Mitochondria & Chloroplasts

Most cells get energy in one of two ways: food molecules sun

Mitochondria Almost all eukaryotes contain mitochondria Converts chemical energy into compounds cells can use Passed down in cytoplasm in egg cell Double membrane – outer and inner Inner membrane folded up inside Increased surface area-produces more ATP

Mitochondria Glucose is the principle energy source in most living organisms More energy in a glucose molecule than the cell can immediately use Mitochondria break down glucose to produce ATP – cellular respiration

ATP-Energy Source Adenosine triphosphate - stores energy A-P~P~P When energy is needed, the 3rd phosphate bond is broken releasing energy A-P~P Adenosine diphosphate (ADP)

Chloroplasts Contained in plants Converts energy from sun into chemical energy – photosynthesis Double membrane Contain green pigment - chlorophyll

Endosymbiotic Theory Single-celled prokaryotes microfossils found dating back to 3.5 bya About 2 bya, prokaryotes began evolving internal cell membranes Other prokaryotic organisms began to enter the ancestral eukaryotic cells forming a symbiotic relationship

Some prokaryotic could use oxygen to generate ATP – these became mitochondria Some carried out photosynthesis – plants The endosymbiotic theory supposes the eukaryotic cells arose from living communities formed by prokaryotic organisms

Evidence Mitochondria and chloroplasts contain DNA similar to bacterial DNA Both have ribosomes similar to bacteria Both reproduce by binary fission like bacteria