Cellular Transport

AP Bio

Eukaryotic cells

• unicellular

• with nucleus

• mid Proterozoic era

• 100x larger than bacteria

origin of nucleus and ER

• infolding of cell membrane

• similar bacteria to psyn membrane

• surrounded DNA

• formed er

origin of mitochondria and chloroplasts

• endosymbiotic theory

• Eukaryotic cells take in bacteria as

  endosymbionts

  • Aerobic Bacteria became mitochondria

  • Cyanobacteria become chloroplasts

endosymbiotic theory evidence 4

1) Two membrane layers of

A) Outer membrane like host cell

B) Inner membrane like a bacteria

2) Mito. & chloro. have their own DNA

Circular Chromosome

Different genes than nucleus

3) Mito. & Chloro have own ribosomes &

Make own proteins

Ribosomes like bacteria

4) Mito & Chloro grow and reproduce on own

Phanerozioc Eon

540 million years ago -present

Phspholipid bilayer

hydrophilic heads phosphate

hydrophobic tails fatty acids

move and held together by hydrophobic interactions

Selective permeability

• very small or nonpolar molecules

• large polar monomers like glucose slow

• ions do not cross

• polar macro molecules not cross

cholesterol

• found in animal cells

• maintains membrane fluidity

• high temp restraints phospholipid movement

• low temp prevents close packing

membrane proteins

intergral - in the ecm

peripheral- on top of on bottom of ecm

membrane enzymes

• often grouped in teams

• active in metablism

• bind to cytoplasmic structures

attachment proteins

•  bind to ECM and cytoskeleton

•   maintain cell shape and location

•   non-covalent

recognition proteins

• . sort cells in embryo

• immune system self-recognition

• often glycoproteins (glycolipids)

inter cellular joining

•   a. gap junctions

•   b. adhering junctions

Receptor Proteins

• receptors – bind to chemical messenger  

                          (hormones, cAMP)

• b. binding signal molecule changes protein shape

• c. signals inside of cell by binding cytoplasmic protein causing transduction

Transport proteins

• a. channel proteins (aquaporin)

•   b. carrier proteins (glucose transporter)

•   c. protein pump

2 Types of Cellular Transport

Passive Transport = no energy needed

Active Transport = takes energy

diffusion

molecules make it through cell membrane on their own

facilitated diffusion

molecules that have to go through proteins to enter the cell

osmosis

diffusion of water must be through a membrane

tonicity

isotonic, hypertonic, hypotonic

isotonic

no net movement

hypertonic

more solute in solution

hypotonic

less solute in solution

osmoregulation

Control of solute and water concentrations inside a cell

Homeostasis to

remain isotonic

protein pumps

• Transport proteins that require energy

• Protein pushes molecules into areas where they are in high concentration.

• ATP is the energy used

endocytosis

• Cell takes in molecules by forming new vesicles at CM 

exocytosis

How cells secrete materials like hormones

a. transport vesicle buds from Golgi body

b. vesicle moved to C.M. by motor protein