Transcript PARTS of a CELL

7-2 and 7-3: Plasma Membrane and
Cell Structures
Plasma
Membrane of
aveolar sac
But first...
Let’s Review
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What is cell theory?
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Light microscopes vs. electron microscopes
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Prokaryotic vs. eukaryotic
Basic Cell Structures
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Cell Membrane
Cell Wall
Nucleus
Cytoplasm
VOCABULARY
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Chromatin
Chromosome
Nucleolus
Nuclear envelope
Cytoskeleton
Microtubule
Microfilament
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Endoplasmic Reticulum
Golgi Apparatus
Lysosome
Vacuole
Chloroplast
Mitochondrion
Ribosome
Plasma Membrane
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Boundary between cell
and environment
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Allows for nutrients to
enter and exit cell
Maintains cell’s
homeostasis
Nerve cell plasma membrane
How does plasma membrane maintain
homeostasis?
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Selective permeability
 Allows
certain molecules in while keeping others out
 Water usually enters/exits cells freely
 Ion (e.g. Ca and Na) allowed in at certain times
Structure of PM
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Composed of 2 layers
of phospholipids (oh
no…not again!)
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Phospholipids
 Hydrophilic
head (outside/inside of cell)
 Hydrophobic tail (inside of membrane)
 These form a barrier and do not allow water-soluble
molecules to pass through
Fluid mosaic
Thin flexible layer
What else is in the plasma membrane?
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Cholesterol
 Aids
in phospholipid stability by preventing them to
stick together
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Proteins
 Transport
 Help
 Cell
proteins
with allowing nutrients come in and wastes exit cell
identification
 Cell structure and support
Cytoplasm
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Cytoplasm
Material inside the cell
membrane but not
including the nucleus
Cell Wall
in some cells, including plants,
algae, fungi, and nearly all prokaryotes (NOT
animal cells)
Found
Surrounds
the cell
membrane (allows water
and gases to pass
through)
Provides support and
protection for the cell
Nucleus
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Nucleus (pl. Nuclei)
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Large structure that
contains the genetic
information (DNA) and
controls the cell’s activities
DNA contains the instructions for
making proteins
*the nucleus is important because making
proteins is one of the main functions of
cells
Protein Synthesis
CHROMATIN &
CHROMOSOMES:
Chromatin: DNA chain wound
around a protein visible DNA
(looks granular—is spread
throughout the nucleus)
Chromosomes: when a cell
divides, chromatin continues to
condense into these structures
these are distinct
structures
NUCLEOLUS:
•Dense region inside most nuclei
(looks darker)
•Ribosome assembly begins here
NUCLEAR ENVELOPE:
•Double-membrane layer which surrounds
nucleus
•Thousands of pores allow material into and out of
the nucleus
Nucleus
Cytoskeleton
Network of protein filaments that helps the cell
maintain shape & move around
Help in cell division!!!
Ribosomes
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Ribosomes are made of
RNA & protein
Proteins are assembled
(made) here
Proteins are produced
following the specific
code in DNA
ENDOPLASMIC RETICULUM (ER):
•Some proteins are modified
•Components of the cell membrane are assembled
ROUGH ER: ribosomes on the ER make
proteins & these new proteins move into the
ER where they may be chemically modified
SMOOTH ER: no ribosomes; contains
specialized enzymes that perform specific
tasks (ex: make lipids)
WWWhat’s
W
missing??
Real Picture…
“Fake” Picture
GOLGI APPARATUS:
• Proteins produced by Rough ER ribosomes
move into these sac-like structures
• Enzymes attach carbohydrates & lipids to
the proteins
• These proteins are then sent to their final
destination
Lysosomes
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Filled with digestive
enzymes: break down
carbo’s, lipids, &
proteins for use by
cell
Break down old cells
Vacuoles
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Store materials like
water, salts, proteins,
& carbo’s for the cell
Large central vacuole
in plants is the reason
plants are rigid!
•PLANTS ONLY!
•Use energy from sun to make
glucose (photosynthesis)
•Visible stacks of membranes
Mitochondria
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Release energy from
food—cell uses that
energy to power
growth, movement,
etc.
Cilia and Flagella
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Aid in locomotion or
feeding