The Cell Theory
1. All living things are composed of one or more cells.
2. Cells are the basic units of structure and function.
3. Cells are produced only from existing cells.
All living things have cells
Unicellular creatures have
1 cell
Multicellular creatures have 2 or more cells
ProProkaryotickaryotic(Pre) (Pre) ( Nucleus)( Nucleus)
• Always single- celledAlways single- celled
• lacks organelleslacks organelles
• Few specialized functionsFew specialized functions
• BacteriaBacteria are the are the onlyonly groupgroup of of organisms that are prokaryotic!!!organisms that are prokaryotic!!!
EuEukaryotickaryotic(True) (True) ( Nucleus)( Nucleus)
• Single-celled or multi-celled
• Has many organelles
• Specialized functions
EX: nerve cells: for transmitting info
• All other living things EX: (Plants, Animals, Fungi)
Nerve Cell
The DifferencesANIMAL CELL
• Roundish– Lysosomes– Centrioles
PLANT CELL
• Squarish– Chloroplast– Cell Wall– Central Vacuole
CELL MEMBRANEFunction: controls what goes in & out & makes
cells waterproof
Facts:• Selectively Permeable: only lets certain
things enter or leave• Made of Phospholipid Bilayer
– Made of lipids & proteins – Double layer
Analogy: Main gate/security booth
phospholipid
cell membrane
CYTOPLASMFunction: Prevents cell from collapsing
Facts:– fluid inside the membrane– made of water, sugar, protein, etc.– “framework” called a cytoskeleton
AnalogyAnalogy: Floor of the Factory
cytoskeleton
cytoplasm
NUCLEUS
Function: Stores genetic information (DNA)
Facts:•most but not all cells have a nucleus
Analogy: CEO/Boss of the factory
ChromatinFunction: Is the Genetic information
FACTS:
• Made of Nucleic Acids
• Unorganized form of DNA
• Becomes Chromosomes during cell division
Analogy: Blueprints for the cell phones
RibosomesRibosomes
Function: makes proteins
Facts:
―found on rough ER
Analogy: factory workers who build the cell phones
Endoplasmic Reticulum Endoplasmic Reticulum (ER)(ER)Function: passageway for
supplies to move about the cell
Facts: • Also makes lipids & carbs
Analogy: Assembly line
Golgi apparatusGolgi apparatusFunction: prepares proteins and
other molecules for shipping outside of the cell.
Facts: ― The more molecules a cell makes
the bigger the Golgi
Analogy: packaging center for cell phones
MitochondriaMitochondriaFunction: makes energy for cells
Facts: changes Glucose from food into fuel called ATP
Analogy: generator for factory
LysosomesLysosomesFunction: digests old cell parts
Facts:
–Filled with enzymes that break down large molecules
–Only in animal cells
Analogy: Janitors
CentriolesCentriolesFunction: move and organize chromosomes
during cell division
Facts:–Only in animal cells
Analogy: filing cabinet for blueprints
ChloroplastChloroplastFunction: makes energy for
plant cells
Facts:– Site of photosynthesis
– Uses sunlight to change water & Carbon Dioxide into Glucose and Oxygen
Analogy: solar panels
CELL WALLCELL WALLFunction: Gives structure & support to
plant cells
Facts: – helps plant to grow upright (stiff)
– Is outside the membrane
– In bacteria and plant cells
Analogy: Factory building wall
VACUOLEVACUOLEFunction: Stores water & nutrients
Facts: - Large and in the center in plant cells
- Many small ones in animal cells
– keeps plants from drying out
Analogy: Break room Refrigerator
VESSICLEVESSICLE
Facts:
- Made from cell membrane
-Don’t live very long
-Get recycled
-Analogy: Plastic grocery bags
Function: carries materials around the cell
The DifferencesANIMAL CELL
• Roundish– Lysosomes– Centrioles
PLANT CELL
• Squarish– Chloroplast– Cell Wall– Central Vacuole
Cell energy
• All nutrients must be broken down to GLUCOSE.
• Breakdown of nutrients to glucose is done by enzymes
Make glucose through Photosynthesis
Release energy from glucose Release energy from glucose through cellular respiration through cellular respiration
and ATP Productionand ATP Production
Get glucose from food
WHERE: ChloroplastWHO: plant cellsWHY: turns water and carbon
dioxide into glucose and oxygen!
WHEN: in the presences of light energy (sun)
1.1. LightLight is absorbed by chlorophyll
2. Light splits watersplits water into H2 and O
3. Energy from this split is used to make ATPATP
“Calvin Cycle”
Steps1.Energy from ATP used to make sugarsugar
(C6H12O6) from H2O & CO2
2.Oxygen is “leftover”
Cell Respiration WHERE: MITOCHONDRIA
WHO: All Eukaryotic Cells
WHY: to turn sugar (glucose) into fuel (ATP)
CC66HH1212OO66+ 6 O+ 6 O22 6 CO 6 CO2 2 + 6 H+ 6 H22OO
and 36 ATPand 36 ATP
carbon dioxide & water are “leftovers”
Two TypesAerobic• Most Eukaryotic
cells
• needs oxygen
• makes 36 ATP
• 3 steps
Fermentation• Yeast & Bacteria• If oxygen isn’t available• only makes 2 ATP
– (ok for small things)
• This is how we make bread, yogurt, beer wine!
