2. Cells Key Terms Pg 151, 162 all definitions will be collected on the next exam day… They will not be allowed to be used on the exam. Reading assignment Pg 154 & 162 Prok Pg 155 & 163 Euk Pg 163-164 Plant Euk vs animal Euk Pg 156-161 Euk cellular structure

3. The Discovery of Cells Microscope observations of organisms led to the discovery of the basic characteristics common to all living things. Scientists first discovered cells in the 1600s using crude microscopes. Observations made by scientists using more powerful microscopes in the 1800s led to the formation of the cell theory.

4. Early Compound Microscopes 1-4 The first cells seen were plant cell walls in a section of dried cork. (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: Courtesy of the Armed Forces Institute of Pathology; b: © Corbis–Bettmann Anton van Leeuwenhoek of holland and Robert Hooke were given credit for the invention fo the microscope and the discovery of cells.

5. Cell Theory 1. All living things are made up of one or more cells. 2. Cells are the basic units of structure and function in organisms 3. All cells arise from existing cells.

6. Features of Prokaryotic and Eukaryotic Cells

7. Cell Features Features of Prokaryotic Cells A prokaryote is an organism made of a single prokaryotic cell. Prokaryotic cells do not have a nucleus or other internal compartments. The genetic material of a prokaryotic cell is a single loop of DNA. For millions of years, prokaryotes were the only organisms on Earth.

8. Diversity in Cells, continued Diversity in Prokaryotes Prokaryotes can vary in shape, the way they obtain and use energy, and their ability to move. Many prokaryotes have a flagellum, a long, hair-like structure that grows out of the cell and enables the cell to move through its environment. Prokaryotes may also have pili, short outgrowths that allow the cell to attach to surfaces or other cells.

9. Flagella On Prokaryotic Cells A B C D E F Click to animate the image.

10. Cell Features, continued Features of Eukaryotic Cells A eukaryote is an organism made up of one or more eukaryotic cells. All multicellular organisms are made of eukaryotic cells. The DNA of a eukaryotic cell is found in an internal compartment of the cell called the nucleus. All eukaryotic cells have membrane-bound organelles. An organelle is a small structure found in the cytoplasm that carries out specific activities inside the cell.

11. Cell Features, continued Each organelle in a eukaryotic cell performs distinct functions. The complex organization of eukaryotic cells enables them to carry out more specialized functions than prokaryotic cells.

12. Diversity in Cells, continued Eukaryotic Cell Specialization Eukaryotic cells can vary in shape and external features. Depending on their function, eukaryotic cells can also vary in their internal organelles. For example, muscle cells, which use large amounts of energy, contain many mitochondria. Animal and plant cells are two types of eukaryotic cells. Both have many of the same organelles, but plant cells also have chloroplasts, a large central vacuole, and a cell wall.

13. Comparing Prokaryotes and Eukaryotes

15. Plant Cell

16. Eukaryotic Cells A B B C D D C A E E F F G G H H I I J J K L M

17. Body Types Unicellular organisms can thrive independently or live together in groups. Cells that are permanently associated but do not work together or integrate cell activities are called colonial organisms. A multicellular organism is composed of many individual, permanently associated cells that coordinate their activities with each other. True multicellularity occurs only in eukaryotes.

18. Levels of Organization Plants and animals have many highly specialized cells that are arranged into tissues, organs, and organ systems. A tissue is a distinct group of similar cells that perform a common function. An organ is a collection of tissues that work together to form a structure which performs a specific function. An organ system is composed of a group of organs that work together to perform major body functions.

