2.2 Prokaryotic Cells

 Smooth pencil lines, ruled label lines, labels parallel to top of page, label lines do not cross  The diagram should show the cell wall, plasma membrane, cytoplasm, pili, flagella, 70S ribosomes and nucleoid (region containing naked DNA)

 cell wall ◦ Protection, support shape  plasma membrane ◦ Permeability, binary fission  Cytoplasm ◦ Suspends internal structures  pili, flagella ◦ Pili-Hair-like, for attachment during conjugation ◦ Flagella-motility  ribosomes ◦ All prokaryotes, protein synthesis  Nucleoid ◦ region containing naked DNA (single, circular chromosome) ◦ May contain plasmids—not connected to main chromosome; “extra” DNA may help bacterial cell adapt to unusual circumstances

 DNA copied  2 daughter chromosomes attach to diff regions of plasma membrane  Cell divides into 2 genetically identical daughter cells

Asexual Reproduction

 What’s a disadvantage of prokaryotic cells having their DNA free in the cytoplasm without a nuclear membrane?  What structures are involved in sexual reproduction in prokaryotic cells? 

2.3 Eukaryotic Cells

EndosymbioticEndosymbiotic Theory

 free ribosomes,  rough endoplasmic reticulum (rER),  lysosome,  Golgi apparatus,  Mitochondrion  nucleus  Smooth pencil lines, ruled label lines, labels parallel to top of page, label lines do not cross

 free ribosomes ◦ Protein synthesis (in cytoplasm); RNA + protein  rough endoplasmic reticulum (rER) ◦ Transports materials through cell ◦ Attached ribosomes, protein synthesis (closer to nuc memb & continues to smooth ER, attached to pl memb)  Lysosome ◦ Single membrane, from Golgi ◦ contain hydrolytic enzymes (brkdown ptn, nuc acids, lipids, carbs) ◦ Phagocytosis; recycle cell parts; usually only in animal cells

 Golgi apparatus ◦ Collect, package, modify, distribute materials ◦ Cis near ER; trans near pl memb ◦ Vesicles  Mitochondrion ◦ ~size of bacterial cell ◦ Own circular DNA, own 70S ribosomes ◦ Double membrane, matrix ◦ Cell respiration to produce ATP  Nucleus ◦ Contains DNA  Wrapped around histones ◦ nuclear (dbl) membrane regulates in/out somewhat (pores)

PROKARYOTESEUKARYOTES Naked DNA, in a ringNot cuircular; Assoc w/proteins DNA in cytoplasmEnclosed w/in nuclear envelope No mitochondriaMitochondria 70S ribosomes80S ribosomes (bigger, denser) No compartmentalizationInternal membranes compart. To form organelles and separate functions/chem rxns; increases efficiency Peptidoglycan cell wallPlants, algae – cellulose; Fungi – chitin; yeast – glucan/mannan Binary fissionMitosis Small (1-10 um)Larger (5-100 um)

 Outer boundary, always at least includes plasma membrane  Both carry out all functions of life  DNA in each

Comparison Video

PLANTSANIMALS Outer cell wall, inner plasma membrane Outer plasma membrane (no cell wall) Chloroplasts in cytoplasmNo chloroplasts Large central vacuoleNo vacuoles or are small Store carbs as starchStore carbs as glycogen No centrioles within centrosome area Contain centrioles within centrosome area Rigid cell wall gives it a fixed, often angular shape No cell wall, so it’s flexible and more likely rounded shape Similarities—other organelles

 The plant cell wall maintains cell shape, prevents excessive water uptake, and holds the whole plant up against the force of gravity.  Animal cells secrete glycoproteins that form the extracellular matrix. ◦ Collagen + glycoproteins anchor matrix to pl membrane ◦ Adhesion between cells ◦ Cell migration, movement ◦ MAY be related to stem cell differentiation

 Why do muscle cells have a large # of mitochondria?  Name 2 organelles that are similar to prokaryotic cells  If plant cells have chloroplasts for photosynthesis, why do they need mitochondria?