Discovery of the CellDiscovery of the Cell
We could not have We could not have discovered the cell without discovered the cell without the invention of the the invention of the microscope in the 17th microscope in the 17th centurycentury
Robert Hooke (1635-1703)Robert Hooke (1635-1703)
1.1.Used a microscope to Used a microscope to examine cork, trees examine cork, trees carrots, and ferns. carrots, and ferns.
2.2.He saw little boxes that he He saw little boxes that he compared to the rooms compared to the rooms that monks live in: cells.that monks live in: cells.
Anton van LeeuwenhoekAnton van Leeuwenhoekwas the first person to observe live cells.was the first person to observe live cells.
The Cell Theory:The Cell Theory:
All living things are composed of one or more All living things are composed of one or more cellscells
Cells are the basic unit of structure and function Cells are the basic unit of structure and function of all living organismsof all living organisms
Cells come from other cellsCells come from other cells
SizeSize
A nerve cell can extend all the ways A nerve cell can extend all the ways down a giraffe’s leg.down a giraffe’s leg.
Most cells are not visible without a Most cells are not visible without a microscopemicroscope
ShapeShape• cells have a cells have a
variety of shapesvariety of shapes• Nerve cells have Nerve cells have
long extensions, long extensions, skin cells are flat, skin cells are flat, and white blood and white blood cells can change cells can change their shapetheir shape
Internal OrganizationInternal Organization– Eukaryotic cells contain organelles that Eukaryotic cells contain organelles that
can be compared to our organs.can be compared to our organs.– All cells have a cell membrane and All cells have a cell membrane and
genetic information called DNA (called genetic information called DNA (called chromosomes when compacted)chromosomes when compacted)
Prokaryotic vs. Eukaryotic Prokaryotic vs. Eukaryotic
– Prokaryotic cells: have a Prokaryotic cells: have a membrane and DNA only. THEY membrane and DNA only. THEY HAVE NO nucleus or HAVE NO nucleus or organelles. EXAMPLE: Bacteriaorganelles. EXAMPLE: Bacteria
– Eukaryotic cells: have a Eukaryotic cells: have a membrane, DNA, and membrane, DNA, and organelles. EXAMPLE: plant, organelles. EXAMPLE: plant, animal, fungi, and protist cellsanimal, fungi, and protist cells
Parts of all cellsParts of all cells
Cell membrane: surrounds and Cell membrane: surrounds and protects the cell and protects the cell and selectivelyselectively allows nutrients in and waste out allows nutrients in and waste out
(present in prokaryotes and (present in prokaryotes and eukaryotes)eukaryotes)
ChromosomesChromosomes
Compact DNA Compact DNA present in prokaryotes and present in prokaryotes and
eukaryotes eukaryotes
MitochondriaMitochondria
Transfers energy from organic Transfers energy from organic compounds to ATP (energy) compounds to ATP (energy)
Muscle cellTumor cell
RibosomesRibosomes
Organizes the synthesis of proteins Organizes the synthesis of proteins found in cytoplasm and on Rough ER found in cytoplasm and on Rough ER
Endoplasmic ReticulumEndoplasmic Reticulum
prepares proteins for export prepares proteins for export RoughRough-packages proteins -packages proteins
SmoothSmooth-makes steroids -makes steroids
Golgi ApparatusGolgi Apparatus
Processes and packages substances Processes and packages substances made by cell.made by cell.
LysosomeLysosome
digests waste (old molecules, digests waste (old molecules, organelles, and foreign substance) organelles, and foreign substance)
CiliaCilia
short hair-like structures on the short hair-like structures on the outside of the cell present in large outside of the cell present in large numbers that assist in movement. numbers that assist in movement.
Example: in respiratory system to Example: in respiratory system to keep out foreign particles keep out foreign particles
FlagellaFlagella
long hair-like structures that whip long hair-like structures that whip back and forth to propel the cell back and forth to propel the cell forward. forward.
Example: sperm cell Example: sperm cell
Cell WallCell Wall supports and protects (plant cells supports and protects (plant cells
only) only)
ChloroplastChloroplast
use energy from the sun and convert use energy from the sun and convert it into energy. (plant cells only)it into energy. (plant cells only)