l04 eukaryotes (lecture slides) eukaryotes (lecture slides).pdf2/3/20 1 l04: eukaryotes biol 153/l...
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L04: Eukaryotes
BIOL 153/LBlack Hills State Univ.Ramseys See 'Tree of Life' Lecture
Three Domainsof Life
I. Prokaryotic vs. eukaryotic cells Prokaryotes EukaryotesDNA X XNucleus XMitosis & meiosis XRibosomes X XMembrane-bound organelles XCell wall X Many (not animals)
Multicellularity Often
II. Eukaryotic 'Plant' vs Animal cells
for this lecture:
'plant' => land plants + algae
land plantsgreen algaered algae
brown algaegolden algaediatoms
See 'Tree of Life' Lecture
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'Plant' cells Animal cells
Cell wall X
Cell type diversity Less More
Mitochondria X X
Chloroplasts X
Vacuoles Always(large vacuoles)
Often(small vacuoles)
III. Eukaryotic cell components
A. Nucleus
membrane-bound compartment containing linear DNA (chromosomes)
nucleus disassociates during mitosis and meiosis
B. Cytoplasm
living matter of cell, outside nucleus
cytosol is term for the cytoplasm 'goo'
nucleus
cytosol
cell membrane C. Organelles
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1. Definition of organelle
• Narrow: membrane-bound structure in cytoplasm
• Broad: any cell structure outside nucleus
2. Membrane-bound organelles (examples)
a. Mitochondria
2x membrane-bound organelle; performs aerobic respiration
b. Chloroplast
2x membrane-bound organelle; performs photosynthesis
c. Vacuole
membrane-bound space with water, organic + inorganic molecules, enzymes
functions in storage, materials isolation, turgor pressure
d. Eyespot apparatus
membrane-bound organelle;senses light direction + intensity
found in many unicellular photosynthetic organisms
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nucleus
cytosolmitochondria
chloroplast
cell membrane
vacuole
3. Non-bound organelles (examples)
a. Ribosome
small structure composed of protein + RNA
site of protein synthesis in cell cytoplasm
b. Flagella
threadlike structure protruding from cell;function in movement
found in many unicellular photosynthetic organisms, sperm of many multicellular photosynthetic organisms
D. Cytoskeleton
network of microtubules + actin filaments in cytosol
in-cell movement (cell division, cytoplasmic streaming, etc.)
E. Cell wall
structural layer outside cell membrane; provides support + protection
complex composition usually including carbohydrate polymers and microfibril structures
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eukaryotes very traditionally called 'plants'(prokaryote cell walls different)
1. Taxonomic distribution
land plants, algae, fungi, many protists
2. Land Plant cell walls
a. Multiple layers
• 1º cell wall: flexible, exterior
• 2º cell wall: rigid, interior (not always present)
• middle lamella: interface between cells
b. Composition
• 1º cell wall: cellulose, hemicellulose, pectin
• 2º cell wall: lignin, cutin, suberin
c. Plasmodesmata
small channels traversing cells walls
allow regulated communication + transport among cells
intercellular space
plasmodesmata
nucleus
cytosolmitochondria
chloroplast
cell wall
cell membrane
middle lamella
vacuole
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3. Other cell walls • Fungi: chitin
carbohydrate that provides rigidity to fungal cell walls
• Fungi: chitin • Diatoms: silica (glass)
SiO2 provides strength and ridigity to cell wall
• Diatoms: silica (glass) • Brown algae: alginate
reacts with calcium in ocean water, creates flexible gel