Respiration Flashcards
All the energy required for life processes is obtained by ________ of some macromolecules -food .
Oxidation
Only _____and ______ can prepare their own food .
Green plants
Cyanobacteria
By the process of photosynthesis , green plants trap LIGHT energy and convert it to ____ that is stored in the _________ .
Chemical energy
Bonds of carbs like GLUCOSE ,SUCROSE and STARCH
In green plants ,all cells ,tissues and organs photosynthesise .T/F
F
In green plants , other organs and cells that are non-green , need food for _____.
Oxidation
Only cells containing ___ often located in the superficial layers .
Chloroplasts
_______is the breakdown of food materials within the cell to release energy and the trapping of this energy for synthesis of ATP .
Cellular respiration
Cellular respiration takes place in the ______and ______.
Cytoplasm
Mitochondria
Cellular respiration takes place in pro/eukaryotes ?
Only eukaryotes
The breaking of the _______bonds of ____ compounds through _____within the cels , leads to release of energy and is called respiration .
C-C bonds
Complex
Oxidation
The compounds that are OXIDISED during respiration are called -
Respiratory substrates
Usually carbs are oxidised to release energy , but ____,_____ and even ____ can be used as respiratory substrates in SOME PLANTS under CERTAIN CONDITIONS .
Proteins
Fats
Organic acids
Energy is released in a series of ____ reactions controlled by _____.
Slow step-wise
Enzymes
The energy released by oxidation ______ directly but is used to synthesise ______ , which is broken down whenever energy needs to be utilised .
Is not used / cannot be used
ATP
____ produced during respiration is used as precursors for biosynthesis of other molecules in the cell .
Carbon skeleton
Give the reasons why plants can get without respiratory organs ?
1) each plant takes care of its own gaseous needs , there is very little transport of gases from one part to another .
2) plants do not present great demands for gas exchange .
3) the distance that gases must diffuse even in large bulky plants is not great .
When cells PHOTOSYNTHESISE , availability of __ is not a problem in these cells . Why ?
O2
Since O2 is released within the cells
In stems , the cells in the interior are __ and provide ______.
Dead
Only mechanical support
Most cells of the plant have at least a part of their surface in contact with the _.
AIR
Loose packing of _____cells provide a interconnected network of AIR SPACES .
Parenchyma
In stems , the ___ cells are organised in thin layers inside and beneath the BARK .
Living cells
The strategy that the plant cells use is to catabolise the glucose molecule i such a way that _____
Not all the liberated energy goes out as heat
What is the key of the strategy adopted by plant cells to catabolise glucose molecule ?
The key is to catabolise glucose molecule not in one step but in several small steps enabling some steps to be large enough such that the energy release can be coupled with ATP SYNTHESIS .
During respiration. _ is utilised , and _ ,__ and _____ are released .
O2
CO2, H2O and energy
The __reaction in respiration requires O2 .
Combustion
Exceptions - facultative or obligate anaerobes do not require O2 .
In any case ,ALL LIVING organisms retain the enzymatic machinery to ___ glucose without the help of ____ .
Partially oxidise
O2
The breakdown of glucose to __is called GLYCOLYSIS .
Pyruvic acid
The schemes of GLYCOLYSIS was given by ___ ,_____ and _____ therefore it is also called EMP pathway .
Gustav Embden
Otto Meyerhoff
J. Parnas
In __organisms , glycolysis is the only process in respiration .
Anaerobic
Glycolysis occurs in the _____ of the cell and is present in all living organisms .
Cytoplasm (cytosol )
In glycolysis , glucose undergoes ___ to form 2 molecules of pyruvic acid .
Partial oxidation
In plants , the GLUCOSE for glycolysis is derived from _____.
Sucrose - (end product of photosynthesise)
Or from some storage carb
Sucrose is converted to glucose and fructose by the enzyme ______.
Invertase
Which 2 monosaccharides readily enter the GLYCOLYTIC PATHWAY .
Glucose
Fructose
Glucose and fructose are PHOSPHORYLATED to give rise to ______ by the activity of the enzyme ____
Glucose-6-phosphate
Hexokinase
(1st step)
In the 2nd step , the phosphorylated form of GLUCOSE ISOMERISES to produce _______.
