Download The Cell Offical Notes

Biology
The Study of Living Organisms
What is Living?

Use Energy

Metabolism
Develop and Grow
 Homeostasis



Maintain themselves
Reproduction


Asexual – reproduction by yourself
Sexual reproduction
Evolve
 Made of Cells

Macromolecules
Large molecules made of smaller
molecules linked together
 Four Major Types:

Protein
 Carbohydrates
 Lipids
 Nucleic Acids

Macromolecules

Protein
Subunit: amino acids
 20 amino acids in
living organisms
 Skin, hair, feathers,
insulin, hemoglobin,
antibodies, enzymes

Macromolecules

Carbohydrates
Subunits: Saccharides (sugars)
 Starch, glycogen, cellulose

Macromolcules

Lipids
Fatty acid + carboxyl group
 Used for long term energy storage
 Fats, oils

Macromolecules

Nucleic Acids
Subunit: Nucleotide
 DNA and RNA
 Store Genetic Information

The Cell Theory
Some Random Cell Facts
The average human being is composed
of around 100 Trillion individual cells!!!
 It would take as many as 50 cells to
cover the area of a dot on the letter “i”

WOW!!!
Discovery of Cells
Robert Hooke (1665)
 Discovered cells while looking at a thin slice of cork.
 He described the cells as tiny boxes
 He thought that cells only existed in plants

Anton van Leuwenhoek



1673- Observed single-celled organisms in pond
water
He called them “animalcules”
The cells were living
Therefore, it was known
that cells are found
in animals as well as plants
Spirogyra
Development of Cell Theory


1838- Matthias Schleiden, concluded that all
plant parts are made of cells
1839- Theodor Schwann, stated that all animal
tissues are made of cells.
Development of Cell Theory

1858- Rudolf Virchow (physician) found that
cells must arise from preexisting cells while
studying disease.
The Cell Theory

HAS 3 PARTS:
1. All organisms are composed of one or more cells.
(Schleiden & Schwann)
2. Cells are the basic units of structure and function
in an organism. (Schleiden & Schwann)
3. Cells come only from the reproduction of existing
cells. (Virchow)
Two Types of Cells
1.
Prokaryotes
First living cells
Bacteria and Archaea
No organelles
No nucleus
2.
Eukaryotes
Animals and Plants
Organelles
Nucleus
Prokaryotic or Eukaryotic?
Cell Parts
Membrane and Wall
 Genetic Material
 Organelles


Structures that
perform specific
functions in the cell
Cell Membrane
Selectively permeable phospholipid bilayer
 Found in prokaryotes and eukaryotes

Nucleus


Nickname: “The Control Center”
Function: holds the DNA
Mitochondria


Nickname: “The Powerhouse”
Function: Energy formation

Breaks down food to make ATP
– ATP: is the major fuel for all cell activities that
require energy
Mitochondria
Mitochondrial DNA
 Ancient Eukaryotic cell ate a prokaryotic
cell

Ribosomes


Function: makes proteins out of Amino
Acids
Found in all cells
prokaryotic and eukaryotic have
different types
Endoplasmic Reticulum

2 Types:
1. Rough ER:
– Ribosomes on surface
– Function: helps make proteins and
phospholipids
Endoplasmic Reticulum

2 Types:
2. Smooth ER:
– NO ribosomes
– Function: makes fats or lipids, breaks down
drugs
Golgi Apparatus


Nickname: The Post Office
Function: packages, modifies, and
transports materials to inside/outside of
the cell
Lysosomes



Nickname: “Clean-up Crews”
Function: Digest food particles, waste,
cell parts, and foreign invaders
Have lower pH and special enzymes
Cytoskeleton
Gives Cells Shape and Support
 Microtubules
 Intermediate Filaments
 Microfilaments
Cilia and Flagella
Both help with cell movement
Cilia
Flagella
•Short
•Long
•Hairlike
•One or two per cell
•numerous
What do Plant Cells Have?
1.
2.
3.
Cell Wall
Vacuole
Chloroplasts
Pine Needle
Plant Cell

Cell Wall
Outside of plasma membrane
 Made of cellulose

Plant Cell

Vacuole
Stores water, waste, enzymes
 Can make up 90% of plant cell volume
 Causes plant to stand upright

Plant Cell

Chloroplasts


Make carbohydrates from CO2 and H2O using light
energy
Contain Thylakoids with chlorophyll
Animal Cell vs. Plant Cell
Cell Membrane
Hydrophobic and Hydrophilic
 Membrane Proteins

Communication
 Join cells together
 Control transport across membrane


Carbohydrates


Allow cells to recognize each other
Fluid Mosaic Model

Phospholipids and proteins can slide past
each other
Transport Across Membrane

Diffusion


Osmosis


Tendency of molecules to move from high
concentration to low concentration
Diffusion of water
Works for small hydrophobic molecules
Transport Across Membrane

Facilitated Diffusion
Ions and large molecules
cannot pass freely across
the membrane
 Carrier proteins

Allow molecules to move
down the concentration
gradient
 NO ENERGY NEEDED!
 Passive Transport

Transport Across Membrane

Active Transport
Carrier proteins move molecules AGAINST
the concentration gradient
 Requires energy

Transport Across Membrane

Endocytosis

Portion of membrane folds inward and
pinches off
Transport Across Membrane

Exocytosis

Vesicle fuses with membrane and dumps
contents outside
Cell Size
Most cells are 10 to
50µm in diameter

Prokaryotes are
typically smaller
than eukaryotes
YUM….You’re eating an entire cell!
Cell Size
The ratio of the surface area to the
volume limits cell size
 Which increases faster, surface area or
volume?

Why would
having a low
surface area
to volume
ratio be
important?
Cell Shape

Different cells have different shapes
based on function