Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Active Transport
We have mentioned above that Transmembrane potential develops due to active transport of ions (H+) outside the cell. Since this transport takes place again& a concentration gradient it utilises energy of hydrolysis of ATP. The proton motive force generated by proton pumping provides the driving force for the transport of solutes including cations, anions, amino acids and sugars. Electrical potential and pH measurements of intact plant cells have suggested that proton pumps are localised on the plasma membrane. The plant plasma membrane ATPase is a transmembrane protein composed of a single polypeptide chain of 100 KD. The most possible coupling mechanism between ATP hydrolysis and proton transport is shown in Figure.
Figure: Simplified picture of active transport.
The enzyme exists in two conformations differing in catalytic and transport properties. In conformation I, the transport site faces the cytoplasm and has high affinity for protons. In conformation II the transport site is externally oriented and has low affinity for protons. The enzyme is forced to alternate between these two conformations and to bind and release the transported proton because neither conformation can affect the complete catalytic cycle. In conformation I, the enzyme acts as a kinase; after binding a proton it catalyses the formation of phosphorylated intermediate. In the new state (conformation II) if acts as a phosphatase and after releasing the proton it returns to its original state, conformation I.
Organisms are made to compete for their needs from the environment. The competition as we pointed earlier could be for the food and territory, to overcome the adverse climatic cond
Define Proteins in the immune system? Proteins such as γ-globulin serve to protect the body against foreign cells. The immunoglobulin produced by lymphocytes is the large polyp
What are secondary roots? In origin how secondary roots differentiate from shoots? Secondary roots are ramifications of the primary (major) root. The secondary roots emerge fro
Explain Bidirectional Glenn Shunt under cardiopulmonary Bypass ? The ascending aorta and SVC at innominate jugular vein junction and IVC are cannulated and child connected to c
Intergenic: Amongs the two genes; for example intergenic DNA is the DNA found amongs two genes. The term is frequently used to mean non-functional DNA (or at least DNA with no kno
Light and Heavy Soils The presence of silt and especially clay in a soil imparts to it a fine texture, and a slow water and air movement. Such a soil is highly plastic becoming
Point out some Guidelines for breast-feeding? 1) Follow demand feeding of the baby instead of a fixed schedule. 2) Initiate breast-feeding within 2 h after a normal delivery
Cages for keeping animals in the science room It is frequently desirable in elementary and general science to stay animals caged in the science room for short periods of observ
Fowl pox Fowl-pox is a highly infectious disease of poultry, especially chickens and turkeys. Pheasants, ducks, geese and guineafowls also suffer from an infection similar to f
Explain Conventional Factors ? Smoking, Hypertension, diabetes mellitus, obesity, hypercholesterolemia, and reduced physical activity are considered as conventional risk factor
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd