The Cell

Life inside the Cell

Light microscope

Light through specimen refracted by lens up to eye

Magnify 1,000 times (bact. .2um micrometer)

Condenser lens: below specimen aim light

Objective lens: above specimen magnify

Ocular lens: magnify

Electron microscope

Lens = electromagnet NOT glass.2 nm (nanometer)

Magnification = ratio of image to its real size

Resolving power = clarity of picture (2 point differentiation)

The Cell

Structure relates to functionEvolution: all cells evolved from earlier

cells with modificationsInteraction with environment: cells

sense: sound, sight, hot/cold

Prokaryotic and Eukaryotic

Cytosol - fluid around organelles: found within membranes (cytoplasm; region)

Ribosomes - create the proteinsPlasma membranesChromosomes (DNA): genetic code

Eukaryotic

DNA found in nucleus True nucleus

Organelles Bigger 10-100 um in diameter Domain

EukaryaAnimalPlantFungiProtista

Prokaryotic

DNA found in nucleoid1-10 um in diameterDomains

Archaea Found in inhospitable environments

Ex: places with 0 light, wicked salty places, hot

Bacteria

Prokaryote

Bacteria: smallest cells mycoplasmasSmallest package with enough DNA to

program metabolism and enough cell equipment to sustain life and reproduce

Cell Membrane

Phospoholipid bilayerEmbedded proteinsCell size

Selectively permeable Based on diffusion, osmosis

Nucleus

Chromatin condenses to chromosomes(46 in humans)

mRNADNA

Nucleolus

Ribosomal RNA synthesized here on instructions from DNA

Ribosomal subunits: rRNA and proteinsMultiple subunits leave nucleus and

form ribosomes

Smooth Endoplasmic Reticulum

Passage: labyrinth of membranes Synthesize: Sex hormones and lipids Carbohydrate metabolism, detoxify In Muscle: holds Ca++ out of cytosol

stimulation: Ca++ rushes back into muscle cell and allows contraction

Rough Endoplasmic Reticulum

Ribosomes bound to nuclear memb or rough ER: protein synthesis Make membranes Lysosomes secretion

Free floating: make proteins that work in cytosol

Ribosomes in mitochondria or chloroplasts: make membrane for same

Golgi apparatus

Golgi Apparatus: packagingCisterna: small sacs

2 poles cis and trans Cis: receiving Trans: shipping

Organelles

Lysosome: phagocytosisautophagy (eat old cell parts-

recycle)Ameoba: digestion macrophage: eat bacteria

Peroxisomes:oxidation; Take H from other things add it to O = H2O2 (has enzyme to change that to H2O) = detoxify

Use O2 to break fatty acids…detox alcoholMany in liver

Plants

Glyoxysomes: specialized peroxisomes Found in plant seeds Begin to convert fatty acids to sugar for

use by seed

Organelles

Vacuoles: Storage Hydrolysis

Food vacuoleContractile vacuole: in fresh water

protists

Plant vacuoles

Plants: large central vacuole store: Sap, waste, poison color

Tonoplast: outer membranes of vacuole

Chloroplasts

Photosynthesis: synthesize organic molecules

Chloroplasts belong to group of organelles: plastids

Chromoplasts: color orange/yellowAmyloplasts: store amylose starch in

roots

Chloroplasts

Contain chlorophyll and enzymesHas double membrane (mitochondria)Thylakoid: membrane sacs

granum: stack of thylakoidStroma: fluid outside the thylakoids

contains the chlorplast DNA + ribosomes

Mitochondria

Bilipid membrane with cristaeSome DNACell respiration

electron transport chain in inner membrane

Energy

Eukaryotic cellsMitochondria: cell respirationMake ATP: extracting energy from

sugar, fat with oxygenFound in nearly all eukaryotic cells

(plant, animal, fungi, protists)# of mitochondria related to activity

Centrosome

Region where the cell’s microtubules are initiated

Animal cells: centriolesPlant cells : no centrioles

Animal cells + Plant cells

Both: eukaryotic Nucleus (nuc envelope, nucleolus,

chromatin)Centrosome CytoskeletonRough/ smooth ER Plasma Memb.Ribosomes PeroxisomesGolgi apparatusmitochondria

Plants not Animal

ChloroplastCentral vacuole and tonoplastCell wallPlasmodesmata (holes in cell wall

allowing cytosol of 1 cell contact with neighboring cells

Animal cells

LysosomesCentrioles

Intercellular Junctions

Plants: PlasmodesmataAnimals:

Desmosomes: anchor cells (skin)Tight juntions: seal cells (intestine)Gap junctions: allow communication (heart)

Cytoskeleton

Cytoskeleton: Movement: with motor proteins and with

cilia, flagella Organelle placement

Cytoskeleton: Cilia and Flagella

Cilia: attached to fixed cell. 1 cell has many cilia…..sweep food or waste along

Flagella: 1 cell has 1. for movement

Cilia and Flagella (Both)

9 and 2 configuration: 9 microtubules around 2 in middle

Attach to basal body in cell (similar structure to centriole)

Cytoskeleton: Microtubules

Microtubules: hollow made of tubulinGrow out of centrosome (pair of

centrioles)Function in cell divisionTracts for organelle movement: motor

molecules

Cytoskeleton: Microfilaments

Microfilaments: solid rods, made of Actin

Muscle cells have 1,000’sUse motor molecules (to get myosin to

slide along actin)Psuedopodia of amoeba: cytoplasmic

streaming

Extracellular Matrix

Glycoproteins: cell to cell communication

Proteoglycans: on outside of cell for ID

Intergrins:all proteins bind to these on outside of cell and make serious changes INSIDE and OUTSIDE the cell.

Cell Wall: plants

Cell wall: Cellulose Proteins Polysaccharides Pectin (starch)

Cell Membrane

Cell Membrane (animal) Phospholipid bilayer Imbedded proteins: protein channels Cholesterol Glycoproteins: cell to cell recognition