Cells: Basic Structures & Functions

1. Cells: Basic Structures & Functions

2. Historical Timeline of The Cell and Development of The Cell Theory Hooke observes dead plant cells under a microscope and names them “cells” Virchow, german medical doctor, looks at cells dividng under a microscope. Leeuwenhooke first to look at living things through a microscope Schleiden, a botanist, concludes that all plants must be made of cells. Schwann, a zoologist, concludes the same about animals, all must be made of cells. Invention of the microscope

3. In 1665, Robert Hooke used a microscope to examine a thin slice of cork(dead plant cell walls). What he saw looked like small boxes.

4. Hooke is responsible for naming cells. Hooke called them “CELLS” because they looked like the small rooms that monks lived in called Cells.

5. Anton van Leeuwenhoek • In 1673, Leeuwenhoek (a Dutch microscope maker), was first to view organisms (living things) in pond water. • Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth

6. Cell Theory Nearly a century after Hooke’s findings, several other scientist’s discoveries led to the formation of the cell theory.

7. Beginning of the Cell Theory • In 1838, a German botanist named Matthias Schleidenconcluded that all plants were made of cells • Schleidenis a cofounder of the cell theory

8. In 1839, a German zoologist named Theodore Schwann concluded that all animals were made of cells • Schwannalso cofounded the cell theory

9. In 1855, a German medical doctor named Rudolph Virchow observed, under the microscope, cells dividing • He reasoned that allcells come from other pre-existing cells by cell division

10. CELL THEORY IS FORMED • All living things are made of cells • Cells are the basic unit of structure and function in all living organisms (basic unit of life) • Cells come from the reproduction of existing cells (cell division)

11. Discoveries Since the Cell Theory • In 1970, American biologist, Lynn Margulis, provided evidence that some organelles within cells were at one time free living cells themselves • Supporting evidence included organelles with their own DNA • Chloroplast and Mitochondria

12. Simple or Complex Cells

13. AlthoughALLliving things are made of cells, organisms may be: • Unicellular – composed of one cell • Multicellular-composed of many cells that may organize into tissues, etc.

14. Types of Cells Living organisms are made of either prokaryotic or eukaryotic cells – the two major kinds of cells which can be distinguished by structural organization

15. Prokaryotes – The first Cells • Cells that lack a nucleus or membrane-bound organelles • Includes bacteria • Simplest type of cell • Single, circular chromosome

16. No nucleus, DNA scattered through center of the cell. • Surrounded by cell membrane & cell wall made of (peptidoglycan) • Contain ribosomes (no membrane)in their cytoplasm to make proteins Examples of bacteria: E.coli, Streptococcus

17. Eukaryotes • Cells that HAVE a true nucleus and membrane-bound organelles • Includes protists, fungi, plants, and animals • More complex type of cells

18. Eukaryotes contain 3 basic cell structures: • Nucleus • Cell Membrane • Cytoplasm with organelles

19. Two Main Types of Eukaryotic Cells Animal Cell Plant Cell

20. Cell Boundaries Cell Wall Outer boundary in bacteria, plant and fungi cells NOT found in animal cells Primary function: provide support and structure

21. Plasma Membrane Also call the cell membrane Found in ALL cells Primary function: maintain homeostatsis Provides protection from environment Regulates exchange with the environment Selectively permeable Controls what enters and what does not

22. Plasma Membrane Composed of 3 Biomolecules: Lipids Phospholipidsmake up the phospholipid bilayer Hydrophillic head and hydrophobic tails Two phospholipids orient themselves tail to tail to form the phospholipid bilayer Cholesterol Found in plasma membrane of animal cells Provides stabilization

23. Plasma Membrane 2. Carbohydrates “ID tags” to identify cells 3. Proteins Embedded in the phospholipid bilayer Function: serve as channels and pumps for transport in and out of cell

24. Plasma Membrane

25. Plasma Membrane