19. Hierarchy of Complexity Organism is composed of organ systems Organ Systems composed of organs Organs composed of tissues Tissues composed of cells Cells composed of organelles Organelles composed of molecules Molecules composed of atoms 1-19 Organism Organ system Organ Tissue Cell Organelle Macromolecule Molecule Atom Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 1.7

20. Organization in Multicellular Organisms

21. 3-21 Nucleus Largest organelle most cells have one nucleus a few cells are anuclear or multinucleate nuclear envelope - two unit membranes surround nucleus regulate molecular traffic through envelope nucleoplasm – material in nucleus chromatin (thread-like matter) composed of DNA and protein nucleoli – one or more dark masses where ribosomes are produced

22. 3-22 Micrograph of The Nucleus Figure 3.25a Figure 3.25b Nucleolus Nucleoplasm Nuclear envelope 2  m (a) Interior of nucleus Nuclear pores 1.5  m (b) Surface of nucleus a: © Richard Chao; b: © E.G. Pollock

23. 3-23 Ribosomes Ribosomes - small granules of protein and RNA found in nucleoli, in cytosol, and on outer surfaces of rough ER, and nuclear envelope they ‘read’ coded genetic messages (messenger RNA) and assemble amino acids into proteins specified by the code

24. 3-24 Endoplasmic Reticulum Figure 3.26aFigure 3.26b Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 µm Cisternae of rough ER Nucleus Ribosomes of rough ER (a)(b) Oil droplet (inclusion) Smooth endoplasmic reticulum 1 µm © Don Fawcett/Photo Researchers, Inc.

25. 3-25 Smooth and Rough ER Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Rough endoplasmic reticulum Ribosomes Smooth endoplasmic reticulum

26. 3-26 endoplasmic reticulum - system of interconnected channels Rough endoplasmic reticulum – composed of parallel, flattened sacs covered with ribosomes produces the phospholipids and proteins of the plasma membrane synthesizes proteins that are packaged in other organelles or secreted from cell Endoplasmic Reticulum

27. 3-27 Endoplasmic Reticulum smooth endoplasmic reticulum lack ribosomes synthesizes steroids and other lipids detoxifies alcohol and other drugs manufactures all membranes of the cell rough and smooth ER are functionally different parts of the same network

28. 3-28 Golgi Complex Figure 3.27 Golgi vesicles Golgi complex Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Visuals Unlimited 600 nm

29. 3-29 Golgi Complex Golgi complex - synthesize carbohydrates and put the finishing touches on protein receives newly synthesized proteins from rough ER packages the protein into membrane-bound Golgi vesicles some become lysosomes some migrate to plasma membrane and fuse to it some become secretory vesicles for later release

30. 3-30 Lysosomes Lysosomes - package of enzymes bound by a single unit membrane extremely variable in shape Functions Cellular digestion Example: Proteins, worn out mitochondrion ‘cell suicide’ – some cells are meant to do a certain job and then destroy themselves

31. 3-31 Mitochondrion Figure 3.29a,b Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (Left): Dr. Donald Fawcett & Dr. Porter/Visuals Unlimited Matrix Crista Outer membrane Inner membrane Intermembrane space Mitochondrial ribosome 1 µm

32. 3-32 Mitochondrion mitochondria – organelles specialized for synthesizing ATP surrounded by a double unit membrane inner membrane has folds called cristae spaces between cristae are called matrix “Powerhouses” of the cell energy is extracted from organic molecules and transferred to ATP Figure 3.29b Matrix Crista Outer membrane Inner membrane Intermembrane space Mitochondrial ribosome Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

33. 3-33 Evolution of Mitochondrion It is a virtual certainty that mitochondria evolved from bacteria that invaded another primitive cell, survived in the cytoplasm, and became permanent residents has its own mtDNA small circular molecule resembling bacterial DNA replicates independently of nuclear DNA mitochondrial DNA is almost exclusively inherited through the mother mutates more readily than nuclear DNA no mechanism for DNA repair

34. Quiz Identify the structures 1 2

35. Quiz 3) What invention made cellular biology possible? 4) These type of cells make up multicellular creatures? These types of cells make up unicellular creatures? 5) Where are ribosomes made? On what structure would you find ribosomes attached?