more H atoms per gram, the more reduced NAD and FAD, so more ATP is generated in oxidative phosphorylation, meaning they have more energy per gram.
what is the energy content of carbohydrates?
16 kJg -1
what is the energy content of proteins?
17 kJg -1
what is the energy content of lipids?
39 kJg -1
give some details on carbohydrates as a respiratory substrate?
-they are the first substrate a cell uses, but stores are used up quickly
-all cells respire glucose, which comes from hydrolysis of stored starch or glycogen
give some details on proteins as a respiratory substrate?
-not normally respired, except during starvation
-amino acids are released by digestion are respired
-excess amino acids are deaminated to urea and carbohydrate
give some details on lipids as a respiratory substrate?
-lipids are hydrolysed into glycerol and fatty acids (contain a high proportion of H atoms)
-glycerol is converted into carbohydrate, which is used in glycolysis
-fatty acids are converted to acetate, into Kreb’s Cycle
what is the RQ calculation?
RQ= respiration quotient
RQ = CO2 produced / O2 consumed
what is the RQ for carbohydrates?
1
what is the RQ for protein?
0.9
what is the RQ code for lipids?
0.7
what is used to measure the respiratory quotent?
a respirometer
why is the RQ value for carbohydrates 1?
it takes 6 oxygen molecules to completely respire one glucose molecule, which results in the production of 6 carbon dioxide molecules
why is the RQ value for protein 0.9?
the structure of amino acids leads to an RQ between carbohydrates and lipids
why is the RQ value for lipids 0.7?
lipids contain a greater proportion of carbon-hydrogen bonds so they produce more ATP in respiration
the greater number of carbon-hydrogen bonds, more oxygen is required to break them down and so less carbon dioxide is released
what is a respirometer?
a device used to measure the rate of respiration of a living organism by measuring its rate of exchange of oxygen and carbon dioxide.
what is the equation used to calculate respiration rate in a given time?
pi x r2 x h / t
what units are used for respiration rate?
cm3/min
why does anaerobic respiration produce a lower yield of ATP than aerobic respiration?
as there is no oxygen, glucose is not completely broken down and so less energy is released
how much energy is released in the reaction of converting ATP into ADP and Pi?
30.6 kJ
what is the last acceptor in oxidative phosphorylation?
oxygen
how much ATP is released in glycolysis?
2
how much ATP is released during the KREB’S CYCLE?
2
how much ATP is released during oxidative phosphorylation?
28
in total, how much reduced NAD is released during respiration?
10
in total, how much reduced FAD is released during respiration?
2
