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CHAPTER 7 SECTION 7.1: Life is Cellular. Robert Hooke: Discovered cells in 1665 Looked at cork with a microscope. Anton van Leewenhoek looked at pond water with a microscope. Wee Beasties!!!. MOST CELLS ARE MICROSCOPIC. CALCULATING TOTAL MAGINIFICATION WITH THE CONPOUND LIGHT MICROSCOPE:
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Robert Hooke: • Discovered cells in 1665 • Looked at cork with a microscope
CALCULATING TOTAL MAGINIFICATION WITH THE CONPOUND LIGHT MICROSCOPE: • Power of the eyepiece lens x power of the objective lens = total magnification • Our eyepieces have a 10x lens • Our microscopes have four objective lenses: • 4x _____ • 10x _____ • 40x _____ • 100x _____
WHAT IF WE NEED TO SEE SOMETHING SMALLER THAN THE LIGHT MICROSCOPE CAN DISPLAY? • Viruses • Organelles • Many other things • Electron microscopes! • Transmission electron microscopes (TEM) shows images of slices of specimens • Scanning electron microscopes (SEM ) shows 3D images of whole specimens
Liver cell Red blood cells mitocondrion HIV virus
The CELL THEORY: • All living things are made of cells • Nerve cells • Skin cells • Muscle cells • blood cells • Single celled organisms (bacteria)
2. The cell is the basic unit of life; all living things are made of cells
PROKARYOTES VERSUS EUKARYOTES: • ALL cells have: • A plasma membrane • Cytoplasm • DNA • Ribosomes • In addition, ALL Eukaryotes have: • A nucleus • Membrane-bound organelles • All plants, animals, fungi, and protists • Prokaryotes do NOT have: • A nucleus • Membrane bound organelles • All bacteria
WHAT IS IN A CELL? • Cytoplasm • organelles
ORGANELLES THAT STORE, CLEAN UP, AND SUPPORT • Vacuoles and vesicles • Food storage: food vacuole • Water storage: large central vacuole
WASTE VACUOLES: • Contractile vacuoles • Removes excess water from aquatic single celled organisms • Example: Paramecium
Lysosomes: • Small sacs that contain digestive enzymes • Break down proteins, lipids, carbohydrates • Also break down damaged organelles • Important in ‘sculpting’ embryos
CYTOSKELETON: • Web of proteins that: • Gives the cell shape • Helps move materials within the cell • Helps the cell itself move • Made of: • Actin • Myosin • tubulin
Microfilaments • Made of actin • Are constantly being built, broken down, and rebuilt
Microtubules • Made of tubulin • Also helps the cell keep • its shape • Helps in cell division • Mitotic spindle
CENTRIOLES • Found in animal cells, NOT in plant cells! • Help with organization during cell division
CILIA AND FLAGELLA: • Both allow a cell to move • Cells have one or the other, but not both • CILIA: • Many • short
Flagella • One or two • Long!
ORGANELLES THAT BUILD PROTEIN: • Ribosomes • Made of RNA and protein • Make proteins using instructions from DNA • Some ribosomes are floating free in the cytoplasm (‘free ribosomes’) • Some ribosomes are attached to the rough endoplasmic reticulum (RER)
ENDOPLASMIC RETICULUM: • Made of membranes • Membranes are made here • Two types:
Rough Endoplasmic Reticulum (RER) • Proteins are made here, on the ribosomes that are attached to the membranes • These proteins actually go inside the RER where they are modified • All proteins that leave the cell are made here
Smooth Endoplasmic Reticulum (SER) • Does not have ribosomes on its surface • Detoxify cells • Make membranes
GOLGI APPARATUS: (sometimes called Golgi ‘body’ or Golgi ‘complex’) • Formed by a stack of sacs made of membranes • Modifies, sorts, packs, and ‘ships’ molecules made by other organelles • Vesicles containing those molecules ‘bud’ off the Golgi and travel to other place inside the cell OR travel to the plasma membrane and release their molecules outside the cell
ORGANELLES THAT CAPTURE AND RELEASE ENERGY! • Mitochondria (found in animals AND plants!) • Chloroplasts (only found in plants)
CELLULAR BOUNDARIES: • Cell walls: prokaryotes and plant cells • Provides shape • Provides support • Are OUTSIDE the plasma membrane • NOTE: cells that have cell walls also have plasma membranes: ALL cells have plasma membranes! • In plants, cell walls are made of cellulose Cell wall
Cell membrane (plasma membrane) • Surrounds ALL cells!!!! • Made of phospholipids • Selectively permeable