1 cell structure & function cells cells are the basic units of life. it is important to note...
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Cell Structure & FunctionCell Structure & Function
Cells• Cells are the basic units of life.
• It is important to note that each cell in your body is alive all on its own.
• The cell theory (which you should have learned about in grade 8), states 3 very important things that we need to be familiar with:
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Cell Theory
1. All living things are composed of cells.
2. Cells are the basic units of structure and function in living things.
3. All cells are produced from other cells.
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Basic Structure of a Cell
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First to View CellsFirst to View Cells• In 1665, Robert
Hooke used a microscope to examine a thin slice of cork (dead plant cells)
•What he saw looked like small boxes
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First to View CellsFirst to View Cells•Hooke is
responsible for naming cells
•Hooke called them “CELLS” because they looked like the small rooms that monks lived in called Cells 6
Anton van Leeuwenhoek• In 1674,
Leeuwenhoek (a Dutch microscope maker), was first to view organisms (living things)
• Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth
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History of Cells & the History of Cells & the Cell TheoryCell Theory
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VirchowCell
Specialization
Introduction to CellsIntroduction to CellsCells are the basic units of organisms
Basic types of cells:
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Bacterial Cell
Number of Cells
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Organisms may be:• Unicellular – composed of one cell• Multicellular- composed of many cells that may organize
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Cells May be Prokaryotic or Eukaryotic Prokaryotes include bacteria
& lack a nucleus or membrane-bound structures called organelles
Eukaryotes include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals)
Prokaryotes
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Nucleoid region contains the DNA
•Cell membrane & cell wall
• Contain ribosomes (no membrane) to make proteins in their cytoplasm
Eukaryotic Cell
Contain 3 basic cell structures:
•Nucleus•Cell Membrane•Cytoplasm with
organelles
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Two Main Types of Eukaryotic Cells
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Animal Cell
OrganelleOrganelless
• Very small size
• Can only be observed under a microscope
• Have specific functions
• Found throughout cytoplasm
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Control Organelle
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Controls the normal activities of the cell
Contain the DNABounded by a nuclear membrane
Contains chromosomes
Nucleus
More on the More on the NucleusNucleus
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Each cell has fixed number of chromosomes that carry genes
Genes control cell characteristics
Nucleus
Golgi Bodies• Stacks of Stacks of flattened flattened
sacssacs• Have a shipping side Have a shipping side
& a receiving side& a receiving side• Receive & Receive & modify modify
proteinsproteins made by ER made by ER• Transport vesiclesTransport vesicles
with modified with modified proteins pinch off proteins pinch off the endsthe ends
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Transport
vesicle
Lysosome• Contain digestive Contain digestive
enzymesenzymes• Break down food and Break down food and
worn out cell parts worn out cell parts for cells for cells
• Programmed for cell Programmed for cell death (lyse & release death (lyse & release enzymes to break enzymes to break down & recycle cell down & recycle cell parts)parts)
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Nucleolus• Cell may have Cell may have 1 1
to 3to 3 nucleoli nucleoli• Inside nucleusInside nucleus• DisappearsDisappears when when
cell dividescell divides• Makes ribosomesMakes ribosomes
that make that make proteinsproteins
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Smooth & Rough Endoplasmic Reticulum
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Smooth ER lacks ribosomes & makes proteins USED In the cell
Rough ER has ribosomes on its surface & makes proteins to EXPORT
Cell PowerhouseCell Powerhouse
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Rod shapeSite of Cellular respiration
Mitochondrion( mitochondria )
In Animal Cells:In Animal Cells:
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Active cells like muscles have more mitochondriaBurn sugars to produce energy ATP
Mitochondria
Surrounding the Surrounding the CellCell
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Lies immediately against the cell wall in plant cells
Made of protein and phospholipids
Selectively permeable
Cell membrane
Cell or Plasma Cell or Plasma MembraneMembrane
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Living layerControls the movement of materials into and out of the cell
Selectively permeable
Cell membrane
Cell WallCell Wall
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Nonliving layerGives structure and shape to plant and bacterial cells
Cell wall
Cytoplasm of a Cytoplasm of a Cell Cell
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Jelly-like substance enclosed by cell membrane
Provides a medium for chemical reactions to take place
Cytoplasm
More on More on CytoplasmCytoplasm
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Contains organelles to carry out specific jobs
Examples: chloroplast & mitochondrion
Cytoplasm
Plant Cell OrganellesPlant Cell Organelles
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Contain the green pigment chlorophyll
Traps sunlight to make to make sugars (food)
Process called photosynthesis
Chloropla
st
Plant CellPlant Cell
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Dead layerLarge empty spaces present between cellulose fibers
Freely permeable
Cell wall
Plant CellPlant Cell
Made of cellulose which forms very thin fibers
Strong and rigidFound in plant cells
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Cell wall
Plant CellPlant Cell
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Protect and support the enclosed substances (protoplasm)
Resist entry of excess water into the cell
Give shape to the cell
Cell wall
Plant Cell OrganellesPlant Cell Organelles
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Have a large central vacuole
Surrounded by tonoplast
Contains cell sapSugars, proteins,
minerals, wastes, & pigments
Vacuole
Different kinds of Different kinds of plant cellsplant cells
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Onion Epidermal Cells
Root Hair Cell
root hair
Guard Cells
Animal cellAnimal cell
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mitochondrion
nucleus
glycogen granule
cell membrane
cytoplasm
No cell wall or chloroplastStores glycogen in the cytoplasm for food energy
vacuole
Animal Cell OrganellesAnimal Cell Organelles
•Near the nucleus•Paired structures•Help cell divide
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Different kinds of Different kinds of animal cellsanimal cells
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white blood cell
red blood cell
cheek cells
sperm
nerve cell
muscle cell
Amoeba
Paramecium
Similarities between Similarities between plant cells and animal plant cells and animal
cellscellsBoth have a cell membrane surrounding the cytoplasm
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Both have a nucleus
Both contain mitochondria
Differences between Differences between plant cells and animal plant cells and animal
cellscells
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Animal cells Plant cells
Relatively smaller in
sizeIrregular shape
No cell wall
Relatively larger in size
Regular shapeCell wall present
Differences between Plant Differences between Plant Cells and Animal CellsCells and Animal Cells
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Animal cells Plant cells
Vacuole small or absent
Glycogen as food storage
Nucleus at the center
Large central vacuole
Starch as food storage
Nucleus near cell wall