Cells
Chapter 5
Organelles With Their Structure
and Function
Organelles
•Tiny structures inside of
eukaryotic cells that
perform specialized jobs
•Similar to organs in the
human body
1. Cell Membrane
• Separates the cell from its environment
• Regulates what enters and leaves the cell
• “Selectively permeable”
– Only leaves certain substances into or
out of the cell
Structure of a cell
• Found in all cells
– Bacteria
– Plants
– Animals
– Fungi
– protists
membrane:
1. Phospholipid bilayer
2. Proteins which can be:
1. embedded (on surface)
2. Integral (all the way through)
Fluid Mosaic Model
2. Cell Wall
• Found outside of the cell membrane on
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Algae
Plants
Fungi
And some bacteria
• Support structure
• Non-living
• Parts
– Primary cell wall
• Made first and found on the very outside
– Secondary cell wall
• Made second and found between the primary cell
wall and the cell membrane
– Middle Lamella
• Gluey pectin that holds the cells together
Cell Wall
3. Nucleus
• Dark structure found inside all eukaryotic cells
• Contains all genetic material for the cell (DNA)
• Controls all cellular function with the DNA, therefore
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controls all function in the organism
Usually the largest organelle in the cell
Parts
– Nuclear membrane
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Boundary between the cell and the nucleus
Double phospholipid bilayer
Regulates what enters and leaves the nucleus
Contains pores
– Nucleolus
• Made of RNA and protein
• Makes ribosomes
– Chromosomes
• Genetic material (DNA)
Nucleus Structure
4. Mitochondria
• Inner and outer membrane
• Inner membrane is folded into “cristae”
• Takes food (sugar) and converts it into usable energy for
the cell (ATP)
• Process is called cellular respiration
• ATP
– Adenosine triphosphate
– Cellular energy
– Found in all cells
5. Chloroplast
• 2 membranes
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– Inner and outer
Found only in plants, algae and some protists
Captures light energy and makes food for the
plant
Contains chlorophyll (green pigment)
6. Cytoplasm
• Fluid between nucleus and cell membrane
• Contains the rest of the organelles
• Mostly water with the following materials
dissolved in it
– Food
– Wastes
– Pigments
– Electrolytes
cytoplasm
7. Ribosomes
• Make protein for the cell and the rest of the
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organism
Can be free floating in the cytoplasm
Can be attached to the endoplasmic reticulum
Made of 2 parts
– RNA
– Protein
Made in the nucleolus of the nucleus
8. Endoplasmic Reticulum (ER)
• Large complex network of canals that begins with the
nucleus and meanders through out the cell to the cell
membrane
• Rough ER
• Smooth ER
– Has no ribosomes on
the surface
– Move and store
• Chemicals
• lipids
– Has ribosomes
attached to the
surface
– Proteins made on the
ribosomes travel
through the rough er
– Highway system of the
cell
9. Golgi Apparatus (Body)
• Named after Camillo Golgi (discovered it)
• Looks like a stack of flattened pancakes
• Modify proteins that are made on the ribosomes
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on the rough ER
Modify carbohydrates and lipids being attached
to the proteins
Collects, packages and distributes proteins to
other cells
10. Lysosomes
• Contain digestive enzymes
• Digestion centers
– Food vacuoles join with lysosomes to digest the food inside of
them
• Clean up crews
– Break down old and broken organelles
Lysosome
11. Vacuoles
• Storage tanks for
– Water
– Proteins
– Salts
– Carbohydrates
– Wastes
– Simple membrane bound organelles
– Very large in plants
– Very small in animals
12. Plastids
• Store food and pigment
• Many varieties all found in plants
– Chloroplasts
– Leukoplasts- store starch granules
– Chromoplasts- store pigment molecules
13. Cytoskeleton
• Framework of the cell
• Filaments and fibers that give the cell
shape
– Microfilaments
•Long thin solid strands of protein
– Microtubules
•Long thicker hollow tubes of protein
14. Centrioles
• Found in animals only
• Used in cellular division to separate
chromosomes
15. Cilia
• Tiny hair-like projections that are in the surface
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of the cell membrane
Help cells to move
Made of microtubules
Many on one cell
May be found on tissues to move substances
along ex. mucus
16. Flagella
• Long- thread-like projection on the surface
of a cell
• Few on one cell
• Made of microtubules
• Helps cells move
17. Central Vacuole
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Large vacuole found in the center of most plant cells
Contains water
Keeps plant from wilting
Pushes against cell walls and helps give the cell its shape