Biology Q98 – NEET-UG 2025

Home Biology Cell: Unit of LifeQuestion #128

From the statements given below choose the correct option : A. The eukaryotic ribosomes are

80 S

and prokaryotic ribosomes are

70 S

. B. Each ribosome has two sub-units. C. The two sub-units of

80 S

ribosome are

60 S

and

40 S

while that of

70 S

are

50 S

and

30 S

. D. The two sub-units of

80 S

ribosome are

60 S

and

20 S

and that of

70 S

are

50 S

and

20 S

. E. The two sub-units of

80 S

are

60 S

and

30 S

and that of

70 S

are

50 S

and

30 S

Clue 1 of 3: Ribosome Types

Recall the two main types of ribosomes based on their sedimentation coefficient and the organisms they are found in.

🧠 Full Solution Path

Step 1: Evaluate each statement regarding ribosomes✦ Active

A. Eukaryotic ribosomes are $80 S$ (found in the cytoplasm) and prokaryotic ribosomes are $70 S$ . This statement is **True**.

B. All ribosomes (both $70 S$ and $80 S$ ) are composed of two subunits: a large subunit and a small subunit. This statement is **True**.

C. The $80 S$ eukaryotic ribosome consists of $60 S$ (large) and $40 S$ (small) subunits. The $70 S$ prokaryotic ribosome consists of $50 S$ (large) and $30 S$ (small) subunits. This statement is **True**.

D. This statement incorrectly lists the subunits of $80 S$ as $60 S$ and $20 S$ (should be $40 S$ ) and $70 S$ as $50 S$ and $20 S$ (should be $30 S$ ). This statement is **False**.

E. This statement incorrectly lists the subunits of $80 S$ as $60 S$ and $30 S$ (should be $40 S$ ). This statement is **False**.

💡 Teacher's Secret Hint

Remember that Svedberg units (S) are a measure of sedimentation rate, not molecular weight, so the S values of subunits do not add up directly to the S value of the whole ribosome.

Step 2: Identify the correct combination of true statements○ Expand

From the evaluation in Step 1, statements A, B, and C are true. Statements D and E are false.

Step 3: Select the option that matches the true statements○ Expand

Option (1) states that A, B, C are true, which aligns with our findings. Therefore, option (1) is the correct answer.

💡 Teacher's Secret Hint

Carefully cross-reference your true statements with each given option to avoid errors.

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Biology Question 98 – NEET-UG 2025

Clue 1 of 3: Ribosome Types

🧠 Full Solution Path