Mitochondria and Chloroplasts explained in detail For A-Level Double plasma membranes (envelopes) of mitochondria and chloroplasts included

1. Chloroplasts and
Mitochondria
By Sebastian Thomas

2. Mitochondrion
Chloroplast

3. Chloroplast

4. Chloroplasts
 Chloroplasts have a inner membrane and an outer membrane. So chloroplasts
have a double plasma membrane, which is called an envelope.
 Chloroplasts actually have three phospholipid bilayers. The third chloroplast
membrane is arranged in disks called thylakoids.
 These disks are stacked on top of each other, making a structure called a
granum. There are many of these in the chloroplast.
 The main function of the chloroplast takes place in the thylakoid membrane.
 Here the green pigment chlorophyll is held in place by membrane proteins.
 The reactions of photosynthesis take place in the membranes and stroma of
the chloroplast.

5. The Function
 The reactions of photosynthesis take place in the membranes and stroma of
the chloroplast.
 Chlorophyll converts the energy from the sun into electrical energy
 This electrical energy is then passed from one membrane protein to another,
providing the power to pump protons from the stroma into the thylakoid
lumen
 the protons (hydrogen ions, or H+) rush back across the membrane into the
stroma, and ATP synthase, an enzyme, converts the generated energy into ATP
 At this point, ATP and other products produced by the thylakoid membrane
proteins are combined with molecules of carbon dioxide (CO2) in the stroma
to make glucose.

6. Grana
Lamella
Starch granule

9. The inner membrane is folded inwards to
form projections called cristae. Inside this
is the matrix.

10. Mitochondria
 Most of the reactions for aerobic respiration take place in the mitochondria so
it is an incredibly important organelle.
 During respiration, ATP is produced, which is used to provide energy for the
cells' reactions. Most of the ATP is produced on the inner mitochondrial
membrane.It is highly folded so there is maximum surface area available.

11.  The bilayer closest to the cytoplasm, or the outer mitochondrial membrane
has integral proteins called porins that allow small molecules to pass freely
into the mitochondria.
 The space inside a crista is called a matrix.
 The mitochondria is responsible for converting the chemical energy in
macromolecules, like glucose into molecules of ATP.

12. The Process of Respiration
 In a process called glycolysis, which occurs in the cytoplasm just outside the
mitochondrion, electrons are stripped from glucose and passed through the
outer mitochondrial membrane into the intermembrane space.
 Electrons pass through the protein channel in the inner membrane.
 As the electrons move from one membrane protein to the next, energy is
released and protons (hydrogen ions, or H+) in the matrix are pumped across
the inner membrane and into the intermembrane space. Fairly quickly, a
large number of protons accumulate in the intermembrane space, and, like
water behind a dam, exert great pressure on the inner membrane.
 The rush of protons through a special protein channel which produces energy
and the ATP synthase harnesses it. ATP synthase has a rotor that spins when
protons push past.

13. The energy generated by the turning of the rotor is converted
into ATP

16. My Sources
 http://floydmiddle.typepad.com/.a/6a00d83452932669e2013489b1b5a7970c-
pi
 http://www.bbc.co.uk/education/guides/z9hyvcw/revision/2
 http://www.shmoop.com/biology-cells/chloroplast-membrane.html
 http://www.s-cool.co.uk/a-level/biology/cells-and-organelles/revise-
it/organelles
 http://emp.byui.edu/wellerg/The%20Cell%20Lab/Images/Eukaryotic%20Cell/
mitochondria%2002.jpg