Essential Questions: What is the cell theory? Why do cells have organelles?

1. Unit 3: • Chapter 7: Cell Structure & Function • Georgia Standards: • Analyze the nature of the relationships between structures and functions in living cells. • Explain the role of cell organelles for both prokaryotic and eukaryotic cells. Essential Questions: What is the cell theory? Why do cells have organelles? How do prokaryotes and eukaryotes differ?

2. All living things are made up of cells. Some organisms are composed of only one cell. Other organisms are made up of many cells. Answer the following questions in your binder: 1. What are the advantages of a one-celled organism? 2. What are the advantages of an organism that is made up of many cells? Warm-up: Are all cells alike?

3. Anton van Leeuwenhoek (lay-vuhn-hook) (early 1600’s) became one of the first people to use a microscope to study nature. He was the first person, for example, to see tiny living organisms in a drop of water. Robert Hooke (1665) used one of the first light microscopes to look at thin slices of plant tissues, specifically cork. They looked like tiny chambers, so he called them “cells” The Cell Theory

4. The Cell Theory • The cell theory states the following: • All living things are composed of cells. • Cells are the basic units of structure and function in living things. • New cells are produced from existing cells.

5. Prokaryotes Evolved first smaller and simpler than eukaryotes. cell membranes cytoplasm NO nuclei No membrane-bound organelles Ex: Allbacteria are prokaryotes Escherichia coli, which live in your intestines Staphylococcus aureus, which can cause skin infections. Eukaryotes Evolved from prokaryotes Large Multicellular Do contain nuclei cell membrane cytoplasm specialized membrane-bound organelles, that perform important cellular functions Ex: All plants, animals, and fungi, and protists. Prokaryotes and Eukaryotes

6. Origin of Eukaryotic Cells • The endosymbiotic theory proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms. • Evidence: • First, mitochondria and chloroplasts contain DNA similar to bacterial DNA. • Second, mitochondria and chloroplasts have ribosomes whose size and structure closely resemble those of bacteria. • Third, like bacteria, mitochondria and chloroplasts reproduce by binary fission when the cells containing them divide by mitosis.

7. Cell membrane Cytoplasm Cell membrane Cytoplasm Prokaryotic and Eukaryotic Cells Prokaryotic Cell Nucleus Eukaryotic Cell Organelles

8. Ribosome Cell wall Cell membrane Peptidoglycan Pili Flagellum DNA The Structure of a Eubacterium Section 19-1 Flagella = Flagella are whiplike structures used for movement. Go to Section:

9. 1. What three statements describe the cell theory? 2. What are the two main characteristics that distinguishes eukaryotes from prokaryotes? 3. What evidence supports the endosymbiotic theory? 4. If microscopes had not been invented, do you think the cell theory would have been developed? Explain your answer. OR Pg. 186 # 1-4 Homework

10. Basic Cell Structures (Organelles): • Organelles isolate cell activities • Organelles contribute to the specialization of eukaryotic cells • Cells Reproduce, manufacture and release energy, and maintain homeostasis

11. Despite differences in cell size and shape, certain structures are common to most cells. Cell membrane Cytoplasm Cell Membrane = thin, flexible barrier around the cell. Maintains homeostasis Cell Wall = support and protect cells, while allowing them to interact with their surroundings (Not in animal cells). Nucleus = contains the cell’s genetic material (DNA) and controls the cell’s activities Cytoplasm =inside the cell membrane—but not including the nucleus, contains many organelles. Basic Cell Structures

12. Found in many organisms, including plants, algae, fungi, and nearly all prokaryotes. Animal cells, however, do not contain cell walls. The cell wall lies outside the cell membrane. Most cell walls allow water, oxygen, carbon dioxide, and other substances to pass through them.   Made of carbohydrates (cellulose) and proteins The main function of the cell wall is to provide support and protection for the cell. Cell Wall

13. The nucleuscontrols most cell processes and contains the hereditary information of DNA (deoxyribonucleic acid). Almost all eukaryotic cells, including the plant and animal cells contain a nucleus. Nucleus

