Cells Structure, Function and other stuff

GETTIN’ THE JOB DONE: A Blast from the Past REMEMBER OUR CHARACTERISTICS OF LIVING THINGS? REMEMBER OUR CHARACTERISTICS OF LIVING THINGS? The Toy Lab… The Toy Lab… Evolution Evolution Reproduction Reproduction Reacting to Environmment Reacting to Environmment Homeostasis (Balance) Homeostasis (Balance) Movement Movement Organization Organization Energy (getting it, using it) Energy (getting it, using it)

CELL ORGANELLES Each organelle performs specific functions Each organelle performs specific functions The organelle’s function accomplishes one or several of the necessary requirements for life… The organelle’s function accomplishes one or several of the necessary requirements for life… e.g., NUCLEUS… e.g., NUCLEUS… a “Two-for-the-price-of-one” special a “Two-for-the-price-of-one” special REPRODUCTION REPRODUCTION Instructions for ORGANIZATION of cell Instructions for ORGANIZATION of cell

A REAL Alien Invasion… They come in peace Read Lewis Thomas’ essay Read Lewis Thomas’ essay Answer the following as you read: Answer the following as you read: What does Thomas mean when he says that “some [organelles], and the most important ones at that, are total strangers”? What does Thomas mean when he says that “some [organelles], and the most important ones at that, are total strangers”? Which organelles does he suggest are the “strangers”? Which organelles does he suggest are the “strangers”? What evidence does he provide for this suggestion? What evidence does he provide for this suggestion? In the “master and slave” relationship that Thomas alludes to in the reading, in what ways are we “slaves” to our organelles? In the “master and slave” relationship that Thomas alludes to in the reading, in what ways are we “slaves” to our organelles? What is Thomas’s overall emotional reaction to the idea of strangers living inside our cells? How can you tell? What is Thomas’s overall emotional reaction to the idea of strangers living inside our cells? How can you tell?

CELLULAR EVOLUTION A tale of intrigue, suspense, and neverending commitment to one another… A tale of intrigue, suspense, and neverending commitment to one another… Scene 1: A tale of two cell types Scene 1: A tale of two cell types

Prokaryotes (used to be Monera in the 5 kingdom classification) Archebacteria Archebacteria Harshest habitats Harshest habitats First life forms? First life forms? Eubacteria Eubacteria Most modern bacteria Cyanobacteria (sometimes called blue-green algae)

Eukaryotes All complex cells that have membrane bound organelles. All complex cells that have membrane bound organelles. 10 – 100 X the size of prokaryotic cells 10 – 100 X the size of prokaryotic cells May be single cell organisms (still are complex and have membrane bound organelles). May be single cell organisms (still are complex and have membrane bound organelles). Cells making up all multicellular organisms. Cells making up all multicellular organisms. In multicellular organisms, cells can group together to form a various “levels of organization In multicellular organisms, cells can group together to form a various “levels of organization

Cell categories Prokaryotes Prokaryotes Smaller than eukaryotes Smaller than eukaryotes All bacteria All bacteria Archaebacteria Archaebacteria eubacteria eubacteria No membrane covered organelles No membrane covered organelles Eukaryotes Eukaryotes Much larger than prokaryotes Anything not bacteria Protista Plantae Fungi Animalia Membrane bound organelles special focus on nucleus

6 kingdoms connection

BUT…WHY DID THEY DIVERGE? Remember their differences? Remember their differences? Where did all of these cell parts come from? Where did all of these cell parts come from? Scene 2: Intrigue… “Having a friend for dinner”… Scene 2: Intrigue… “Having a friend for dinner”…

ECOLOGY: INTERACTION WITH THE ENVIRONMENT Living things interact with one another Living things interact with one another Lots of different kinds of interactions Lots of different kinds of interactions Predator-prey Predator-prey Mutualists Mutualists Etc…more to come on these later Etc…more to come on these later

Prokaryote vs Eukaryote sizes

Phagocytosis(food)/Pinocytosis (liquid) same process Cell interior Cell interior

Endocytosis/Exocytosis

SO…WHAT SHOULD HAPPEN? A cell takes in “prey” using the cell membrane A cell takes in “prey” using the cell membrane Vesicles form and the food is digested by the lysosomes, right? Vesicles form and the food is digested by the lysosomes, right? BUT NOT IN THIS CASE… SUSPENSE! BUT NOT IN THIS CASE… SUSPENSE!

REMEMBER: Prokaryote vs Eukaryote sizes

What do we know about mitochondria and chloroplasts? Same size as prokaryotes (A.K.A. Bacteria) Same size as prokaryotes (A.K.A. Bacteria) Have their own DNA Have their own DNA Have similar structure to prokaryotes Have similar structure to prokaryotes Reproduce like prokaryotes Reproduce like prokaryotes Membrane structure is like prokaryotes Membrane structure is like prokaryotes Double membrane makes sense Double membrane makes sense

Enter…Lynn Margulis…Eukaryote

Lynn Margulis Her hypothesis originally proposed that: Her hypothesis originally proposed that: mitochondria are the result of endocytosis of aerobic bacteria mitochondria are the result of endocytosis of aerobic bacteria chloroplasts are the result of endocytosis of photosynthetic bacteria chloroplasts are the result of endocytosis of photosynthetic bacteria in both cases by large anaerobic bacteria who would not otherwise be able to exist in an aerobic environment. in both cases by large anaerobic bacteria who would not otherwise be able to exist in an aerobic environment. this arrangement became a mutually beneficial relationship for both cells (symbiotic). this arrangement became a mutually beneficial relationship for both cells (symbiotic).

HUH? Instead of eating your roommate, you let them live and pay rent… Instead of eating your roommate, you let them live and pay rent… It’s win-win for both of you! It’s win-win for both of you!

Endosymbiotic theory Simply stated, the theory of endosymbiosis is the concept that: Simply stated, the theory of endosymbiosis is the concept that: mitochondria and chloroplasts are the result of years of evolution mitochondria and chloroplasts are the result of years of evolution initiated by the endocytosis of bacteria and blue-green algae initiated by the endocytosis of bacteria and blue-green algae instead of becoming digested, became mutualistic. instead of becoming digested, became mutualistic. HENCE…A NEVERENDING COMMITMENT TO EACH OTHER! HENCE…A NEVERENDING COMMITMENT TO EACH OTHER!

BiologicallevelsOforganization

CELL ENERGY 2 PROCESSES: 2 PROCESSES: Photosynthesis (chloroplast) Photosynthesis (chloroplast) Builds sugar using the energy from sunlight and matter from the atmosphere Builds sugar using the energy from sunlight and matter from the atmosphere Cell Respiration (mitochondria & cytoplasm) Cell Respiration (mitochondria & cytoplasm) Releases energy from sugar Releases energy from sugar