ENERGY-CONVERTING ORGANELLES

1. ENERGY-CONVERTING ORGANELLES

2. 4.14 Mitochondria • Mitochondria harvest chemical energy from food • Where cellular respiration occurs • GlucoseATP (Energy) • If a cell has mitochondrial problems, the rate of energy (ATP) being made decreases significantly.

3. Mitochondrion Outer membrane Intermembrane space Inner membrane Cristae Matrix

4. 4.15 Chloroplasts • Where photosynthesis occurs in plants • Photosynthesis is the conversion of light energy to chemical energy of sugar molecules • Light Energy  Glucose

5. Chloroplast Stroma Inner and outer membranes Granum Intermembrane space

6. 4.16 EVOLUTION CONNECTION: Mitochondria and chloroplasts evolved by endosymbiosis • When compared, you find that mitochondria and chloroplasts have (1) DNA and (2) ribosomes • The structure of both DNA and ribosomes is very similar to that found in prokaryotic cells, and mitochondria and chloroplasts replicate much like prokaryotes • The hypothesis of endosymbiosis proposes that mitochondria and chloroplasts were formerly small prokaryotes that began living within larger cells • Symbiosis benefited both cell types

7. Mitochondrion Engulfing of photosynthetic prokaryote Some cells Engulfing of aerobic prokaryote Chloroplast Host cell Mitochondrion Host cell

8. INTERNAL AND EXTERNAL SUPPORT: THE CYTOSKELETON AND CELL SURFACES

9. 4.17 Cytoskeleton • The cytoskeleton is composed of three kinds of fibers: • Microfilaments (actin filaments) support the cell’s shape and are involved in motility • Intermediate filaments reinforce cell shape and anchor organelles • Microtubules (made of tubulin) shape the cell and act as tracks for motor protein

10. Nucleus Nucleus Tubulin subunit Actin subunit Fibrous subunits 10 nm 25 nm 7 nm Intermediate filament Microfilament Microtubule

11. 4.18 Cilia and Flagella • Used for movement • Cells that sweep mucus out of our lungs have cilia

12. Cilia

13. Flagellum

14. Fig. 6-23 Direction of swimming (a) Motion of flagella 5 µm Direction of organism’s movement Power stroke Recovery stroke (b) Motion of cilia 15 µm

15. Plant, but not animal cells, have a rigid cell wall It protects and provides skeletal support that helps keep the plant upright against gravity Plant cell walls are composed primarily of cellulose 4.22 Cell wall

16. Walls of two adjacent plant cells Vacuole Primary cell wall Secondary cell wall Cytoplasm Plasma membrane

17. FUNCTIONAL CATEGORIES OF CELL STRUCTURES

18. 4.23 Review: Eukaryotic cell structures can be grouped on the basis of four basic functions • It is possible to group cell organelles into four categories based on general functions of organelles • In each category structure is correlated with function

20. a. l. b. c. k. j. i. h. d. g. e. f.

21. You should now be able to • Describe microscopes and their importance in viewing cellular structure • Distinguish between prokaryotic and eukaryotic cells • Describe the structure of cell membranes and how membrane structure relates to function

22. You should now be able to • Describe the function of each cellular organelle that is involved in manufacture and breakdown of important cellular materials • Describe the function of each cellular organelle that is involved in energy conversion • Describe the function of each cellular organelle that is involved in structural support of the cell