Respiration ncert Flashcards
All living organisms need — for carrying out daily life activities, be it absorption, transport, —-, reproduction or even —.
Where does all this energy come from?
energy
movement, breathing
The process of breathing is very much connected to the process of —- from food.
release of energy
All the energy required for ‘life’ processes is obtained by —– —– that we call ‘food’.
oxidation of
some macromolecules
Only —- and —- can prepare their own food; by the process of photosynthesis they trap light energy and convert it into —- energy that is stored in the bonds of carbohydrates like —-, —- and —-.
green plants and
cyanobacteria
chemical
glucose, sucrose and starch
In green plants, all cells, tissues and organs
photosynthesise. T/F
False
only cells containing chloroplasts, that are most often located in the superficial layers, carry out photosynthesis.
Food has to be translocated to all —-parts of a plant.
nongreen
Animals are — , i.e., they
directly (herbivores) or indirectly (carnivores).
heterotrophic
—- like fungi are
dependent on dead and decaying matter.
Saprophytes
Ultimately all the food that is respired for life processes comes from
—.
photosynthesis
Cellular respiration is —-
the mechanism of breakdown of food within the cell, by releasing energy and trapping it to form ATP
Photosynthesis, takes place within the —- (in the
eukaryotes), whereas the breakdown of complex molecules to yield energy
takes place in the — and — (also only in eukaryotes).
chloroplasts
cytoplasm and in the mitochondria
The breaking of the — of complex compounds
through — within the cells, leading to release of considerable amount of energy is called respiration.
C-C bonds
oxidation
The compounds that are oxidised during cellular respiration are known as —
respiratory substrates
Usually — are oxidised to release energy, but proteins, fats and even
—- can be used as respiratory substances in some plants, under
certain conditions.
carbohydrates
organic acids
During oxidation within a cell, all the energy contained in respiratory substrates is —- .
not released free into the cell, or in a single step
Energy from breakdown of food is released in a series of —- reactions controlled by — , and it is trapped as chemical energy in the form of ATP.
slow step-wise , enzymes
Energy released by oxidation in
respiration is used directly for other reactions in the body. T/F
False. It is used to
synthesise ATP, which is broken down whenever (and wherever) energy
needs to be utilised.
ATP acts as the —- of the cell.
energy currency
This energy trapped in ATP is utilised in various energy-requiring
processes of the organisms, and the —- produced during respiration is used as precursors for – of other molecules in the cell.
carbon skeleton, biosynthesis
Plants require —
for respiration to occur and they also give out –
O2, CO2
Plants have systems in place that ensure the availability of O2. T/F
True
Plants, unlike animals,
have no specialised organs for gaseous exchange but they have — and —- for this purpose.
stomata
and lenticels
Why can plants get along without respiratory organs?
- Each plant part takes care of its own gaseous needs- Transport is very lil.
- Low demands for gas exchange. Roots, stems and leaves- respire at lower rate than animals (except ps- which leaves take care of + already get O2)
- Distance that gases must diffuse even in large, bulky plants is not great.
Each living cell in a plant is located quite close to the — of the plant.
surface
In stems, the ‘living’ cells are organised in thin layers — and — the bark. They also have openings called —.
inside and beneath
lenticels
The cells in the interior of stem are dead and provide —.
only mechanical support
Most cells of a plant have at least a part of their surface in —. This
is also facilitated by the loose packing of —- in leaves, stems and roots, which provide an interconnected network of air spaces.
contact with air
parenchyma cells
The complete combustion of —, which produces CO2 and H2O as end products, yields energy most of which is —
glucose, given out as heat
If this energy is to be useful to the cell, it should be able to —- .
utilise it to synthesise other molecules that the cell requires
The strategy that the
plant cell uses is to — the glucose molecule in such a way that not all the liberated energy goes out as heat.
catabolise,
The key is to oxidise glucose not in one step but in —- enabling some steps to be just large enough such that the energy released can be —.
several small steps, coupled to ATP synthesis
The combustion
reaction requires —.
oxygen
But some cells live where oxygen may or may
not be available. There are reasons to believe that the —- that lacked oxygen.
first cells on this planet lived in an atmosphere
Among present-day living organisms, we know of several that are adapted
to — conditions.
anaerobic
Some of these organisms are — anaerobes, while in others the requirement for anaerobic condition is
—.
facultative, obligate
All living organisms retain the enzymatic machinery
to —- without the help of oxygen.
partially oxidise glucose
Breakdown of glucose to — acid is called —-.
pyruvic , glycolysis
The term glycolysis has originated from the —words, glycos for —,
and lysis for —.
Greek ,
sugar, splitting
The scheme of glycolysis was given by —, — and —, and is often referred to as the EMP pathway.
Gustav Embden, otto Meyerhof, J. Parnas
In anaerobic organisms, — is the only process in respiration.
