Transcript Chapter 3 The Basic Structure of a Cell

Cell or Plasma Membrane
Living layer
Cell membrane
Controls the movement
of materials into and
out of the cell
Selectively permeable
1
Cell Wall
Cell wall
Nonliving layer
Gives structure and
shape to plant and
bacterial cells
2
Organelles
• Very small (microscopic)
• Perform various functions for a cell
• Found in the cytoplasm
• May or may not be membrane-bound
3
Animal Cell Organelles
Nucleolus
Nucleus
Nuclear envelope
Rough
endoplasmic
reticulum
Golgi apparatus
Ribosome (attached)
Ribosome (free)
Cell Membrane
Mitochondrion
Smooth
endoplasmic
reticulum
Centrioles
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Plant Cell Organelles
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Cellular Structure
• Cytoplasm
cytoplasm
-Jelly-like substance
enclosed by cell membrane
-Provides a medium for
chemical reactions to take
place
• Cytoskeleton
-Cellular
framework made
of microtubules and
microfilaments
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Nucleus
• Controls the normal
activities of the cell
• Contains the DNA in
chromosomes
• Bounded by a double layer
nuclear envelope
(membrane) with pores
• Usually the largest organelle
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Nucleolus
• Inside nucleus
• Cell may have 1 to
3 nucleoli
• Disappears when
cell divides
• Makes ribosomes
that make proteins
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Ribosomes
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•
•
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Made of PROTEINS and rRNA
“Protein factories” for cell
Connect amino acids to make proteins
Process called protein synthesis

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Endoplasmic Reticulum - ER
• Network of hollow membrane tubules
• Connects to nuclear envelope & cell
membrane
• Functions in Synthesis of cell products &
Transport
Two kinds of ER ---ROUGH & SMOOTH
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Smooth & Rough
Endoplasmic Reticulum
Smooth ER lacks
ribosomes & makes
proteins USED In
the cell
Rough ER has
ribosomes on its
surface & makes
proteins to EXPORT
OUT of the cell
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Golgi Bodies
• Stacks of flattened
sacs
• Have a shipping side &
a receiving side
• Receive & modify
proteins made by ER
• Transport vesicles
with modified proteins
pinch off the ends
Transport
vesicle
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Lysosomes
• Contain digestive
enzymes
• Break down food,
bacteria, and worn out
cell parts for cells
• Lyse & release
enzymes to break down
& recycle cell parts)
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Vacuoles
• Fluid filled
sacks for
storage
• Small or absent
in animal cells
• Plant cells have
a large Central
Vacuole
• No vacuoles in
bacterial cells
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Mitochondria
• “Powerhouse” of the cell
• Generate cellular energy (ATP)
• More active cells like muscle
cells have MORE mitochondria
• Both plants & animal cells have
mitochondria
• Site of CELLULAR
RESPIRATION (burning
glucose)
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Mitochondria
Surrounded by a DOUBLE
membrane
Has its own DNA
Folded inner membrane
increases surface area
for more chemical
Reactions
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Chloroplasts
• Found only in producers
(organisms containing
chlorophyll)
• Use energy from
sunlight to make own
food (glucose)
• Energy from sun
stored in the Chemical
Bonds of Sugars
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Chloroplasts
• Surrounded by double
membrane
• Contains its own DNA
• Contains enzymes &
pigments for
Photosynthesis
• Never in animal or
bacterial cells
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Cilia & Flagella
• Cilia are shorter
and more
numerous on
cells
• Flagella are
longer and fewer
(usually 1-3) on
cells
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Cell Movement with
Cilia & Flagella
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