10/16/24, 11:30 BISC 2202 Notes Lectures
AM 15-19
Lecture 10/30/18
➢ Mitochondria - oxidative phosphorylation
○ H+ gradient used to make ATP
○ Makes around 30 ATP per glucose molecule
○ Stage 1
■ Electrons transferred along the electron transport chain
■ Electrons are used as fuel to make an H+ gradient
○ Stage 2
■ H+ flows back through the membrane which gives energy
■ Known as CHEMIOSMOTIC COUPLING*
■ Energy from gradient → ADP + Pi
○ Binary fission - mitochondrial cell division
➢ Endosymbiosis
○ Mitochondria and chloroplasts both resemble bacteria
○ Evidence:
■ Inner and outer membranes
■ Independent DNA
■ Independent ribosomes
➢ Mitochondria are found in places that use a lot of ATP
○ Example: tons of mitochondria are found in skeletal muscle and flagella
○ Can even fuse to form huge mitochondrial tubes
➢ Mitochondrial
structure
○ 4 compartments
■ Matrix - equivalent of cytosol. Includes lots of material for
oxidative phosphorylation
■ Inner membrane - folded into cristae. Allows for separation of
compartments to make an H+ gradient for the electron
transport chain. Also contains ATP synthase in the membranes
themselves
■ Outer membrane - highly permeable to many substances.
Has many porins (large channels)
■ Intermembrane space - between inner and outer
membranes. Has enzymes that use ATP to phosphorylate
other nucleotides (ie GTP) as well as proteins that can
induce apoptosis
➢ Acetyl CoA - involved in making ATP for both fatty acids and sugars
➢ Electron transport chain →
➢ Products overall: H2O, CO2
➢ Activated carriers involved: NADH/FADH2
➢ Enzymes complexes
○ Contain ions/metals to help take electrons from carriers
○ Electron affinity increases: 3 >2 >1
○ Consume most of the oxygen breathed in
■ O2 → H2O
➢ Electrochemical H+ gradient is fuel for making ATP *
○ Proton motor force - the combination of the concentration and pH gradient*
about:bl 1
, 10/16/24, 11:30 BISC 2202 Notes Lectures
AM 15-19
○ Mostly fueled by the concentration/electrochemical gradient but
somewhat from the pH gradient too
➢ ATP synthase
○ Has a rotor that uses the flow of H+ back with their gradient to fuel
binding ADP and Pi
○ Can also move backwards and break down ATP to push H+ back
across the membrane
○ An example of coupled transport: coupling a favorable and an
unfavorable reaction
➢ Products:
○ Glycolysis: 2 NADH, 2 ATP
○ Pyruvate → acetyl CoA: 2 NADH, 5 ATP
○ Oxidative phosphorylation - 30 ATP, H2O, CO2, NAD+
➢ Water plays a strong role in providing products for redox: H+ and e-
➢ Quinones - proteins in the electron transport chain that take up
electrons in their structures as H+ + e-
○ Can carry 2 electrons on H
➢ Cytochrome C oxidase - reduces O2. Has the highest e- affinity in the ETC.
Removes electrons from carrier protein cytochrome c and gives them to
O2
➢ Chloroplasts
○ Capture light with chlorophyll
○ Use photosynthesis - the conversion of CO2 to sugar
➢ Structure
○ Stroma - equivalent of matrix (mitochondria) or cytosol
○ Thylakoid membrane - contains the ETC and ATP synthase
○ Thylakoid stacks = grana
➢ Stage 1 - ETC in thylakoid membrane uses energy to pump H+ into the thylakoid
○ Gradient drives ATP synthase
○ Electrons come from chlorophyll molecules that have been excited by
sunlight
○ Dependent on light (“light” reaction)
➢ Stage 2 - ATP and NADPH drive sugar synthesis
○ Independent of light (“dark” reaction)
○ Begins in stroma, then products are exported to the cytosol to make
sucrose
➢ Regulated by light-sensitive proteins
➢ Chlorophyll
○ Absorbs red and blue wavelengths (hence green/yellow is reflected,
giving plants their green color)
○ Light excites electrons in chlorophyll molecules, making it unstable
○ Once made unstable with electrons, chlorophyll wants to get rid of
excess energy and donates electrons to photosynthetic proteins
➢ Photosynthetic proteins
○ Chlorophyll dimer - holds e- at lower energy, trapping it
➢ “Special pairs” bind to electrons and transfer them to electron carriers
about:bl 2
AM 15-19
Lecture 10/30/18
➢ Mitochondria - oxidative phosphorylation
○ H+ gradient used to make ATP
○ Makes around 30 ATP per glucose molecule
○ Stage 1
■ Electrons transferred along the electron transport chain
■ Electrons are used as fuel to make an H+ gradient
○ Stage 2
■ H+ flows back through the membrane which gives energy
■ Known as CHEMIOSMOTIC COUPLING*
■ Energy from gradient → ADP + Pi
○ Binary fission - mitochondrial cell division
➢ Endosymbiosis
○ Mitochondria and chloroplasts both resemble bacteria
○ Evidence:
■ Inner and outer membranes
■ Independent DNA
■ Independent ribosomes
➢ Mitochondria are found in places that use a lot of ATP
○ Example: tons of mitochondria are found in skeletal muscle and flagella
○ Can even fuse to form huge mitochondrial tubes
➢ Mitochondrial
structure
○ 4 compartments
■ Matrix - equivalent of cytosol. Includes lots of material for
oxidative phosphorylation
■ Inner membrane - folded into cristae. Allows for separation of
compartments to make an H+ gradient for the electron
transport chain. Also contains ATP synthase in the membranes
themselves
■ Outer membrane - highly permeable to many substances.
