1. Chapter 4: Structure and Function of the Cell
Essential Question: How do the cell structures vary with their functions?

2. I. Introduction to the cell
A. Discovery of cells was made possible by the development of the microscope
1. Robert Hooke in 1665 was the
first to call the “little boxes” he saw in
cork cells (dead plant cells)
2. Anton van Leeuwenhoek in 1673 was the
first to observe living cells

3. B. Cell theory
1. All living things are composed of one or more cells
2. Cells are the basic units of structure and function in an organism
3. Cells come only from the reproduction of existing cells

4. 4. Three German scientists showed evidence to support the theory
a) Matthias Schleiden: plant cells
b) Theodor Schwann: animal cells
c) Rudolf Virchow: cells come from cells
Timeline Cell Theory

5. II. Introduction to Cells
A. Size: Some cells are visible to see with your eyes, but most are only visible with a microscope
1. Most plant and animal cells are 10-50m (.002 in) in diameter and some bacteria cells are 0.2m ( in)
2. Cells are limited in size by the ratio between their outer surface area and their volume
3. If the cell grows larger, at some point its surface area becomes too small to allow nutrients to quickly enter the cell Demo

6. B. Shape: cells come in a variety of shapes and the shape reflects what function it performs
1. nerve cells: long extensions
2. skin cells: flat for covering the body
3. white blood cells can change shape

7. Basic Parts of a Cell
1. Plasma membrane: (cell membrane): outer boundary that covers a cell’s surface and acts as a barrier
2. Cytoplasm: region inside the plasma membrane that includes the fluid, cytoskeleton, and all organelles
a) cytosol: part of cytoplasm that contains molecules and small particles
3. Nucleus: membrane bound organelle that contains the cell’s genetic information and controls the cell parts of cell

8. D. Two types of cells
1. Eukaryotes: organisms whose cells contain a membrane- bound nucleus and other organelles
a) organelles: intracellular bodies that perform specific functions for the cell (little organs)
b) plants, animals, fungi and protists
c) multicellular and unicellular
d) larger and complex

9. 2. Prokaryotes: unicellular organisms that lack a membrane -bound nucleus and other organelles
a) simple
b) bacteria
Prokaryotes and eukaryotes

10. Prokaryotic and Eukaryotic Cells
Section 7-1
Cell membrane
Cytoplasm
Prokaryotic Cell
Nucleus
Eukaryotic Cell
Organelles
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12. E. Cellular organization
1. Colonies: collection of genetically identical cells that live together in a connected group
2. Multicellular organisms: cells are specialized and can not survive on their own
a) tissue: group of similar cells
b) organ: group of tissues that perform a certain function
c) organ system: group of organs that accomplish related tasks

13. Section 7- 4
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14. Review of Prokaryotes and Eukaryotes
Comparison Prezi

15. III. Cell Organelles and Features
A. Plasma or Cell membrane: thin membrane that controls which substance pass into and out of the cell
1. Selectively permeable: allows some substances to cross membrane and other substances cannot cross Selectively
2. Membrane lipids
a) Phospholipid: polar head (hydrophilic) and 2 nonpolar tails (hydrophobic)

16. b) Creates two layers called the phospholipid bilayer
c) Polar heads are toward the outside of the cell
d) Nonpolar tails are toward the interior
e) sterols: lipids that fit between the tails and make the membrane more firm Example: cholesterol

17. The Structure of the Cell Membrane
Section 7-3
Outside
of cell
Cell
membrane
Proteins
Protein
channel
Lipid bilayer
Carbohydrate
chains
Inside
of cell
(cytoplasm)
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18. 3. Membrane proteins
a) peripheral proteins: attach to the surface of cell membrane on interior and exterior surface
b) integral proteins: embedded in the bilayer and may have a carbohydrate attached that extends to the outside of the cell
i) act as channels or pores to move substance across membrane or to bind to substance to carry them across
Proteins

19. The Structure of the Cell Membrane
Section 7-3
Outside
of cell
Cell
membrane
Proteins
Protein
channel
Lipid bilayer
Carbohydrate
chains
Inside
of cell
(cytoplasm)
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20. 4. Fluid mosaic model: cell membrane behaves more like a fluid than a solid
a) proteins can move within the lipid bilayer
b) lipids and proteins in the membrane are constantly changing
Fluid mosaic

