MITOCHONDRIA AND
CHLOROPLASTS
Structure and function - a review
The Exam Question
“Contrast and compare
mitochondria and chloroplasts –
structure and function. “
Do you know what it means?
• What is the function of a
mitochondrion?
• What is the function of a chloroplast?
• How are they similar? How are they
different?
Energy Conversion
• Mitochondria convert the chemical energy
of reduced carbon compounds into ATP.
• Chloroplasts convert light energy to the
energy of reduced carbon compounds
• Fundamental to both processes is an
electron transport chain, where energy is
passed from compound to compound in
coupled oxidation:reduction reactions
2 membranes
Outer Membrane - has
large aqueous
channels made of a
protein called porin permeable to most
small molecules
Inner Membrane impermeable to ions
and small molecules
except by specific
membrane-transport
proteins
Mitochondria
Mitochondria
Fig 1-11
2 compartments
• MATRIX - enzymes -TCA
cycle, DNA - several
copies, ribosomes, tRNA,
etc
• INTERMEMBRANE
SPACE
Inner Membrane is folded
into cristae,that greatly
increase its surface area.
This is where you find the
Electron Transport Chain
(ETC), ATP synthase,
transport proteins to allow
substances in to matrix
Mitochondrial Structure
A
C
E
D
B
How many compartments
do mitochondria have?
Which letter corresponds
to:
• the matrix?
• a crista?
• the intermembrane
space?
• the outer membrane?
• the inner membrane?
Where would you find the
DNA? the ribosomes?
ELECTRON TRANSPORT CHAIN:
• The ETC is found on the inner membrane
• High energy electrons are passed along the ETC
generating a proton gradient across the inner
membrane
• H+ gradient drives ATP synthesis
Mitochondria have 2 membranes
Chloroplasts have 3 membranes
There are 3
compartments
…what are
they?
Chloroplast
Thylakoid membrane –
proteins of ETC, ATP
synthase
• Inner membrane –
membrane transport
protein for Rubisco
• Outer membrane porin
• Stroma – enzymes for
Calvin Cycle,
chloroplast DNA.
Chloroplasts
Plant Cell
Fig 13-26
Chloroplasts vs Mitochondria
These are mitochondria
So are these
Chloroplasts have different forms too
Thylakoids
Mitochondria
But their structure and
function remain linked
Think of 3 similarities between
mitochondria and chloroplasts.
Think of 3 ways they are different
NEXT TUTORIAL:
• Vesicle Trafficking
• Models of Golgi function
• Receptor-mediated endocytosis
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