It’s a 3 STEP PROCESS
Why: to slowly release energy without heating up the cell too much!
1. Glycolysis: Happens in the cytoplasm to break down glucose
– All living things do glycolysis
2. Krebs Cycle: In the mitochondria, makes a few ATP (not efficient)
3. Electron Transport: In the mitochondria, makes a lot of ATP
The Big Picture1. All nutrients must be
broken down to Glucose
2. Glucose must be converted to ATP
ANALOGY:
Money Tokens
• The main energy molecule in organisms
• Energy is held in the Chemical Bonds
– Breaking a bond releases energy
• ATPADP
– Making a bond stores energy
• ADP ATP
Cellular Energy in the form of ATP gets used to drive cell
processes
EX: Cell Division
Cell Transport
Several items make Cell Transport possible
1. The Phospholipids ( Cell Membrane)
2. A Concentration Gradient
3. Selective Permeability
4. Membrane Bound Proteins
Selectively Permeability: A property of biological membranes that allows some substances to cross the membrane more easily than others.
Concentration gradient: The difference in the amount of solution on each side of a cell membrane
The Phospholipid
HEAD: LOVES WATER hydrophilic
TAIL: HATES WATER hydrophobic
Hydro: Water
Philia: Love
Phobia: Fear or hate
Heads out, tails in… Heads out, tails in…
the membrane forms a bi-layer (2)the membrane forms a bi-layer (2)
Types of Cellular Types of Cellular TransportTransport
Passive Transport– Diffusion– Facilitated Diffusion
• Need Channel Proteins• No ATP
Active Transport– Needs Carrier Proteins– Requires ATP
• Endocytosis• Exocytosis
Passive transportDiffusion: The tendency of a substance to move
from an area of high conc. to an area of low conc. across a membrane in which the cell expends no energy.
(sliding down a slide)
Facilitated Diffusion: the process of transporting molecules by channel proteins during diffusion, requires no energy output
(someone else carrying you down the slide)
Needs: Energy!
Transport of molecules against a concentration gradient (from low conc. to high conc.) using carrier proteins in the cell membrane and energy from ATP.
(walking up the slide)
Active transport
How Does that Look in a Cell?
A:A: Passive Diffusion
B:B: Facilitated Diffusion (needs channel protein)
C:C: Active Transport
(needs ATP & carrier protein)
Types of Active Transport
Exocytosis: The release of materials out of the cell (pooping)
Endocytosis
The taking of materials from outside the cell (eating)
Cell Size and Diffusion• Cells must remain small to maximize diffusion
• The larger a cells volume becomes, the less efficient it becomes.– Prokaryotes - Limited by efficient metabolism– Animal Cells (Eukaryotic) - Limited by surface area
to volume ratio
• Surface area of cells must be proportionally larger than it’s size (volume)
Solvent: a liquid that dissolves the solute, usually water or alcohol Solute: Anything dissolved in a solventTogether they make a Solution
Salt Sucks!Salt Sucks!
When salt is inside or outside the cell, it draws water in its direction.
This is why you get thirsty after eating something salty.
Same thing applies for all other solutes
Solutions and Cells• All solutions want to be equal on both
sides of the membrane for homeostasis.
• Substances dissolved in solution have special vocabulary to describe them
• Hypertonic
• Hypotonic
• Isotonic
Hypertonic
• The conc. of solute outside the cell is higher than the conc. inside
• The solution outside is hypertonic
• Water diffuses out of the cell until equilibrium is established. – The cell will shrink and lose mass
Hypotonic• The conc. of solute outside the
cell is lower than the conc. inside
• The solution outside is hypotonic
• Water diffuses into the cell until equilibrium is established. – The cell will get bigger and gain
mass
Isotonic• The conc. of solute
outside and inside the cell are equal
• The solution outside is isotonic
• Water diffuses into and out at equal rates – No net change in size or
mass
IsotonicHypotonicHypertonic
H2O
CHO
H2O
H2O
H2OH2O
H2O
H2O
H2O
H2O
H2O
H2OH2O
H2OH2O
H2O
CHO
CHO
CHO
CHO
CHO
CHO
CHOCHO
CHOCHO
CHO
CHO
CHO
H2O
H2O
H2OH2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
•Water moves out
•Cell Shrinks
•Water moves in and out
•Cell Size remains same
•Water moves in
•Cell Swells
Why doesn’t the Glucose (CHO) move into the cell?