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: 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 _____

COMPOUND LIGHT MICROSCOPE

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

3. All cells come from other 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: Membrane bound organelles All bacteria

WHAT IS IN A CELL? Cytoplasm organelles

PROKARYOTES:

THE ANIMAL CELL:

THE NUCLEUS

CHROMATIN

NUCLEAR ENVELOPE AND NUCLEAR PORES

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

Vesicles

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)

Mitochondria Structure:

Chloroplast Structure:

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