What is a cell?

1. What is a cell?

2. Pyramids • The Great Pyramids of Egypt are made of stone blocks

3. Buildings • Buildings are put together with bricks....

4. Nests • Birds build their nests with grass, twigs and twine

5. YOU! • Everything is made up of smaller parts.... • Even You!

6. C is for cells.... • All living things are made up of cells • The cell is the basic unit of structure in all living things • All living things are made of cells, so sometimes cells are called the “building blocks” of life • The cell is the basic unit of function in all living things • All life processes (STRANGER-C) in a living organism are carried out by cells... and cells perform all of life processes on their own as well! • Cells come from pre-existing cells

7. Unicellular • Some organisms are made up of only one cell • Bacteria • Protists

8. Multicellular • Many organisms are made of many different cells which work together

9. Cell Structure and Function • Organelles

10. Eukaryotes have Organelles • YOU are a EUKARYOTE! • Eukaryotes have many small, membrane bound structures located inside the cell • The structures are called ORGANELLES (which means “little organs”) • Organelles perform specific functions which keep the cell (and the organism) alive EU=YOU/NU & PRO=NO

11. Prokaryotes • Have NO organelles • Bacteria NO nucleus

12. Plant Vs. Animal • Some organelles are found only in animal cells • Centrioles • Lysosomes • Others are found only in plant cells • Chloroplasts • Cell Walls • Most organelles, however, are found in both plant AND animal cells (Cytoplasm & Membrane are found in EVERY CELL!)

13. Cell Membrane (AKA Plasma Membrane) • SUPER important! • A double-layered structure that surrounds the cell • Provides a boundary between the cell and its environment • MAIN JOB: To control what goes into and what comes out of the cell!

14. Tell me more! • The cell membrane is SEMI-PERMEABLE which means some substances can pass through it and others cannot • It is “selective” about what it allows to get through • So it is sometimes said to be “selectively permeable” • Small substances pass through easily without using energy... • Water Glucose • Oxygen Carbon Dioxide

15. So? What's it look like? And what's it made of (mostly)? Carbohydrates Proteins (make up a channel) Protein Lipid Bilayer

16. Fluid Mosaic Model • Made of a double layer of lipids (fats) which contain large floating protein molecules • Because everything is “floating” and can move around, small molecules (water, oxygen, carbon dioxide, glucose) can squeeze through.... • Larger molecules (starch, protein) must be digested first!

17. Life Process: Transport • Because the membrane controls the passage of materials into and out of the cell it is part of the “transport system” • The membrane is involved in two kinds of transport: • Active (which requires energy) • Passive (which doesn't!)

18. Cytoplasm • Streaming jelly-like fluid that contains the cell organelles • Acts like a “cushion” for the organelles • Contains salts and nutrients • “Streaming” means it is moving • This allows for materials to move around inside the cell • Cytoplasm is located between the cell membrane and the nucleus • Many life processes (and chemical reactions) take place in the cytoplasm

19. Nucleus • Controls ALL of the cell activities • Nicknamed the “Brain” of the cell • It is surrounded by its own membrane (nuclear membrane) • Acts like a “vault” to store hereditary information (DNA) • It contains other organelles (chromosomes and nucleolus) • Nucleolus makes Ribosomes

20. Chromosomes • Long threadlike structures located in the nucleus of the cell • Contains heredity information organized as genes • Genes are hereditary units made of DNA • Genes are passed on to the next generation

21. Mitochondria • “Powerhouse” of the cell (the “mighty” mitochondria!) • Produces ENERGY (ATP) from Oxygen and Glucose • This process is called Cell Respiration • Cells which need more energy have more Mitochondria

22. Ribosomes • Make Protein • Think BBQ “Rib” (Ribs are MEAT. Meat is PROTEIN!) • Can be found attached to the E.R. (Endoplasmic Reticulum) or floating freely in the cytoplasm

23. Endoplasmic Reticulum • System of channels that transports material around the INSIDE of the cell • Attached or Near the Nucleus! • Two types: • Rough ER – has ribosomes attached • Smooth ER – no ribosomes

24. Golgi • Packages proteins and ships them OUTSIDE of the cell in packaged vesicles

25. Remember this… • Ribosome Makes ‘em • E.R. Takes ‘em • Golgi Stacks & Packs This is all about Proteins!

26. Vacuole • A storage area • Used to store water, wastes, food… • Located in the cytoplasm • Plant cells have one or two large vacuoles • Animals cells have many small ones!

27. Cell Wall • Surround PLANT and GREEN ALGAE (and some Bacteria) CELLS • Made of Cellulose (a non-living material) • Humans CAN NOT DIGEST Cellulose! • Protects cell’s contents • Supports plant as it grows

28. Chloroplast • FOUND ONLY IN PLANT and GREEN ALGAE CELLS • Float in cytoplasm • Large, irregular shaped GREEN structure • Shown with “stacks” inside • Contains Chlorophyll (green pigment) • Captures sun’s energy & makes food (glucose) for plant • CALLED PHOTOSYNTHESIS!