Has many porins (large channels)
■ Intermembrane space - between inner and outer
membranes. Has enzymes that use ATP to phosphorylate
other nucleotides (ie GTP) as well as proteins that can
induce apoptosis
➢ Acetyl CoA - involved in making ATP for both fatty acids and sugars
➢ Electron transport chain →
➢ Products overall: H2O, CO2
➢ Activated carriers involved: NADH/FADH2
➢ Enzymes complexes
○ Contain ions/metals to help take electrons from carriers
○ Electron affinity increases: 3 >2 >1
○ Consume most of the oxygen breathed in
■ O2 → H2O
➢ Electrochemical H+ gradient is fuel for making ATP *
○ Proton motor force - the combination of the concentration and pH gradient*
about:bl 1
, 10/16/24, 11:30 BISC 2202 Notes Lectures
AM 15-19
○ Mostly fueled by the concentration/electrochemical gradient but
somewhat from the pH gradient too
➢ ATP synthase
○ Has a rotor that uses the flow of H+ back with their gradient to fuel
binding ADP and Pi
○ Can also move backwards and break down ATP to push H+ back
across the membrane
○ An example of coupled transport: coupling a favorable and an
unfavorable reaction
➢ Products:
○ Glycolysis: 2 NADH, 2 ATP
○ Pyruvate → acetyl CoA: 2 NADH, 5 ATP
○ Oxidative phosphorylation - 30 ATP, H2O, CO2, NAD+
➢ Water plays a strong role in providing products for redox: H+ and e-
➢ Quinones - proteins in the electron transport chain that take up
electrons in their structures as H+ + e-
○ Can carry 2 electrons on H
➢ Cytochrome C oxidase - reduces O2. Has the highest e- affinity in the ETC.
Removes electrons from carrier protein cytochrome c and gives them to
O2
➢ Chloroplasts
○ Capture light with chlorophyll
○ Use photosynthesis - the conversion of CO2 to sugar
➢ Structure
○ Stroma - equivalent of matrix (mitochondria) or cytosol
○ Thylakoid membrane - contains the ETC and ATP synthase
○ Thylakoid stacks = grana
➢ Stage 1 - ETC in thylakoid membrane uses energy to pump H+ into the thylakoid
○ Gradient drives ATP synthase
○ Electrons come from chlorophyll molecules that have been excited by
sunlight
○ Dependent on light (“light” reaction)
➢ Stage 2 - ATP and NADPH drive sugar synthesis
○ Independent of light (“dark” reaction)
○ Begins in stroma, then products are exported to the cytosol to make
sucrose
➢ Regulated by light-sensitive proteins
➢ Chlorophyll
○ Absorbs red and blue wavelengths (hence green/yellow is reflected,
giving plants their green color)
○ Light excites electrons in chlorophyll molecules, making it unstable
○ Once made unstable with electrons, chlorophyll wants to get rid of
excess energy and donates electrons to photosynthetic proteins
➢ Photosynthetic proteins
○ Chlorophyll dimer - holds e- at lower energy, trapping it
➢ “Special pairs” bind to electrons and transfer them to electron carriers
about:bl 2
