Energy-Converting Organelles & Endosymbiosis (2A)

Mitochondria Function

• carry out cellular respiration in nearly all eukaryotic cells

  • converts the chemical energy in foods to chemical energy in ATP

ATP

• adenosine triphosphate

• primary energy carrier in cells

• stores and transfers energy for cellular processes

Mitochondria Structure

• have 2 membranes - outer & inner (2 internal compartments)

  • intermembrane space (between the 2 membranes)

  • mitochondrial matrix

    • enclosed by the inner membrane

The Matrix Contains…

mitochondrial DNA, ribosomes, and enzymes for cellular respiration

Mitochondria’s Inner Membrane

• contains many embedded protein molecules that function in ATP synthesis

• has folds (cristae)

  • increases its surface area, enhancing the mitochondrion’s ability to produce ATP

Chloroplast Function

• the photosynthesizing organelles of plants and algae

Photosynthesis

photosynthesis is the conversion of light energy from the sun to the chemical energy of sugar molecules

Chloroplasts Structure

• ALSO have an outer and inner membrane separated by an intermembrane space

• Stroma

  • enclosed by the inner membrane

The Stroma Contains…

thylakoids, chloroplasts DNA, ribosomes, and enzymes for photosynthesis

Thylakoids

a network of interconnected sacs that contain chlorophyll

Granum

a stack of thylakoids

Endosymbiosis Theory

mitochondria and chloroplasts were formerly small prokaryotes that began living within larger cells

an endosymbiont is one organism that lives inside of another one

Evidence for the Endosymbiosis Theory

1. divide by binary fission (as do all prokaryotes)

2. contain their own DNA - with genes more like those from prokaryotes

3. membrane lipids are similar to those of modern prokaryotes

4. ribosomes that are the same size of prokaryotic ribosomes (smaller than ribosomes of eukaryotes)