1. Chapter 5: Cell structure & function
Unit 4 cells: the basic theory of life

2. Section 5-2: the cell structure
Name the 3 structures common to most cells.
Discuss the structure & function of the nucleus.
Distinguish between the cell membrane & the cell wall in both structure & function.
Vocabulary: cell membrane, cell wall, nucleus, eukaryote, prokaryote, nuclear envelope, nucleolus, chromosome, cytoplasm
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Biology: Cell Structure & Function

3. Biology: Cell Structure & Function
cells vary in shape & size
structures common to most cells:
cell membrane
outer boundary of cell
nucleus (only in eukaryotes)
control center
cytoplasm
material between cell
membrane & nucleus
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Biology: Cell Structure & Function

4. Cell Structure: cell Membrane
cell (plasma) membrane cell structure that regulates passage of materials between cell & its environment; aid in protection & support of cell
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Biology: Cell Structure & Function

5. Cell Structure: cell Membrane
cell (plasma) membrane cell structure that regulates passage of materials between cell & its environment; aid in protection & support of cell
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Biology: Cell Structure & Function

6. Cell Structure: cell Membrane
composed of several organic molecules
lipids - double layer of lipid molecules (bilayer) forms basic unit from which cell membrane is constructed
proteins - stick to surface of lipid bilayer. Others free to move around within layer. Some free-moving act as channel through which molecules can pass. Others act like pumps, actively pushing molecules from one side of membrane to other.
carbohydrates - attached to proteins or lipids at membrane surface. Many act like chemical identification cards, allowing cells to recognize & interact with each other.
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Biology: Cell Structure & Function

7. Cell Structure: cell wall
cell wall – cell structure that surrounds cell membrane for protection & support in plants, algae, fungi & some bacteria
very porous - water, oxygen, CO2, & other substances pass through easily
cell wall – surrounds plasma membrane of cell in plants, bacteria, & fungi
Plant cell walls contain cellulose while fungi cell walls contain chitin.
Picture of Lily Parenchyma cell. The cell wall which provides a rigid structure is in green. Copyright Daniel Kunkel
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Biology: Cell Structure & Function

8. Cell Structure: Nucleus
nucleus - organelle that controls the cell’s activities & contains DNA
Transmission electron micrograph of a thin section of a rat liver cell nucleus.
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Biology: Cell Structure & Function

9. Cell Structure: Nucleus
parts of nucleus:
nuclear envelope - 2 membranes that surround nucleus of a cell
nucleolus - cell structure that contains RNA & proteins; where ribosomes are made
chromosomes - threadlike structure
in a cell that contains genetic
information that is passed on from
one generation of cells to the next
chromatin – long, tangled strands of DNA
Transmission electron micrograph of a thin section of a rat liver cell nucleus.
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Biology: Cell Structure & Function

10. Cell Structure: Nucleus
Transmission electron micrograph of a thin section of a rat liver cell nucleus.
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Biology: Cell Structure & Function

11. Cell Structure: Nucleus
Transmission electron micrograph of a thin section of a rat liver cell nucleus.
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Biology: Cell Structure & Function

12. Cell Structure: cytoplasm
cytoplasm – (jelly-like) area between nucleus & cell membrane of a cell
surrounds
organelles
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Biology: Cell Structure & Function

13. Cell structure REVIEW QUESTIONS
Distinguish between prokaryotes & eukaryotes. Why is this distinction important?
What are the 3 basic structures found in most cells?
What is the function of the cell membrane?
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Biology: Cell Structure & Function

14. Chapter 5: Cell structure & function
Unit 4 cells: the basic theory of life

15. Section 5-3: Cytoplasmic organelles
Define organelle.
Compare the functions of the mitochondria & chloroplasts.
Discuss the function of the two types of endoplasmic reticulum.
Name the two major components of the cytoskeleton & discuss their importance.
Vocabulary: organelle, mitochondrion, chloroplast, ribosome, endoplasmic reticulum, Golgi apparatus, lysosome, vacuole, plastid, cytoskeleton
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Biology: Cell Structure & Function

16. Biology: Cell Structure & Function
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Biology: Cell Structure & Function

17. Cytoplasmic organelles
organelle – tiny cell structure that performs a specialized function
within the cell
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Biology: Cell Structure & Function

18. Cytoplasmic organelles
cellular activities necessary for life include chemical reactions that facilitate:
acquiring energy
reproduction
adaptation
maintaining homeostasis
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Biology: Cell Structure & Function

