Take out your homework

Endosymbiont TheoryMitochondria and chloroplasts were once free-living bacteria and were taken inside another cell (not the same cell at first) and ‘became’ organelles.• IF this is true, what would be true about their•DNA?• Their membranes (draw it out if you need to)?

Endosymbiont Theory

•Mitochondria and Chloroplasts•DNA – DNA is ‘bacteria-like’, circular, etc• Their membranes – TWO membranes and inner

membrane is ‘bacteria-like’ (made of same components)

Endosymbiont Theory

Endosymbiont TheoryMitochondria and chloroplasts were once free-living bacteria and were taken inside another cell (not the same cell at first) and ‘became’ organelles.• IF this is true, what would be true about their•DNA?• Their membranes (draw it out if you need to)?

•and their relatedness to “their cell” vs bacteria?

ONE Example•Chloroplast DNA from

a EUKARYOTE• Is most closely related

to PROKARYOTE DNA

ONE Example

• SO, the DNA in the chloroplast of a EUKARYOTE is more closely related to DNA of bacteria than it is to the DNA in ITS OWN NUCLEUS•Common throughout

plants• Similar results for

Mitochondria

Think about that…• The DNA in a chloroplast is more closely related to

the DNA in cyanobacteria than it is to the DNA in the nucleus of the cell it’s in•ALSO, the DNA in the chloroplast of a carrot is

more closely related to the DNA in the chloroplast of a soybean than either chloroplast is to the DNA in the nuclei of the cells they’re in.

Think about that…•What ELSE should mitochondria and chloroplasts

be able to do if they were once free-living cells?•What else do cells do? Think Cell Theory…• Yep! When removed from the cell, mitochondria

and chloroplasts can replicate on their own!•Mitochondria can multiply in YOUR cells too!• It’s one of your body’s responses to increased

exercise.

• “Just” another “theory”?

Endosymbiont Theory

Obj 19 – Bacteria and Plant Cell Walls

• Plant Cell walls are made of?•Cellulose – Glucose is monomer•Bacteria Cell Walls:•Basically glucose, galactose (and other

monosaccharide) monomers put together a little differently

Obj 19 – Bacteria and Plant Cell Walls

•BUT the cell wall and the cell capsule protect bacteria pretty well•Antibiotics target the capsule and wall.• LOTS of variations of capsule and wall among

bacteria•Different antibiotics

HOMEWORK•What questions do you have?

Review•Cell Theory•Prokaryotes vs Eukaryotes•Compare/Contrast•BOTH have a CELL MEMBRANE•Cytoplasm•Organelles•Nucleus•Ribosomes

Review•Cell Membrane!

HOMEWORK•Review for Test•Bring Questions

Obj. 12•Ready…. GO!•Another example of structures getting used for

different function•We’ll see that often