cells types of cells prokaryotes no organelles bacteria cells eukaryotes organelles animal cells...
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Cells
Types of Cellsprokaryotes
no organellesbacteria cells
eukaryotesorganelles
animal cells
plant cells
also fungus & protist cells
Cell size comparison
• Most bacteria• 1-10 microns
• Eukaryotic cells• 10-100 microns
Bacterial cellAnimal cell
micron = micrometer = 1/1,000,000 meterdiameter of human hair = ~20 microns
Why study cells?
• Cells• Bodies are made of cells• Cells do all the work for life
Tissues Organs Bodies
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• 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
• Make more cells• For growth• For repair (replace damaged or diseased cells)
ATP
Our organelles doAll of these jobs?!
AWESOME!!
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 pre-existing 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• 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• Appeared 1.5 billion years ago• Complex• More than 10 µm in size• Contain membrane- bound 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
identical daughter cells
DNA Copies
Cytokinesis
Clones!
Prokaryotic reproduction
• Sexual = conjugation• Uses conjugation
pili to exchange plasmids
Parts of aEukaryotic Cell
Plasma Membrane• Also called the
Cell Membrane• Separates
cell from its environment
Plasma Membrane• Semi-
permeable• 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• Create proteins• Composed of 2
interlocking subunits
• Some float free in cytosol
• Some attach to the ERsmall
subunit
large subunit
ribosome
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)
cytoplasm
cisternalspace
mRNA
ribosome
membrane ofendoplasmic reticulum
polypeptide
signalsequence
ribosome
Synthesizing proteins
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)
• Transport (FedEx/UPS of the cell)
• Collects, packages, modifies, and distributes materials made in the cell
• Prevalent in cells that secrete substances
Golgi Apparatus
• Lysosomes• Contain digestive
enzymes• Digest organic
molecules, worn organelles, or dying cells
Vesicles
lysosomes
nucleus
Vesicle transport
vesiclebuddingfrom roughER
fusionof vesiclewith Golgiapparatus
migratingtransportvesicle
protein
ribosome
• 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 – Plant cells
• Food vacuoles• Store and process
food• Contractile
vacuoles• Removes excess
water from cell• Prevents cell from
exploding
Vacuoles – Animal cells
Working together …
vesicle
ER
vesicle
Golgi complex
vesicle
vacuole
• Centrosome• Assembles
microtubules• May contain
centrioles• Used during cell
division
Centrosome
• Cilia• Hair-like• Short &
numerous• Flagella
• Tail-like• Long & less
numerous
Cilia/Flagella
Plant Cellversus
Animal Cell
• Cytoskeleton• Network of
microtubules & filaments
• Gives the cell shape
• Holds organelles in place
Animal 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
Plant Cells Only!
Any Questions??
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