AP BIOLOGY CHRISTMAS BREAK ASSIGNMENT

1. AP BIOLOGYCHRISTMAS BREAK ASSIGNMENT 2013-2014

2. 1 Its volume grow proportionately more than its surface area. A high surface to volume ratio facilitates the exchange of materials between a cell and its environment.

4. 2 Cell fractionation- spinning centrifuge forces will cause a fraction of cell components to settle at the bottom forming a pellet Lower speeds  larger organelles (nuclei, mitochondria) Higher speeds  smaller organelles (membranes, ribosomes)

5. TECHNIQUE Homogenization Tissue cells Homogenate 1,000 g (1,000 times the force of gravity) 10 min Fig. 6-5 Differential centrifugation Supernatant poured into next tube 20,000 g 20 min 80,000 g 60 min Pellet rich in nuclei and cellular debris 150,000 g 3 hr Pellet rich in mitochondria (and chloro- plasts if cells are from a plant) Pellet rich in “microsomes” (pieces of plasma membranes and cells’ internal membranes) Pellet rich in ribosomes

6. 3 Prokaryotic cells do not have a membrane bound nucleus, have a nucleoid (region of genetic material). No membrane bound organelles. Generally smaller than eukaryotic cells.

7. Fimbriae Nucleoid Ribosomes Fig. 6-6 Plasma membrane Cell wall Bacterial chromosome Capsule 0.5 µm Flagella (a) A typical rod-shaped bacterium (b) A thin section through the bacterium Bacillus coagulans (TEM)

8. 4 • They form compartments that provide different local environments that facilitate specific metabolic functions happening simultaneously. • Membranes also have many built in enzymes.

9. (a) TEM of a plasma membrane Outside of cell Fig. 6-7 Inside of cell 0.1 µm Carbohydrate side chain Hydrophilic region Hydrophobic region Hydrophilic region Phospholipid Proteins (b) Structure of the plasma membrane

10. 5 • ER (endoplasmic reticulum)- membrane synthesis and other synthetic and metabolic processes • Nucleus- contains most of the genes • Plasma membrane- selective barrier that encloses the cell • Ribosomes- site of protein synthesis • Golgi bodies- synthesis, modification, sorting, and secreting of cell products

11. Lysosome- digestive organelle • Mitochondrion- cellular respiration and generates most of cell’s ATP • Peroxisome- specialized metabolic functions • Microvilli- increases cell’s surface area • Cytoskeleton- reinforces cell’s shape, movement • Flagellum- locomotion

12. Central vacuole- storage, breakdown of waste products • Chloroplast- site of photosynthesis • Cell wall- maintains cell’s shape and protection • Plasmodesmata- connect cytoplasms of adjacent cells

13. 6 • Chromosomes are made up of chromatin (complex of proteins and DNA) • In preparation for cell division, chromatin condense into chromosomes.

14. 7 • rRNA is synthesized from instructions in the DNA  ribosomes for protein synthesis

15. 8 • Free ribosomes are suspended in the cytosol and produce most of the proteins that function in the cytosol. • Bound ribosomes are attached to ER or nuclear envelope and make proteins for insertion into membranes, for packaging or export from the cell.

16. Cytosol Endoplasmic reticulum (ER) Free ribosomes Fig. 6-11 Bound ribosomes Large subunit Small subunit 0.5 µm Diagram of a ribosome TEM showing ER and ribosomes

17. 9 • Components: nuclear envelope, ER, Golgi bodies, lysosomes, vacuoles, and plasma membrane • Membranes are related either through direct physical continuity or by transfer of membrane segments as vesicles.

18. Nucleus Rough ER Fig. 6-16-3 Smooth ER cis Golgi Plasma membrane trans Golgi

19. 10 • Smooth ER- lacks ribosomes; synthesis of lipids, detoxify drugs and poisons, stores calcium ions • Rough ER- has ribosomes attached; secrete proteins, synthesize membranes

20. Smooth ER Nuclear envelope Rough ER Fig. 6-12 ER lumen Cisternae Transitional ER Ribosomes Transport vesicle 200 nm Rough ER Smooth ER

21. 11 • Tiny sacs made of membrane used to transport materials.

22. 1 µm Nucleus Vesicle containing two damaged organelles 1 µm Fig. 6-14 Mitochondrion fragment Peroxisome fragment Lysosome Digestive enzymes Lysosome Lysosome Plasma membrane Peroxisome Digestion Food vacuole Digestion Mitochondrion Vesicle (a) Phagocytosis (b) Autophagy

23. 12 • Functions- modifies, stores and ships products of ER, manufactures certain macromolecules • Structure- The cis face is locates near ER. The trans face gives rise to vesicles that pinch off and travel to other sites.

