Cell Types and Cell Structure

1. Cell Types and Cell Structure

2. All Organisms are Made of Cells • The cell is the basic unit of structure & function in living things • The cell is the smallest unit that can still carry on all life processes • Both unicellular (one celled) and multicellular (many celled) organisms are composed of cells • Before the 17th century, no one knew cells existed

3. In 1665, an English scientist named Robert Hooke made an improved microscope and viewed thin slices of cork viewing plant cell walls • Hooke named what he saw "cells" because they looked like • In the 1830’s, Matthias Schleiden (botanist studying plants) & Theodore Schwann (zoologist studying animals) stated that all living things were made of cells and in 1855, Rudolf Virchow stated that cells only arise from pre-existing cells.

4. Modern Cell Theory • All living organisms are composed of cells. They may be unicellular or multicellular. • The cell is the basic unit of life. • Cells arise from pre-existing cells.

6. Prokaryotes • ● no nucleus • ● no membrane enclosed • organelles • ● single chromosome • ● no streaming in the cytoplasm • ● cell division without mitosis • ● simple flagella • ● smaller ribosomes • ● simple cytoskeleton • ● no cellulose in cell walls • ● no histone proteins

7. Eukaryotes ● nucleus ● membrane enclosed organelle ● chromosomes in pairs ● streaming in the cytoplasm ● cell division by mitosis ● complex flagella ● larger ribosomes ● complex cytoskeleton ● cellulose in cell walls ● DNA bound to histone proteins

8. Prokaryotic vs. Eukaryotic Examples: Bacteria Examples: Plant cells Animal cells Fungi Protists

9. Cell Structure • Organelles- Any of a number of organized or specialized structures that perform a specific function within a living cell.

10. Cell Membrane 1. Surrounds Cells 2. Has Semipermeable membrane that allows certain materials to enter but not others.

11. Cytoplasm 1. substance between the cell membrane and the nucleus (organelles are in the cytoplasm)

12. Nucleus 1. Membranous nuclear envelope 2. Chromosomes of DNA and protein (Histones)

13. Endoplasmic reticulum (ER) 1. Rough ER - Transport of proteins (roughness is the attached ribosomes) 2. Smooth ER –(lacks ribosomes) Processes & transports lipids and helps breaks down poisons, wastes and other toxic chemicals

14. Ribosomes 1. Attached to Rough ER 2. Site of protein synthesis

15. Golgi Apparatus 1. Assembly and editing of proteins

16. Lysosomes 1. Contain enzymes that break down and help recycle large proteins in animal cells

17. Mitochondria 1. Powerhouse ‑ site of ATP synthesis

18. Flagella and Cilia 1. Cell surface projections for movement

19. Microtubules and Microfilaments 1. Structural components of the cell (cytoskeleton) in eukaryotes

20. Vacuoles 1. Large central vacuoles in plant cells contain enzymes and pigments in plant cells Vacuoles

21. Cell Wall 1. Rigid wall outside of cell membrane that protects cell

22. Chloroplasts 1. Photosynthetic organelles in plant cells, containing the chlorophyll pigments Chloroplasts

23. Comparison:Plant cellsAnimal cells • Large, central vacuole • Chloroplasts • Rigid cell wall outside • of cell membrane • No large, central vacuole • No chloroplasts • No rigid cell wall