Glycolysis
Glycolysis occurs in the —of the cell and is present in all living organisms.
cytoplasm
Glucose undergoes partial oxidation to form —.
two molecules of pyruvic acid
In plants, this glucose is derived from —, which is the end product of —, or from storage carbs
sucrose, ps
Sucrose is converted into — and — by the enzyme, —, and these two monosaccharides readily enter the glycolytic
pathway.
glucose and fructose
invertase
Glucose and fructose are
— to give rise to glucose-6- phosphate by the activity of the enzyme
– .
phosphorylated , hexokinase
This —- form of glucose
then isomerises to produce —-.
phosphorylated, fructose-6-phosphate
Steps of metabolism of
glucose and fructose are same after the formation of
Fructose 6-phosphate
In glycolysis, a chain of — reactions, under the
control of —, takes place to produce pyruvate from glucose.
ten , different enzymes
In glycolysis, ATP is utilised at two steps: first in the —— and second in the conversion of —-
conversion of:
- glucose into glucose 6-phosphate,
- fructose 6-phosphate to fructose 1, 6-bisphosphate.
The fructose 1, 6-bisphosphate is split
into — and — .
dihydroxyacetone phosphate and
3-phosphoglyceraldehyde (PGAL)
There is – step where NADH + H+ is
formed from NAD+
one ,
Step in which NADH + H+ is formed
This is when
3-phosphoglyceraldehyde (PGAL) is converted
to 1, 3- bisphosphoglycerate (BPGA).
Two —- are removed (in the form of two —- atoms) from PGAL and transferred to a molecule of NAD+. PGAL is oxidised and with —- to get converted into
BPGA.
redox equivalents hydrogen
inorganic phosphate
The conversion of BPGA to —-, is also an energy
yielding process; this energy is trapped by the
formation of ATP.
3-phosphoglyceric acid (PGA)
Another ATP is synthesised during the conversion of — to —-
PEP to pyruvic acid.
— is then the key product of glycolysis.
Pyruvic acid
Metabolic fate of pyruvate depends on
Cellular need
There are — major ways in which different cells handle pyruvic acid
produced by glycolysis. These are —-.
three
1. lactic acid fermentation, 2. alcoholic fermentation
3. aerobic respiration
Fermentation takes place under anaerobic conditions in many — and —-
prokaryotes and unicellular eukaryotes.
For the complete oxidation of glucose to CO2 and H2O, however, organisms adopt —- which is also called as —-.
Krebs’ cycle , aerobic respiration
In fermentation, say by —, the incomplete oxidation of glucose is achieved under — by sets of reactions where pyruvic
acid is converted to —.
yeast, anaerobic conditions
CO2 and ethanol
The enzymes, —- and —-catalyse alcoholic fermentation reactions.
pyruvic acid decarboxylase and alcohol dehydrogenase
Other organisms like some — produce lactic acid from pyruvic acid. In animal cells also, like —
during exercise, when oxygen is inadequate for cellular respiration pyruvic acid is reduced to lactic acid by —-.
bacteria, muscles
lactate dehydrogenase
The — is NADH+H+ which is reoxidised to NAD+
in both the anaerobic processes.
reducing agent
In both lactic acid and alcohol fermentation not much energy is released; —- of the energy in glucose is released and not all of it is trapped as —-.
less than seven per cent
high energy bonds of ATP
Also, the anaerobic processes are —– either acid or alcohol is produced.
hazardous
Yeasts — themselves to death when the concentration of alcohol reaches about —.
poison , 13 per cent
—- the process by which organisms can carry out complete oxidation of glucose and extract the energy stored to synthesise —-
needed for cellular metabolism?
Aerobic resp, a larger number of ATP molecules
In eukaryotes these steps take place within the —and this requires O2
mitochondria ,
Aerobic respiration is the
process that leads to a complete oxidation of —- in the presence of oxygen, and releases CO2
, water and a — present in the substrate; most common in —-
organic substances
large amount of energy
higher organisms.
For aerobic respiration to take place, pyruvate is transported from the —- to —.
cytoplasm into mitochondria
The crucial events in aerobic respiration are:
* The complete oxidation of pyruvate by the stepwise removal of all
the —-, leaving —-
.
* The passing on of the —removed as part of the hydrogen atoms to — with simultaneous synthesis of — .
hydrogen atoms, three molecules of CO2
electrons, molecular O2
ATP
First process (—-) takes place in the — of the mitochondria while the second process (—) is located on the —- of the mitochondria.
