LEQ: How did eukaryotic cells evolve? Reading: 12.4 (final); 13.2 (unit 4) Test tomorrow! Activator: evolution Define the terms “organism” and “biodiversity.” In your opinion – Do you think biodiversity has increased or decreased through the history of life? Do you think biodiversity is increasing or decreasing presently? Why? Key terms – stromatolite, endosymbiosis

LEQ: How did eukaryotic cells evolve? Which of the following is a network of proteins that supports and gives shape to a cell? A) vesicles B) vacuole C) cytoskeleton D) cytoplasm Which organelle contains enzymes that break down damaged cell parts? A) centriole B) lysosomes C) vacuole D) mitochondria What is the main function of the Golgi apparatus? A) communicate with other cells B) convert solar energy C) process and deliver proteins D) copy DNA

Microbes have changed the physical and chemical composition of Earth. The oldest known fossils are a group of marine cyanobacteria. prokaryotic cells added oxygen to atmosphere deposited minerals

Fossil stromatolites provide evidence of early colonies of life.

Eukaryotic cells evolved through endosymbiosis. Endosymbiosis is a relationship in which one organism lives within the body of another. Mitochondria chloroplasts (plastids).

Mitochondria (pl.) supply energy to the cell. Contain DNA

Mitochondria have life cycles

Photosynthetic cells have chloroplasts. Chloroplasts convert solar energy to chemical energy. Contain DNA

Evolutionary background: The endomembrane system: Cell membrane “copy” mitochondria, chloroplasts: “very microbial” Cytoskeleton: some bacteria produce cytoskeletal proteins

How did cells evolve? Events could have occurred near-simultaneously step-wise

Relay summary: Write one summary sentence about what you learned in this unit, pass to the next member How many times can you go around? Journal entry: 5 things I need to work on when I study are:

Summary: What are the functions of the cytoskeleton? Describe how the endoplasmic reticulum, mitochondrion, and Golgi apparatus are structurally similar. How does the endomembrane system work together with the cytoskeleton to transport materials across a cell? What similarities do mitochondria and chloroplasts share?

Both membrane-bound organelles have their own DNA and help make energy available to the cell All are composed of membrane-enclosed chambers. The surface area of each is greatly increased by folds and layers

The evolution of sexual reproduction led to increased diversity. Genetic variation is an advantage of sexual reproduction. Sexual reproduction may have led to the evolution of multicellular life.