Problem 7 - Biology: Concepts and Applications

Question

Accessory pigments of________ allow them to carry a. euglenoids b. green algae c. brown algae d. red algae

Step-by-Step Solution

Answer

Red algae have accessory pigments allowing them to function in specific light conditions.

Step 1: Understand the Question

The question is asking us to identify which type of organism, from the given options, has accessory pigments that allow them to carry out a specific function, likely related to photosynthesis.

Step 2: Identify Accessory Pigments

Accessory pigments are compounds found in photosynthetic organisms that absorb light wavelengths not absorbed by chlorophyll. Common accessory pigments include carotenoids and phycobiliproteins.

Step 3: Recognize Pigment Significance

Different organisms have different accessory pigments that allow them to adapt to various light conditions. This is crucial for their survival and effective photosynthesis.

Step 4: Assess List of Options

The options are euglenoids, green algae, brown algae, and red algae. Each group has distinct accessory pigments that influence their photosynthetic capabilities.

Step 5: Analyze Key Characteristics

Red algae contain a significant accessory pigment known as phycoerythrin, which helps them absorb blue and green light, allowing them to live deeper in the water where these light wavelengths penetrate.

Step 6: Determine the Correct Answer

Based on the accessory pigment related to unique light absorption features, red algae's phycoerythrin allows them to carry out photosynthesis efficiently under certain conditions.

Key Concepts

Photosynthesis

Photosynthesis is a vital process that transforms light energy into chemical energy. This process primarily takes place in the chloroplasts of plant cells and is used by green plants, algae, and some bacteria. During photosynthesis, organisms capture light energy and convert it into glucose and oxygen using carbon dioxide and water. The equation for photosynthesis is:\[6 CO_2 + 6 H_2O + light \rightarrow C_6H_{12}O_6 + 6 O_2\]This process is essential for providing energy to the living world and for producing the oxygen we breathe. Light-absorbing pigments like chlorophyll play a central role in capturing sunlight. Accessory pigments, on the other hand, assist by capturing wavelengths not absorbed by chlorophyll.
These pigments extend the range of light that can be used for photosynthesis.

Phycoerythrin

Phycoerythrin is an accessory pigment found primarily in red algae. This pigment is responsible for capturing light energy and contributes to the reddish color characteristic of these algae. Phycoerythrin absorbs blue and green light wavelengths, which penetrate deeper into the ocean.

• This adaptation allows red algae to inhabit deeper water niches, where light availability is low.
• It transfers absorbed energy to chlorophyll for photosynthesis.

The unique absorption capabilities of phycoerythrin enable red algae to thrive in environments where other photosynthetic organisms might struggle.

Red Algae

Red algae, scientifically known as Rhodophyta, are a group of primarily marine algae that are often found in deeper water. These algae are notable for their reddish or purplish color, which results from the presence of the accessory pigment phycoerythrin. Red algae can photosynthesize efficiently at greater ocean depths due to their pigment composition. They have various ecological roles such as being vital components of coral reefs.
Additionally, red algae are important in food production, used in products like nori, agar, and carrageenan, which are used in different culinary and industrial applications.

Chlorophyll

Chlorophyll is the primary pigment involved in photosynthesis. Present in the chloroplasts, chlorophyll gives plants their green color because it reflects green light. Chlorophyll's role includes:

• Absorbing sunlight, mainly blue and red wavelengths.
• Initiating the conversion of light energy into chemical energy.

While chlorophyll is crucial for photosynthesis, it cannot capture all wavelengths of light on its own. Hence, organisms also contain accessory pigments to help maximize light absorption. Chlorophyll's effectiveness is supplemented by these pigments, enabling plants and algae to optimize energy capture.

Carotenoids

Carotenoids are another group of accessory pigments found in many photosynthetic organisms. These pigments absorb light in the blue and green spectra and are responsible for the yellow, orange, and red colors seen in leaves during autumn. Some important functions of carotenoids include:

• Supporting chlorophyll by broadening the range of light used in photosynthesis.
• Protecting plant cells from damage caused by excess light.

By assisting chlorophyll and providing photoprotection, carotenoids play an integral role in maintaining the health and efficiency of photosynthetic organisms.