cell parts

light microscopes

magnification

resolution

contrast

visible light is passed through the specimens and then through the glass lens

the lens refractions (bends) the light so that the specimen is magnified

mag → ratio of objects image size to real size

resolution → clarity of the image (2 points distinguishable as 2 points)

contrast → accentuates differences in parts of sample

electron microscope

focuses a beam of electrons through the specimen or onto its surface

inversely related to wave length and = 0.002 nm

scanning electron microscope

topography of a speciment. E beam scns surface of smaple (usually coated with gold) → image of surface that appears 3-d

transmission electron microscope

study internal of cells. electron beam through thin section of cell

cytology = the study of cell structure

cell fractionation

take cells apart and separates organelles

centrifuge

Euk vs Pro

euk: DNA in nucleus, larger/more complex, membrane bound organelles (plants, animals, fungi)

pro: DNA not membrane enclosed (nucleiod), smaller, bacteria and archaea

both: cytoplasm, cytosol, chromosomes, ribosomes, plasma membrane

Surface area to volume

as size increases, volume increases proportionally more

smaller object has greater ratio of SA to volume

larger organisms have more cells (not larger)

plasma membrane

selectively permeable

nucleus

where genes are contianed, big, enclosed in nucleolus)

chromosomes → contain one long DNA molecule and proteins

nucleolus → fibers adjoining parts of the chromatin (mRNA synthesized here)

nuclear envelope

double membrane lipid bilayer

nuc pores → pore complex lines each pore and plays an important role in the cell by regulating the entry and exit of proteins and RNA and macromolecules, regulate entry

nuclear lamina → network array of proteins filament that maintain shape

ribosomes

made of rRNA

no membrane

carry out protein synthesis

free → cytosol

bound RNA → ER or nuc envelope

cells designed for secretion (pancreas) with transport vesicles have higher bound R levels

endomembrane system

nuclear envelope, ER, golgi, lysosomes, vesicles, vacuoles, plasma membrane

synthesize proteins transport of proteins, metabolism, movement of lipids, detoxification

direct physical cont or vesicles

not identical in structure or function

function can be modified during mems life

ER

Functions: synthesizes membranes, compartmentalize the cell to keep proteins formed in the rough er separate from those of free ribosomes

smooth er → synthesis of lipids, metabolism of carbs, detoxification, storage of calcium ion

lipids → oils, phospho, steroids (sex hormones)

posions → enzymes (liver)

calcium → cytosol → er lumen (muscles)

rough er

protein synthesis → r translate mRNA → polypeptide chains that thread directly into the er lumen

folding and modification → in lumen, modifications, 3d shape

quality control, transport to golgi

golgi

functions: recieves transport vesicles with material from the er, proteins modified and stored, add molecular tags (help reach final destination), packages materials into new transport vesicles that exit the membrane via exocytosis

flatten membranous sacs (cisternae, not connected) → separate sacs from th cytosol

cis face receives vesicles and trans face sends (vesicles pinches off, delivery)

cis → modified → trans

lysosomes

membranous sac of hydroytic enzymes (made in r er → golgi) that hydrolysize mac molecules

lysosomal enzymes work best in lysosome acid

autophagy: lysosomes can recycle their own cell’s organic materials (allows the cell to renew itself)

vacuoles

large vesicles derived from er and golgi, selective in transport

food vacuole → fuses with lysosome to digest (phago, cell eating), lysosome fuses with it and digest contents inside

contractile vacuole → pumps water out cell (freshwater protists)

central vacuole → central vacuole (growth with water) found in plants, important for turgor pressure, contains inorganic ions and water

endosymbiant theory

the theory that explains the similarities mitochondria and chloroplasts have to a prokaryote

an early euk cell engulfed a prok

pro cell became an endosymbiont (cell that lives in another cell)

became one functional organism

evidence: double membrane, rubo, circular DNA, capable of functioning on their own

mitocondria

animal, plant, fungi, protists: site of cellular respiration

two phospholipid bilayer membranes, double membrane: outer membrane is smooth, inner has folds call cristae

most cells have many determined by metabolic activity (muscles)

cristae - interfolds into two compartments and gives large SA

inner membrane space: space between inner and outer membrane

mitocondria matrix (enclosed by inner membrane): location for the krebs cycle (contains enzymes and DNA and ribo)

chloroplasts

chlorophyll and photosynthesis = green pigment found in green organs of plants and algea

Inside of its double membrane: thylakoids (membranous sacs that can organize into sacs called grana, LD reaction occur here)

stroma = fluid outside thylakoids, (contains DNA, enzymes, ribosomes, location for CC)

membranes divide into 3 compartments → inner membrane space, stroma, thylakoid space

plastid family

peroxisome

single membrane

contains enzymes that remove H atoms from various substrates and transfer them to 02 = hydrogen peroxide (H2O2) as biproduct

different functions → break fatyt acids for mito, liver detox

H2O2 is toxic → enzyme converts it to H2O (split into parts so poison can’t spread)

cytoskeleton

structural support, mechanical support, motitily (anchors to keep shape, dynamic), signal transmission

network of fibers

allow for movement of vesicles and organelles and/or the whole cell

motility

motility = changes in cell location + limited movements in part of the cell, interactions with motor proteins (allow whole cell to move along fibers outside the cell, used as feet to walk)

cilia and flagella

microtubules

hollow rods, wall constructed from tubulin, a tubulin and b tubulin (grow from centrosome)

assist in microtubule assembly, serve as structural support for the movement of organelles that are interacting with motor proteins, motility

assist in sep chromosomes during cell division

shape and support, tracks with motor proteins to help organelles move

guide secretory vesicles from golgi → plas mem, separate chromosomes

centrosome

near nucleus, organize microtubules

centrioles

in centrosome

cilia and flagella

movement (cilia can be signal receiving)

made of microtubules

microfilaments

thin solid rods, built from actin protein, double helix, maintain cellular integrity

pseudopodia _> crawling movements

muscle contraction, maintain cell shape

actin and myosin cause a contraction

cytokinesis

intermediate filaments

fibrous proteins made up of varying subunits

permanent strucrual elements of cells

maintain cell shape, anchor nucleus and organelles, form the nuclear lamina (lines the nuclear envelope)

cell wall

protects, shapes, uptake of water

hold plants up against gravity

microfibrils made of cellulose

middle lamella between primary walls of adjacent cells, thin layer with protein glues cells together

extracellular matrix (ecm)

glycoproteins (collagen)

fibrocencrim attach ecm to cell

integrin - receptor proteins

compartmentalization

membrane bound structures in euk important for compartmentalization

allows for different metabolic reaction to occur in diffeernt locations

icnreases SA for reations

prevents interfering reations from occuring in the same location.

plants vs animals

plants: plasmodesmata, cell wall, central vacuole, chloroplasts

animal: lysosomes, centrosomes, flagella