Question

Transporters, in contrast to channels, work by specific binding to solutes. A gating mechanism filtering solutes by charge filtering solutes by size.

Answer 1

20.C as all the cells at the resting conditions have a potential difference across the membranes,with the inside of the cell negatively charged with respect to outside.

21.A specific binding to solutes.Solutes that are either small organic or inorganic ions can pass via tranporters.

22.B because even a small increase in calcium ions influx significantly increases the concentration of calcium in the cytosol and the flow of calcium down its steep concentration gradient in response to extracellular signals.

23.C

24.C usually found at the n-terminus of the protein and its location determines where the protein will end up.

25.C in a cell that lacks mannose 6 phosphate receptor for lysosomal enzymes,then the lysosomal enzymes becomes glycosylated and secreted from the cell.

26.D insulin contains hydrophobic signal sequence for the transport of nascent protein through the microsomal membranes of the rough endoplasmic reticulum.