1. LE 7-2 Hydrophilic head Hydrophobic tail WATER

2. LE 7-3 Hydrophilic region of protein Hydrophobic region of protein Phospholipid bilayer

3. LE 7-5b Viscous Fluid Unsaturated hydrocarbon tails with kinks Membrane fluidity Saturated hydro- carbon tails

4. LE 7-5c Cholesterol Cholesterol within the animal cell membrane

5. LE 7-8 EXTRACELLULAR SIDE N-terminus C-terminus CYTOPLASMIC SIDE  Helix

6. LE 7-15a EXTRACELLULAR FLUID Channel protein Solute CYTOPLASM

7. LE 7-17a Diffusion Facilitated diffusion Passive transport

8. LE 7-17b ATP Active transport

9. LE 7-17 Diffusion Facilitated diffusion Passive transport ATP Active transport

10. LE 6-9a Flagellum Centrosome CYTOSKELETON Microfilaments Intermediate filaments Microtubules Peroxisome Microvilli ENDOPLASMIC RETICULUM (ER Rough ER Smooth ER Mitochondrion Lysosome Golgi apparatus Ribosomes: Plasma membrane Nuclear envelope NUCLEUS In animal cells but not plant cells: Lysosomes Centrioles Flagella (in some plant sperm) Nucleolus Chromatin

11. LE 6-9b Rough endoplasmic reticulum In plant cells but not animal cells: Chloroplasts Central vacuole and tonoplast Cell wall Plasmodesmata Smooth endoplasmic reticulum Ribosomes (small brown dots) Central vacuole Microfilaments Intermediate filaments Microtubules CYTOSKELETON Chloroplast Plasmodesmata Wall of adjacent cell Cell wall Nuclear envelope Nucleolus Chromatin NUCLEUS Centrosome Golgi apparatus Mitochondrion Peroxisome Plasma membrane

12. LE 6-10 Close-up of nuclear envelope Nucleus Nucleolus Chromatin Nuclear envelope: Inner membrane Outer membrane Nuclear pore Pore complex Ribosome Pore complexes (TEM)Nuclear lamina (TEM) 1 µm Rough ER Nucleus 1 µm 0.25 µm Surface of nuclear envelope

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

14. LE 6-2 Measurements 1 centimeter (cm) = 10 –2 meter (m) = 0.4 inch 1 millimeter (mm) = 10 –3 m 1 micrometer (µm) = 10 –3 mm = 10 –6 m 1 nanometer (nm) = 10 –3 µm = 10 –9 m 10 m 1 m Human height Length of some nerve and muscle cells Chicken egg 0.1 m 1 cm Frog egg 1 mm 100 µm Most plant and animal cells 10 µm Nucleus 1 µm Most bacteria Mitochondrion Smallest bacteria Viruses 100 nm 10 nm Ribosomes Proteins Lipids 1 nm Small molecules Atoms 0.1 nm Unaided eye Light microscope Electron microscope

15. LE 6-3a Brightfield (unstained specimen) 50 µm Brightfield (stained specimen) Phase-contrast

16. LE 6-6 A typical rod-shaped bacterium A thin section through the bacterium Bacillus coagulans (TEM) 0.5 µm Pili Nucleoid Ribosomes Plasma membrane Cell wall Capsule Flagella Bacterial chromosome

17. LE 6-7 Total surface area (height x width x number of sides x number of boxes) 6 125 150 750 1 1 1 5 1.2 6 6 Total volume (height x width x length X number of boxes) Surface-to-volume ratio (surface area  volume) Surface area increases while Total volume remains constant

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

19. LE 6-14a Phagocytosis: lysosome digesting food 1 µm Plasma membrane Food vacuole Lysosome Nucleus Digestive enzymes Digestion Lysosome Lysosome contains active hydrolytic enzymes Food vacuole fuses with lysosome Hydrolytic enzymes digest food particles

20. LE 6-14b Autophagy: lysosome breaking down damaged organelle 1 µm Vesicle containing damaged mitochondrion Mitochondrion fragment Lysosome containing two damaged organelles Digestion Lysosome Lysosome fuses with vesicle containing damaged organelle Peroxisome fragment Hydrolytic enzymes digest organelle components

21. LE 6-15 5 µm Central vacuole Cytosol Tonoplast Central vacuole Nucleus Cell wall Chloroplast

22. LE 6-16-1 Nuclear envelope Nucleus Rough ER Smooth ER

23. LE 6-16-3 Nuclear envelope Nucleus Rough ER Smooth ER Transport vesicle cis Golgi trans Golgi Plasma membrane

24. LE 6-17 Mitochondrion Intermembrane space Outer membrane Inner membrane Cristae Matrix 100 nm Mitochondrial DNA Free ribosomes in the mitochondrial matrix

25. LE 6-18 Chloroplast DNA Ribosomes Stroma Inner and outer membranes Granum Thylakoid 1 µm