15. The granular material visible within the nucleus is called chromatin. It consists of DNA bound to protein. Most of the time, chromatin is spread throughout the nucleus. When a cell divides, however, chromatin condenses to form chromosomes (kroh-muh-sohms). Chromatin and Chromosomes 

16. Most nuclei also contain a small, dense region known as the nucleolus (noo-klee-uh-lus). The assembly of ribosomes begins. Ribosomes aid in the production of proteins within the cell. The nucleus is surrounded by a double-membrane layer called the nuclear envelope. Nuclear pores, which allow material to move into and out of the nucleus. The nucleus sends a steady stream of RNA and other information-carrying molecules to the rest of the cell through the nuclear pores. Nucleolus & Nuclear Envelope

17. The cytoskeleton is a network of protein filaments that helps the cell to maintain its shape and is involved in many forms of cell movement • Microtubules • Microfilaments

18. Ribosomes - Proteins are assembled on ribosomes small particles made of RNA (ribonucleic acid) and protein. Endoplasmic Reticulum  Transports molecules in cell. SER – smooth endoplasmic reticulum has no ribosomes attached RER – rough endoplasmic reticulum has ribosomes attached Organelles in the Cytoplasm

20. Golgi Apparatus  Proteins produced by the rough endoplasmic reticulum move into a stack of membranes called the Golgi apparatus. Enzymes in the Golgi apparatus attach carbohydrates and lipids to proteins. Lysosomes(ly-suh-sohmz) are small organelles filled with enzymes. break down lipids, carbohydrates, and proteins from food help break down organelles that have outlived their usefulness removing debris that might otherwise accumulate and clutter up the cell Organelles in the Cytoplasm

22. Cells often store materials such as water, salts, proteins, and carbohydrates in saclike structures known as vacuoles (vak-yoo-ohlz). Many plant cells have a single large, central vacuole filled with liquid. Vacuoles are also found in single-celled organisms and in animals. Smaller vacuoles, especially those involved in transporting substances within the cell, are often also called vesicles. Organelles in the Cytoplasm

23. The chloroplasts are found in plants and some bacteria and protists. Animal and fungal cells do not contain chloroplasts.   Chloroplasts use the energy from sunlight to make energy-rich food molecules in a process known as photosynthesis. Organelles in the Cytoplasm

25. Mitochondria: • The mitochondriaare organelles that release energy from stored food molecules.   • Mitochondria are found in nearly all eukaryotic cells, including those of plants and algae. • Mitochondria use energy from food to make high-energy compounds that the cell can use to power growth, development, and movement in a process called cellular respiration.

27. Ribosome (attached) Ribosome (free) Nucleolus Nucleus Cell Membrane Nuclear envelope Mitochondrian Smooth endoplasmic reticulum Rough endoplasmic reticulum Centrioles Golgi apparatus Animal Cells Animal Cell

28. Smooth endoplasmic reticulum Vacuole Ribosome (free) Chloroplast Ribosome (attached) Cell Membrane Nuclear envelope Cell wall Nucleolus Golgi apparatus Nucleus Mitochondrian Rough endoplasmic reticulum Plant Cells Plant Cell

29. Classwork Assignments: • Construct a Venn diagram that compares and contrasts eukaryotes and prokaryotes. • Construct a Venn diagram that compares and contrasts the various organelles that exist in animal and plant cells.

30. Cell Wall Chloroplasts Large central vacuole Venn Diagrams Prokaryotes Eukaryotes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell membrane Ribosomes Cell wall cytoplasm Animal Cells Plant Cells Cell membrane Cytoplasm Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Vacuoles Mitochondria Cytoskeleton Lysosomes Centrioles

31. Agenda: • Go to www.cellsalive.com • Complete handout

32. Formative Assessment: • 1. Describe the functions of the endoplasmic reticulum, Golgi apparatus, chloroplast, and mitochondrion. • 2. What does the cell wall provide for a cell? • 3. Describe the role of the nucleus in the cell. • 4. What are two functions of the cytoskeleton? • 5.Name two structures that all cells have. • 6. How is a cell like a factory?