Bio Lesson 5

organelles

-discrete internal macromolecular structures w/ specialized functions

-can be pro/eukaryotic

electron microscope

-a microscope is needed to observe most cells

-illuminated w/ a beam of electron instead of light

prokaryotic cells

-unicellular

-small

-lack internal compartments

-have cell wall

-may have capsule, pili, flagella

common features btwn prokaryotic and eukaryotic celss

-plasma membrane separates the cell interior (cytoplasm) from the extracellular environ.

-DNA is genetic material

-control of gene expression (DNA translates into proteins that carry out cellular functions controlled through gene expression)

-metabolic pathways (glycolysis, respiration, photosynthesis). all living things generate energy to stay alive

a common organelle btwn pro/eukaryotes

-the ribosome

-synthesize proteins by converting nucleotide sequence information into amino acid sequence information

-exist in cytoplasm in both P+E and on rough ER in eukaryotes. also exist in mitochondria and chloroplast of eukaryotes

animal cells

-nucleus

-ER and golgi

-lysosomes

-peroxisomes

-mitochondria

plant cells

-nucleus

-ER and golgi

-peroxisomes

-mitochondria

-chloroplasts

-vacuole

-cell wall

cytoplasm

everything inside cell membrane

applies to both P and E

cytosol

includes all cellular material enclosed by plasma membrane except for organelles

only applies to E

nucleus

-surrounded by 2 membranes

-has 2 functions: protect DNA and separate RNA synthesis from protein synthesis

-consists mostly of chromatin

-nucleolus synthesizes the RNA components of the ribosome

ER

-protein and lipid synthesis

-calcium ion storage

-detoxes harmful compounds

-proteins and lipids synthesized here move to other parts of the extensive membrane system via transport vesicles (golgi)

golgi

-protein and lipid modification

-protein sorting

endomembrane system

1. proteins and lipids synthesis in ER

2. move to golgi

3. after being processed in golgi, new vesicle forms and travels to plasma membrane, lysosme, or environment

exocytosis

1. vesicle containing protein buds from ER diffuses through cell and fuses to golgi

2. the proteins are modified and packaged into vesicles from transport

3. the vesicle may travel to the plasma membrane, releasing its content to the extracellular environment

lysosomes

-contain digestive enzymes that carry out the breakdown of molecules allowing the cell to recycle building blocks for the cell’s own synthetic reactions

-degrade old/damaged organelles and materials ingested by the cell

peroxisomes

-enclose variety of enzymatic reactions:

1. oxidation of fatty acids

2. biosynthetic reactions

3. detoxification (ex: H2O)

vacuole

-maintain water balance

-storage of small molecules

-storage of waste products

-macromolecule degradation

endosymbiosis

-accounts fro the origin of mitochondria and chloroplasts

-explains why both contain their own circular DNA and ribosomes, and why they divide within the eukaryotic cell via binary fission (normally only in prokaryotic cells)

-mitochondria came from bacteria that performed oxidative metabolism

-chloroplasts came from bacteria that perform photosynthesis

mitochondria

-contain ribosomes to facilitate expression of DNA

-in both animal/plant cells

-metabolize sugar to synthesize ATP

-reproduce by binary fission (1 divides into 2 to produce another mitochondria)

-2 membrane structure (inner and outer membrane)

-circular DNA

-ATP synthesis reaction occurs in inner membrane

-outer membrane interacts w/ cytosol

chloroplasts

-in plants

-uses light energy to synthesize ATP and sugars

-reproduce by binary fission

-3 membrane structure

-circular DNA

-ribosomes

cytoskeletal filments

-in eukaryotes only

-each filament system is…

1. polymers of protein subunits

2. dynamic due to non-covalent interactions

-assembled from

1. actin monomers

2. tubulin dimers (make up microtubules)

3. various monomers (ex: keratin make up intermediate filaments)

-3 types of filaments that comprise eukaryotic cytoskeleton: actin filaments, microtubules, intermediate filament

actin filaments

-generate the sliding mechanism that allows for muscle contraction

-in non muscle cells, actin is involved in cell shape/cell crawling

internal microtubules

-organization: vesicles use these microtubules to move btwn organelles, forming a transport system

-cell division: microtubules are anchored to DNA and helping to pull the DNA apart during cell division

external microtubules

-cell swimming

-cilia and flagella: microtubules work tg to create the movement and force needed to propel the cell

motor proteins

-drives movement

-requires energy (ATP)

-drive internal transport and external movement

intermediate filments

serve to support and protect the cell

the animal extracellular matrix

-while cytoskeleton provides structural support from the outside of cell, eukaryotic cells also secrete material that provide support from outside

-synthesized in the ER and sent to cell surface via endomembrane pathway

cell wall

-plants and fungi have this

-E+P cell walls are different

-plant cell walls are comprised of carbs (cellulose)

-fungi cell walls are comprised of chitin