Question

What are the sizes of the subunits of the E. coli 70S ribosome?

A. 40S and 60S
B. 30S and 50S
C. 50S and 70S
D. 60S and 80S

Answer 1

The sizes of the subunits of the E. coli 70S ribosome are 30S and 50S. So the correct answer is B. 30S and 50S. The 30S subunit is smaller and the 50S subunit is larger, and together they form the 70S ribosome. Each subunit plays a crucial role in protein synthesis.

Answer 2

The E. coli 70S ribosome is composed of 30S and 50S subunits, which represent the sizes of the small and large subunits respectively.

Step-by-step explanation:

The sizes of the subunits of the E. coli 70S ribosome are the 30S small subunit and the 50S large subunit. This is because the E. coli ribosome is prokaryotic and its subunits add up to form the 70S ribosome, where S represents Svedberg units, a measure of the rate at which particles sediment in a centrifuge. It's important to note that Svedberg units are not additive, so the 30S and 50S subunits combine to form the 70S ribosome, but their individual numbers don't simply add up to 70. In contrast, cytoplasmic eukaryotic ribosomes are 80S ribosomes, composed of a 40S small subunit and a 60S large subunit.