24. cis face (“receiving” side of Golgi apparatus) 0.1 µm Cisternae Fig. 6-13 trans face (“shipping” side of Golgi apparatus) TEM of Golgi apparatus

25. 13 • Functions- use hydrolytic enzymes to digest macromolecules (phagocytosis), breakdown damaged or old organelles (autophagy), recycle organic molecules • Tay-Sachs= a lipid-digesting enzyme is missing or inactive, brain becomes impaired by an accumulation of lipids in cells

26. 14 • Food vacuoles- formed by phagocytosis • Contractile vacuoles- pump excess water out of cells • Central vacuole- stores organic compounds, dispose of metabolic by-products, contains pigments

27. 15 • Both organelles convert energy to forms that cells can use for work and have double membranes. • They are unique because they contain DNA. • Mitochondria- site of cellular respiration • Chloroplast- site of photosynthesis

28. 16 • Use oxygen to break down fatty acids into smaller molecules, detoxify alcohol in liver, converts H2O2 into water

29. 17 • Motor proteins that attach to receptors on vesicles can move it along cytoskeleton. • The streaming of cytoplasm can circulate organelles around cell.

30. Vesicle ATP Receptor for motor protein Motor protein (ATP powered) Microtubule of cytoskeleton Fig. 6-21 (a) Microtubule Vesicles 0.25 µm (b)

31. 10 µm Table 6-1a Column of tubulin dimers 25 nm Tubulin dimer  

32. 10 µm Table 6-1b Actin subunit 7 nm

33. 5 µm Table 6-1c Keratin proteins Fibrous subunit (keratins coiled together) 8–12 nm

34. 19 • Circular flow of cytoplasm within cells that speeds the distribution of materials within cells.

35. Cortex (outer cytoplasm): gel with actin network Inner cytoplasm: sol with actin subunits Extending pseudopodium Fig. 6-27bc (b) Amoeboid movement Nonmoving cortical cytoplasm (gel) Chloroplast Streaming cytoplasm (sol) Vacuole Parallel actin filaments Cell wall (c) Cytoplasmic streaming in plant cells

36. 20 • Primary cell wall- secreted by young plants, relatively thin and flexible • Middle lamella- between primary wall of adjacent cells, thin sticky layer of pectins • Secondary cell wall- between plasma membrane and primary wall, strong and durable

37. Secondary cell wall Primary cell wall Middle lamella Fig. 6-28 1 µm Central vacuole Cytosol Plasma membrane Plant cell walls Plasmodesmata

38. 21 • Collagen, proteoglycans, and fibronectin • Bind to cell surface receptor proteins called integrins, transmit cell signals between ECM and cytoskeleton to integrate changes

39. Proteoglycan complex Collagen EXTRACELLULAR FLUID Fig. 6-30a Fibronectin Integrins Plasma membrane CYTOPLASM Micro-filaments

40. 22 • Cells often adhere, interact, and communicate through direct physical contact.

41. Tight junction Tight junctions prevent fluid from moving across a layer of cells 0.5 µm Fig. 6-32 Tight junction Intermediate filaments Desmosome Desmosome Gap junctions 1 µm Extracellular matrix Space between cells Gap junction Plasma membranes of adjacent cells 0.1 µm

42. 23 • mRNA from nucleus is translated by ribosomes on rough ER • Cis face of Golgi bodies • Leaves trans face as a vesicle that breaks off and fuses with mitochondria • Used by mitochondria • Fuses with lysosome

43. Nucleus Rough ER Fig. 6-16-3 Smooth ER cis Golgi Plasma membrane trans Golgi

44. CELL COMMUNICATION

45. 1 • The process by which a signal on a cell’s surface is converted to a specific cellular response in a series of steps. • Studied in the yeast Saccharomyces cerevisiae

46.  factor Receptor a  Exchange of mating factors 1 a factor Fig. 11-2 Yeast cell, mating type a Yeast cell, mating type  a  Mating 2 a/ New a/ cell 3

47. 2 • A secreted molecule that influences cells in the vicinity. • Paracrine signaling- a secreting cell acts on nearby target cells by discharging molecules of a local regulator into the extracellular fluid • Synaptic signaling- a nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell

48. Local signaling Target cell Electrical signal along nerve cell triggers release of neurotransmitter Fig. 11-5ab Neurotransmitter diffuses across synapse Secreting cell Secretory vesicle Local regulator diffuses through extracellular fluid Target cell is stimulated (a) Paracrine signaling (b) Synaptic signaling

49. 3 • Secreted chemicals formed in specialized cells that travel in body fluids and act on specific target cells in other parts of the body to change their functioning.

50. Long-distance signaling Endocrine cell Blood vessel Fig. 11-5c Hormone travels in bloodstream to target cells Target cell (c) Hormonal signaling