Cell structure & Function

1. Cell structure & Function

2. Cell Wall • Main function – provide support & protection for the cell • Made of cellulose (carbohydrates) and protiens • Located outside the cell membrane of plant, fungi, and some protist cells

3. Cell Membrane • Main function – outer boundary of cell; regulates what can enter and exit the cell • Composed of a phospholipid bilayer w/ proteins embedded in the membranes; carbohydrates may attach to proteins

4. Cytoplasm • Main function – substance where organelles are suspended; site of many chemical reactions • Fluid substance that fills the space between the cell membrane and the nucleus

5. Nucleus • Main function – controls most cell processes and contains hereditary information (DNA) • Composed of a • Nuclear membrane • Nuclear pores • Nucleolus • Chromatin/Chromosomes • Located in all eukaryotic cells Scanning ↑ Transmission ↓

6. Chromatin/Chromosomes • Chromatin – DNA & Protein when it is loose and thread-like; granular looking; most of the time • Chromosomes – DNA & Protein when it condenses to form distinct structures; when cells are dividing

7. nucleolus • Main function – production / assembly of ribosomes • Dense region within the nucleus

8. Nuclear Membrane • Main function – surround and protect the contents of the nucleus • Double membrane layer • Dotted with thousands of nuclear pore which allow material to move into and out of the nucleus

9. Cytoskeleton • Main function – help the cell maintain its shape; also involved in many forms of cell movement • Network of protein filaments • Microfilaments – smallest; movement & support • Intermediate filaments – medium sized • Microtubules – largest; transport; cilia; flagella

10. Ribosomes • Main function – site of protein synthesis • Composed of RNA and protein • Can be free floating in the cytoplasm or attached to endoplasmic reticulum

11. Endoplasmic Reticulum • Rough ER Main function – manufacture and distribution of proteins; ribosomes are attached • Smooth ER Main function – manufacture of lipids and break down toxins; NO ribosomes are attached

12. Golgi Apparatus • Main Function – modifies, packages, and distributes material in the cell; Material is received from the ER, modified in the Golgi, then sent to the cell or out of cell. • Stack of membranes

13. Lysosome • Main function – break down food and/or worn out organelles • Small sack containing digestive enzymes

14. Vacuole • Main function – store materials such as water, salts, proteins, and carbohydrates • Plants have a large central vacuole that help the plant stand upright • Saclike structures

15. Chloroplasts • Main function – use energy from sunlight to make energy-rich food molecules; site of photosynthesis • Double membrane structure that contain large states of green membranes; green color is due to the pigment chlorophyll

16. Mitochondria • Main function – use energy from food to make high-energy compounds that eh cell can use to power growth, development, and movement • Double membrane structure; inner membrane is highly folded

17. Theory that states - mitochondria and chloroplasts are descendents from ancient prokaryotic cells that were engulfed by other cells; the two cells formed a symbiotic relationship where both cells benefited. Evidence = mitochondria & chloroplasts have DNA, ribosomes, and can divide independently of the cell Endosymbiosis