Test 3 Flashcards
Why are fats better than polysaccharides
fatty acids carry more energy per carbon because they are more reduced.
Fatty acids carry less water because they are nonpolar.
Fats Provide Efficient Fuel Storage
_,_are for short-term energy needs and quick
delivery
Glucose and glycogen
are for long-term (months) energy needs, good storage, and
slow delivery.
fats
Horome: Insulin->Origin_->Target_
Pancreatic Beta Cell:Liver, Muscle, others
Horome: GLucagon->Origin_->Target_
Pancreatic alpha cell: liver
Horome: Epinephrine->Origin_->Target_
adrenal gland:liver, muscle, others
_Between meals, glucose
concentration drops
feed/fasting
Decreases insulin release
Feeding / Fasting
Stimulates glucagon release
Feeding / Fasting
_released in
response to low blood glucose
epinephrine
During a meal – _moves from
digestive tract to blood stream
glucose
is downregulated in liver
and muscle
glycogenolysis
Stimulation of glucose transport in muscle
feeding/fasting
Suppression of liver
gluconeogenesis
Triggers insulin release activates glycogen
synthesis in liver and muscle
feeding/fasting
works on
nonreducing ends until it reaches
four residues from an (alpha 1→ 6)
branch point.
Glycogen phosphorylase
transfers a
block of three residues to the
nonreducing end of the chain.
Debranching enzyme
cleaves the
single remaining (alpha1→6)-linked
glucose, which becomes a free
glucose unit (i.e., NOT glucose-1-
phosphate).
Debranching enzyme
occurs After 11 glucosyl units have been
added
Branching step
(also
named branching
glycosyltransferase)
Glycogen branching enzyme
Break alpha-1,4 bond at least 6-7
glucosyl units from reducing end
of a chain at least 11 residues
long
Glycogen synthesis
– Branching step
Transfers segment to interior 6-
hydroxyl position at least 4
residues away from any branching
point
Glycogen synthesis
– Branching step
Creates alpha-1,6 bond called
branch point
Glycogen synthesis
– Branching step
Glucose 6-P is incorporated into
glycogen
Glycogen synthesis
Formation of glucose 1-P by
Phosphoglucomutase
– Reversible, near equilibrium enzyme
– Same mechanism as phosphoglycerate
mutase in glycolysis
Glycogen synthesis-– First step
Formation of uridine diphosphate (UDP)
glucose or activated glucose.
– Glucose 1-P is not reactive enough (activation)
– Carrier function similar to acetyl-CoA
Glycogen synthesis-– second step
Tiny soluble granules in
cytoplasm
Structure of glycogen
– _increases the solubility
Branching
increases the rate
of synthesis and breakdown
(more terminal non-reducing
ends
Structure of glycogen-Branching
protein molecule at
the core of glycogen
glycogenin
Primer for formation of glycogen
Glycogenin
Polymers of _can weigh
up to 100 million daltons
glycogen
Straight chain links – alpha 1,4
linkages
– Branch points – alpha 1,6
linkages (more than starch)
Structure of glycogen
ATP Synthase=
=Power Generator
ATP Synthesis Mechanism =
(Binding change Mechanism
– The beta subunit has the active site for synthesis of ATP from ADP and Pi
ATP Synthesis Mechanism
– Conformational change of the beta subunits propagated by the y subunit rotation is key
ATP Synthesis Mechanism
ATP Synthesis Mechanism-step 1
– Step 1- ADP and Pi bind to the open beta subunit (OPEN)
ATP Synthesis Mechanism-step 2
– Step 2- The y rotate 1/3, ADP and Pi are locked in but not close enough (LOOSE)
ATP Synthesis Mechanism-step 3
– Step 3- The y rotate 1/3, ADP and Pi are brought together and react to form ATP (TIGHT)
ATP Synthesis Mechanism-back to step 1
– Back to step 1- The y rotate 1/3, ATP is released and the subunit can accept ADP and Pi
– One full rotation generate _ in the atp synthesis mechanism
3 ATPs (speed estimated at 100 rotations per second!)
Need _
to get one full rotation or 3 ATPs (3.3 H+
for 1 ATP) in the ATP synthesis metabolism
10 H+
The _rotates until the next empty c subunit become accessible to the next H+
atp rotation mechanism- c ring
The c ring (10 subunits) keep rotating until the _are released through the matrix channel (low [H+])
atp rotation mechanism-protons
rotation is transmitted by the _to the F1
region.
