Question

Arrange the following centrifugal speeds in an order to be used when a cell homogenate is to be separated into various fractions. A. \(1000\, g\)
B. \(80{,}000\, g\)
C. \(1{,}50{,}000\, g\)
D. \(20{,}000\, g\)
E. \(60{,}000\, g\)
Choose the correct answer from the options given below :

• A. \(A, D, E, B, C\)
• B. \(A, E, C, D, B\)
• C. \(C, B, E, D, A\)
• D. \(E, D, B, A, C\)

Hint:

Remember: \[ \text{Lower speed} \rightarrow \text{Larger organelles} \] \[ \text{Higher speed} \rightarrow \text{Smaller particles} \] Typical order in differential centrifugation: \[ \text{Nuclei} \rightarrow \text{Mitochondria} \rightarrow \text{Microsomes} \rightarrow \text{Ribosomes} \]

Answer 1

The Correct Option is A

Concept: Differential centrifugation is used to separate cellular components based on:
• Size
• Density
• Sedimentation rate In this technique:
• Larger and heavier particles sediment at lower centrifugal speeds.
• Smaller particles require progressively higher centrifugal speeds. Thus, centrifugation speeds are applied in increasing order.

Step 1: Lowest centrifugal speed. The first centrifugation is performed at: \[ 1000\, g \] This pellets:
• Nuclei
• Cell debris Thus: \[ \boxed{A} \]

Step 2: Intermediate centrifugal speed. Next: \[ 20{,}000\, g \] is used to pellet:
• Mitochondria
• Lysosomes
• Peroxisomes Thus: \[ \boxed{D} \]

Step 3: Higher centrifugal speed. Then: \[ 60{,}000\, g \] is applied to sediment smaller membrane fractions. Thus: \[ \boxed{E} \]

Step 4: Very high centrifugal speed. After that: \[ 80{,}000\, g \] is used for even smaller particles such as microsomes. Thus: \[ \boxed{B} \]

Step 5: Ultracentrifugation. Finally: \[ 1{,}50{,}000\, g \] is used to pellet:
• Ribosomes
• Viruses
• Macromolecular complexes Thus: \[ \boxed{C} \] Therefore, the correct order is: \[ \boxed{1000\, g \rightarrow 20{,}000\, g \rightarrow 60{,}000\, g \rightarrow 80{,}000\, g \rightarrow 1{,}50{,}000\, g} \] Hence, the correct answer is: \[ \boxed{(A)\ A, D, E, B, C} \]