Cells are the smallest
units of life
CH 3
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
Prokaryotic
(Pre) ( Nucleus)
• Always single- celled
• lacks organelles
• Few specialized functions
• Bacteria are the only group of
organisms that are prokaryotic!!!
Eukaryotic
(True) ( 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
CELLS:
What do you think
these cells are?
Cell Organelles
little “organs” that have
specific jobs in a cell
The Differences
ANIMAL CELL
• Roundish
– Lysosomes
– Centrioles
PLANT CELL
• Squarish
– Chloroplast
– Cell Wall
– Central Vacuole
A cell is like a cell phone factory
CELL MEMBRANE
Function: 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:
phospholipid
Main gate/security booth
cell membrane
CYTOPLASM
Function: Prevents cell from collapsing
Facts:
– fluid inside the membrane
– made of water, sugar, protein, etc.
– “framework” called a cytoskeleton
Analogy: 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
Chromatin
Function: Is the Genetic
information
FACTS:
• Made of Nucleic Acids
• Unorganized form of DNA
• Becomes Chromosomes during cell division
Analogy: Blueprints for the cell phones
Ribosomes
Function: makes proteins
Facts:
―found on rough ER
Analogy: factory workers who
build the cell phones
Endoplasmic Reticulum (ER)
Function: passageway for
supplies to move about the
cell
Facts:
• Also makes lipids & carbs
Analogy: Assembly line
Golgi apparatus
Function: 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
Mitochondria
Function: makes energy for cells
Facts: changes Glucose from food
into fuel called ATP
Analogy: generator for factory
Lysosomes
Function: digests old cell parts
Facts:
–Filled with enzymes that break
down large molecules
–Only in animal cells
Analogy: Janitors
Centrioles
Function: move and organize
chromosomes during cell division
Facts:
–Only in animal cells
Analogy: filing cabinet for blueprints
Chloroplast
Function: makes energy for
plant cells
Facts:
– Site of photosynthesis
– Uses sunlight to change water &
Carbon Dioxide into Glucose and
Oxygen
Analogy: solar panels
CELL WALL
Function: 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
VACUOLE
Function: 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
VESSICLE
Function: carries materials around the cell
Facts:
- Made from cell membrane
-Don’t live very long
-Get recycled
-Analogy: Plastic grocery bags
The Differences
ANIMAL 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
Get glucose from
food
Release energy from glucose
through cellular respiration
and ATP Production
WHERE: Chloroplast
WHO: plant cells
WHY: turns water and carbon
dioxide into glucose and
oxygen!
WHEN: in the presences of light
energy (sun)
1. Light is absorbed by chlorophyll
2. Light splits water into H2 and O
3. Energy from this split is used to
make ATP
“Calvin Cycle”
Steps
1. Energy from ATP used to make sugar
(C6H12O6) from H2O & CO2
2. Oxygen is “leftover”
Light energy + 6 CO2 + 6 H2O
C6H12O6 + 6O2
GLUCOSE
( Monosaccharide sugar)
Where did they Go?
Reactants
6 CO2
Products
C6H12O6
6H2O
6O2
The Big Picture
Cell Respiration
WHERE: MITOCHONDRIA
WHO: All Eukaryotic Cells
WHY: to turn sugar (glucose) into fuel (ATP)
C6H12O6+ 6 O2  6 CO2 + 6 H2O
and 36 ATP
carbon dioxide & water are
“leftovers”
Two Types
Aerobic
• 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 Picture
1. 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
• ATPADP
– 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.
2.
3.
4.
The Phospholipids ( Cell Membrane)
A Concentration Gradient
Selective Permeability
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
Hydro: Water
HEAD: LOVES WATER
hydrophilic
Philia: Love
Phobia: Fear or hate
TAIL: HATES WATER
hydrophobic
Heads out, tails in…
the membrane forms a bi-layer (2)
Types of Cellular
Transport
Passive Transport Active Transport
– Diffusion
– Facilitated Diffusion
• Need Channel Proteins
• No ATP
– Needs Carrier Proteins
– Requires ATP
• Endocytosis
• Exocytosis
Passive transport
Diffusion: 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)
Active transport
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)
How Does that Look in a Cell?
A: Passive Diffusion
B: Facilitated Diffusion
(needs channel protein)
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
solvent
Together they make a Solution
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
Hypertonic
Hypotonic
H2O
CHO
CHO
CHO
H2O
H2O
H2O
CHO
H2O
H2O
CHO
CHO
H2O
H2O
CHO
CHO
CHO H O
2
H2O
H2O
CHO
H2O
H2O
H2O
CHO
H2O
H2O
H2O
CHO
CHO
Isotonic
H2O
H2O
CHO
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
•Water moves out
•Water moves in
•Water moves in and out
•Cell Shrinks
•Cell Swells
•Cell Size remains same
Why doesn’t the Glucose (CHO) move into the cell?