Cells

• Mostly microscopic– Light microscopy upto 1000x

• Passes light through• E.g. typical plant & animal

cells

– Electron microscopy upto 100000x

• Scans sample with electron beam

• E.g. molecules (DNA)

• Prokaryotic– Bacteria and bacteria-like

• Eukaryotic– Fungi, Protista, Plants,

Animals

Prokaryotes vs. Eukaryotes

• Simpler• Smaller size• DNA without nucleus• Cell wall & other crude

protective layers• Lack organelles

• Complex• >10x larger• DNA in nucleus• Cell membrane

– Some also have cell wall

• Membrane bound organelles– specialization

Nucleus

• Genetic control center• DNA

– Replicates during cellular division

– Fibers = chromatin

• Sends instructions as RNA (in nucleolus) through pores – To synthesize proteins

(writes amino acid sequence)

Endoplasmic Reticulum

• Rough ER• Studded by ribosomes

– Assembles proteins for further processing

• Membrane system– Continuous with

nuclear membrane• Creates compartments• Acts as highway or

conveyer belt

Smooth ER

• Continuous with Rough ER

• Lacks the ribosomes• Uses enzymes to make

lipids– In sex cells, SER makes

sex hormones– In liver cells, SER

detoxifies– In muscle cells, SER stores

and releases Calcium for muscle contraction

Golgi apparatus• Shipping / Receiving department

– Receives proteins from ER, modifies, packages, labels for destination, within or outside of cell

Lysosomes – breakdown bodies

• RER packaged enzymes

• Golgi modified• Digests:

– Food in vacuole– Bacteria in blood– Damaged organelle

(recycles)

Vacuoles

• Membranous sacks w/o digestive enzymes

• Carry food in

• Storage– Water– Chemicals– Waste– Pigments– Poisons

Contractile vacuoles

• Water regulation– Water continues

to seep inside• Osmotic

properties and differences in concentrations

– Pump out excess– Prevents cells

from over-swelling or burst

Chloroplasts

• Photosynthesis = converts solar E to glucose• Continuous double membrane/compartment

system– Fluid stroma– disks or grana = solar power packs

Mitochondria

• Converts glucose (stored E) into cellular E (ATP)– Potential E to chemical

E to Kinetic E– Via cellular respiration

• Double membrane & compartment system– Fluid matrix– Folds or Cristae to

increase Surface Area

Cytoskeleton – structural proteins• Microfilaments – cell structure & cell contraction• Intermediate filaments – cell structure and anchoring• Microtubule – organelle support & movement

Cilia & Flagella

• Locomotor microtubules

• Short, numerous• Long less numerous

Cell Surfaces

• Cell wall, plasma membrane, or capsules

• Plant cell wall– Cellulose fibers for

structure & support– E.g. wood is almost all cell

wall material– Plasmodesmata for

intercellular communication• Animal cell membranes

– Tight junctions = leakproof– Anchoring junctions =

strength– Gap junctions =

intercellular communication