bioenergetics Flashcards
The study of the transformation of energy in living organisms.
bioenergetics
It helps to explain how living organisms are obtaining energy and using it for biological work.
bioenergetics
is the main “energy currency” for organisms.
Adenosine triphosphate (ATP)
the goal of metabolic and catabolic processes are to ??? from available starting materials (from the environment), and to ??? and ??? by utilizing it in biological processes.
synthesize ATP;
break- down ATP (into ADP);
inorganic phosphate
Within a cell, the ratio of concentrations of ATP to ADP is known as the cell’s “???”
energy charge
A cell will use this ??? to relay information about cellular needs;
energy charge
if more ATP is available than ADP, the cell can ?
use ATP to do the job
but if more ADP is available than
ATP, the cell will ??? by ???
synthesize ATP by oxidative phosphorylation
Living organisms generate ATP by way of ??? from energy sources.
oxidative phosphorylation
LAWS OF THERMODYNAMICS:
The ??? is constant, including its surroundings
??? must increase for a spontaneous reaction to occur
total energy of a system;
Total entropy of a system
is the portion of the total energy change in a system available for
doing work.
Gibbs change in free energy (△G)
Gibbs change in free energy (△G) is also known as
the chemical potential
△G =
△H -T △S
Useful energy = ?
change in Enthalpy -
change in entropy
energy content
Enthalpy
randomness of the system
Entropy
Is a spontaneous reaction that releases energy. If the free energy change is negative, this reaction is due to loss of energy form reactants
exergonic
is an anabolic reaction that consumes energy. If the free energy change is positive
endergonic
is the primary and universal carrier of chemical energy in the cell
ATP
Terminal (alpha) phosphate group of ATP on hydrolysis yields [??] kcal/mol
-7.3
The phosphate compounds whose
△G values higher than that of ATP,
they are called ???
high energy
phosphates
Cellular Respiration equation
C6H12O6 + 6 O2 = 6CO2 + 6H2O + ATPs
??? and other molecules from food are broken down to release energy in a complex series of chemical reactions that together are called ???
Glucose;
cellular respiration
is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into ATP, and then release waste products.
Cellular respiration
The reactions involved in respiration are ???, which break large molecules into smaller ones, releasing energy in the process. These processes require a ??? which each perform one specific chemical reaction.
catabolic reactions;
large number of enzymes
Requires oxygen- this is the reason why we breathe oxygen in from the air.
This type of respiration releases a large amount of energy from glucose that can be stored as ATP.
aerobic respiration
Aerobic respiration happens all the time in animals and plants, where most of the reactions occur in the ???
mitochondria
Even some ??? can perform aerobic
respiration
prokaryotes
aerobic respiration:
One molecule of glucose can be broken down in the presence of ??? gas to produce waste products of ??? and ???
oxygen;
carbon dioxide and water.
aerobic respiration: This process has an overall release of energy which is captured and stored in ?
38 molecules of ATP
Aerobic respiration is a complex process that can be divided into three basic stages:
glycolysis,
the citric acid cycle,
oxidative phosphorylation.
It occurs in the absence of oxygen.
It does not release enough energy to power human cells for long
anaerobic respiration
Anaerobic respiration occurs in ???during hard exercise (after the oxygen has been used up).
muscle cells
anaerobic respiration:
It also occurs in ??? when brewing beer. Many prokaryotes perform anaerobic respiration.
yeast
All the types of anaerobic respiration involve ???, and none of them go through the ??? or ???
glycolysis;
citric acid cycle or oxidative phosphorylation.
anaerobic respiration overall reaction
C6H12O2 NAD+ → various waste products + NADH + 2 ATP
are two states of a molecule that will carry energy during anaerobic respi process.
NAD+ and NADH
??? carries energy (similar to ATP) and ??? is the form that carries less energy (similar to ADP)
NADH;
NAD+
only ??? are generated in anaerobic respiration.
2 molecules of ATP
There are two ways to generate ATP
- Chemiosmosis
- Substrate-Level Phosphorylation
In ???, the hydrogen ion gradient formed by the ??? is used by ??? to form ATP
oxidative phosphorylation;
electron transport chain;
ATP synthase
??? like NADH and FADH donate electrons to the ??? during chemiosmosis.
