DAT bio Chapter 3. Cellular Energy Flashcards
What is metabolism?
Refers to all the metabolic pathways (series of chemical reactions) that are happening in a given organism
Catabolic processes
breaking down larger molecules for energy
Anabolic processes
using energy to build larger macromolecules
Aerobic cellular respiration
Break down carbohydrates for energy. (consumes oxygen, more energy produced)
Anaerobic cellular respiration
no oxygen needed, but less energy prodcued
Adenosine triphosphate (ATP)
RNA nucleoside triphosphate. It contains an adenine
nitrogenous base linked to a ribose sugar (RNA
nucleoside part), and three phosphate groups
connected to the sugar (triphosphate part).
What is the cellular energy currency?
ATP
What makes ATP a good cellular energy currency
due to its high energy bonds between the phosphate groups. These bonds release energy upon hydrolysis (breaking bonds)
Reaction coupling
process of powering an
energy-requiring reaction with an energy-releasing
one. It allows an unfavorable reaction to be
powered by a favorable reaction, making the net
Gibbs free energy negative
Is ATP stable or unstable
unstable
ATP hydrolysis reactions are exergonic and spontaneous T/F?
True
Which organelle produces ATP through cellular respiration?
MItochondria
Structure of Mitochondria
Double membrane. Meaning it has a outer and inner membrane. Inner membrane contains many infoldings called cristae
Where is the intermembrane space located in the mitochondria?
located between the outer and inner membranes
Where is the mitochondrial matrix located
inside the inner membrane
Summary of endosymbiotic theory
Eukaryotes developed when aerobic bacteria were internalized as mitochondria while PHOTOSYNTHETIC bacteria became chloroplasts.
Evidence for endosymbiotic theory?
includes size
similarities and the fact that mitochondria and
chloroplasts contain their own circular DNA and
ribosomes.
Aerobic cellular respiration involves what 4 catabolic processes?
- Glycolysis
- Pyruvate manipulations
- Krebs cycle
- Oxidative phosphorylation
What is aerobic cellular respiration? (catabolic processes) uses oxygen
Phosphorylate ADP to ATP by breaking down glucose and moving electrons around!
In Glycolysis it makes…
Glucose makes
2 ATP
2 NADH
2 Pyruvate
Where does glycolysis take place and does it require oxygen
cytosol and it does not require oxygen
What is the process used to generate ATP in glycolysis?
Substrate level phosphorylation
What happens in substrate level phosphorylation?
Phosphate group is transferred to ADP directly from a phosphorylated compound
Glycolysis has 2 phases
Energy investment and energy payoff phase
In pyruvate manipulation it makes….
2 pyruvates make 2 CO2 2 NADH 2 Acetyl-CoA If only one pyruvate it would only make one of each product
What enzyme carries out the pyruvate manipulation
Pyruvate dehydrogenase
3 steps of pyruvate manipulations ( Look at picture in the book)
- DECARBOXYLATION - Pyruvate molecules (3
carbon molecule) move from the cytosol into
the mitochondrial matrix (stays in the cytosol
for prokaryotes), where they undergo
decarboxylation, producing 1 CO2 and one
two-carbon molecule per pyruvate. - OXIDATION - The two-carbon molecule is
converted into an acetyl group, giving
electrons to NAD+ to convert it into NADH. - COENZYME A (CoA) - CoA binds to the acetyl
group, producing acetyl-CoA.
What does krebs cycle make
2 acetly- CoA makes 4 CO2 6NADH 2 FADH2 2 GTP
Where does the kreb cycle take place?
mitochondrial matrix and the cytosol for prokaryotes
Where does pyruvate manipulations take place
mitochondrial matrix
Kreb cycle
- Acetyl-CoA joins oxaloacetate (four-carbon)
to form citrate (six-carbon). - Citrate undergoes rearrangements that
produce 2 CO2 and 2 NADH. - After the loss of two CO2 , the resulting
four-carbon molecule produces 1 GTP through
substrate-level phosphorylation. - The molecule will now transfer electrons to 1
FAD, which is reduced into 1 FADH2 . - Lastly, the molecule is converted back into
oxaloacetate and also gives electrons to
produce 1 NADH. - Two acetyl-CoA molecules produce 4 CO2 + 6
NADH + 2 FADH2 + 2 GTP.
