1. Biology: Cell Review Modern Biology©2009 Holt, Rinehart, & Winston Chapter 4

2. Cell History Robert Hooke, 1665, saw cork under light microscope, and called individual units “cells”. van Leeuwenhoek, 1673, saw living cells under microscope with 10x greater magnification M. Schleiden, 1838, said all plants were made of cells T. Schwann, 1839, said all animals were too. R. Virchow (1821-1902) said all cells came from preexisting cells

3. First Cells Seen Hooke’s Cork Cells Leeuwenhoek’s Giardia cells

4. Cell Theory Has 3 essential parts: Cells come only from reproduction of existing cells. Cells are basic unit of structure & function in organisms. All living organisms are composed of 1 or more cells.

5. Cell Structure Form follows function: Shapes evolve to allow cells to perform their function. Sizes range from nm to 2 m in length, but average cells are 10 – 50  m. Surface-area-to-volume ratio limits size. – Volume increases more quickly. – Cells’ need for nutrient intake & waste disposal depends on proximity to cell membrane.

7. Cell Types Two basic types 1.Prokaryotic i. Has no membrane-bound organelles or nucleus ii.Is divided into 2 domains a)Bacteria – similar to 1 st cellular life forms b)Archaea 2.Eukaryotic i.Has membrane-bound organelles, including nucleus

8. Protists (from earlier lab)

9. Plasma Membrane Phospholipid bilayer – Outer & inner phosphate heads are polar – Inner portion composed of lipid tails Regulates passage in/ out of cell Separates cellular activities from environment Interfaces with environment Includes integral & peripheral proteins & lipids (sterols)  Fluid Mosaic Model

11. Cellular Organelles & Functions Nucleus: houses/protects genetic info (DNA) Nucleolus: site of ribosomal RNA production Mitochondrion: energy production Ribosomes: protein production Endoplasmic reticulum: intracellular highway – RER: phospholipids & proteins; SER: lipids + detox Golgi apparatus: sort/package proteins + lipids Lysosomes: digest large molecules & invaders Peroxisomes: break down R-OH, f.a., bacteria

12. Nucleus/ nucleolus; Mitochondrion; RER/ SER; Golgi; Lysosome

13. Cytoskeleton Network crisscrossing cytoplasm Gives shape to cell Acts as system of internal tracks Has 3 structural elements – Microtubules: made of tubulin; make flagella/cilia Centrioles: organize microtubules in cell division – Microfilaments: made of actin, help in cell movement – Intermediate filaments: rods: anchor nucleus et al, make up hair shaft

15. Plant Cells Unique Structures but have no centrioles – Cell Wall: primary + secondary Made of cellulose – Central Vacuole Made as smaller vacuoles fuse together Stores water, enzymes, wastes, etc… – Plastids Chloroplast: site of photosynthesis Chromoplast: has colored pigments + photosynthesis Amyloplasts: store starch