Section 1 Cell Structures and Ultrastructures

1. Section 1Cell Structures and Ultrastructures

2. Cell Compartmentalization • Organelles- “tiny organs” inside the cell • have a specific job to maintain homeostasis (healthy cell) • Some are in all cells • Some are only found in either animal or plant cells

3. Structure- parts of a cell visible through a light microscope • Ultrastructure- parts of a cell visible through only an electron microscope • Plasma Membrane- “wall and gate” of the cell; 7nm wide • Selective permeability - allows some molecules to pass through while keeping others out. • Transport proteins- special tunnels or doors that only let in specific molecules Organelles of an Animal Cell

4. The Nucleus • The “brain” of the cell; contains loosely coiled DNA (Chromatin) • Nucleolus- Compact, largely inactive DNA in chromosome form • Makes ribosomes • Nuclear envelope- two membrane outer layer • Nuclear pores- small openings to allow exchange of materials

5. The ERs Endoplasmic Reticulum- system of membrane sacs (cristernea) branching off of the nucleus; does various of chemical reactions Smooth ER- no ribosomes; makes lipids and hormones Rough ER- ribosomes; makes proteins Ribosomes- take copy of DNA’s information (mRNA) and use it as a guide to create proteins ER ribosomes- proteins move on to Golgi apparatus Free ribosomes- proteins move to cytoplasm

6. Golgi Apparatus Golgi Apparatus- membrane sacs (cisternae) that put proteins into small membrane-bound packages called vesicles which are sent out or around the cell; makes lysosomes Lysosomes- sacs of hydrolytic enzymes that digest old organelles, food, and viruses/bacteria

7. The Mitochondria • power house of the cell; produces ATP(energy unit for cells) by breaking down sugars and other organic compounds (aerobic respiration) • Two membranes with inner one folded into cristae • Matrix (inner area) produces ATP and lipids

8. Organelles for Support Cytoplasm- clear gel-like fluid inside cells; help holds organelles in place Cytoskeleton- “Bones” of the cell; crossing rods, filaments, and tubes, that hold the cells shape. Also act at a “train” system to move things around the cell

9. Cilia and Flagella • Flagella- long, wipe-like tail that pushes and rolls the cell • Cilia- short, hair-like paddles that push the cell along • Both made from microtubules that form a basal body • Basal body- cylinder shape of 9 pairs of tubules + 2 central tubes • 9 + 2 formation

10. Centrioles • two 9+2 cylinders stuck at 90o from each other • move chromosomes during cell division by growing spindle fibers • animal cells only

11. Organelles of a Plant Cell • The organelles already covered (except centrioles, cilia, and flagella) can also be found in plant cells • Plants have a few extra organelles • Cell wall- thick, rigid wall made of cellulose that gives the plant cell a definite shape • Plasmodesmata- small connecting points between the cells walls of neighboring plant cells; allow exchange

12. Photosynthesis Centers Chloroplasts- perform photosynthesis to make energy from sunlight in planets and some unicellular organisms Chlorophyll- chemical that absorbs wavelengths of sunlight, expect green Grana- stacks of membranes containing chlorophyll

13. Vacuoles- Both Large and Small • Vacuoles- storage compartments for food, enzymes, etc. • In plant cells- they are very large and hold lots of water and nutrients; tonoplast membrane controls exchange; also holds pigments the give flowers color • In animal cells- very small; transport things inside the cell

14. Animal Cells Vs. Plant Cells

17. Homework • Review Section 1 for a quiz next Tuesday • Cell Analogy worksheet There is too much vocabulary!