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Cell Structure & Function
Cell Theory1. All living things are made of cells2. Cells are the basic unit of life3. All cells come from pre-existing
cells
What do all cells have in common?
1.Genetic information (DNA)
2.Cytoplasm – fluid-filled region between center and cell membrane
What do all cells have in common?3. Cell membrane (plasma membrane) – surrounds cell
◦ Function: regulates what enters and leaves cell
4. Ribosomes – make proteins using instructions from DNA
Surface Area to Volume Ratio•Why are cells so small?•Ratio of surface area to volume •Much greater for small cells
•Space is important for cells to receive nutrients, oxygen, and to remove waste•Volume increases faster than surface area as cells grow•Greater volume= more metabolic reactions BUT more difficult to transport wastes and nutrients•The smaller the cell, the more efficient it is to transport materials across it
Organisms can be:
o Unicellularo Consist of only 1 cell
o Multicellularo Consist of multiple cells
PROKARYOTIC EUKARYOTIC
2 Basic Cell Types
•Smaller/unicellular•Simple•No organelles•No nucleus•Ex: Bacteria
Prokaryotic
Eukaryotic•Larger-multi or unicellular•More complex•Many organelles • Structures that have a
specific function; “mini-organs”
•Nucleus – encloses DNA•Control center of the cell
EukaryoticoEx: Plants, animals, fungi, protistsoUnicellular eukaryotes = Protists
Unicellular Eukaryote
Amoeba
Paramecium
Dinoflagellates
ProtistsWhy are protists eukaryotes if they are only made up of ONE cell?
Prokaryote vs. Eukaryote-What is different between the two types of cells?
Prokaryotes•Simple internal structure•Nucleoid Region (no nucleus)•Flagellum → whip-like tail used for movement
ProkaryotesoPili – short projects that help bacteria attach to surfaces
oMost primitive organisms
Bacteria
E. Coli Strepococcus mutans
Bacteria
Mycobacterium tuberculosisStaphylococcus aureus
Cell Organelles and Functions EUKARYOTIC CELLS INTERNAL STRUCTURE
Eukaryotes
CAN BE SPLIT INTO PLANT AND ANIMAL CELLS
Animal Cell
Animal Cell
Plant cell
Nucleus oFunction: Control center of the celloEukaryotic cells ONLY!!!
Nucleus 3 parts: ◦1.Contains DNA◦A. Chromosome – DNA coiled around proteins called histones◦Humans contain 46 chromosomes in nucleus of all cells ◦ Exceptions: Red blood cells (no nucleus), sex cells
◦B. Chromatin – uncoiled DNA; DNA usually found in this form
Nucleus 2. Nuclear envelope (nuclear membrane) – membrane w/ pores to allow materials in and out of the nucleus
3. Nucleolus – inside the nucleus; makes ribosomes
CytoplasmoOrganelles can be found in the cytoplasmoCytoplasm- portion of the cell outside of the nucleus
Endoplasmic Reticulum(ER) Folded membranes attached to nucleus Smooth ER →
◦Not lined with ribosomes
◦Synthesizes lipids◦Detoxifies chemicals (i.e. liver)
Rough ER◦Lined with ribosomes◦Function: Modifies proteins that are being transported
Ribosomes- made of RNA & protein- Function: Assemble proteins
based on instructions from DNA
C4U Difference between Rough and smooth ER
What are ribosomes? Where can they be found?
Golgi apparatus (golgi body)
Looks like a flattened stack of pancakes Functions:
◦Receives vesicles (sacs) from the ER and finishes, sorts, and ships protein
◦“Packages protein”
One side = receiving; other side = shipping
Lysosomes•Lysosome – Function: Contains powerful digestive enzymes•Digests food particles to release nutrients to cell
Fun Fact enzyme in lysosome destroys skin between fingers/toes during embryo development
Lysosomes◦“Demolition/cleanup crew”◦Destroys damaged organelles◦Ex: neutrophils (WBC) engulf bacteria
◦Produced by the Golgi
Peroxisomes• Functions:• Breakdown fatty acids, H2O2
(catalase), synthesis of myelin (for nerve cells)
• Produced by the ER• Disease: ALD – caused by
peroxisome not functioning properly
Inside the cellWORKING AS A TEAM
Vacuoles
Function: Storage “containers”◦ store various substances
Animals = small and numerous Plants = one large central vacuole◦ Stores mostly water◦ Helps with the structure of a
plant cell
Central Vacuole•Also functions as a large lysosome- contains enzymes which break down materials•Increases turgor pressure (internal cell pressure)
Turgor Pressure
Cell shrinks due to water loss
Cell swells due to influx of water
Vacuoles Contractile vacuole → gets rid of excess water; found in some protists◦Prevents bursting of cell & dilution
Energy Organelles
CHLOROPLAST•Plants only•Some protists and algae•Function:•Site of photosynthesis•Use sun energy to make food energy
Energy Organelles
MITOCHONDRIA
•All eukaryotes•Function:•Site of cellular respiration•Creates energy for cell (ATP) from food
Mitochondria•Contain 2 membranes•Outer membrane•Inner membrane- folded up inside the organelle
Plant cells ONLY!oCell WalloFunction: Rigid layer to protect and support celloKeeps cell from burstingoMade of cellulose (carbohydrate)oChloroplasts – used for photosynthesisoLarge central vacuole
Plant Cell
Cytoskeleton
- network of protein filaments (fibers) that help the cell maintain its shape
• Function: Helps with support/internal structure and movement• Like wood and nails of house
Cytoskeleton
• Made up of microfilaments and microtubules
Cytoskeleton
Microfilaments◦Made of solid globular protein called actin
◦Used for movement and supports shape◦Ex: Muscle contractions
Intermediate Filaments
◦Made of fibrous proteins
◦They reinforce cell shape and anchor organelles◦Ex: Holds nucleus in place
Microtubules◦Hollow tubes of protein called tubulin
◦They often disassemble and reassemble
◦Helps with movement)◦Ex: lysosome may slide along to reach food
◦Ex: movement of chromosomes when cells divide
Movement Both made of microtubules wrapped in membrane Cilia → short and numerous; beat together
◦ Ex: Cells of human windpipe sweep pollen & mucous containing debris from lungs
Flagella → few; long and whip-like
◦ Ex: sperm cells
Centrioles•Type of microtubule •Function: Organize DNA during cell division•ONLY IN ANIMAL CELLS
PLANT ANIMALBOTH
Use these terms to fill in your Venn DiagramCell membrane
Ribosomes
Nucleus
Rough & smooth ER
Chloroplast
Lysosome Cell Wall
Golgi body
Mitochondria
Cytoskeleton
Central vacuole
Centrioles
Small vacuoles