The Microscope & The Cell

1. The Microscope & The Cell

3. Discovery of the Cell • Anton VanLeeuwenhoek: a Dutch scientist • He developed the first microscope • Used a lens grinder to create the lenses • Looked at pond water • Robert Hooke: an English scientist who named the cell • Looked at corks • “Cells” were consistently rectangular

4. Discovery of the Cell, cont… • Robert Brown: A Scottish scientist • He discovered nucleus shapes • Mathias Schleiden: a German botanist • Discovered that plant tissues are made of cells • Theodore Schwann: a German zoologist • Discovered that animal tissues are made of cells • Discovered “Schwann cells”

5. Discovery of the Cell, cont… • Rudolph Virchow: German scientist • Plant and animal cells are produced only by the division of cells that already exist • The Cell Theory: • All living things are made of cells • Cells are the smallest working units of living things. • All cells come from pre-existing cells

6. Prokaryotic Cells vs. Eukaryotic Cells

7. Prokaryotic Cells vs. Eukaryotic Cells

8. Prokaryotic Cells vs. Eukaryotic Cells

9. Cellular Organelle Functions • Cell Membrane • Has 3 Basic Functions: • Controls what gets in/out (Selectively permeable) • Protection + support • Homeostasis = balanced state

10. Cell Membrane Function • Materials can move across the cell membrane in 5 different ways • Video on Movement across membrane(2:08) • PASSIVE TRANSPORT substances move across the cell membrane without the cell using any energy

11. Cell Membrane Function, cont… • PASSIVE TRANSPORT(0:45) • DIFFUSION • High to low concentration • No energy required by the cell • FACILITATED DIFFUSION • High to low concentration • No energy required by cell • Requires help of a carrier protein • OSMOSIS • Diffusion of water

12. Cell Membrane Function, cont… • ACTIVE TRANSPORT • Movement of substances against a concentration gradient therefore requires energy from the cell • (1) Sodium-Potassium Pump(1:20)

13. Cell Membrane Function, cont… ENDOCYTOSIS vs. EXOCYTOSIS(1:20) Phagocytosis & Pinocytosis used for solids used for liquids

14. More About Cell Membrane • Known as the phospholipid bilyar • Phospholipid: Made up of… 1. Phosphate head: polar (charged) i. Hydrophilic (water loving) 2. Lipid tails: nonpolar (non-charged) i. Hydrophobic (water fearing) b. Bilayer: Two layers

15. Phospholipid Bilayer

16. Cellular Organelle Functions, cont.. B. Nucleus • Function: contains nearly all of the cell’s DNA • Contains coded instructions for making proteins and other important molecules • Surrounded by two layered membrane called the nuclear envelope • Contains chromatin which is made up of DNA molecules and protein. • When a cell is getting ready to divide, this material changes in form to become chromosomes

17. Nucleus, continued… 4. DNA stands for Deoxyribonucleic Acid • DNA makes RNA (directs protein synthesis) • Discovered by James Watson & Francis Crick • DNA is shaped like a Double Helix • spiral staircase • twisted ladder

19. Cellular Organelle Functions, cont… • DNA Structure: a. Sugar =deoxyribose Nucleotide includes b. Phosphate c. Base: 2 Types d. Hydrogen bond

20. Types of Bases • Purines: • Adenine • Guanine • Pyrimidines: • Cytosine • Thymine

22. Cellular Organelle Functions, cont… • Nucleolus • Location: inside the nucleus (p. 181) • Function: Stores RNA Used to decode the information contained in DNA • RNA stands for Ribonucleic Acid • RNA makes, assembles, and produces ribosomes • RNA directs protein synthesis

23. Comparing DNA and RNA

24. Comparing DNA and RNA

25. Comparing DNA and RNA

26. Cellular Organelle Functions, cont… D. Ribosome • Tiny particles made of protein + DNA • Function: protein synthesis • Site where proteins are assembled (with directions from DNA) • Amino acids are the building blocks of protein • Found Attached to Endoplasmic Reticulum ( know then as the Rough E.R.) • Also Found free floating throughout the cytoplasm of the cell. Known as Free Ribosomes

27. Cellular Organelle Functions, cont… • Endoplasmic Reticulum a. an internal membrane system b. A system of membranes inside the cell that: 1. Modify proteins made in the Rough E.R. 2. Manufacture Lipid components of the cell membrane c. There are 2 forms of ER: • Smooth • Rough (with ribosomes)

28. Cellular Organelle Functions, cont… F. Golgi Apparatus (body, complex) • These 2 organelles modify + add components to proteins and then ship them to their final destination • A membranous, stacked plate-like structure which functions in: • Packaging protein • Storing protein • Exporting protein • Making lysosomes

29. Cellular Organelle Functions, cont… • Lysosomes • Sac-like membranes filled with enzymes and peroxide that digest things in the cell *Responsible for eating away tissue to sculpt ears, fingers, toes • Sometimes referred to as ‘suicide sacs’ because they digest the cell itself

30. Cellular Organelle Functions, cont… • Mitchondria • Often referred to as the Powerhouse of the cell because they supply energy • Site of Cellular Respiration a. O2 + C6H12O6  CO2 + H2O + energy b. Oxygen + Glucose yields Carbon dioxide + water and energy c. Energy is in the form of ATP (adenosine tri phosphate) d. Each glucose molecule form 36 ATP molecules e. Fatty acids and lipid produce much more E. ATP is broken to release energy and reformed to store energy over and over again resulting in daily expenditure ranging the trillions of ATP molecules

31. Cellular Organelle Functions, cont… • Microtubules (cytoskeleton) & Microfilaments • Structure + Support • Make up cilia + flagella • Cell Wall (not found in animal cells) • Made of cellulose (indigestible for us) • Function: protection, support

32. Cellular Organelle Functions, cont… • Vacuoles • A sac-like structure which functions in storage • 2 types: • Food Vacuole ; stores food • Contractive Vacuole: pumps out excess H2O Like a sump pump Helps with homeostasis

33. Cellular Organelle Functions, cont… • Plastids – pigment holders (only found in plant and some protists) • Chloroplast = green pigment (most important for photosynthesis Accessory pigments are needed to capture light energy throughout the entire visible spectrum Photosynthesis: H2O + CO2 => C6H12O6 + O2 • Water + Carbon dioxide yields glucose + oxygen • Plants have mitochondria also used to convert glucose into ATP • Leucoplasts = starch grains (glucose is converted and stored as starch)

34. Where did the Cell Come From? A. Oparin: Russian scientist who proposed the idea that cells arose from a chemical mixture known as “primordial soup”