Fructose-6-phosphate
Glucose6phosphate ———->fructose6phosphate
The steps of metabolism of glucose and _____are same .
Fructose
In glycolysis , a chain of _______ rxns under the control of diff /same enzymes , takes place to produce pyruvate from glucose .
10
Diff
During glycolysis , ___or ____ of ATP or ____ takes place .
Utilisation
Synthesis
NADH + H+
ATP is UTILISED IN ____ steps . What are they ?
2
1) in the conversion of glucose to glucose-6-phosphate
2) fructose-6-phosphate to fructose-1,6-bisphosphate
ATP is synthesised in ____steps in glycolysis . WHAT are they ?
2
1) BPGA (1,3- bisphosphoglyceric acid )——->PGA (3-phosphoglyceric acid )
2) PEP ——> pyruvic acid
The fructose-1,6 bisphosphate is split into _____and _____.
Dihydroxyacetone phosphate
PGAL (3-phosphoglyceraldehyde )
In glycolysis , there are _____ steps in which NADH +. H+ is formed from NAD. Which ?
1
PGAL. ———————-> BPGA
(3-phosphoglyceraldehyde). 1,3-bisphosphoglycerate
2 _____ are removed in the form of _____ (during the conversion of PGAL to BPGA ) from _____ and transferred to _____.
Redox-equivalents
2 H atoms
PGAL
NAD+
PGAL is oxidised with ______ to get converted into BPGA .
Inorganic phosphate
The conversion of BPGA to ______ is also an energy yielding process .
PGA
The metabolic fate of pyruvate depends on the ________ .
Cellular need
There are ____ ways in which diff cells handle pyruvic acid produced by glycolysis . What are they ?
3
Lactic acid fermentation
Alcoholic fermentation
Aerobic respiration
Fermentation takes place under _____conditions in many _____ and ______.
Anaerobic
Prokaryotes
Unicellular eukaryotes
For the COMPLETE oxidation of glucose into ___ and ____ ,organisms adopt _______ .
CO2
H2O
Kreb’s cycle
Kreb’s cycle is also called -
Aerobic respiration
Req O2 supply
In fermentation , say by YEAST , the ____oxidation of glucose is achieved under _______ conditions by sets of rxns where __ is converted to ____ and ___ .
Incomplete
Anaerobic
Pyruvic acid
CO2 and ethanol
The enzymes ____ and _____ catalyse the rxns btw pyruvic acid ——->CO2 and ethanol .
Pyruvic acid decarboxylase
Alcohol dehydrogenase
The conversion of PYRUVIC ACID to CO2 and ethanol is the ________ of glucose .
Incomplete oxidation
In the muscles during exercise , where O2 is inadequate for cellular respiration , PYRUVIC ACID is reduced to _____ by ______.
Lactic acid
Lactate dehydrogenase
When pyruvic acid is reduced to lactic acid , the reducing agent is -
NADH. +. H+
(Which is reoxidised to NAD+
Organisms like _____produce LACTIC ACID from PYRUVIC ACID .
Some bacteria 🧫
In both _____ and ______ , not much energy is released .
LACTIC ACID and ALCOHOL fermentation
_____% of energy in glucose is released in fermentation(bth lactic acid and alcohol) and not all of it is trapped as high energy bonds of ATP
Less than 7%
Fermentation ( both alcoholic and lactic acid ) are ______ because ______.
Hazardous
Either acid or alcohol is produced
Yeasts poison themselves to death when the conc of ___ reaches about ____%.
Alcohol
13%
_____ is the process that leads to the __________of organic substances in the presence of oxygen and release CO2 , H2O and LARGE AMOUNT OF energy .
Aerobic respiration
Complete oxidation
Aerobic respiration is most common in ________.
Higher organisms
Aerobic respiration in eukaryotes takes place within the ______.
Mitochondria
For aerobic respiration to take place , pyruvate is transported from _____to ____.
Cytoplasm
Mitochondria
Give the 2 crucial events in aerobic respiration -
1) complete oxidation of pyruvate by the stepwise removal of all H atoms , leaving 3 molecules of CO2 .