How many ATP are produced per glucose molecule within glycolysis?
2!
Since 2 ATP are used up in the energy investment phase and 4 ATP are produced in the energy payoff phase, a net of 2 ATP
What other molecules can be modified to enter cellular respiration?
other types of carbs, fats, and proteins
Common molecules that enter during glycolysis
other carbohydrates
Glycogenolysis
release of glucose-6-phosphate from glycogen
disaccharides can under hydrolysis and release how many carbohydrate monomers?
2 monomers that can enter glycolysis
What is the preferred energy source for
carbohydrates. There are easily catabolized and are high yield
glycogenesis
reverse process. conversion of glucose into glycogen to be stored in the liver when energy and fuel is sufficient
Where is glycogen stored?
liver and muscle cells
fats are present in the body as
triglycerides
What is require to first digest fats into free fatty acids and alcohols. What is this process called?
lipases
lipolysis
The digested pieces of fats are absorbed by what?
enterocytes in the small intestine and reform triglycerides
What is the cell that that store fat (triglycerides)
and have hormone-sensitive lipase enzymes to
help release triglycerides back into circulation as
lipoproteins or as free fatty acids bound by a
protein called albumin.
adipocytes
What is the lipoprotein transport structures
formed by the fusing of triglycerides with proteins,
phospholipids, and cholesterol. They leave
enterocytes and enter lacteals, small lymphatic
vessels that take fats to the rest of the body.
chylomicrons
Can a glycerol molecule undergo a conversion to enter glycolysis when it travels to the liver?
yes
Making of new glucose in the liver by glycerol is called what
gluconeogenesis
What is the least desirable energy source?
proteins, due to lots of energy being spent just to get them into cellular respiration
If protein has to be used cellular respiration, what happens?
protein must be broken down into amino acids which much undergo oxidative deamination (removal of NH3) before shuttled to various parts of cellular respiration
Ammonia Nh3
toxic, must be converted into uric acid or urea and secreted from body.
oxidative phosphorylation
Electron carriers (NADH+FADH2) + O2 equals ATP+ H20
electron transport chain (ETC) and
chemiosmosis (ions moving down electrochemical
gradients) work together to produce what
ATP in oxidative phosphorylation
In the electron transport chain, what acts as the final electron acceptor and gets reduced to form water?
oxygen
Location of the electron transport chain in eukaryotes
The mitochondrial inner membrane
Location of the electron transport chain in prokaryotes
cell membrane
How many protein complexes are responsible for moving electrons through a series of oxidation - reduction reactions in the Electron transport chain?
4
How is electrochemical gradient formed?
As the series of redox reactions occurs,
protons are pumped from the mitochondrial matrix
to the intermembrane space,
The intermembrane space is highly acidic or basic?
acidic
In ETC, ____ is more effective than _____
NADH and FADH2, NADH also drops electrons off directly at complex-I, regenerating
NAD+
For FADH2, where does it drop off its eletrons?
complex-II,
regenerating FAD.this results in the
pumping of fewer protons due to the bypassing of
complex-I.
Chemiosmosis goal:
Use the proton
electrochemical gradient (proton-motive force) to
synthesize ATP.
What is ATP synthase?
channel protein that provides a
hydrophilic tunnel to allow protons to flow down
their electrochemical gradient (from the
intermembrane space back to the mitochondrial
matrix).
The spontaneous movement of protons
generates energy to do what
convert ADP + p to ATP, a condensation reaction that is endergonic (requires energy + nonspontaneous)
Is aerobic respiration endergonic or exergonic?
exergonic, with a ΔG = -686
kcal/mol glucose.
The estimated yield fir aerobic respiration
1 atp per 4 protons
NADH produces how many atp
3 ATP
(NADH from glycolysis
produces less)*
FADH2 produces how many atp
2 atp
Fermentation
anaerobic pathway (no
oxygen) that only relies on glycolysis by
converting the produced pyruvate into different
molecules in order to oxidize NADH back to NAD+..