stalk
– Need 10 H+ to get one full rotation of the _
ring and stalk
Culmination of aerobic cell respiration
Oxidative
Phosphorylation
Pathway that oxidizes electron carriers from
Krebs cycle
oxidative phosphorylation
NADH and FADH2 are mobile carriers from Krebs cycle in_
Oxidative
Phosphorylation
Responsible for most of produced ATP in cells
Oxidative
Phosphorylation
Has proton gradient that acts as the energy
intermediate
Oxidative
Phosphorylation
Oxidative
Phosphorylation Has proton gradient that acts as the energy
intermediate
– Mechanism is called the
chemiosmotic hypothesis
Oxidative phosphorylation term refers to two
processes:
Oxidation
– Phosphorylation
In isolated mitochondria, these processes are
coupled
-Oxidation
– Phosphorylation
Electron flow from _to Q (ubiquinone) to O2
NADH
NADH is oxidized to _
NAD
O2
is reduced to
water
Continuous consumption of O2 and production of _
water
Takes place within inner membrane of mitochondria
Oxidative phosphorylation
As electrons move through the
membrane
* Protons are pumped across the
membrane
Oxidative phosphorylation
Electrical and chemical gradient across
the mitochondrial membrane
Oxidative phosphorylation
Electron transport chain procedures
- Electrons transfer
- Protons pumped
- Oxygen reduction
- ATP generation
Energy transformed
several times
Large pores in the outer membrane
(The porins let small & charged
molecules crossing and connect
inner membrane space to
cytoplasm)
Essential Features of the
Mitochondria
Intermembrane space
Essential Features of the
Mitochondria
Relatively high concentration of
proteins
Inner membrane of Mitochondria
Impermeable to charged molecules
Inner membrane of Mitochondria
Carrier proteins
Inner membrane of Mitochondria
Protein complexes control flow of
protons and electrons
Inner membrane of Mitochondria
Matrix
Essential Features of the
Mitochondria
Electrons transferred to FMN to form FMNH2
Pathway of Electrons: Complex I
– Transfer from FMN to Fe-S clusters
- Pathway of Electrons: Complex I
– Transfers its electrons to Q
- Pathway of Electrons: Complex I
This results in QH2
formation
- Pathway of Electrons: Complex I
– Q and QH2 are mobile cofactor
- Pathway of Electrons: Complex I
– Complex releases 4 protons to cytosol
- Pathway of Electrons: Complex I
Electrons from succinate dehydrogenase (Succinate to
Fumarate, Krebs cycle
- Pathway of Electrons: Complex II
FAD/FADH2
is bound cofactor
- Pathway of Electrons: Complex II
Complex does not release any proton to cytosol
(less ATP produced)
- Pathway of Electrons: Complex II
– Electrons move through a series of Fe-S clusters
- Pathway of Electrons: Complex II
– Transfers its electrons to Q
- Pathway of Electrons: Complex II
This results in QH2
formation
- Pathway of Electrons: Complex II
– Also known as bc1 complex or Qcytochrome c reductase
- Pathway of Electrons: Complex III
– Complex of 10 proteins
- Pathway of Electrons: Complex III
– QH2 donates electrons to complex
- Pathway of Electrons: Complex III
– Complex releases 4 protons to cytosol
- Pathway of Electrons: Complex III
– Complex reduces cytochrome c
- Pathway of Electrons: Complex III
– Cytochrome c is a soluble mobile cofactor
- Pathway of Electrons: Complex III
– Final complex of electron transport
- Pathway of Electrons: Complex IV
– Also known as cytochrome c oxidase
- Pathway of Electrons: Complex IV
– Contain both Heme groups and Cu atoms
- Pathway of Electrons: Complex IV
– 2x Cytochrome c donate electrons to complex
- Pathway of Electrons: Complex IV
Electrons from complex react with O2 to form H2O
- Pathway of Electrons: Complex IV
- Complex uses proton gradient to form ATP
complex 5
– Complex releases 2 protons to cytosol
- Pathway of Electrons: Complex IV
Mechanisms for electron and
proton flows overall result
proton gradient is produced across the inner mitochondrial membrane
-Re-entry of protons drive the synthesis of ATP
– First part of pathway