2) passing on of e- removed as part of the H atoms to mol O2 with simultaneous synthesis of ATP .
The complete oxidation of pyruvate by the stepwise removal of all H atoms leaving __________ molecules of ______ is the 1st step of aerobic respiration .
3
CO2
The 1st step of aerobic respiration which is the complete oxidation of pyruvate takes place in the ________.
matrix of Mitochondria
In aerobic respiration , the passing of e- to mol O2 with simultaneous synthesis of ATP (2nd step ) ,is located on the -
Inner membrane of mitochondria
Pyruvate which is formed by the ______ of carbs in the cytosol ,after it enters mitochondrial matrix undergoes ________.
GLYCOLYTIC catabolism
Oxidative DECARBOXYLATION
Pyruvate undergoes OXIDATIVE CATABOLISM catalysed by a complex set of rxns catalysed by _____ .
Pyruvic dehydrogenase
The reactions catalysed by pyruvic DEHYDROGENASE req the participation of several _______
Coenzymes
Name the coenzymes which need to participate in the rxn catalysed by pyruvic dehydrogenase (OXIDATIVE DECARBOXYLATION ).
NAD+
Coenzyme A
Give the complete rxn catalysed by pyruvic dehydrogenase .
Pyruvic acid +CoA + NAD ———->Acetyl CoA +CO2 +NADH + H+
Mg2+
Oxidative decarboxylation
During oxidative decarboxylaton , ____molecules of ____are produced from 2 molecules of PYRUVIC ACID (produced from 1 glucose ).
2
NADH
Where does oxidative decarboxylation occurs ?
Mitochondrial matrix
The _____ from oxidative decarboxylation enters a cyclic pathway , KREB’s cycle .
Acetyl CoA
The kreb’s cycle also called ____ is named after the scientist ____.
Tricarboxylic acid cycle
Hans kreb
The TCA cycle starts with the _____of ACETYL group with ______ and ____to yield _____.
Condensation
OAA
Water
Citric acid
In yeast (fungi ) what kind of fermentation occurs ?
Alcoholic fermentation ( where pyruvic acid is converted to CO2 and alcohol by enzymes alcohol dehydrogenase and pyruvate carboxylase )
{in bacteria - lactic acid fermentation occurs }The rxn btw OAA and Acetyl CoA to yield citric acid is catalysed by -
Citrate synthase
Citrate is isomerised to -
Isocitrate
When Acetyl group is condensed with OAA and water , yielding citric acid , during TCA ,_______is released .
A molecule of CoA
The isomerization of citrate to isocitrate is followed by _____successive steps of _____ leading to the formation of alpha-keto glutaric acid .
2
Decarboxylation
After isocitrate formation , 2 successive steps of decarboxylation lead to the formation of _____ and THEN ______.
Alpha-keto glutaric acid
Succinyl-CoA
In the remaining steps of citric acid cycle succinylcholine CoA is oxidised to ____ allowing the cycle to continue .
OAA
Succinylcholine CoA is _______OAA .
Oxidised
During the conversion of succinyl CoA to SUCCINIC acid , a molecule of _________ is synthesised .
GTP
In a COUPLED rxn ,GTP is converted to GDP with the simultaneous synthesis of _____from ____ . This process is called -
ATP from ADP
Substrate level phosphorylation
When is a molecule of GTP synthesised in TCA ?
When succinyl CoA is converted to SUCCINIC ACID
Substrate level phosphorylation
In the citric acid cycle (kreb’s) ,there are ____ points where NAD+ is reduced to NADH + H+ and ____ points where FAD+ is reduced to FADH2 .
3
1
The first member of the TCA cycle is -
OAA
The continued ___ of ____ via the TCA cycle req the continued replenishment of OAA (1st member )
Oxidation
Acetyl CoA
The TCA cycle req regeneration of __ , ___ and ____.
NAD+ from NADH
FAD+ from FADH2
OAA
____ molecules of ATP are synthesised in the TCA CYCLE .
2
After the TCA cycle , how many molecules of NADH are we left with when 1 glucose molecule has been broken down ?