21. Nucleus
1. Large organelle near the center of the cell
2. Function: cell’s genetic information and controls activities of the cell
3. Nucleoplasm: jellylike liquid which holds the contents of the nucleus
4. Nuclear envelope (membrane): double membrane around the nucleus

22. 5. Chromatin: fine strands made of DNA and protein
6. Chromosomes: densely packed chromatin during division
7. Nuclear pores: small holes in the nuclear envelope that allows RNA to pass
8. Nucleolus: site where ribosomes are made and partially assembled
Nucleus

23. C. Mitochondria: makes energy (powerhouse of cell)
1. Function: site of chemical reactions that transfer energy from ATP
2. Inner and outer membranes
a) Cristae: folds in the inner membrane which increases the surface area so more reactions can take place
3. Mitochondria have their own DNA

25. D. Ribosomes: small, spherical organelle
1. Function: role in making proteins
2. Made of protein and RNA
3. Some ribosomes are free in the cytosol and make proteins used by the cytosol
4. Some ribosomes attach to the endoplasmic reticulum and make proteins for membrane or exported from the cell

26. E. Endoplasmic reticulum: ER
1. System of membranous tubules and sacs
2. Function: intracellular highway that moves molecules from one part of the cell to another
3. Rough ER: contains ribosomes
4. Smooth ER: no ribosomes, performs other functions depending on type of cell ER

27. F. Golgi apparatus
1. Function: processing, packaging, and secreting proteins
2. System of membranes or series of flattened sacs
3. Modifies proteins for export by the cell
Golgi

28. G. Vesicles: small, spherical sacs that perform various functions
1.Lysosomes: small and spherical with digestive enzymes produced by Golgi
a) Function: uses enzymes to digest proteins, carbohydrates, lipids, DNA, RNA, old organelles, bacteria
2. Peroxisomes: contain enzymes that breakdown alcohol, drugs, and fatty acids and they produce hydrogen peroxide

31. H. Cytoskeleton: network of long protein strands
1. Function: structure of the cell to maintain its shape and size and participates in the movement of organelles within the cytosol
2. Microfilaments: small threads made of a protein called actin and are used for cell movement and contraction of muscle cells
3. Microtubules: large strands of hollow tubes that group together during cell division, hold organelles in place, maintain cell shape, and act as tracks that guide organelles

32. Cytoskeleton Cell membrane Endoplasmic reticulum Microtubule
Section 7-2
Cell membrane
Endoplasmic
reticulum
Microtubule
Microfilament
Ribosomes
Michondrion
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33. 4. Cilia and Flagella
a) hairlike organelles that extend from the surface of the cell
b) assist in movement
c) cilia: short and occur in large numbers
d) flagella: long and less numerous
Cilia and Flagella

34. 5. Centrioles: two short cylinders of microtubules located near nuclear envelope
a) occur in animal cells only
b) organize microtubules during cell division

37. Unique Features of Plant Cells
A. Plant Cells: need three additional structures because they go through photosynthesis
B. Cell wall: rigid covering outside the cell membrane with pores
1. Supports and protects the plant
2. Made of cellulose

38. 3. Primary cell wall: when plant cell is forming
4. Secondary cell wall: when cell reaches its full size, a woody tough wall develops
Cell Wall

39. C. Central vacuoles: fluid-filled organelles that store enzymes and wastes
1. Large and can take up most of the cell
2. Separates toxic substance from the rest of the cell
Vacoule
D. Plastids: two membranes and contains DNA

40. 1. Chloroplast: type of plastid where photosynthesis occurs
a) thylakoids: flattened membranous sacs in the chloroplast
b) chlorophyll: green pigment that absorbs light
2. Chromoplasts: contain colorful pigments that may or may not take part in photosyntheis
( orange pigment in carrots)
Chloroplast

42. E. Comparing Cells
1. All cells share common features (cell membrane, cytoplasm, ribosomes, and genetic information)
2. Prokaryotes vs. Eukaryotes
a) Prokaryotes: lacks nucleus and organelles
b) Eukaryotes: nucleus and organelles

44. 3. Plant cells vs. Animal cells
a) Plants: 3 different features
important for plant function are
cell wall, central vacuole, plastids
b) Animal: do not need
these extra features