1. Week # 9 Lecture – pp 129-133 Lecture Presentations for Integrated Biology and Skills for Success in Science Banks, Montoya, Johns, & Eveslage

2. Expectations for the course Community Working with others—in class, in lab, in study groups Learning Complete all assignments for deep comprehension Respect Fellow students, instructors and self

3. Guiding Principles for the Course Looking at seemingly simple things deeply Conceptual understanding Practical Applications Contextualized

4. Transport Mechanisms, Organelles, By the end of the lecture today, students will be able to: Explain the importance of and describe the processes of diffusion, osmosis, facilitated diffusion and active transport. Describe which types of membrane transports require energy and which do not require energy. List the major organelles in a eukaryotic cell and describe their major roles in the cell.

5. Membrane Transport plasma membrane – a barrier and a gateway between the cytoplasm and ECF selectively permeable – allows some things through, and prevents other things from entering and leaving the cell passive transport mechanisms requires no ATP random molecular motion of particles provides the necessary energy diffusion, osmosis, facilitated diffusion active transport mechanisms consumes ATP active transport and vesicular transport

7. Simple Diffusion Simple Diffusion – the net movement of particles from area of high concentration to area of low concentration due to their constant, spontaneous motion Also known as movement down the concentration gradient – concentration of a substance differs from one point to another Down gradient Up gradient Cy.

9. Osmosis Osmosis - flow of water from one side of a selectively permeable membrane to the other from side with higher water concentration to the side with lower water concentration reversible attraction of water to solute particles forms hydration spheres makes those water molecules less available to diffuse back to the side from which they came Aquaporins - channel proteins specialized for passage of water Side ASide B (a) Start.

10. 3-10 Facilitated Diffusion facilitated diffusion – passive transport of solute through a membrane down its concentration gradient does not consume ATP solute attaches to binding site on carrier, carrier changes confirmation, then releases solute on other side of membrane. ECF ICF 123A solute particle enters the channel of a membrane protein (carrier). The solute binds to a receptor site on the carrier and the carrier changes conformation. The carrier releases the solute on the other side of the membrane.

11. Active Transport active transport – carrier-mediated transport of solute through a membrane up (against) its concentration gradient ATP energy consumed to change carrier Examples of uses: sodium-potassium pump keeps K+ concentration higher inside the cell bring amino acids into cell pump Ca 2+ out of cell

12. Sodium-Potassium Pump each pump cycle consumes one ATP and exchanges three Na+ for two K+ keeps the K+ concentration higher and the Na+ concentration lower with in the cell than in ECF necessary because Na + and K + constantly leak through membrane half of daily calories utilized for Na+ - K+ pump. 2 K + in Extracellular fluid Intracellular fluid + ATP P i ADP + 3 Na + out

13. http://www.youtube.com/watch?v=RPAZvs4hvG A

14. The Cell Interior structures in the cytoplasm organelles, cytoskeleton, and inclusions all embedded in a clear gelatinous cytosol Organelles – internal structures of a cell that carry out specialized metabolic tasks membranous organelles – those surrounded by one or two layers of unit membrane nucleus, mitochondria, lysosome, peroxisome, endoplasmic reticulum, and Golgi complex organelles not surrounded by membranes ribosome, centrosome, centriole, basal bodies

15. Nucleus Largest organelle (5  m in diameter) most cells have one nucleus a few cells are anuclear or multinucleate nuclear envelope - two unit membranes surround nucleus perforated by nuclear pores formed by rings of protein regulate molecular traffic through envelope hold two unit membranes together nucleoplasm – material in nucleus chromatin (thread-like matter) composed of DNA and protein nucleoli – one or more dark masses where ribosomes are produced

16. endoplasmic reticulum - system of interconnected channels called cisternae enclosed by unit membrane rough endoplasmic reticulum – composed of parallel, flattened sacs covered with ribosomes continuous with outer membrane of nuclear envelope produces the phospholipids and proteins of the plasma membrane synthesizes proteins that are packaged in other organelles or secreted from cell Endoplasmic Reticulum

17. smooth endoplasmic reticulum lack ribosomes cisternae more tubular and branching cisternae are thought to be continuous with those of rough ER synthesizes steroids and other lipids detoxifies alcohol and other drugs manufactures all membranes of the cell rough and smooth ER are functionally different parts of the same network

19. Ribosomes Ribosomes - small granules of protein and RNA found in nucleoli, in cytosol, and on outer surfaces of rough ER, and nuclear envelope they ‘read’ coded genetic messages (messenger RNA) and assemble amino acids into proteins specified by the code

20. Golgi Complex Golgi complex - a small system of cisternae that synthesize carbohydrates and put the finishing touches on protein and glycoprotein synthesis receives newly synthesized proteins from rough ER sorts them, cuts and splices some of them, adds carbohydrate moieties to some, and packages the protein into membrane-bound Golgi vesicles some become lysosomes some migrate to plasma membrane and fuse to it some become secretory vesicles for later release

22. Lysosomes Lysosomes - package of enzymes bound by a single unit membrane extremely variable in shape Functions intracellular hydrolytic digestion of proteins, nucleic acids, complex carbohydrates, phospholipids, and other substances autophagy – digest and dispose of worn out mitochondria and other organelles autolysis – ‘cell suicide’ – some cells are meant to do a certain job and then destroy themselves

24. 3-24 Mitochondrion mitochondria – organelles specialized for synthesizing ATP variety of shapes – spheroid, rod-shaped, kidney bean-shaped, or threadlike surrounded by a double unit membrane inner membrane has folds called cristae spaces between cristae are called matrix matrix contains ribosomes, enzymes used for ATP synthesis, small circular DNA molecule – mitochondrial DNA (mtDNA) “Powerhouses” of the cell energy is extracted from organic molecules and transferred to ATP Matrix Crista Outer membrane Inner membrane Intermembrane space Mitochondrial ribosome.

25. 3-25 Mitochondrion Matrix Crista Outer membrane Inner membrane Intermembrane space Mitochondrial ribosome 1 µm

26. http://www.youtube.com/watch?v=aczbMlSMr8U

27. Exit Quiz 1). What transport mechanism is responsible for moving water molecules from an area of high concentration to low concentration? 2). In order for active transport mechanism to work there must be an input of what molecule? Why this molecule? 3). What part of the nucleus is responsible for producing rRNA (ribosomes)? 4). What organelle is responsible for modifying proteins after they are synthesized? 5). Why is the mitochondria known as the “powerhouse of the cell”?