8
3 -kreb’s / TCA
1-oxidative decarboxylation (pyruvate to Acetyl CoA)
(4*2 =8 , 2 pyruvates are formed from 1 glucose )
{ only 1 NADH is released in glycolysis - not counted here )
ETS is also called -
Oxidative phosphorylation
The following steps after the TCA cycle are to release and utilise the energy stored in -
NADH +. H+
FADH2
The energy stored in NADH and FADH2 is utilised when they are OXIDISED through the _____ and the e- are passed on to O2 resulting in teh formation of -
ETS
H2O
The metabolic pathway through which the e- passes from one carrier to another -
ETS
The ETS is present in the ______.
Inner mitochondrial membrane
Complex 1 of ETS .
NADH dehydrogenase
Complex 2 of ETS .
FADH2
Complex 3 of ETS -
Cytochrome bc1
Complex 4 of ETS :
Cytochrome c oxidase complex ( containing cytochromes a and a3 and 2 Cu centres )
E- from NADH produced in the mitochondrial matrix during TCA cycle are oxidised by an __________
NADH dehydrogenase (complex 1 )
E- released after oxidation of NADH are transferred to _______ located within the inner membrane .
Ubiquinone
Ubiquinone is located within the _______ .
Inner membrane
Ubiquinone also receives reducing equivalents via -
FADH2 (complex 2 )
by oxidation of NADH also
FADH2 is generated during _____of ______ in the citric acid cycle .
Oxidation
Succinate
How is obiquinone reduced ?
By receiving reducing equivalents via FADH2 (complex 1)
By receiving e- from the oxidation of NADH by NADH dehydrogenase(com 2)
When obiquinone is reduced , it forms ______.
Ubiquinol
The reduced obiquinone(obiquinol) is oxidised with the transfer of e- to _____ via _____.
Cytochrome c
Complex 3 -cyto bc1 complex
______ is a small protein attached to the outer surface of the inner membrane and acts as a mobile carrier for transfer of e- from complex 3 to 4 .
Cytochrome c
Cytochrome c is located on the ______surface of __membrane .
Outer
Inner
Cytochrome c is a small protein that acts as a MOBILE CARRIER between complex____ and ___
3
4
Complex 4 refers to CYTOCHROME C OXIDASE complex containing _____, ____ and _____.
Cytochrome a
Cytochrome a3
2 Cu centres
Complex 5 in ETS is -
ATP synthase
When e- pass from one carrier to another via complex 1 to 4 in the ETC , they are coupled to _____ .
ATP synthase (complex 5 )
E- are coupled to ATP synthase for the production of ___from ___and _____.
ATP
ADP
Inorganic phosphate
In ETC , the no of ATP molecules synthesised depends on _______.
Nature of e- donor
_____ of 1 molecule of NADH gives rise to ______molecules of ATP and 1 molecule of FADH2 produces __ ATPs .
Oxidation
3
2
Although aerobic respiration takes place in the presence of O2 , the role of O2 is limited to the ______stages of ETC .
Terminal
The presence of ____is vital since it drives the whole process of ETC by removing H from the system .
O2
_____ acts as the final H acceptor in ETC .
O2
Why is ETC also called oxidative phosphorylation ?
Becoz it is the energy of oxidation-reduction utilised for production of proton gradient .
(Unlike photosynthesis - when light energy is utilised for the production of proton gradient )
Oxygen acts as the final __ acceptor in ETC .
H
Complex 5 ( ATP synthase ) consists of which 2 components ?
F1 -headpiece
F0-integral
The F1 headpiece of ATP synthase is a ____ protein and contains the site for synthesis of ____ .
Peripheral membrane
ATP (from ADP and inorganic phosphate )
Fo is an _____protein that forms the channel through which ___cross the ____
Integral
Protons
Inner membrane
The passage of protons through the _____ is coupled to the catalytic site of _____ for the production of ATP .
Fo channel
F1 component
For each ATP produced , ____ pass through Fo .
2 H+
For each ATP produced , 2 H+ passes through the Fo from the _____ to the _____ .
