Unit 2: Part 1 Cell structure and function Membrane Functions

1. Unit 2: Part 1 Cell structure and functionMembrane Functions

2. Cell Structure and Function

3. Scientists Book section 3.1 Hooke – cells Leeuvenhoek – “animacules” Shleiden – all plants made up of cells Schwann – All animals are make up of cells Virchow – cells come from other cells

4. The Cell theory has three principles. • All living things are composed of one or more cells. 2. The cell is the most basic unit of structure of all living things. • unicellular organisms- one cell • Multicellular – specialized regions called tissues. 3. All existing cells are come from previously existing cells. • The ability of cells to divide to form new cells is the basis for all reproduction and for the growth and repari of all multi organisms.

5. Cell Diversity • Cell Shape – shape induces function • Cell Size – too big and nothing can get done. Smaller cells have better homeostasis

6. 2.33 basic parts of all cells • Plasma membrane – barrier to outside • Selectively permeable • Cytoplasm – fluid inside, also includes the cytoskeleton, and organelles • Control Center – Either just DNA or Nucleus.

7. 2 MAIN TYPES OF CELLS • The major difference between prokaryotic cells and eukaryotic cells is the presence of a nucleus. • 1. prokaryotic cells do not have a true nucleus, the DNA in pro cell is circular and called plasmid. • 2. Eukaryotic cells, the DNA is organized into structures called chromosomes and the chromosomes are separated from the cytoplasm by a nuclear membrane.

8. PROKARYOTE • No nuclei • Can have cell membrane, cell wall, plasmid (circular DNA) • Smaller and simpler (size of mitochondria) • On Earth before others • Most bacteria • Divide by binary fission (asexual)

9. Thee are two cell types: eukaryotic cells and prokaryotic cells

10. 2. EUKARYOTES • Have nuclei • Higher level membrane bound organelles • All plants, animal, fungi (all but monera) • Most are Multicellular, but can be unicellular • PLANTS AND ANIMALS

12. Plants

13. 2.2 Cell Organelles and Features Organelle: is a cell structure the performs a specialized function within a eukaryotic cells. Organelles found in a eukaryotic cell are mentioned on the next 84 slides.

14. 1. Nucleus • “brain” • Processes and contains DNA • Nucleolus – dense section inside nucleus • Production of ribosome's (protein makers)(rRNA) • Nuclear envelope – double membrane with pores to allow passage of RNA and Ribosome • Chromatin – loose or granular genetic material. Most common state of DNA. • During cell division the chromatin coagulates together forming chromosomes (threads)

16. 2. Mitochondria • Sites of cellular respiration, a process that turns glucose into ATP or energy • “powerhouse” of cell • The more active, more mitochondria, you have in your muscle cells. • Has own DNA, plasmid • Found in both plant and animal

17. 3. Chloroplast • Are found only in plants cells, contain the green pigment, chlorophyll, which absorbs energy from the sun to convert CO2 and H2O into sugar through the process of photosynthesis. • Has its own DNA - Plants do have mitochondria

19. Vesicles • 4. Lysosomes – Bud from the GA, filled with enzymes that break down carbs, lipids and proteins, also breakdown dead organelles and waste from cell. • Peroxisomes – Neutralize free radicals and detox. • Produce H2O2 as the break substances down.

20. 5. Vacuoles – large bubbles that store water, salts, proteins and carbs • Plants have 1 large vacuole, the pressure within the sac is sole provider for support of stems and leaves (turgor pressure). When full, stiff, when empty, limp. • Some animals have contractile vacuoles.

21. Large central vacuole • Contains water and enzymes. • Controls turger pressure.

22. 6. ribosomes The sites of protein synthesis; some are located on the ER, others are found in the cytoplasm.

23. 7. Endoplasmic Reticulum (ER) - Continuous organelles. - tubes and sacs - cisternae • Rough ER – maker of cell membrane (phospholipids) and proteins (ribosomes) • Has little balls on the outside • RER found more in cells that have glands and secretions. • Smooth ER– No attached ribosomes. contains enzymes that perform specialized tasks. Creates steroids (lipids), helps as a detox station.

26. 8. Golgi Apparatus – Stack of membranes that attach carbohydrates and lipids to proteins (ribosomes) • Modifies, collects, packages, and distributes proteins

27. Cytoskeleton Microfilament – Protein filaments that help the cell maintain shape • Crawling of white blood cells. • Very small Microtubules – hollow tubes of protein, shape and give “tracks” • In cell division of animals, they pair up (centrioles) and help separate chromosomes • Also can cluster to form cilia and flagella allow cell for swim and motion.

28. 9. Cilia are tiny hair like projections responsible for the movement animal cells or protists. • Made from microtubules. • 10. Flagella are long whip like projections responsible for the movement of some animal cells, bacteria, or protists. • Made from microtubules.

31. 11. Plasma Membrane (Cell Membrane) - protects the cell and regulates the passage of material between the cell and its environment. Also provides support. • Flexible phospholipid bilayer (hydrophilic heads, hydrophobic tails) • Knows as a fluid mosaic model. • Sterols – lipids, in tails, gives shape and protects during low temps

32. CM – fluid mosaic model • Have proteins immersed inside for transport of materials in and out of the cell.

33. 12. Cell Wall • Surround the cell membrane for protection and support in plants, bacteria and fungi. • Made of cellulose – complex carbohydrates

34. 13. cytoplasm • The semi – fluid material inside the cell containing molecules and the organelles. • Microfilaments and microtubules

35. 14. Centrioles – clusters of microtubules that form an organelle used during mitosis that secretes fibers that helps to pull the cell apart during reproduction.