Electron carriers;
electron-transport chain
chemiosmosis:
The electrons cause changes in the ??? to ??? across a selectively permeable cell membrane.
shapes of protein;
pump H+
chemiosmosis:
Due to the positive charge of the hydrogen ions and their aggregation on one side of the
membrane, unequal distribution of H+ ions across the membrane creates both ??? and ??? (thus, an
??? gradient).
concentration and electrical gradients;
electrochemical
chemiosmosis:
If the hydrogen ions were to open the membrane to diffusion, the ions would tend to spontaneously spread back into the matrix, driven by their ???
electrochemical gradient
chemiosmosis:
without the aid of ???, many ions cannot diffuse through the non-polar regions of the phospholipid membranes. Likewise, hydrogen ions can only move through the inner mitochondrial membrane via a membrane protein called ??? in the matrix space.
ion channels;
ATP synthase
chemiosmosis:
ATP synthase functions as a tiny generator powered by the ???, down their electrochemical gradient. Turning this molecular
machine harnesses the potential energy contained in the hydrogen ion gradient to ???.
hydrogen ions diffusing through it;
add a phosphate to ADP and to form ATP
Chemiosmosis is used to generate ??? percent of the ATP made during aerobic glucose catabolism.
90
The production of ATP using the process of chemiosmosis in mitochondria is called ???
oxidative phosphorylation
It is also the method used in the light reactions of photosynthesis to harness the energy of sunlight
in the process of photophosphorylation.
chemiosmosis
is a complex, molecular machine that uses a proton (H+) gradient to form ATP
ATP synthase
ATP Synthase:
ATP is formed from ?
from ADP and inorganic phosphate (Pi)
There are 5 protein complexes:
- I
- II
- III
- IV
- V
- I - NADH-ubiquinone oxidoreductase
- II - succinate-ubiquinone oxidoreductase
- III - ubiquinol-cytochrome c oxidoreductase
- IV - cytochrome c oxidase
- V - ATP synthase
§ Transfers 2e- from NADH to Q as hydride ion (H-)
§ First electron transferred to FMN –> FMNH2 —> Fe-S cluster —> Q
§ Also pumps 4H+/2e- into intermembrane space
NADH-ubiquinone oxidoreductase
§ Transfers e- from succinate to Q
§ First transferred to FAD —> FADH2 —>
3 Fe-S clusters —> Q
§ Not enough energy to contribute to proton gradient via proton pumping
Succinate-Ubiquinone Oxidoreductase
§ Transfers e- from QH2 to cytochrome c facing
intermembrane space
§ Composed of 9-10 subunits including 2 Fe-S clusters,
cytochrome b560, cytochrome b566, and cytochrome
c1.
§ Transports 2H+ from matrix into intermembrane space
Ubiquinol-Cytochrome c Oxidoreductase
§ Contains cytochromes a and a3
§ Contributes to proton gradient in two ways
§ Carbon monoxide (CO) and cyanide (HCN) bind her
Cytochrome c Oxidase
complex IV Contributes to proton gradient in two ways:
- pumps 2H+ for each pair of e-
transferred (per O2 reduced) - consumes 2H+ when oxygen is
reduced to H2O – -> lowers
[H+]matrix
§ Does not contribute to H+ gradient, but helps relieve it
ATP synthase
ATP synthase is also called
FOF1 ATP synthase
ATP Synthase component contains catalytic subunits
F1
ATP Synthase component is proton channel that is transmembrane
FO
Per ATP synthesized, ??? move through ATP synthase
3H+
antibiotic that binds to channel and prevents proton entry –> no ATP synthesized
oligomycin
process in which NADH and QH2 are oxidized and ATP is produced.
Oxidative phosphorylation
Enzymes are found in ??? in
eukaryotes.
inner mitochondrial membrane
In prokaryotes, enzymes are found in ???
cell membrane
OXIDATIVE PHOSPHORYLATION:
Process consists of 2 separate, but coupled processes:
1) respiratory electron-transport chain
2) ATP Synthesis
Responsible for NADH and QH2 oxidation
respiratory electron-transport chain
respiratory electron-transport chain final e- acceptor is
molecular oxygen
Energy generated from electron transfer is used to pump H+ into intermembrane space from
matrix —> ????
matrix becomes more alkaline and negatively charged.
Proton concentration gradients represents
stored energy
When H+ are moved back across inner mitochondrial membrane through ATP synthase —> ADP is ??? to form ATP
phosphorylated
