Cell biology is the study of cell structure and function,
and it revolves around the concept that the cell is the
fundamental unit of life.
Discovery of Cells 1665- English Scientist, Robert Hooke, discovered cells
while looking at a thin slice of cork.
He described the cells as tiny boxes or a honeycomb.
He thought that cells only existed in plants and fungi.
Anton van Leuwenhoek
1673- Used a handmade microscope to observe pond scum & discovered single-celled organisms
He called them “animalcules”
He also observed blood cells from fish, birds, frogs, dogs, and humans
Therefore, it was known that cells are found in animals as well as plants
Development of Cell Theory 1838- German Botanist, Matthias Schleiden,
concluded that all plant parts are made of cells.
1839- German physiologist, Theodor Schwann,
who was a close friend of Schleiden, stated that all
animal tissues are composed of cells.
Development of Cell Theory
1858- Rudolf Virchow, German physician, after
extensive study of cellular pathology,
concluded that cells must arise from preexisting
cells.
The Cell Theory Complete
The 3 Basic Components of the Cell Theory were
now complete:
1. All organisms are composed of one or more
cells. (Schleiden & Schwann)(1838-39)
2. The cell is the basic unit of life in all living things.
(Schleiden & Schwann)(1838-39)
3. All cells are produced by the division of
preexisting cells. (Virchow)(1858)
Modern Cell TheoryModern Cell Theory contains 4 statements, in addition to the original Cell Theory:
The cell contains hereditary information(DNA) which is passed on from cell to cell during cell division.
All cells are basically the same in chemical composition and metabolic activities.
All basic chemical & physiological functions are carried out inside the cells.(movement, digestion,etc)
Cell activity depends on the activities of sub-cellular structures within the cell(organelles, nucleus, plasma membrane)
Characteristics of all cells
Surrounded by cell membrane (plasma)
Contain DNA – genetic material.
Contain cytoplasm
Prokaryotic No nucleus (nucleoid
region).
Few internal structures - have simple ribosomes.
Smaller & simpler than eukaryotic cells.
One-celled organisms
Ex. Bacteria
Prokaryotic Cells Some use flagellum for locomotion
threadlike structures protruding from cell
surface Bacterial cell wall
Flagellin
Rotarymotor
Sheath
Eukaryotic Have a membrane bound nucleus,
control center that holds DNA (genetic material)
Contain organelles surrounded by membranes (small organs)
Most living organisms – lots of variety
Larger & more complex than prokaryotic cells
Diversity of Life
Unicellular Organisms 1 cell
Ex. Bacteria, Amoeba
Multicellular Organisms 2 or more cells
Ex. Plants & Animals
Levels of Organization Cells
Tissues
Organs
Organ Systems
Plant Cells vs. Animal Cells Plant Cells
Chloroplasts
Large Central
Vacuole
Cell Wall
Animal Cells
Lysosome
Centrioles
Cell Membrane / Plasma Outer membrane of cell that
controls movement in & out of the cell
Double layer (Lipid Bilayer)
Plasma Membrane
Selectively permeable boundary between the cell and the environment
All cells have this!!
Nucleus
Directs cell activities
Separated from
cytoplasm by nuclear
membrane
Contains genetic
material - DNA
Nuclear Membrane
Surrounds nucleus
Made of two layers
Openings allow material to
enter and leave nucleus
Chromosomes/Chromatin
In nucleus
Made of DNA &protein
Contain instructions for traits & characteristics
Contains instructions for making proteins
Ribosomes
Each cell contains thousands
Make proteins (site for protein synthesis)
Found on Rough ER & floating throughout the cell
Endoplasmic Reticulum A system of tubes & sacs
formed by membranes (an enclosed space)
Moves materials around inside of the cell
Smooth: lacks ribosomes Lipid synthesis, drug
detoxifcation
Rough type (pictured): ribosomes embedded in surface Transports proteins to the
Golgi body
Golgi Bodies
Protein “packaging
plant”
Modifies protein
Attach lipids &
carbohydrates to
the protein
Mitochondria Produces energy
through chemical reactions – cellular respiration
Converts glucose into ATP
Cristae – inner membrane
Matrix – inner membrane space
What is ATP?
Nucleotides
“Carry” chemical energy
from easily hydrolyzed
phosphoanhydride bonds
• Combine to form coenzymes (coenzyme A (CoA)
• Used as signaling molecules (cyclic AMP)
Lysosome
Digestive sac for proteins, fats, &carbohydrates
Transports undigested material to cell membrane for removal
Cell breaks down if lysosome explodes(A)
Cytoskeleton Network of protein fibers supporting cell shape and
anchoring organelles
Microfilaments
Actin
Cell movement
Support of cell
Microtubules
Hollow tubes
Movement of organelles
Forms cilia, flagella, centrioles
Cell membrane
Endoplasmic
reticulum
Microtubule
Microfilament
Ribosomes Michondrion
Centrioles
Assemble
microtubules during
cell division
Barrel shaped –
pairs
Found In animal
cells (used during
cell reproduction)
Chloroplast
Found in plant cells
Contains green chlorophyll
Location where photosynthesis takes place in the cell
Vacuoles
Membrane-bound sacs for storage, digestion, and waste removal
Contains water solution
Help plants maintain shape- large central vacuole
Top Related