Download Ch 7 Cell Overview and Theory

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.......
1. 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?