1. Cells
Chapter 4
p.57-82

2. Chapter 4 Outline - Cells
Biology, 9th ed,Sylvia Mader
Chapter 04
Chapter 4 Outline - Cells
Cell Theory
Cell Size
Prokaryotic Cells
Eukaryotic Cells
Organelles
Nucleus
Endomembrane System
Cytoskeleton
Centrioles, Cilia, and Flagella
Cell Structure and Function

3. Biology, 9th ed,Sylvia Mader
Chapter 04
Cell Theory
Originated from the work of biologists in 1838 and 1850
States that:
All organisms are composed of cells
All cells come only from preexisting cells
Smallest unit of life
Cell Structure and Function

4. Biology, 9th ed,Sylvia Mader
Chapter 04
Sizes of Living Things
Cell Structure and Function

5. Figure 4A
Figure 4A

6. Microscopy and Cheek Cells
Biology, 9th ed,Sylvia Mader
Chapter 04
Microscopy and Cheek Cells
Cell Structure and Function

7. Biology, 9th ed,Sylvia Mader
Chapter 04
Cell Size
Most much smaller than one millimeter (mm)
Some as small as one micrometer (mm)
Size restricted by Surface/Volume (S/V) ratio
Surface is membrane, across which cell acquires nutrients and expels wastes
Volume is living cytoplasm, which demands nutrients and produces wastes
As cell grows, volume increases faster than surface
Cells specialized in absorption modified to greatly increase surface area per unit volume
Cell Structure and Function

8. Prokaryotic Cells:Domains
Biology, 9th ed,Sylvia Mader
Chapter 04
Prokaryotic Cells:Domains
Lack a membrane-bound nucleus
Structurally simple
Two domains:
Bacteria
Three Shapes
Bacillus (rod)
Coccus (spherical)
Spirilla (spiral)
Archaea
Live in extreme habitats
Cell Structure and Function

9. Shapes of Bacterial Cells
Biology, 9th ed,Sylvia Mader
Chapter 04
Shapes of Bacterial Cells
Cell Structure and Function

10. Prokaryotic Cells: Visual Summary
Biology, 9th ed,Sylvia Mader
Chapter 04
Prokaryotic Cells: Visual Summary
Cell Structure and Function

11. Prokaryotic Cells:The Envelope
Biology, 9th ed,Sylvia Mader
Chapter 04
Prokaryotic Cells:The Envelope
Cell Envelopes
Glycocalyx
Layer of polysaccharides outside cell wall
May be slimy and easily removed, or
Well organized and resistant to removal (capsule)
Cell wall
Plasma membrane
Like in eukaryotes
Form internal pouches (mesosomes)
Cell Structure and Function

12. Prokaryotic Cells:Cytoplasm & Appendages
Biology, 9th ed,Sylvia Mader
Chapter 04
Prokaryotic Cells:Cytoplasm & Appendages
Cytoplasm
Semifluid solution
Bounded by plasma membrane
Contains inclusion bodies – Stored granules of various substances
Appendages
Flagella – Provide motility
Fimbriae – small, bristle-like fibers that sprout from the cell surface
Sex pili – rigid tubular structures used to pass DNA from cell to cell
Cell Structure and Function

13. Biology, 9th ed,Sylvia Mader
Chapter 04
Eukaryotic Cells
Domain Eukarya
Protists
Fungi
Plants
Animals
Cells contain:
Membrane-bound nucleus
Specialized organelles
Plasma membrane
Cell Structure and Function

14. Eukaryotic Cells :Organelles
Biology, 9th ed,Sylvia Mader
Chapter 04
Eukaryotic Cells :Organelles
Compartmentalization:
Allows eukaryotic cells to be larger than prokaryotic cells
Isolates reactions from others
Two classes:
Endomembrane system:
Organelles that communicate with one another
via membrane channels
Via small vesicles
Energy related organelles
Mitochondria & chloroplasts
Basically independent & self-sufficient
Cell Structure and Function

15. Hypothesized Origin of Eukaryotic Cells
Biology, 9th ed,Sylvia Mader
Chapter 04
Hypothesized Origin of Eukaryotic Cells
Cell Structure and Function

16. Figure 4.6a
Figure 4.6a

17. Figure 4.7a
Figure 4.7a

18. Biology, 9th ed,Sylvia Mader
Chapter 04
Nucleus
Command center of cell, usually near center
Separated from cytoplasm by nuclear envelope
Consists of double layer of membrane
Nuclear pores permit exchange between nucleoplasm & cytoplasm
Contains chromatin in semifluid nucleoplasm
Chromatin contains DNA of genes
Condenses to form chromosomes
Dark nucleolus composed of rRNA
Produces subunits of ribosomes
Cell Structure and Function

19. Biology, 9th ed,Sylvia Mader
Chapter 04
Anatomy of the Nucleus
Cell Structure and Function

20. Biology, 9th ed,Sylvia Mader
Chapter 04
Ribosomes
Serve in protein synthesis
Composed of rRNA
Consists of a large subunit and a small subunit
Subunits made in nucleolus
May be located:
On the endoplasmic reticulum (thereby making it “rough”), or
Free in the cytoplasm, either singly or in groups called polyribosomes
Cell Structure and Function