Intermembrane space
Matrix
The 2 H+ pass from the intermembrane space of the mitochondria to the matrix in ETC ______ the _____ gradient .
Down
Electrochemical proton
It is possible to make calculations of the net gain of ATP for every glucose molecule oxidised .T/F
T
But - this is only a theoretical exercise based on assumptions
What are the assumptions made while making the RESPIRATORY BALANCE SHEET .
1) orderly pathway , with 1 substrate forming another and with glycolysis , TCA cycle and ETS pathway following one after other .
2) NADH synthesised in glycolysis is transferred to mitochondria and undergoes oxidative phosphorylation.
3) none of the intermediates in the pathway are utilised to synthesise any other compound .
4) only glucose is being respired , no other alternatives are entering the pathway .
The assumptions(4) made in the respiratory balance sheet are valid in a living system .T/F
F
In reality , all pathways work ____and do not take place one after other .
Simultaneously
When do substrates enter the TCA pathway , and when is atp utilised ?
When necessary
In TCA cycle enzymatic rates are controlled by ______ means .
Multiple
If respiratory balance sheet is not valid , then why is it useful to do this exercise ?
To appreciate the beauty and efficiency of the living system in extraction and storing energy .
There can be a net gain of _____ATP molecules during aerobic respiration of 1 molecule of gllucose .
38
In fermentation , there is net gain of ____ molecules of ATP for each molecule of glucose .
Only 2
NADH is oxidised to nad+ rather slowly in _____.
Fermentation
___is the favoured SUBSTRATE for respiration .
Glucose
All ____ are first converted to ___ before they are used for respiration .
Carbs
Glucose
Other substrates can also be respired but they do not enter the pathway at the ___
1st step
Fats would be needed to broken down into ____ and ____ before entering the pathway .
Glycerol
Fatty acid
If fatty acids were to be respired ,they would first be degraded to _____ and enter the pathway .
Acetyl CoA
Glycerol would enter the pathway after being converted to ___
PGAL
The proteins would be degraded by ____ and the individual _____ would enter the pathway at some stage within the Kreb’s cycle or even as _____ or _____ .
Proteases
Amino acids
Pyruvate
Acetyl CoA
The proteins after being degraded to amino acids after_____ enter the pathway depending on _______.
Deamination
Their structure
The respiratory process has traditionally been considered a __process becoz _____
Catabolic
Involves breakdown of substrates
The respiratory pathway comes into picture both during ____and _____of fatty acids or proteins .
Breakdown
Synthesis
Becoz the respiratory pathway is involved in both ____and __ ,it is better to consider it as an _________ rather than a catabolic process .
Anabolism
Catabolism
AMPHIBOLIC pathway
When the organism needs to synthesise __, Acetyl CoA would be withdrawn from the respiratory pathway for it .
Fatty acids
Anabolism
The respiratory quotient depends on the __________ used during respiration .
Type of respiratory substrate
When ______are used as respiratory substrates , the RQ is 1 .why ?
Carbs
Completely oxidised
The ratio of volume of co2 _____ and O2 ____ is called respiratory quotient .
Evolved
Consumed
When FATS are used as respiratory substrates , the RQ is ______.
Less than 1
For fatty acids , the RQ is __
0.7
When proteins are respiratory substrates ,the RQ is _____
0.9
Give an example of a substance with RQ 0.7 .
Tripalmitin -fatty acid
In living organisms , the respiratory SUBSTRATES are often _______.
More than 1
Pure _____or ______are never used as respiratory substrates .
Fats
Proteins
Where is the F1headpiece of atp synthase located ?
Matrix of mitochondria
Compare fermentation and aerobic respiration -
Aerobic - complete degradation of glucose to CO2 and H2O F - partial breakdown F-net gain of 2 atp A- net agin of 38 atp F-NADH is oxidised to nad+ slowly A - oxidation is vigorous
During TCA cycle , at which point is FADH2 synthesised ?
During the conversion of succinate/succinic acid to FUMARATE .
At which points in the Kreb’s cycle is NADH synthesised ?
Iso-citrate to oxalo-succinate
Alpha-keto glutarate to succinyl CoA
Malate to oxaloacetate
