Question

In ABC transporters, the ATP binding cassette faces the?

1) cytoplasm
2) periplasm
3) There is no set orientation of the protein in the membrane
4) extracellular environment

Answer 1

In ABC transporters, the ATP binding cassette is oriented towards the cytoplasm. It uses energy from ATP to change shape and transport substances across the cell membrane.

Step-by-step explanation:

In ABC transporters, the ATP binding cassette faces the cytoplasm. When ATP binds to the transporter, it induces a conformational change in the protein, resulting in the transported substance being moved across the membrane. Specifically, the process usually involves the following steps: (1) with the enzyme oriented towards the cell's interior, the carrier has a high affinity for ions or molecules. After binding, (2) ATP is hydrolyzed and a low-energy phosphate group attaches to the carrier protein. Consequently, (3) the transporter changes its shape and re-orients itself towards the exterior of the membrane, releasing the substances due to a decreased affinity.