21. Biology, 9th ed,Sylvia Mader
Chapter 04
Endomembrane System
Restrict enzymatic reactions to specific compartments within cell
Consists of:
Nuclear envelope
Membranes of endoplasmic reticulum
Golgi apparatus
Vesicles
Several types
Transport materials between organelles of system
Cell Structure and Function

22. Endomembrane System: The Endoplasmic Reticulum
Biology, 9th ed,Sylvia Mader
Endomembrane System: The Endoplasmic Reticulum
Chapter 04
Rough ER
Studded with ribosomes on cytoplasmic side
Protein anabolism
Synthesizes proteins
Modifies proteins
Adds sugar to protein
Results in glycoproteins
Smooth ER
No ribosomes
Synthesis of lipids
Cell Structure and Function

23. Biology, 9th ed,Sylvia Mader
Chapter 04
Peroxisomes
Similar to lysosomes
Membrane-bounded vesicles
Enclose enzymes
However
Enzymes synthesized by free ribosomes in cytoplasm (instead of ER)
Active in lipid metabolism
Catalyze reactions that produce hydrogen peroxide H2O2
Toxic
Broken down to water & O2 by catalase
Cell Structure and Function

24. Biology, 9th ed,Sylvia Mader
Chapter 04
Vacuoles
Membranous sacs that are larger than vesicles
Store materials that occur in excess
Others very specialized (contractile vacuole)
Plants cells typically have a central vacuole
Up to 90% volume of some cells
Functions in:
Storage of water, nutrients, pigments, and waste products
Development of turgor pressure
Some functions performed by lysosomes in other eukaryotes
Cell Structure and Function

25. Energy-Related Organelles: Chloroplast Structure
Biology, 9th ed,Sylvia Mader
Energy-Related Organelles: Chloroplast Structure
Chapter 04
Bounded by double membrane
Inner membrane infolded
Forms disc-like thylakoids, which are stacked to form grana
Suspended in semi-fluid stroma
Green due to chlorophyll
Green photosynthetic pigment
Found ONLY in inner membranes of chloroplast
Cell Structure and Function

26. Energy-Related Organelles: Chloroplasts
Biology, 9th ed,Sylvia Mader
Energy-Related Organelles: Chloroplasts
Chapter 04
Captures light energy to drive cellular machinery
Photosynthesis
Synthesizes carbohydrates from CO2 & H2O
Makes own food using CO2 as only carbon source
Energy-poor compounds converted to enery rich compounds
Cell Structure and Function

27. Energy-Related Organelles: Chloroplast Structure
Biology, 9th ed,Sylvia Mader
Energy-Related Organelles: Chloroplast Structure
Chapter 04
Cell Structure and Function

28. Energy-Related Organelles: Mitochondria
Biology, 9th ed,Sylvia Mader
Chapter 04
Energy-Related Organelles: Mitochondria
Bounded by double membrane
Cristae – Infoldings of inner membrane that encloses matrix
Matrix – Inner semifluid containing respiratory enzymes
Involved in cellular respiration
Produce most of ATP utilized by the cell
Cell Structure and Function

29. Energy-Related Organelles: Mitochondrial Structure
Biology, 9th ed,Sylvia Mader
Energy-Related Organelles: Mitochondrial Structure
Chapter 04
Cell Structure and Function

30. Biology, 9th ed,Sylvia Mader
Chapter 04
The Cytoskeleton
Maintains cell shape
Assists in movement of cell and organelles
Three types of macromolecular fibers
Actin Filaments
Intermediate Filaments
Microtubules
Assemble and disassemble as needed
Cell Structure and Function

31. Figure 4.18
Figure 4.18

32. Microtubular Arrays:Centrioles
Biology, 9th ed,Sylvia Mader
Chapter 04
Microtubular Arrays:Centrioles
Short, hollow cylinders
Composed of 27 microtubules
Microtubules arranged into 9 overlapping triplets
One pair per animal cell
Located in centrosome of animal cells
Oriented at right angles to each other
Separate during mitosis to determine plane of division
May give rise to basal bodies of cilia and flagella
Cell Structure and Function

33. Microtubular arrays: Cilia and Flagella
Biology, 9th ed,Sylvia Mader
Chapter 04
Microtubular arrays: Cilia and Flagella
Hair-like projections from cell surface that aid in cell movement
Very different from prokaryote flagella
Outer covering of plasma membrane
Inside this is a cylinder of 18 microtubules arranged in 9 pairs
In center are two single microtubules
This pattern used by all cilia & flagella
In eukaryotes, cilia are much shorter than flagella
Cilia move in coordinated waves like oars
Flagella move like a propeller or cork screw
Cell Structure and Function

34. Table 4.1
Table 4.1

35. Chapter review assignment
Complete the Testing Yourself section of the chapter review on page (#1-15)
Discuss the bioethical issue about stem cells.
Find all vocabulary words in your notes.
If a word was not defined in the notes, define it here.
Answer the matching questions a. – e.