19. Cytoplasmic organelles: Mitochondria & Chloroplasts
“Power Stations” - change energy from 1 form to another
mitochondria – organelle that changes chemical energy stored in food into compounds that can be used by the cell
2 membranes – inner membrane increases surface area
cristae – internal compartments formed by inner membrane
chloroplast – organelle that converts sunlight into chemical energy in plants & algae
3 membranes – 3rd sun’s radiant energy  chemical energy
contains chlorophyll – green pigment that traps light energy
chloroplast are larger & more complex than mitochondria.
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Biology: Cell Structure & Function

20. Cytoplasmic organelles: Mitochondria & Chloroplasts
chloroplast - site of photosynthesis
mitochondria - site of cellular respiration
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Biology: Cell Structure & Function

21. Cytoplasmic organelles: ribosomes
“Protein Factories”
ribosomes – organelles in which proteins are made
smallest of organelles
assembled in nucleolus
composed of RNA & protein
some attached to membranes
while others free in cytoplasm
free in cytoplasm: makes proteins for use w/in cell
attached to RER- makes proteins for export out of cell
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Biology: Cell Structure & Function

22. Cytoplasmic organelles: Endoplasmic reticulum & Golgi Apparatus
“Manufactures & Shippers”
endoplasmic reticulum – complex network that transports materials throughout the inside of a cell
2 types: smooth & rough
smooth - storage of special enzymes & chemicals; contains enzymes for phospholipid synthesis
rough – involved in synthesis of proteins (ribosomes stuck to it)
Golgi apparatus – organelle that modifies, collects, packages, & distributes molecules made at one location of the cell & used at another
newly made lipids & proteins from E.R. repackaged &
shipped to plasma membrane
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Biology: Cell Structure & Function

23. Cytoplasmic organelles: Endoplasmic Reticulum
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Biology: Cell Structure & Function

24. Cytoplasmic organelles: Endoplasmic Reticulum
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Biology: Cell Structure & Function

25. Cytoplasmic organelles: Endoplasmic Reticulum
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Biology: Cell Structure & Function

26. Cytoplasmic organelles: Golgi Apparatus
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Biology: Cell Structure & Function

27. Cytoplasmic organelles: RER & Golgi Apparatus
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Biology: Cell Structure & Function

28. Cytoplasmic organelles: Lysosomes
“Cleanup Crews” (& Storage)
lysosome – organelle that contains chemicals & enzymes necessary for digesting certain materials in the cell
not found in plant cells
removes junk (i.e. organelles that have outlived their usefulness) that might accumulate & clutter the cell
can fuse with vacuoles to digest food or worn cell parts
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Biology: Cell Structure & Function

29. Cytoplasmic organelles: Vacuoles & Plastids
“Storage Tanks”
vacuole – organelle that stores materials such as water, salts, proteins, and carbohydrates
stores food, fluid, waste products
plants have a large central vacuole for water storage
unicellular animals can use contractile vacuoles for movement
plastid – plant cell organelle involved in storage of food and pigments
can take many forms (like chloroplast)
i.e. leukoplasts ( store starch granules) & chromoplasts (store pigment molecules)
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Biology: Cell Structure & Function

30. Cytoplasmic organelles: Cytoskeleton
“Framework” (& attached locomotion structures)
cytoskeleton – framework of the cell composed of a variety of filaments & fibers that support cell structure and drive cell movement
composed of a variety of filaments & fibers that support cell structure & drive cell movement.
microtubules (hollow tubes made of proteins) – support, move organelles through cell, role in cell division by forming centrioles (animal & eukaryotic cells but not in plants)
cilia & flagella – help move
microfilaments – (solid filaments of protein) movement & support of cell
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Biology: Cell Structure & Function

31. Cytoplasmic organelles: cytoskeeton
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Biology: Cell Structure & Function

32. Cytoplasmic organelles: Cytoskeleton
Cell Division
centrioles
play role in cell division (splitting of cell into 2 cells)
found in animal and fungi cells
made of hollow, tubular structures arranged in bundles
composed of protein
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Biology: Cell Structure & Function

35. Cytoplasmic organelles REVIEW QUESTIONS
What are organelles? Give 2 examples of organelles.
How do lysosomes function to digest particles?
Compare mitochondria & chloroplasts.
What components make up the cytoskeleton?
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Biology: Cell Structure & Function