1. Copyright © 2010 Pearson Education, Inc. Generalized Cell Human cells have three basic parts: Plasma membrane—flexible outer boundary Cytoplasm—intracellular fluid containing organelles Nucleus—control center

2. Copyright © 2010 Pearson Education, Inc. Figure 3.2 Secretion being released from cell by exocytosis Peroxisome Ribosomes Rough endoplasmic reticulum Nucleus Nuclear envelope Chromatin Golgi apparatus Nucleolus Smooth endoplasmic reticulum Cytosol Lysosome Mitochondrion Centrioles Centrosome matrix Cytoskeletal elements Microtubule Intermediate filaments Plasma membrane

3. Copyright © 2010 Pearson Education, Inc. Plasma Membrane The plasma membrane separates the intracellular fluid (ICF) from extracellular fluid (ECF) The plasma membrane is semi-permeable which means that some things can cross the membrane and some things cannot

4. Copyright © 2010 Pearson Education, Inc. Figure 3.3 Extracellular fluid Intracellular fluid

5. Copyright © 2010 Pearson Education, Inc. Types of Membrane Transport A concentration gradient is: Passive Transport No cellular energy (ATP) required Substance moves down its concentration gradient Active Transport Energy (ATP) required Substances are moved or“pumped” against their gradient

6. Copyright © 2010 Pearson Education, Inc. Passive Transport Two main factors determine whether or not a substance can passively cross the plasma membrane. 1.Is the substance a lipid (Lipid solubility of substance) 2.Size of substance passing

7. Copyright © 2010 Pearson Education, Inc. Three Types of Passive Transport Across Cellular Membranes Simple diffusion- Small, nonpolar, hydrophobic substances diffuse directly through plasma membrane (O 2, CO 2 ) Facilitated diffusion-Larger, hydrophilic molecules (glucose, amino acids) Use membrane proteins to cross Osmosis-Movement of solvent (water) across a selectively permeable membrane from where it is most concentrated to where it is less concentrated Water mainly diffuses through channels (AQP) in the plasma membrane

8. Copyright © 2010 Pearson Education, Inc. Figure 3.7a Extracellular fluid Lipid- soluble solutes Cytoplasm

9. Copyright © 2010 Pearson Education, Inc. Figure 3.7b Hydrophilic molecules A Carrier Protein

10. Copyright © 2010 Pearson Education, Inc. Figure 3.7d Water molecules Lipid billayer Aquaporin A Channel Protein

11. Copyright © 2010 Pearson Education, Inc. Importance of Osmosis When osmosis occurs, water enters or leaves a cell A change in cell volume disrupts cell function Tonicity is the ability of a solution to change a cell’s volume Hypertonic, Hypotonic and Isotonic solutions

12. Copyright © 2010 Pearson Education, Inc. Figure 3.8a (a) Membrane permeable to both solutes and water Solute and water molecules move down their concentration gradients in opposite directions. Membrane H2OH2O Solute (sugar) Both solutions have the same osmolarity: volume unchanged

13. Copyright © 2010 Pearson Education, Inc. Figure 3.8b (b) Membrane permeable to water, impermeable to solutes Both solutions have identical osmolarity, increases on the right because only water is free to move Solute molecules are prevented from moving but water moves by osmosis. Volume increases in the compartment with the higher osmolarity. Left compartment Right compartment Membrane Solute (sugar) H2OH2O

14. Copyright © 2010 Pearson Education, Inc. Figure 3.9 (a) Isotonic solutions (b) Hypertonic solutions (c) Hypotonic solutions

15. Copyright © 2010 Pearson Education, Inc. Other Cellular Organelles Membranous structures Nucleus with chromatin- Mitochondria – Endoplasmic Reticulum (ER) (rough and smooth) – Golgi Apparatus- Lysosomes-

16. Copyright © 2010 Pearson Education, Inc. Figure 3.22 Golgi apparatus Transport vesicle Plasma membrane Vesicle Smooth ER Rough ER Nuclear envelope Lysosome Nucleus

17. Copyright © 2010 Pearson Education, Inc. Figure 3.18a Nuclear envelope Ribosomes Rough ER Smooth ER

18. Copyright © 2010 Pearson Education, Inc. Other Organelles Non-Membranous structures Cytoskeleton- protein filaments that help maintain cell shape, cell movement and in cell division (microtubules)

19. Copyright © 2010 Pearson Education, Inc. Extensions of the plasma membrane Cilia are: short, hairlike structures; move substances across cell surfaces Flagella are: Whiplike, tails that move the entire cell

20. Copyright © 2010 Pearson Education, Inc. THE CELL CYCLE

21. Copyright © 2010 Pearson Education, Inc. The Cell Cycle Includes: Interphase Period from cell formation to cell division Three sub phases of Interphase: G 1, S, G 2 Cell division (mitotic phase or mitosis) Consists of four sub phases of mitosis (PMAT) and cytokinesis

22. Copyright © 2010 Pearson Education, Inc. Figure 3.31 G 1 Growth S Growth and DNA synthesis G 2 Growth and final preparations for division M Mitosis (Cell Division) Mitosis increases the # of cells for growth/tissue repair

23. Copyright © 2010 Pearson Education, Inc. During the S-phase of Interphase DNA is Replicated Helicase untwists the double helix and exposes complementary chains Each nucleotide strand serves as a template for building a new complementary strand DNA polymerase forms new DNA strand

24. Copyright © 2010 Pearson Education, Inc. DNA Replication End result: two DNA molecules formed from the original in a process called semiconservative replication After DNA has been replicated the cell progresses into mitosis and cytokinesis

25. Copyright © 2010 Pearson Education, Inc. Mitosis and Cytokinesis Mitosis—four stages of nuclear division: Prophase- Metaphase- Anaphase- Telophase- Cytokinesis—division of cytoplasm by cleavage furrow

26. Copyright © 2010 Pearson Education, Inc. Figure 3.31 G 1 Growth S Growth and DNA synthesis G 2 Growth M

27. Copyright © 2010 Pearson Education, Inc. Figure 3.33 Early mitotic spindle Early Prophase Centromere Aster Chromosome consisting of two sister chromatids Early Prophase

28. Copyright © 2010 Pearson Education, Inc. Figure 3.33 Microtubule Late Prophase Fragments of nuclear envelope Late Prophase

29. Copyright © 2010 Pearson Education, Inc. Figure 3.33 Spindle Metaphase plate Metaphase

30. Copyright © 2010 Pearson Education, Inc. Figure 3.33 Anaphase Daughter chromosomes Anaphase

31. Copyright © 2010 Pearson Education, Inc. Cytokinesis Begins during late anaphase Ring of actin microfilaments contracts to form a cleavage furrow Two daughter cells are pinched apart, each containing a nucleus identical to the original

32. Copyright © 2010 Pearson Education, Inc. Figure 3.33 Contractile ring at cleavage furrow Nuclear envelope forming Nucleolus forming Telophase Telophase and Cytokinesis