1. Cell Structure

2. Cytology n All cells have –a plasma membrane that separates the cell’s internal parts from the environment –organelles (internal structures in the cytoplasm) –cytoplasm (jelly like spooge, mostly water)

3. Prokaryotes vs Eukaryotes n Prokaryotes lack most of the membrane bound organelles, have DNA in a concentrated region, tend to grow rapidly and divide often. Smaller than eukaryotes… n Includes cyanobacteria and bacteria

4. Eukaryotes n Protists, fungi, plants and animals… n specialized membrane bound organelles (nucleus), nuclear membrane n eukaryotes (10 - 100 micrometers) much larger than prokaryotes (.2 - 5 micrometers)

5. Cell size n Surface to volume ratio limits size of cell. n Volume increases at the cube of the diameter (V=d 3 ) n Surface area increases at the square of the diameter (A=d 2 ) n As a cell grows its volume increases at a rate faster than its surface area

6. So what?

7. n Form follows function n similar functions in different organisms have similar shapes Cell shape

8. Cell structure n See drawing on page 89 n What is the largest organelle? n What is the fluid outside of the nucleus but inside of the cell called? n What is the fluid inside of the nucleus called?

9. Nucleus n Has a double membrane and many nuclear pores n contains the nucleolus where ribosomes are assembled n Ribosomes important in the process of synthesizing protiens n leaves through the nuclear pores and...

10. Nucleus contains DNA n Genetic material stored in nucleus… n Chromatin are seen in cells that are not dividing n Chromosomes are seen in cells that are dividing n How are they related?

11. Endoplasmic reticulum n Sets of membranes connected to the nuclear and plasma membranes n channelize cytoplasm n two types of ER - –rough ER –smooth ER

12. Golgi complex n Stacks of flattened membranes n sorts and modifies proteins from the ER n finished products are stored in cytoplasm or exports them through the plasma membrane

13. Mitochondria n Power plant in the cell n site of cellular respiration (converts organic molecules to ATP) n double membrane bound n have a small amount of their own DNA

14. Chloroplasts n Site of photosynthesis n also double membrane n contain pigments (chlorophyll and others) n also have their own DNA… n what does this suggest?