Detailed Analysis of Krebs Cycle and ATP Production: Biology Practical

This assignment provides detailed answers to biology practical questions focusing on the Krebs cycle, its regulation by calcium, and the electron transport chain. It discusses how intracellular calcium levels affect the Krebs cycle, highlighting the enzymes involved and mechanisms of regulation. The document explores whether calcium levels in the mitochondrial matrix reflect cytosolic levels and explains the role of calcium in cellular physiology. It further delves into the regulation of the Krebs cycle by ATP, the function of ubiquinone and cytochrome c, and the role of uncoupling proteins in ATP synthesis. The electron transport chain's function in ATP production, the electrochemical gradient, and the roles of complexes I, II, III, and IV are thoroughly explained. This assignment provides a comprehensive understanding of mitochondrial function and energy production. Find more solved assignments and study resources on Desklib.

Biology Practical questions
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Question 1
Krebs cycle refers to a series of chemical reactions which provide energy in form of ATP
occurring in the mitochondria. It provides hydrogen and electrons necessary for electron
transport chain. Calcium plays a fundamental role in cellular signalling. It acts on the signal
transduction which results in the activation of ion channels. The mitochondrial calcium
elevates the rate of oxygen intake due to the activation of calcium-activated dehydrogenize
enzyme, and through activation of mitochondrial nitric oxide (Paupe, and Prudent).
Mitochondrion target site of the agonist of Calcium ions signals the organelle modeling
function through direct measurement of the mitochondrion and cytosolic ATP levels. In HeLa
cells and cultures of skeletal myotubules, there is an occurrence of agonist stimulation on
cytosolic and mitochondrial which cases rise in calcium ions thus causing an increase in
ATP. Further increase in calcium ions leads to induced long-lasting agonist washout causing
a significant increase in ATP and overall function of the Krebs cycle. This indicates a direct
role of mitochondrial calcium ions during the Krebs cycle in increasing the production of
ATP (Contreras et al.).
Question 2
ATP is the primary source of high energy phosphate bonds in the cell and acts as allosteric
effects or in numerous cell functions. The intracellular ATP is obtained from the cytosolic
glycolysis and the process of mitochondrial oxidative phosphorylation. The mitochondrial
efflux is linked to the exchange function of the Na+–Ca2+–Li+. Calcium efflux in the
mitochondrial is depended (Santo-Domingo, and Demaurex)
The concentration gradient in the cytosol often diffuses rapidly within its compartment.
Calcium sparks in the cytosolic tend to be produced in a shorter time around the calcium
change, thus making the cytosol to have less intracellular calcium.
There is a higher quantity of calcium ions in the mitochondrial matrix which is key in cellular
function. These flux influents play a key role in the production of energy and initiate cell
death. Thus compared to the cytosol, calcium quantities are high in the mitochondrial matrix
(Mammucari et al.).
Question 3
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Krebs cycle produces high energy molecules such as the ATP during the oxidative
phosphorylation. Citric cycle regulations is an important factor as it ensures that there are
checks on amounts of wasted metabolic energy. The regulation mechanism is undertaken in
two ways; by acetyl CoA and by calcium ions.
Calcium is key in the regulation of the citric acid cycle. An elevated increase in ADP and
calcium ions leads to changes in cellular activity. Calcium ions regulate the critic acid cycle
through the activation of pyruvate dehydrogenase.
Further calcium ions activate enzymes such as isocitrate dehydrogenize and α-ketoglutarate
dehydrogenize responsible for various steps of the Krebs cycle. Their activation through
calcium ions increases the separation rates in the cycle and thus increases the production of
ADP in the overall Krebs cycle process (Matsuura et al.).
Question 7
Ubiquinone is categorized as a parabenzoquinone having methoxy groups at carbon 2 and 3
in the methyl group and in carbon 5 with polyisoprene chain length. An estimate of 80% of
CoQ10 is located in the mitochondrial inner cell. Ubiquinone acts as an electron shuttle
between the different level of carbon and undergoes reduction the radical semiquinone and
autoxidation begin major source superoxide production (Wilk et al.).
Cytochrome c is a hem protein which is localized in the compartment between inner and
outer membranes where it transfers electrons between the complex II and IV respiratory
chain. cytochrome b on the other end is protein found on the mitochondria which form part of
electron transport chain. The drug is likely to act on the protein ubiquinone (cytochrome Q)
in order to reduce to manageable levels.
