Lecture 2A: Nutrient Transport through the cell membrane: Active Transport Flashcards
-utilizes energy, often in the form of ATP, to drive solute uptake against its gradient resulting in a net accumulation of the solute.
Active transport
Consist only of a transmembrane transport proteins
Simple transport
Employs a series of protein in the transport event.
Group Translocation
Consist a substrate-binding protein: a transmembrane protein, and and ATP-hydrolyzing protein
ABC transport system
Transmembrane component of all transport systems is composed of a polypeptide containing ___ _______ that weave back and forth through the membrane to form a channel.
12-domains
Through ________ ____ that the solute is transported into the cell.
Transmembrane channel
Transport is linked to a ________ ______ in this transmembrane protein (occurs when upon binding to specific solutes).
conformation change
Three main transporters of nutrients in Bacteria and Archaea
- Simple Transport
- Group Translocation
- ABC Transporter
driven by the energy inherent in the Proton Motive Force
Simple Active transport reactions
where a solute and a proton are co-transported in one direction
Symport
where a solute and a proton are transported in opposite directions
Antiport
Group translocation differs from simple transport in two ways:
- The transported substance is chemically modified during the transport process.
- an energy-rich organic drives the transport event.
Five proteins for glucose transport in Phosphotransferase system in E.coli
Enzyme 1
Enzyme IIa
Enzyme IIb
Enzyme IIc
and HPr
Transport systems that employ a periplasmic binding protein along with transmembrane and ATP-hydrolyzing components
ABC transport systems
Other mechanisms of moving solutes in and out of cell
- Pinocytosis
- Phagocytosis
- Exocytosis
Cell drinking
Pinocytosis
Cell eating
Phagocytosis
excrete large molecules, generate secreting or transport vesicles
Exocytosis
Group translocation mechanism
Chemical modification
of the transported
substance driven by
phosphoenolpyruvate
simple transport mechanism
Driven by the energy
in the proton motive
force
Mechanism of the phosphotransferase system of Escherichia coli
PEP passes phosphate - Enzyme I - HPR -Enz IIa - Enzyme II b - Enzyme II c
ABC transporter mechanism
Periplasmic binding
proteins are involved
and energy comes
from ATP.
Transport systems that employs a periplasmic binding protein along with transmembrane and ATP-hydrolyzing components
ABC transport system
