1. CELLS CH. 7

2. All organisms are made of cells
Cells conform to the definitions of life
Obtain energy and materials from their food

3. respond to their environments
CELLS…
change with time
highly organized
reproduce
respond to their environments

4. Anton van Leeuwenhoek
- first to observe living things in pond water under a single-lens microscope

5. First Microscopes/First Living Cells

6. Hooke (1665)- - looked at cork under microscope
- gave cells their name

7. Robert Hooke: Cork Cells
1665, the English Scientist used a microscope to examine a thin slice of cork and described it as consisting of "a great many little boxes". 
They looked like "little boxes" and reminded him of the small rooms in which monks lived, so he called the "Cells".
Hook called what he saw “Cells”

8. Schwann–physiologist
Schleiden – botanist
all plants are made of cells (1838)
Virchow – physician
proposed that all cells come from existing cells (1855)
Schwann–physiologist
all animals are made up of cells (1839)

9. CELL THEORY – a summary of the work by Schleiden, Schwann, and Virchow
1. Cells are the basic units of life
2. All organisms are
made of cells
3. All cells come from pre-existing cells (Biogenesis)

10. All cells share three common features…
plasma membrane is cell’s boundary
Genetic information for each cell are contained in molecules of DNA
Cell body is composed of cytoplasm (outside the nucleus but inside the membrane)

11. The shape of a cell depends on it’s function

12. The cell’s need to regulate its internal environment limits its size
Homeostatic regulation of salt concentration and pH
take in useful molecules and dispose of waste

13. Large cells
Find it difficult to maintain just the
right environment for all of the
different molecular activities
This is why most unicellular organisms are microscopic.

14. Limits to cell size
Limited by the RATIO between their Outer Surface Area and Their Volume. 
A SMALL CELL HAS MORE SURFACE AREA THAN A LARGE CELL FOR A GIVEN VOLUME OF CYTOPLASM. 
nutrients, oxygen, and other materials a cell requires must enter through it surface

15. The cell’s nucleus (the brain) can only control a certain amount of living, active cytoplasm.

16. no membrane- bound organelles
TWO TYPES OF CELLS: Prokaryote & Eukaryote
Prokaryotic
no nuclei
no membrane- bound organelles
Do have cell wall, cell membrane, cytoplasm, ribosomes and genetic material.
Bacteria

17. Prokaryotic cells: Bacteria
Prokaryote: before the nut
Uniform cytoplasm
No membrane-bound organelles
DNA—circular & not in a nucleus
Have cell wall, membrane, ribosomes, nucleoid region

18. Eukaryotic Cells Larger than prokaryotes Nuclei
Membrane-bound organelles
Cell wall and/or cell membrane
Genetic Material
plants, animals, fungi and protists

19. Eukaryotic Cells “true” “nut” Nucleus Membrane-bound organelles
Specialized structures
subdivided

20. Eukaryotic Cell Structure
Cell Membrane
Cell Wall
Nucleus
Cytoplasm
Organelles

21. Animal Cell Centrioles Nucleolus Nucleus Nuclear envelope Rough
endoplasmic
reticulum
Golgi apparatus
Smooth
Mitochondrian
Cell
Membrane
Ribosome
(free)
(attached)

22. CELL MEMBRANE –
Regulates what enters and what leaves the cell
Adds protection and support
Lipid bilayer made of phospholipids and protein molecules
* commonly called a “mosaic”

23. NUCLEUS –
* Control center of the cell
* contains nearly all the DNA
* surrounded by a nuclear envelope
* nucleolus where assembly of ribosomes begin

24. CYTOPLASM – outside the nucleus, it holds the organelles in place

25. MITOCHONDRIA: referred to as the “powerhouse” of the cell.
Converts chemical energy stored in food into compounds that is easier for cell to use.
* All or nearly all of mitochondria comes from the cytoplasm of the egg/ovum

26. RIBOSOMES (pink dots)
Organelles (“factories”) that produce proteins from coded instructions that come from the nucleus

27. ENDOPLASMIC RETICULUM
Site where lipid components from the membrane are assembled, along w/proteins and other materials that are exported/transported from the cell.
Rough – makes protein
Smooth – contain enzymes that perform spec. tasks such as detoxification of drugs
Can be Rough or Smooth

28. GOLGI APPARATUS
Function is to modify, sort, and package proteins along w/other materials from the ER for storage or transport out of the cell

29. Lysosomes:
Small organelles filled with enzymes used in digestion or for breaking down macromolecules to be used by the rest of the cell.
Also to break down organelles that have outlived their usefulness.
The “clean-up” crew

30. CYTOSKELETON
A network of protein filaments that help the cell maintain its shape and provide movement

31. Vacuoles
Saclike structures that store water, salts, proteins and carbohydrates.
Mainly found in plant cells, some single-celled organisms and some animal cells.

32. Plant Cell Smooth endoplasmic reticulum Vacuole Chloroplast Cell
Nuclear
envelope
Ribosome
(attached)
(free)
Smooth endoplasmic
reticulum
Nucleus
Rough endoplasmic reticulum
Nucleolus
Golgi apparatus
Mitochondrian
Cell wall
Cell
Membrane
Chloroplast
Vacuole

33. Cell Wall
The main function of the cell wall is to provide support and protection to plant cells.
Porous enough to allow water, O2 and CO2 to pass through easily.
Made mainly of cellulose.

34. Chloroplasts
Structures found in plant cells used to capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis.