A history of the cell · • 1674 Anton van Leeuwenhoek - observed tiny living things in drops of...

A history of the cell• 1607 English settlers found colony at Jamestown Virginia

• 1665 Robert Hooke, looked at cork and discovered and named cells

• 1674 Anton van Leeuwenhoek - observed tiny living things in drops of pond water.

• 1838 Matthias Schleiden - concluded that plants are made of cells

• 1839 Theodor Schwann - concluded that animals are made of cells.

• 1855 Rudolph Virchow - proposes that cells come from existing cells

• 1931 Janet Plowe - demonstrates that the cell membrane in a physical structure not just an interface between two liquids.

• 1945 World War II ends

• 1970 Lynn Margulis - proposes the theory that certain organelles, were once free-living cells themselves

The Cell Theory

• All living things are composed of cells.

• Cells are the basic units of structure and

function in living things.

• New cells are produced from existing cells.

Two Cell Types

• Prokaryotic Cells- 1 to 10 um– have cell membrane and cytoplasm but no nuclei

– smaller and simpler than eukaryotic cells

– bacteria

• Eukaryotic Cells- 10 to 100 um– do contain nuclei and other specialized organelles

– all plants, animals, fungus and protists

Prokaryotic Cell

Cell membrane

Cell membrane

Cytoplasm

Cytoplasm

Nucleus

Organelles

Eukaryotic Cell

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Prokaryotes Eukaryotes

Cell membraneRibosomesCell wall

NucleusEndoplasmic reticulumGolgi apparatusLysosomesVacuolesMitochondriaCytoskeleton

Animal Cells Plant Cells

Lysosomes

Cell membraneRibosomesNucleusEndoplasmic reticulumGolgi apparatusVacuolesMitochondriaCytoskeleton

Cell WallChloroplasts

Section 7-2

Venn Diagrams

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Cell Structures

• Cell Wall

• Cell Membrane

• Nucleus

• Cytoplasm

• endoplasmic Reticulum

• Ribosomes

• Golgi Bodies

• Lysosomes

• Mitochondria

• microtubules / microfilaments

• Centrioles

• Cilia and Flagella

• Vacuoles

• Plastids

Cell Membrane

• All Cells have them

• Controls passage of material into and out of the cell

• double-layered, semi-permeable membrane

• composed of lipids and embedded protein molecules

Outsideof cell

Insideof cell(cytoplasm)

Cellmembrane

Proteins

Proteinchannel

Lipid bilayer

Carbohydratechains

The Structure of the Cell Membrane

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AIR

(a)

(b)

Hydrophobic tail

Hydrophilic head

WATER

WATER

WATER

Cell Wall

• Found in– Plants, algae, fungi and nearly all prokaryotes

• Lies outside the cell membrane

• provide support and protection for the cell

• most commonly made of cellulose

• Made of actin in bacteria

Cytoplasm

• Fluid-like material

• Between cell membrane and nucleus

• Contains organelles

• many biochemical processes occur here

Ribosomes

• Found in prokaryotic and eukaryotic cells

• Sites of protein synthesis

• free in cytoplasm or attached to endoplasmic reticulum

Endoplasmic Reticulum

• Membrane-lined, interconnecting channels through the cytoplasm

• associated with– synthesis

– storage

– transport of material

Endoplasmic Reticulum

Mitochondria

• Found in all eukaryotic cells. (animal, plant, fungi, protist)

• Specialized double membrane structure

• Sites of most energy-producing reactions of aerobic cellular respiration.

• The “powerhouse” of the cell.

• Has its own DNA

Chloroplasts

• Found in plants and some algae

• Specialized double membrane structure

• Contain the green pigment chlorophyll

• Sites of photosynthesis

• Has some DNA

Golgi Bodies (Complex)

• Stack of membrane-bounded channels and vacuoles

• Synthesizes, packages and secretes cell products

Lysosomes

• Membrane-bounded sacs that contain digestive enzymes

• digest food in single celled organisms

• Destroy damaged or old cell parts

• Programmed cell death - apoptosis

Vacuoles

• Small or none in animal cells

• Large in plant cells

• Membrane-bounded , fluid filled sacs in the cytoplasm

• food vacuole

• waste vacuole

• contractile vacuole

Centrioles

• Only in animal cells

• involved in cell division

Plant Cell

Nuclearenvelope

Ribosome(attached)

Ribosome(free)

Smooth endoplasmicreticulum

Nucleus

Rough endoplasmic reticulum

Nucleolus

Golgi apparatus

Mitochondrian

Cell wall

CellMembrane

Chloroplast

Vacuole

Figure 7-5 Plant and Animal Cells

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Animal Cell

Centrioles

NucleolusNucleus

Nuclearenvelope

Rough endoplasmic reticulum

Golgi apparatus

Smooth endoplasmicreticulum

Mitochondrian

CellMembrane

Ribosome(free)

Ribosome(attached)

Figure 7-5 Plant and Animal Cells

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cell membrane

nucleus

mitochondria

cell wall

What type of cell is this? Plant Cell

Cell wall

Chloroplasts

Nucleus

Vacuole

vacuole

endoplasmicreticulum

mitochondria

cell membrane

Sites of protein synthesis. May be free in the cytoplasm or attached to the membranes of the endoplasmic reticulum8.Cell Wall

A series of membrane-lined, interconnecting channels through the cytoplasm. Transports things throughout the cell. The “highway system” of the cell7.Chloroplasts

Watery fluid-like material that fills the space between the plasma membrane and the nucleus of the cell. Contains the organelles. Many biochemical processes occur here.

6.Mitochondria

Nonliving rigid supportive structure found outside the cell membrane in plants, algae, fungi and various other organisms. Most commonly composed of cellulose.5.

Endoplasmic Reticulum

Chlorophyll-containing structures found in cells of green plants and some algae. Sites of photosynthesis.4.Ribosomes

Surrounds the cell and controls the passage of materials into and out of the cell. Double-layered, semi-permeable membrane composed of lipids and containing embedded protein molecules

3.Nucleus

Sites of most energy producing reactions of aerobic cellular respiration. The “power house” of the cell.2.Cytoplasm

Structure that directs the activities of the cell. Contains the hereditary material – the DNA in the chromosomes. Surrounded by the nuclear membrane.1.Cell Membrane

Column BColumn A

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