Download Parts of a Cell - susanpittinaro

Cells
Types of Cells
prokaryotes
eukaryotes
organelles
also fungus &
protist cells
no organelles
plant cells
bacteria cells
animal cells
Cell size comparison
Animal cell
Bacterial cell
• Most bacteria
• 1-10 microns
• Eukaryotic cells
• 10-100 microns
micron = micrometer = 1/1,000,000 meter
diameter of human hair = ~20 microns
Why study cells?
• Cells  Tissues  Organs  Bodies
• Bodies are made of cells
• Cells do all the work for life
The work for life
• STERNGRR
• Synthesis: build molecules (carbs, lipids, proteins,
nucleic acids)
• Transport: move materials in/out & within the cell
• Excretion: remove wastes
• Respiration: gas exchange; make energy
• Nutrition: take in & digest food
• Grow & repair
• Regulation: control internal conditions (homeostasis)
• Reproduction: make more cells
• Respond to external environment
ATP
The main jobs of cells
• Cells have 3 main jobs:
• Make energy
ATP
• Need energy for all activities
• Need to clean up waste produced by energy
production
• Make proteins
• Proteins do all the work in the cell, so we need lots
of them
Our organelles do
of these
jobs?!
• All
Make
more
cells
AWESOME!!
• For growth
• For repair (replace damaged or diseased cells)
Parts of the Cell Theory
• All living things are made
of one or more cells
• Cells are the basic unit of
structure & function in
organisms
• Cells come only from the
reproduction of preexisting cells
Cell Scientists
• Robert Hooke
• looked at cork
under a
microscope
• 1st to use term
“cell”
Cell Scientists
• Anton van
Leeuwenhoek
• looked at pond
water
• 1st to see living
cells
• called them
“animalcules”
Cell Scientists
• Schleiden,
Schwann, &
Virchow
• came up with the
cell theory
Cell Scientists
• Schleiden
• 1838
• claimed plants
are made of
“independent,
separate beings”
called cells
Cell Scientists
• Schwann
• 1839
• claimed animals
are also made of
cells
Cell Scientists
• Virchow
• 1855
• stated that living
cells must come
from other living
cells
Cell Scientists
• Louis Pasteur
• 1860’s
• disproved
spontaneous
generation
The Cell Theory
Prokaryotic vs Eukaryotic Cells
Prokaryotic Cells
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Appeared 3.5 billion years ago
Primitive, simple
Small in size (less than 10 µm)
No membrane-bound organelles
DNA in cytosol (nucleoid region)
Single, circular chromosome
“Naked” DNA
Smaller ribosomes (70S)
BACTERIA
Eukaryotic Cells
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Appeared 1.5 billion years ago
Complex
More than 10 µm in size
Contain membranebound organelles
Larger ribosomes (80S)
Paired, linear chromosomes
DNA wrapped around histones
(proteins)
NUCLEUS
• Let’s draw a prokaryotic cell and label it ….
Prokaryotic reproduction
• Asexual =
binary fission
• Produces two
DNA Copies
identical daughter
cells
Cytokinesis
Clones!
Prokaryotic reproduction
• Sexual =
conjugation
• Uses conjugation
pili to exchange
plasmids
Parts of a
Eukaryotic Cell
Plasma Membrane
• Also called the
Cell Membrane
• Separates
cell from its
environment
Plasma Membrane
• Semipermeable
• Allows only
certain
molecules to
enter or exit
Plasma Membrane
• Phospholipid
Bilayer
• Embedded with
proteins
• Cholesterol is
embedded in
bilayer to help
membrane
fluidity
Nucleus
• “Boss” or
“Brain” of the
cell
• Controls cellular
activities
• Contains DNA
(chromosomes)
Nucleus
• Nuclear
Membrane
• Surrounds nucleus
• Double membrane
• Contains nuclear
pores (holes)
Nucleus
• Nucleolus
• Produces
ribosomes
• Ribosomes leave
through nuclear
pores
Cytoplasm
• Cytosol
• Fluid portion
• Organelles
• Membrane-bound
compartments that
carry out specific
functions
Mitochondria
• Breaks down glucose
to CREATE ENERGY
(ATP)
• Active cells (muscle) ->
hundreds of mitochondria
• Inactive cells (fat) -> few
mitochondria
• Have own DNA &
ribosomes
• Have a double
membrane
Ribosomes
large subunit
small
subunit
ribosome
• Create proteins
• Composed of 2
interlocking
subunits
• Some float free in
cytosol
• Some attach to the
ER
Endoplasmic Reticulum (ER)
• Intracellular
highway
• 2 Types
• Rough ER
• Smooth ER
Endoplasmic Reticulum (ER)
• Rough ER
• Covered in
ribosomes
• Transport and
develop proteins
• may be used in
membranes,
enzymes, and
cell
communication
Endoplasmic Reticulum (ER)
cisternal
space
polypeptide
signal
sequence
ribosome
ribosome
mRNA
Synthesizing proteins
membrane of
endoplasmic reticulum
cytoplasm
Endoplasmic Reticulum (ER)
• Smooth ER
• Lacks ribosomes
• Produces lipids,
estrogen, &
testosterone
• Helps detoxify
drugs & poisons
• Increased use =
increased smooth
ER
• Possibly linked to
increased tolerance
Endoplasmic Reticulum (ER)
Golgi Apparatus
• Transport
(FedEx/UPS of the
cell)
• Collects, packages,
modifies, and
distributes
materials made in
the cell
• Prevalent in cells that
secrete substances
nucleus
Vesicles
• Lysosomes
lysosomes
• Contain digestive
enzymes
• Digest organic
molecules, worn
organelles, or dying
cells
Vesicle transport
protein
vesicle
budding
from rough
ER
ribosome
migrating
transport
vesicle
fusion
of vesicle
with Golgi
apparatus
Vacuoles – Plant cells
• Central vacuole
• Large, fluid-filled
organelle
• Stores water, ions,
enzymes & waste
• Can be up to 90% of
cell’s volume
• Why so big in plants?
Vacuoles – Animal cells
• Food vacuoles
• Store and process
food
• Contractile
vacuoles
• Removes excess
water from cell
• Prevents cell from
exploding
Working together …
ER
vesicle
Golgi complex
vesicle
vesicle
vacuole
Centrosome
• Centrosome
• Assembles
microtubules
• May contain
centrioles
• Used during cell
division
Cilia/Flagella
• Cilia
• Hair-like
• Short &
numerous
• Flagella
• Tail-like
• Long & less
numerous
Plant Cell
versus
Animal Cell
Animal Cells Only!
• Cytoskeleton
• Network of
microtubules &
filaments
• Gives the cell
shape
• Holds organelles
in place
Plant Cells Only!
• Cell Wall
• Rigid layer
surrounding plasma
membrane
• Made of cellulose
• Pores allow water,
ions, & other
molecules to pass
• Bacteria (peptidoglycan), some
protists & fungi (chitin) also
have cell walls
Plant Cells Only!
• Chloroplast
• Contain chlorophyll
• Site of
photosynthesis
• Energy (sunlight)
 food
• Contain own DNA
& ribosomes
• Have a double
membrane
Any Questions??