In most companies, they're just different names for the same role. They're all typically the person who either does outbound calling for an account rep or who answers inbound leads, filtering them for an account rep. The typical progression is the following: BDR, SDR, LDR - development rep. Answers inbound leads, makes outbound calls, generates new opportunities for a rep. Sales Rep, Account Rep, Account Executive - salesperson. does the actual selling, builds longer term relationships, closes deals.
The plasma membrane is the outer lining of the cell. It separates the cell from its environment and allows materials to enter and leave the cell. Ribosomes. Ribosomes are organelles that process the cellâs genetic instructions to create proteins.
Nutrients, such as sugars or amino acids, must enter the cell, and certain products of metabolism must leave the cell. Such molecules can diffuse passively through protein channels such as aquaporins in facilitated diffusion or are pumped across the membrane by transmembrane transporters.