Regenerating NAD+ means glycolysis can continue
to make ATP.
location of fermentation
within the
cytosol. The two most common types of
fermentation are lactic acid fermentation and
alcohol fermentation.
Lactic acid fermentation
fermentation uses the 2 NADH from
glycolysis to reduce the 2 pyruvate into 2 lactic
acid. Thus, NADH is oxidized back to NAD
+ so that
glycolysis may continue. This happens frequently
in muscle cells and occurs continuously in red blood
cells, which do not have mitochondria for aerobic
respiration.
which fermentation is cori cycle used in and it does what?
Lactic acid fermentation.
is used to help convert lactate back
into glucose once oxygen is available again. It
transports the lactate to liver cells, where it can
be oxidized back into pyruvate. Pyruvate can then
be used to form glucose, which can be used for
more ideal energy generation.
Alcohol fermentation
uses the 2 NADH from
glycolysis to convert the 2 pyruvate into 2 ethanol .
Thus, NADH is oxidized back to NAD
+ so that
glycolysis may continue. However, this process has
an extra step that first involves the
decarboxylation of pyruvate into acetaldehyde,
which is only then reduced by NADH into ethanol.
Types of organisms based on ability to grow in
oxygen: Obligate aerobes
only perform aerobic
respiration, so they need the presence of
oxygen to survive.
Types of organisms based on ability to grow in
oxygen: obligate anaerobes
Obligate anaerobes - only undergo anaerobic
respiration or fermentation; oxygen is poison
to them.
Types of organisms based on ability to grow in
oxygen: Facultative anaerobes -
can do aerobic
respiration, anaerobic respiration, or
fermentation, but prefer aerobic respiration
because it generates the most ATP.
Types of organisms based on ability to grow in
oxygen: Microaerophiles
- only perform aerobic
respiration, but high amounts of oxygen are
harmful to them.
Types of organisms based on ability to grow in
oxygen: Aerotolerant organisms
only undergo
anaerobic respiration or fermentation, but
oxygen is not poisonous to them.
Step 1 of glycolysis
Hexokinase uses one ATP to phosphorylate
glucose into glucose-6-phosphate, which
cannot leave the cell (it becomes trapped by
the phosphorylation).
step 2 of glycolysis
Isomerase modifies glucose-6-phosphate into
fructose-6-phosphate.
Step 3 of glycolysis
Phosphofructokinase uses a second ATP to
phosphorylate fructose-6-phosphate into
fructose-1,6-bisphosphate.
Step 4 of glycolyssis
Fructose-1,6-bisphosphate is broken into
dihydroxyacetone phosphate (DHAP) and
glyceraldehyde-3-phosphate (G3P), which
are in equilibrium with one another.
Step 5 of glycolysis
G3P proceeds to the energy payoff phase so
DHAP is constantly converted into G3P to
maintain equilibrium. Thus, 1 glucose molecule
will produce 2 G3P that continue into the next
steps.
step 6 of glycolysis
G3P undergoes a series of redox reactions to
produce 4 ATP through
substrate-level-phosphorylation, 2 pyruvate
and 2 NADH.
Nadh is what
coenzyme that helps in transferring electrosn
Fadh is what
coenzyme that helps in transferring electrosn
Step one for glycolysis
Hexokinase uses one ATP to phosphorylate
glucose into glucose-6-phosphate, which
cannot leave the cell (it becomes trapped by
the phosphorylation).
Step two for glycolysis
Isomerase modifies glucose-6-phosphate into
fructose-6-phosphate
Step three for glycolysis
Phosphofructokinase uses a second ATP to
phosphorylate fructose-6-phosphate into
fructose-1,6-bisphosphate
Step four for glycolysis
Fructose-1,6-bisphosphate is broken into
dihydroxyacetone phosphate (DHAP) and
glyceraldehyde-3-phosphate (G3P), which
are in equilibrium with one another
Step five for glycolysis
G3P proceeds to the energy payoff phase so
DHAP is constantly converted into G3P to
maintain equilibrium. Thus, 1 glucose molecule
will produce 2 G3P that continue into the next
steps.
Step six for glycolysis
G3P undergoes a series of redox reactions to
produce 4 ATP through
substrate-level-phosphorylation, 2 pyruvate
and 2 NADH
