Problem 2 - Biology of Humans: Concepts, Applications, and Issues

Question

Lysosomes a. function in extracellular digestion. b. produce phospholipids to incorporate into membranes. c. have a double membrane. d. function in intracellular digestion.

Step-by-Step Solution

Answer

d. function in intracellular digestion.

Step 1: Understand Lysosomes

Lysosomes are membrane-bound organelles found in animal cells that contain enzymes responsible for breaking down all types of biomolecules.

Step 2: Analyze Option A

Extracellular digestion refers to the breakdown of materials outside of the cell. Identify whether lysosomes perform this function.

Step 3: Analyze Option B

Phospholipid production is a task involved in forming cell membranes. Determine if lysosomes have a role in creating phospholipids.

Step 4: Analyze Option C

A double membrane indicates two lipid bilayers. Find out if lysosomes are structured this way.

Step 5: Analyze Option D

Intracellular digestion involves the breakdown of substances within a cell. Check if lysosomes perform this type of function.

Step 6: Conclusion

Based on the analysis, determine which option correctly describes the function of lysosomes.

Key Concepts

Intracellular Digestion

Lysosomes play a key role in intracellular digestion. They contain hydrolytic enzymes that break down waste materials and cellular debris inside the cell.
These enzymes are capable of digesting all kinds of biomolecules, including proteins, nucleic acids, lipids, and carbohydrates. Intracellular digestion helps maintain cellular health by removing damaged organelles, recycling cell components, and eliminating pathogens.
When lysosomes fuse with other vesicles, they release their enzymes, allowing for the digestion process. This vital function is essential for cell renewal and defense against disease.

Organelle Function

Lysosomes are membrane-bound organelles found exclusively in animal cells. Their primary function is to break down various biomolecules using their repository of enzymes.
This enzymatic activity is crucial for:

• Cell clean-up – by digesting cell waste and debris.
• Nutrient recycling – breaking down macromolecules into simpler substances.
• Defense – neutralizing viruses and bacteria.
• Regulating cellular processes – through controlled enzyme release.
  The unique ability of lysosomes to manage cellular waste makes them essential for maintaining cellular homeostasis and promoting overall cell health.

Lysosome Structure

Lysosomes are characterized by their single-layer membrane, which encases their potent enzymes. Unlike mitochondria, which have a double membrane, lysosomes have just one.
This membrane is critical as it prevents the enzymes within from leaking out and causing damage to other parts of the cell. The interior of lysosomes contains a highly acidic environment (pH 4.5-5.0), which is optimal for the activity of the enzymes.

• Lysosomal membrane – lipid bilayer protecting the cell from self-digestion.
• Enzymes – over 50 types that can degrade various biomolecules.
• Acidic pH – maintained by proton pumps on the membrane.
  These structural features ensure that lysosomes function effectively as the cell’s digestive system.