1. Cell Biology A Tour of the Cell

2. Outline • Cell Structure and Organelles • Electron micrographs, figures and function • Cell Molecular Components

3. Structure of Animal Cells Cell Video

4. Protection and Controlling Entry

5. Cell Membrane

6. Cell Membrane Composition • Plasma membrane encloses cell and cell organelles • Made of hydrophobic and hydrophillic components • Semi-permeable and fluid-like • “lipid bilayer”

7. Cell Membrane Composition • Integral proteins interact with “lipid bilayer” • Passive transport pores and channels • Active transport pumps and carriers • Membrane-linked enzymes, receptors and transducers • Sterols stabilize the lipid bilayer • Cholesterol

9. Cell Wall • Function: provides support and protection to the cell membrane • Found outside the cell membrane in plant cells • Cellulose is porous, rigid and strong

10. Control of the Cell

11. Cell Organelles • Nucleus Nickname:“The Control Center” Function: holds the DNA Parts: Nucleolus: dark spot in the middle of the nucleus that helps make ribosomes Chromatin: loosely coiled DNA (cells not dividing) two types – hetero__ –dark - eu__ - light

12. Organelles that Provide Energy

13. Mitochondria • Double membrane • Mitochondrial (maternal) DNA, • replicates independently from the cell • “Power House” of the cell • Food converted into energy • Adenosine triphosphate (ATP) • Consumes Oxygen, produces CO2

15. Chloroplast Nick name: Sugar Daddies Function: traps energy from the sun to produce food for the plant cell Green in color because of chlorophyll, which is a green pigment Double membrane structure Unique DNA, replicates independently from the cell

17. Packaging and Receiving

18. Endoplasmic Reticulum (ER) • Site where cell membrane and exported material is made • Rough ER (+ Ribosomes) • Make proteins to be shipped out • Smooth ER Make lipids to be shipped out

20. Ribosomes • sites of protein synthesis. • not membrane-bound • consists of a small and larger subunit, • consists of ribosomal RNA (rRNA) and some 50 structural proteins. • Bound ribsosomes make proteins for export, non-bound ribosomes make proteins for internal use • Most plentiful organelle in the cell

21. Lysosomes: circular, but bigger than ribosomes Nickname: “Clean-up Crews” Function: to break down food into particles the rest of the cell can use and to destroy old cells Intracellular digestion Releases nutrients Breakdown of waste

23. Autolysis • Self-destruction of damaged cells: • auto = self, lysis = break • lysosome membranes break down • digestive enzymes released • cell decomposes • cellular materials recycle

24. Golgi Complex/Apparatus Nickname: The shippers Function: packages, modifies, and transports materials to different location inside/outside of the cell Appearance: stack of pancakes

25. Note the direction of the flow Of the material into the cis and Out the trans.

26. Vessicles • Peroxisomes • Hydrogen Peroxide generated and degraded to detoxify the cell • Vessicles • Material transport • Vacuole • stores water • Plastids • Leucoplasts, aka amyloplasts store starch, protein or oils. • Chromoplasts store bright colorpigments

27. Inter mediate filaments Microfilaments Microtubules

28. Structural proteins for shape and strength • Microfilaments • Thin filaments composed of the protein actin: • provide additional mechanical strength • interact with proteins for consistency • Pairs with thick filaments of myosin for muscle movement • Intermediate • Mid-sized between microfilaments and thick filaments: • durable (collagen) • strengthen cell and maintain shape • stabilize organelles • stabilize cell position

29. Microtubules • Large, hollow tubes of tubulin protein: • attach to centrosome • strengthen cell and anchor organelles • change cell shape • move vesicles within cell (kinesin and dynein) • form spindle apparatus • Form cilia and flagella

30. Centrioles in the Centrosome Centrioles form spindle apparatus during cell division Centrosome: cytoplasm surrounding centriole

31. Cell Adhesion Gycocalyx -vecro-like ogliosaccharides that bind and hold to other cells Tight Junctions - seal/adhere cells together Adherens Junctions - actin filaments that bind and hold cells together Gap Junction -trans-cellular protein channels

32. Desmosome -proteins the anchor intermediate filaments from neighbouring cells together