active transport requires use of energy because it does not happen naturally through diffusion or...
TRANSCRIPT
Active Transport
Requires use of energy because it does not happen naturally through diffusion or facilitated diffusion.
Requires a carrier protein* that uses energy from ATP molecules (Adenosine Tri-Phosphate, a nucleotide that stores energy and can release it when bonds are broken.)
Why? Moving stuff against the concentration gradient requires a “pump”.
ORFusing/rebuilding of cell membranes
Compare Membrane ProteinsActive Transport vs. Facilitated Diffusion :
Both use…. Carrier Proteins
But only active transport carrier proteins require…
ATPBecause they need energy to change their
shape!
ATP
Sodium – Potassium Pump
Ph
osp
hol
ipid
B
ilay
er
Na+
Ph
osp
hat
es f
rom
A
TP
bre
akd
own
K+
Active Transport - Bulk Transport
One large or many small particles moved in or out of cell using membrane bubbles called vesicles that can fuse with the cell/plasma membrane
Exocytosis – materials moved out of cellEx.: secretion of tears & sweat
Active Transport - Bulk Transport
Endocytosis – materials moved into cell
Phagocytosis – “cell eating” solid particle(s) taken inEx.: phagocytes such as macrophages & other immune cells ingesting bacteria
Pinocytosis – “cell drinking” liquid/many small particle(s) taken inEx.: Cells “gulping up” plasma from blood, leaving RBCs in blood
08-19a-PhagocytosisAnim.mov
08-19b-PinocytosisAnim.mov
Endocytosis?
Exocytosis?
# 2
# 1
#3
Endocytosis
1. Pinocytosis
2. Phagocytosis
Contractile Vacuole
‘Sump Pump’ in unicellular aquatic organisms
Environment is 99% Water
Cell is 95% Water
Active or Passive?