Module 3 Cells Flashcards
Robert Hooke 1665
Discovery of cells
Cell size limited because:
Huge volumes pose problems for diffusion
Radius, Surface Area, and Volume of Cell
- Radius: 1x, 2x, 3x
- Surface Area: 1(radius), 2(radius), 3(radius)
- Volume: 1(Surface Area), 2(Surface area), 3(Surface area)
Cells overcome surface area-to-volume problem:
- Folding or expanding their shape
- Storing nutrients or compartmentalizing: don’t rely much on external diffusion
Light Microscopes
- Magnifying lenses with VISIBLE light
- 200 nm apart
- Magnifies up to 1,200x
Electron Microscopes
- Beams of electrons
- 0.2 nm apart
- Magnifies more than 500,000x
Atomic Force Microscopy and Nextgen
View molecules beyond picometer scale
Cell components
- Plasma Membrane (Phospholipid bilayer)
- Cytosol (Cytoplasm)
- DNA (Chromosomes)
- Ribsomes (rRNA + Protein)
Plasma Membrane
Controls what goes in/out
Cytosol (Cytoplasm)
Semifluid medium for biochemical processes
DNA (Chromosomes)
Genetic information
Ribosomes (rRNA + Protein)
Make proreins for the cell
Two Cell Types
- Prokaryotic
- Eukaryotic
Prokaryotic Cell Branches
Bacteria and Archaea Branch
Eukaryotic Cell Branches
Eukarya
IMPORTANT*
Prokaryotic Cell
- Lacks membrane-bound nucleus
- One circular chromosome (DNA) in nucleoid
- Plasmid
- Ribosomes
- No membrane-bound organelles
- Cell Wall: Prevent excessive uprake or loss of water
- Can have flagellum
Plasmid
- Small circular DNA that carries extra genes
- Can be exchanged between cells
IMPORTANT*
Eukaryotic Cell
- Multiple linear chromosomes in double-membrane Nucleus
- Extensive compartmentalization and organelles
IMPORTANT*
IMPORTANT: STUDY ALL ORGANELLE LOCATIONS IN EUKARYOTIC CELL (look in slides)
IMPORTANT*
Endosymbiotic theory: Lynn Margulis
Some of today’s eukaryotic organelles evolved by a symbiosis arising between two free-living cells.
Endosymbiotic Theory Evidence
- Double membrane in both mitochondria and chloroplasts
- Ribosomes in organelles similar to bacterial ribosomes
- Mitochondria and Chloroplasts replicate independently in cell (similar to binary fusion)
- Have their own circular DNA
IMPORTANT*
IMPORTANT: STUDY EUKARYOTC ORGANELLES CROSS SECTION (in slides)
Cell Fractionation
- Take cells in culture and put them in Homogenizator (blender) and disrupt membrane to break cells open (Homogenization)
- All contents of cell released into environment. (Homogenization)
- Take Homogenate and centrifuge it. (Differential Centrifugation)
- Pellet: Nuclei and cellular debris
- Supernatent: Solution containing rest of cell
- Take Supernatent out and keep centrifuging. Most centrifuged pellet is rich in ribosomes.
Endomembrane System
series of membranes that are functionally interrelated
* nucleus, nucleur envelope, ER, vessicles, Golgi Body
Endoplasmic Reticulum
- Connected to nucleur envelope
Rough Endoplasmic Reticulum (RER)
- Studded with ribosomes
- Synthesis of membrane proteins and proteins to be secreted by cell
Smooth Endoplasmic Reticulum (SER)
- No ribosomes
- Lipid synthesis, stores CA2+, detoxification
Golgi Apparatus
- Shipping and receiving of endomembrane
- Flattened stacks of interconnected membranes (Golgi bodies)
- Proteins from ER are tagged with moecules that function as addresses for final destination
- Packaged into vesicles with transport molecules to plasma membrae for exocytosis or become lysosomes
Golgi Produces:
Transport vesicles and lysosomes
