the cell theory & cell structure chapter 3, sections 1 and 2
TRANSCRIPT
The Cell Theory
• All living things are made of cells
• Cells are the basic unit of structure & function
• All cells come from pre-existing cells
Scientists and their Contributions
• 1655 – Robert Hooke coins the term “cell” after viewing cork under an early microscope
A drawing of Hooke’s cork cells
Hooke would have used a microscope like this
Scientists and their Contributions
• 1674 – Anton van Leeuwenhoek observes the first living cells under a microscope
Scientists and their Contributions
• 1838 – Matthias Schleiden determines that all plant tissues are made of cells
• 1839 – Theodor Schwann determines that all animal tissues are made of cells
Scientists and their Contributions
• 1855 – Rudolf Virchow asserts that every cell comes from a pre-existing cell
Prokaryotes vs. Eukaryotes
Characteristic
Prokaryote Eukaryote
Outer boundary
Cell wall and cell
membrane always present
Cell membrane always; cell
wall sometimes
Nucleus NO YES
Prokaryotes vs. Eukaryotes
Characteristic
Prokaryote Eukaryote
Other organelles
NO YES
Kingdoms (classification)
Eubacteria, Archaebacteria
Protista, Fungi, Plantae, Animalia
Prokaryotes vs. Eukaryotes
• Prokaryotes: cell that does not have a nucleus or any other membrane-bound organelles
• Eukaryotes: cell that does have a defined nucleus and other membrane-bound organelles
Plants vs. Animals
Characteristic
Plants Animals
Outer boundary Cell wall and cell membrane
Cell membrane only
Nucleus YES YES
Plants vs. Animals
Characteristic
Plants Animals
Chloroplasts YES NO
Vacuoles One large, central vacuole
Many smaller vacuoles throughout
Plants vs. Animals
Characteristic
Plants Animals
Trophic role autotrophic
(producer)
heterotrophic
(consumer)
Kingdom (classification)
Plantae Animalia
Cells vary between and within organisms.
• Cells come in all sizes ex: bacterial cells are much smaller than a typical animal cell
• Some cells may have differences based upon their requirements ex: cells that need to produce lots of energy, like muscle cells, might have more mitochondria (since mitochondria are the “powerhouses” of the cell).
Key Organelles
(1) Nucleus – control center of cell; contains deoxyribonucleic acid (DNA); enclosed by a nuclear membrane with pores; only in eukaryotes
Key Organelles
(2) Ribosomes – site of protein synthesis some are free-floating, some are attached to rough ER
Key Organelles
(3) Endoplasmic reticulum – “highway” of cell; provides path for other substances to travel along; may be smooth (w/o ribosomes) or rough (w/ ribosomes)
Key Organelles
(4) Golgi Apparatus – “post office” of cell; modifies and packages protein & lipids before they are sent out of the cell
Key Organelles
(5) Mitochondria – “powerhouse” of cell; converts food energy into chemical energy (ATP); has a double membrane and its own DNA (which can be considered evidence of endosymbiosis)
Key Organelles
(7) Chloroplast – site of photosynthesis; converts solar/light energy into sugar (glucose); found in plant cells, some bacteria, and some protists; has a double membrane and its own DNA (which can be considered evidence of endosymbiosis)
Key Organelles
(8) Vacuoles – storage tank; primarily for water but also holds some minerals and other dissolved solids; plant cells have one large central vacuole while animal cells multiple, smaller vacuoles