Which type of enzymes are found within lysosomes?

AIIMS CRE, SNO-2024

Biochemistry & Nutrition

Easy

Appeared in: AIIMS CRE, SNO-2024

Explanation

Lysosomes are cellular organelles that function as the cell's digestive system, breaking down waste materials and cellular debris.
They contain a variety of enzymes called acid hydrolases, which work best in the acidic environment (pH ≤5) inside the lysosome.
Phospholipases are a type of hydrolase enzyme that specifically catalyzes the breakdown of phospholipids, the main components of cell and organelle membranes.
This function is vital for processes like autophagy (degrading old organelles) and heterophagy (digesting external material).

Option B: Oxidoreductases catalyze oxidation-reduction (redox) reactions, which involve the transfer of electrons. This is not the primary function of lysosomal enzymes.
Option C: Isomerases catalyze the structural rearrangement of atoms within a molecule, converting it into an isomer. This is a function related to metabolism, not degradation.
Option D: Ligases catalyze the joining of two molecules by forming new chemical bonds, a process that typically requires energy from ATP. This is a synthetic (anabolic) function, opposite to the digestive (catabolic) role of lysosomes.

Visual 1: Diagram of an animal cell. This visual should highlight the lysosome and illustrate its roles in fusing with phagosomes (to digest engulfed material) and autophagosomes (to recycle old organelles).
Visual 2: Flowchart of enzyme classification. This chart should show the six major classes of enzymes (Hydrolases, Oxidoreductases, Isomerases, Ligases, Transferases, Lyases) and their fundamental reaction types, clarifying why only hydrolases fit the lysosome's function.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain This question tests knowledge of the specific types of enzymes found within cellular organelles, particularly the lysosome, and the general classification of enzymes as background academic context rather than a clinical decision trigger.
A congenital absence or malfunction of a specific lysosomal enzyme leads to a group of over 50 genetic disorders known as Lysosomal Storage Diseases (LSDs).
In LSDs, the substance the missing enzyme would normally break down accumulates within the lysosome, causing the organelle to swell and disrupt normal cell function. This leads to severe and progressive multi-systemic diseases.
Examples include Tay-Sachs disease (deficiency of hexosaminidase A, leading to ganglioside accumulation in neurons) and Gaucher disease (deficiency of glucocerebrosidase).

How to Approach the Question

First, identify the core concepts in the question: the organelle is the 'lysosome' and the molecule type is 'enzymes'.
Recall the primary function of the lysosome. It's the cell's 'stomach' or 'recycling center', responsible for breaking down complex molecules.
This breakdown function is called hydrolysis, and the enzymes that perform it are called hydrolases.
Examine the options to see which one fits the category of a hydrolase or performs a digestive function.
Phospholipases break down phospholipids, which is a hydrolytic, digestive action.
Contrast this with the other options: Oxidoreductases (redox reactions), Isomerases (rearrangement), and Ligases (joining molecules). These do not align with the digestive role of the lysosome.

Concept Tested & Keywords

Concept Tested: This question tests knowledge of the specific types of enzymes found within cellular organelles, particularly the lysosome, and the general classification of enzymes.
Stem keywords: enzymes, lysosomes
Lead-in keywords: Which type
Negative lead-in flag: false

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