Krebs cycle, matrix
ETS- inner membrane
Pyruvate, which is formed by the —- of
carbohydrates in the cytosol, after it enters mitochondrial matrix
undergoes —- by a complex set of reactions
catalysed by pyruvic dehydrogenase.
glycolytic catabolism
oxidative decarboxylation
The reactions catalysed by —- require the participation of several coenzymes, including
NAD+ and Coenzyme A.
pyruvic dehydrogenase
The acetyl CoA then enters a cyclic pathway, —-cycle, more commonly called as Krebs’ cycle after the scientist — who
first elucidated it.
tricarboxylic acid , Hans Krebs
The TCA cycle starts with the —- with oxaloacetic
acid (OAA) and — to yield citric acid. The reaction is
catalysed by the enzyme —- and a molecule of — is released.
condensation of acetyl group, water
citrate synthase, CoA
Citrate is then — to isocitrate. It is followed by two successive
steps of —-, leading to the formation of—-
isomerised, decarboxylation, α-ketoglutaric acid and succinyl Coa
In the remaining steps
of citric acid cycle, succinyl-CoA is —
to OAA allowing the cycle to continue.
oxidised
During the conversion of succinyl-CoA to — a molecule of — is synthesised. This is
a —- phosphorylation. In a coupled reaction GTP is converted to GDP with
the simultaneous synthesis of ATP from ADP.
Also there are three points in the cycle where
NAD+
is reduced to NADH + H+ and one point
where FAD+
is reduced to FADH2
. The
continued oxidation of acetyl CoA via the TCA
cycle requires the continued replenishment of
oxaloacetic acid, the first member of the cycle.
In addition it also requires regeneration of
NAD+ and FAD+ from NADH and FADH2
respectively. The summary equation for this
phase of respiration may be written as follows:
succinic acid, GTP
substrate level
Also there are —- points in the cycle where
NAD+ is reduced to NADH + H+ and —- point
where FAD+ is reduced to FADH2
three, one
The continued oxidation of acetyl CoA via the TCA
cycle requires the continued replenishment of — , the first member of the cycle.
In addition it also requires regeneration of
— and — from NADH and FADH2 respectively.
oxaloacetic acid
NAD+ and FAD+
We have till now seen that glucose has been broken down to release
—- and — molecules of NADH + H+ and — of FADH2 have been
synthesised besides just — molecules of ATP in TCA cycle.
CO2 and eight, two
two
The —- steps in the respiratory process are to release and utilise
the energy stored in NADH+H+ and FADH2. This is accomplished when they are —- through and the electrons
are passed on to O2
resulting in the formation of H2O.
ETS, oxidised
The metabolic
pathway through which the electron passes from —- to —- is called the electron transport system (ETS) and it is
present in the —–.
one carrier to another,
inner mitochondrial membrane
Electrons from NADH produced in the mitochondrial matrix during citric acid cycle are oxidised by an —-, and electrons are then transferred to —- located
within the inner membrane.
NADH dehydrogenase (complex I)
ubiquinone
Ubiquinone also
receives —- via —- that is generated during
oxidation of succinate in the citric acid cycle.
reducing equivalents via FADH2 (complex II)
The reduced ubiquinone (—-) is then oxidised with the transfer of electrons to —- via —- complex
(complex III).
ubiquinol, cytochrome c via cytochrome bc 1
Cytochrome c is a —-
attached to the — surface of the inner membrane and acts as a mobile carrier for transfer of electrons between — and —.
small protein, outer
complex III and
IV.
Complex IV refers to —- containing cytochromes a and a3 and —- centres.
cytochrome c oxidase
complex
two copper
When the electrons pass from one carrier
to another via complex I to IV in the electron
transport chain, they are coupled to — (complex V) for the production of
ATP from ADP and inorganic phosphate.
ATP synthase
The number of ATP molecules synthesised in ETS depends on the —.
nature of the electron donor
Oxidation of one molecule of NADH gives rise to – molecules of ATP, while that of one
molecule of FADH2
produces —molecules of
ATP.
3, 2
Although the aerobic process of respiration takes place only in the presence of oxygen, the role of oxygen is limited to the —- of the process.
terminal stage
Yet, the presence of oxygen is —, since it drives the whole process by —- from the system.
vital, removing hydrogen
—- acts as the final hydrogen acceptor.
Oxygen
Unlike photophosphorylation where it is the
light energy that is utilised for the production of —- required for phosphorylation, in respiration it is the —-
utilised for the same process. It is for this reason that the process is called —–.
proton gradient,
energy of oxidation-reduction
oxidative phosphorylation
ATP synthase (complex V) consists of two major components,— and —-
F1and F0
The F1 — is a
—– complex and
contains the site for synthesis of ATP from ADP and inorganic phosphate.
headpiece, peripheral membrane protein
F0 is an —- complex that forms the channel through which protons cross the inner
membrane.
integral membrane protein
The passage of protons through the channel is coupled to the — of the F1 component for the production of ATP.
catalytic site
For each ATP produced, —H+ passes through F0
from the intermembrane space to the matrix down the electrochemical proton gradient.
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