Question 8
Uncoupling protein refers to the inner membrane protein which regulates the proton channel
or the underlying transporter. Uncoupling protein is able to form a dissipating proton gradient
which generates the NADH proteins through pumping protons located in the mitochondrial.
Uncoupling protein is linked to thermogenesis with its positioning placed on the same
membranes as the ATP synthesis which is also a proton channel. The two protons ensure that
they work together to generate heat and ATP and ADP later in oxidative phosphorylation,
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reflecting the link for mitochondria P/O (Letts , James, and Sazanov).
In context, the phosphate/oxygen ratio reflects the ATP produced in the movement of two
electrons through the electron transport chain. The P/O ratio is highly dependent on the
hydrogen atoms moved to access the electrochemical gradient.
When the uncoupling protein is active in a cell, there is an increased rate of dissipation which
works in a complex process to increase generation of ATP and phosphorylation later, playing
a critical role in ATP synthesis. Thus, this will lead to a significant rise in phosphate/oxygen
ratio due to increase production of ATP (Demirel).
Question 10
Electron transport chain functions as a series of complexes which transfers electrons from
donors to acceptors. The simultaneous reactions occur, transferring protons through the
membrane. The net effect is the formation of electrochemical gradient formation which
synthesizes ATP molecule storing chain including peptides and enzymes. The electron
transport is key in extracting energy through redox reactions through the use of oxidation
sugars in cellular transport. The resultant reaction of electron transport is undertaken in
membranes series of proteins and organic molecules arranged in four complexes (Althoff et
al.).
The oxidative phosphorylation electron transport chain located in the inner mitochondrial
membrane entails five major larger protein complexes from C1-CIV. These complexes
perform a key role in converting food into energy. The electron transport chain can be
organized in super complex forms entailing CIV AND CV forms. Super complex models are
able to offer efficient transfer of electrons into predefined pathways is able to take place.
Unique arrangement super complex is able to produce a unique arrangement of the
complexes, with an indicative pathway of small electrons carriers able to travel efficiently
(Popot et al.).
Question 11
ATP synthase to use the electrochemical gradient to produce ATP
Electrochemical gradient plays a fundamental role in proton establishment in oxidative
phosphorylation in mitochondria. This leads to a cellular process of electron transport. The
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four complexes of the inner membrane of the mitochondrion engage in the formation of
electron transport complex. Complexes I, II,II, and IV are able to pump protons to the
interspaces. The resulting flux is able to drive the protons back in the matrix formation
through the ATP synthase which in turn leads to production f ATP through the addition of
inorganic phosphate to ADP process. This, in turn, generates the energy which is essential in
mitochondria production.
Question 12
In complex I, NADH offers a donation of two electrons into complex I, leading to loss of
energy, which is essential in pumping hydrogen ions located in the mitochondrial matrix into
the intermembrane space.
In complex II, the FADH donates two electrons to complex II, this takes place with little loss
in energy. In complex III, the Ubiquinone (coenzyme Q10) is able to move out towards
complex II and donate two electrons into it. In this complex, the electrons lose energy which
is essential in pumping hydrogen ions into the intermembrane space (Kims et al.).
In complex II, the FADH2 offers a donation of 2 electrons t complex II, with minimal energy
loss. The complex II is able to donate 1-2 electrons to ubiquinone. In complex IV, the
Cytochrome c donates one election, in this complex there is a loss of energy and deposit
occur at one time into molecule oxygen which then forms water requiring four electrons,
losing other electrons used in pumping hydrogen ions (Jonckheere et al.).
In this way, these complexes depict the different process and compound with resultant
reactions and process. Hence the cannot be passed from complex I to IV directly in their
form, there is a donation of 1-2 electrons to the ubiquinone while in cytochrome c transport,
complexions donate 1-2 electrons to ubiquinone while complex II offers one electron to
cytochrome.
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References
Althoff, Thorsten, et al. "Arrangement of electron transport chain components in bovine
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Demirel, Yaşar. "Information in biological systems and the fluctuation theorem." Entropy
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Wilk, Laura, et al. "Outer membrane continuity and septosome formation between vegetative
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