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Cells. Chapter 7. Robert Hooke - First person to see cells, he was looking at cork and noted that he saw "a great many boxes”. (1665) Anton van Leeuwenhoek - Observed living cells in pond water, which he called "animalcules" (1673). Early Contributions. Animals vs. Plants!!.
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Cells Chapter 7
Robert Hooke - First person to see cells, he was looking at cork and noted that he saw "a great many boxes”. (1665) • Anton van Leeuwenhoek - Observed living cells in pond water, which he called "animalcules" (1673) Early Contributions
Animals vs. Plants!! • Theodore Schwann– zoologist • observed tissues of animals • contained cells (1839) • MattiasSchleiden– botanist • observed tissues of plants • contained cells ( 1845) • Rudolf Virchow • reported that every living thing is made of vital units, known as cells • predicted that cells come from other cells. (1850 )
The Cell Theory • 1. Every living organism is made of one or more cells. • 2. The cell is the basic unit of structure and function. It is the smallest unit that can perform life functions. • 3. All cells arise from pre-existing cells. *Why is the Cell Theory called a Theory and not a Fact?
ALL cells have these parts • Ribosomes – make protein for use by the organism • Cytoplasm – fluid material within cell • DNA – genetic material • Cytoskeleton – internal framework of cell • Cell Membrane – outer boundary, selectively permeable Cell Features
Structure • Core of DNA/RNA surrounded by a protein coat • Reproduction • Lysogenic or lytic cycle • Disease Causing • HIV and influenza • Mimics living cells, but do not have organelles or self-replication Viruses NOT ALIVE!!
True or false: • Robert Hooke was the first person to see cells.__ • Bacteria cells have a cell membrane.__ • The Cell Theory was developed by a single scientist.__ • Plant cells have cytoplasm.__ • Cells taken from fungi do not have DNA.__ • Cells can only come from pre-existing cells. __ • It only took five years to develop the Cell Theory.__ Comprehension Checkpoint
Got Nucleus? • Cells are classified based on the presence of a membrane bound nucleus “-karyote” • What’s inside the nucleus? • “pro-”=before • “eu-”=true • Prokaryote • Eukaryote
The first cells to inhabit the earth • Simple cells • Bacteria • These cells do NOT have a nucleus, their DNA is circular and floats in the cytoplasm Prokaryote Cells “before a nucleus” Some bacteria have a tail-like structure called a flagella, that helps it to move. A capsule surrounds some bacteria and helps them avoid the body’s immune system
Bacteria Images Bacteria that causes Anthrax. We talked about Anthrax before…remember?
Usually found at center of EUKARYOTIC cell • Has a nuclear membrane & nuclear pores • Contains cell’s DNA in one of 2 forms • chromatin - DNA bound to protein (non-dividing cell) • chromosomes - condensed structures seen in dividing cell • Also contains an organelle called nucleolus - which makes the cell’s ribosomes Nucleus
Mitochondria – this is the cell’s energy center. It turns food into a chemical energy called ATP The mitochondria is sometimes called the “powerhouse” of the cell Cell Organelles
Golgi Apparatus – processes, packages and secretes proteins. It is comparable to a factory or a post office. Cell Organelles *A vesicle forms with Golgi to transport substances outside cell.
Lysosome – Contains digestive enzymes, breaks things down, "suicide sac” Cell Organelles Endoplasmic Reticulum – Transport, "intracellular highway". -Rough ER contains many ribosomes & is involved in protein synthesis -Smooth ER ribosomes not found on surface
Cytoskeleton – Helps cell maintain support & shape and helps with movement a. microtubules-hollow structures; also help build cilia and flagella b. microfilaments-threadlike c. centrioles-only in animal cells; used during cell division (paired) Cell Organelles Vacuole – storage area for water and other substances -Paramecium have a contractile vacuole to get rid of extra water
The cell is like a factory. Its product is protein which goes to body to serve different functions. • DNA has instructions to build protein • These instructions are sent to ribosomes • The ribosomes build protein and send it through ER • The proteins are delivered to golgi where they are completed and “tagged” for export outside cell Protein Production
THE ANIMAL CELL Can you identify the parts?
Have additional structures • CELL WALL – surrounds membrane & provides additional support • CHLOROPLASTS– contain green pigment, function in photosynthesis • CENTRAL VACUOLE– large water container in center of cell Plant Cells
PLANT CELL Can you identify the parts?
Mitochondria and chloroplasts have their own DNA (separate from the nucleus) • This supports the ENDOSYMBIOSIS THEORY which states that eukaryotic cells evolved when prokaryote cells engulfed or absorbed other cells. Organelles With DNA
What does “selectively permeable mean? CELL MEMBRANE • Selectively permeable; it regulates what comes into the cell and what leaves the cell • It is composed of a double layer of phospholipids with proteins embedded throughout Lipids again. Told ya.
Cell Membrane Extensions • Cilia assemble and disassemble for cytoplasmic movements that allow cells, such as amoebas, to crawl along surfaces • Intestines have these as well (called villi) • Flagella • Whip-like tails for movement • Bacteria • sperm