1. Cellular Structure
SOL BIO 4.a-c

2. Cell Theory
The cell theory is the unifying theme in biology because it emphasizes the similarity of all living things.
All organisms are composed of one or more cells.
Cells are the smallest living units of all living organisms.
Cells arise only by division of a previously existing cell.

3. Cell Characteristics
Cells contain specialized structures to perform functions necessary for life.
Cellular activities necessary for life include chemical reactions that facilitate:
acquiring energy
reproduction
adaptation
maintaining homeostasis

4. Cell Characteristics All cells contain: Genetic material
single circular molecule of DNA in prokaryotes
double helix located in nucleus in eukaryotes
Cytoplasm jelly-like substance that fills the cells interior
Plasma membrane encloses the cell
– phospholipid bilayer
Phospholipids
Membrane
proteins

5. Cell Types
Cell structure is one of the ways in which organisms differ from each other.
2 Types of Cells
Prokaryote
Eukaryote

6. Prokaryotic Cells Earth’s first cells were prokaryotes.
The simplest life forms are the prokaryotes.
Prokaryotic cells exist in two major forms: eubacteria and archaebacteria.

7. Prokaryotic Cells
Prokaryotes are the Earth’s most abundant inhabitants. They can survive in a wide range of environments and obtain energy in a variety of ways.

8. Prokaryotic Cells
Prokaryotes are cells that lack a nucleus and membrane bound organelles.

9. Prokaryotic Cells Some use flagellum for locomotion
ALL are UNICELLULAR
Bacteria and related microorganisms are prokaryotes
Rotary
motor

10. Generalized Prokaryotic Cell

11. Eukaryote
Eukaryotes arose from prokaryotes and developed into larger more complex organisms.
Eukaryotes are cells that contain a nucleus and organelles surrounded by a membrane, such as mitochondria and chloroplasts.

12. Eukaryote Can be both unicellular or multi-cellular
Examples of eukaryotes are:
All fungus, plant, and animal cells

13. Generalized Eukaryotic Cell

14. Cell Size
Most cells are relatively small because as size increases, volume increases much more rapidly.
longer diffusion time

15. Visualizing Cells

16. Plant vs. Animal Cell
Cellular differences between plant and animal cells
Plants have:
a cell wall
Chloroplast
Large vacuole
Animal cells do not have these structures

17. Endosymbiosis Heterotrophic bacteria became mitochondria.
Endosymbiotic theory suggests that eukaryotes arose from a symbiotic relationship between various prokaryotes.
Heterotrophic bacteria became mitochondria.
Cyanobacteria became chloroplasts.
Host cell was a large eukaryotic cell.

18. Endosymbiosis Prokaryotic cell is engulfed Eukaryotic cell Symbiosis

19. Cell Differentiation
Cell specialization occurs during the development of a multi-cellular organism.
The genetic information necessary for all cellular functions remains in each cell but may not be used.

20. Nucleus Stores genetic material Contains DNA site where RNA is made
Nucleolus: Chromatin and ribosomal subunits
Nuclear envelope:
Double membrane with pores
Largest organelle
BRAIN of the cell – controls protein synthesis

21. Nucleus

22. Ribosomes
Ribosomes are RNA-protein complexes composed of two subunits that join and attach to messenger RNA.
site of protein synthesis
assembled in nucleolus

23. Ribosomes
They can be found alone in the cytoplasm or attached to the endoplasmic reticulum.
Alone in cytoplasm- makes proteins for use within the cell
Attached to RER- makes proteins for export out of the cell

24. Ribosomes

25. Endoplasmic reticulum
transports materials through the cell
Rough ER - studded with ribosomes
Attached to nuclear membrane
site of protein synthesis and processing
Smooth ER - lacks ribosomes
site of synthesis of phospholipids and the packaging of proteins into vesicles

26. Endoplasmic reticulum

27. Golgi apparatus collection of Golgi bodies Stacked flattened sacks
Site where cell products are packaged for export
Proteins are modified by being combined with fats or carbohydrates

28. Golgi apparatus
Vesicles then pinch off from the Golgi body to be secreted (outside the cell)
Involved in the production of lysosomes

29. Lysosomes vesicles produced by the Golgi apparatus.
Lysosomes contain digestive enzymes and are involved in intracellular digestion of food particles, disease causing bacteria and worn out cell parts

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31. Vacuoles Found in PLANT and ANMAL cells
The vacuole acts a container, storing water and dissolved particles
Plants have a large central vacuole for water storage
Unicellular animals can use contractile vacuoles for movement

32. Mitochondria "Powerhouse of the cell" - cellular metabolism
Structure- outer and inner membranes, cristae
Found in both plant and animal cells
Very active cells have more mitochondria

33. Chloroplasts
Chloroplasts are larger and more complex than mitochondria
Contain green pigment called chlorophyll that absorbs sunlight in the first step of photosynthesis
Found ONLY in PLANTS

34. Cell Membrane controls what enters and leaves the cell
Found in ALL cells
Phospholipid bilayer with transport proteins, and cholesterol (for flexibility)

35. Cell Wall provides support Found in PLANT and BACTERIA cells
Made from cellulose

36. Cytoskeleton
Long slender protein tubes and fibers that extend from the nucleus to the plasma membrane.
The cytoskeleton contains three types of elements responsible for cell shape, movement within the cell, and movement of the cell:
Actin filaments
Microtubules
Intermediate filaments

37. Centrioles Cylindrical structures found near the nucleus
Made of hollow, tubular structures arranged in bundles
Important in cell division
Found ONLY in ANIMAL cells

38. Endoplasmic reticulum
Plant vs. Animal Cells
PLANT CELL
ANIMAL CELL
Cell membrane
Mitochondria
Golgi apparatus
Nucleus
Cytoskeleton
Ribosomes
Endoplasmic reticulum
Lysosomes
HAVE:
Cell Wall
LARGE vacuoles
Chloroplasts
DO NOT HAVE:
Centrioles
HAVE:
Centrioles
DO NOT HAVE:
Cell Wall
LARGE vacuoles
Chloroplasts