Transcript Endosymbiosis and Cyanobacteria

Cyanobacteria and
Endosymbiosis
Objectives
– Students will be able to:
• Assess the magnitude of lake polution.
• Describe endosymbiosis and provide evidence
for the theory.
• Recognize the social impacts of mitochondrial
DNA.
Thought Question
•Before there were
plants, how did oxygen
enter the atmosphere?
Cyanobacteria
• Photosynthetic
Prokaryotes.
• Produced most of the
first oxygen in the
atmosphere.
What happens to all of the chemical
runoff that is dumped into the sea or
lakes?
What happens to all of the chemical
runoff that is dumped into the sea or
lakes?
• It becomes food
for algae and
cyanobacteria.
Satellite image of the Gulf of Mexico
Dangerous cyanobacteria
• Large amounts of
cyanobacteria destroy
the wildlife around
them.
– How?
• Block sunlight
• Take up too many
resources.
Which organelle might have been able to survive
by itself?
Mitochondria!
Chloroplast!
Endosymbiosis
• Theory proposes that mitochondria and
chloroplast are the descendants of bacteria.
Why?
• Size and structure
– Mitochondria (Mt) and chloroplasts (Chl) are
about the same size as most bacteria
Why?
• Size and structure
Mitochondria (Mt) and chloroplasts (Chl) are about
the same size as most bacteria
• Genetic Material
Mt and Chl have unique DNA to that found in the
nucleus of the host cell.
Why?
• Size and structure
Mitochondria (Mt) and chloroplasts (Chl) are
about the same size as most bacteria
• Genetic Material
Mt and Chl have unique DNA to that found in the
nucleus of the host cell.
Why?
• Size and structure
Mitochondria (Mt) and chloroplasts (Chl) are about
the same size as most bacteria
• Genetic Material
Mt and Chl have unique DNA to that found in the
nucleus of the host cell.
• ReproductionMt and Chl reproduce by simple fission.
How might this have happened?
How might this have happened?
• Prokaryotes entered the larger cells either as
parasites or undigested prey.
• Instead of being digested, the bacteria began
to live inside the host cell.
• OPTIONAL: VIDEO
How is mitochondrial DNA passed
on?
• mtDNA is only passed
down through the
maternal line.
• Egg cell contains
mitochondrial DNA.
Argentine Dirty war
• Between 1976-1983
Argentina was
governed by a military
dictatorship.
• Many who were
deemed the opposition
were kidnapped and
tortured.
Argentine mothers
• Kidnapped pregnant
women were taken to
secret detention
centers to have their
babies but were then
tortured and killed.
• Babies were adopted
by military personnel.
Mothers of La Plaza de Mayo
• Grandmothers of the
kidnapped children
wanted vengeance.
• They used mtDNA to
prove that they in fact
were the
grandmothers of the
kidnapped children.
Vengeance accomplished.
• Mothers of La Plaza
de Mayo proved the
identity of 59
children.
• 31 children were
returned to their
biological families.