The Cell Chapter 7 - Cell Structure and Function

Early Contributions Robert Hooke - First person to see cells, he was looking at cork and noted that he saw "a great many boxes. (1665) Anton van Leeuwenhoek - Observed living cells in pond water, which he called "animalcules" (1673)

Theodore Schwann - zoologist who observed tissues of animals had cells (1839) Mattias Schleiden - botanist, observed tissues of plants contained cells ( 1845) Rudolf Virchow - also reported that every living thing is made of up vital units, known as cells. He predicted that cells come from other cells. (1850 )

The Cell Theory 1. Every living organism is made of one or more cells. 2. The cell is the basic unit of structure and function. It is the smallest unit that can perform life functions. 3. All cells arise from pre-existing cells. *Why is the Cell Theory called a Theory and not a Fact?

Cells are always small, how small depends on the type of cell Cells can come in a variety of shapes

Figure 4.3

Single Cheek Cell - at different illuminations

Prokaryote vs Eukaryote Cells Endosymbiosis theory: All organelles seem to share many properties with bacteria. Lynn Margulis proposed endosymbiont hypothesis: that organelles derived from ancient colonization of large bacteria (became the eukaryotic cell) by smaller bacteria (became the mitochondria, chloroplast, etc.) Symbiosis = "living together". *Mitochondria & Chloroplasts have their own DNA Animation at Microbiological Concepts

Prokaryote Cells no membrane bound nucleus, chromosomes grouped together in an area called the "nucleoid" no membrane bound organelles smaller than eukaryotes

have cell wall and cell membrane, some have a capsule on the outside ribosomes make protein consist of bacteria and archaebacteria Appendages include: fimbriae/pili, flagella *pili are usually longer and fewer than fimbriae, both function for attachment and recognition of host cells (or (sexual reproduction)

Figure 4.4a

E. coli

Eukaryotes has a membrane bound nucleus has membrane bound organelles in cytoplasm Organelles perform specific functions much larger than prokaryotes Organisms within the animal, plant and fungi kingdoms are all eukaryotes

We will be spending a lot of time on organelles and their functions.

It may seem that in these slides there were quite a few "more on this later.." notes.... That's because cell biology is a huge area, and is divided into many branches that biologists specialize in... 1) Oncology 2) Microbiology 3) Genetics 4) Paleobiology 5) Pathology to name a few

Quick Recap What are the two main types of cells? 2. Which one is larger? 3. Which one does not have a membrane bound nucleus? 4. What are the three main parts of the cell (that all cells have)? 5. What are the 3 components of the cell theory? 6. What theory explains how eukaryotes evolved?