In basic plant biology, the yellow colour of papaya fruit is mainly due to the presence of which pigment?

Introduction / Context:
Colours of fruits and vegetables are often due to specific pigments present in their cells. Questions in general science and biology frequently test this knowledge by asking about the pigment responsible for the characteristic colour of a familiar fruit. This question focuses on papaya and asks which pigment gives it its typical yellow colour.

Given Data / Assumptions:

- The fruit mentioned is papaya. - The colour under discussion is yellow. - The options include Caricaxanthin, Carotene, Lycopene and Papain. - We assume some knowledge of plant pigments and papaya composition.

Concept / Approach:
The yellow colour of papaya is due to carotenoid pigments, particularly a xanthophyll called Caricaxanthin. While carotene is a general name for a family of orange pigments and papaya does contain carotenoids, exam questions usually expect the more specific name Caricaxanthin. Lycopene is associated with red colour in tomatoes and some other fruits. Papain is an enzyme found in papaya latex and is unrelated to colour. Therefore, the correct answer is Caricaxanthin.

Step-by-Step Solution:
1. Recall that plant colours often come from three major groups of pigments: chlorophylls (green), carotenoids (yellow to orange), and anthocyanins (red to purple). 2. Papaya pulp is typically yellow to orange, indicating the presence of carotenoid pigments rather than chlorophyll or anthocyanins. 3. Among carotenoids, a specific xanthophyll known as Caricaxanthin is characteristic of papaya and contributes strongly to its yellow colour. 4. Carotene is a more general term and not the precise name often tested in exam questions about papaya colour. 5. Lycopene primarily gives red colour to tomatoes and watermelons, not the yellow seen in papaya. 6. Papain is a proteolytic enzyme used in meat tenderisers and digestive aids, with no direct role in pigment formation. 7. Hence, Caricaxanthin is the most accurate pigment name for the yellow colour of papaya.

Verification / Alternative check:
Biology question banks and general awareness resources often include the same question and consistently mark Caricaxanthin as the correct option. Additional explanations in these sources mention that papaya chromoplasts contain carotene and xanthophyll pigments, with Caricaxanthin being the specific xanthophyll responsible for the yellow appearance. This repeated mapping confirms that Caricaxanthin is the expected exam answer, not the broader term carotene.

Why Other Options Are Wrong:
Carotene, while present, is a generic name and does not uniquely identify the pigment most closely linked with papaya yellow colour in standard questions. Lycopene is a red pigment and is not responsible for yellow hues, so it does not fit the description here. Papain is an enzyme involved in protein digestion and commercial uses but has no connection with fruit colour. Therefore, these three options do not correctly answer the question about the pigment causing papaya yellow colour.

Common Pitfalls:
Many candidates quickly choose carotene because it is a familiar term associated with carrots and vitamin A, without noticing that a more specific pigment name is available. Others may confuse Lycopene due to its popularity in health discussions. To avoid such mistakes, students should pay attention to more precise pigment names linked with specific fruits, such as Caricaxanthin for papaya and Lycopene for tomato, and not rely only on the most commonly heard pigment terms.

Final Answer:
The yellow colour of papaya is mainly due to the pigment Caricaxanthin present in its pulp.