Problem 12 - Biology

Question

Which of the following structures is not found in bryophytes? a. a cellulose cell wall b. chloroplast c. sporangium d. root

Step-by-Step Solution

Answer

d. root

Step 1: Understand the Question

Identify which structure among the options is not found in bryophytes, a group of non-vascular plants that include mosses, liverworts, and hornworts.

Step 2: Recall Characteristics of Bryophytes

Bryophytes are known for having structures like a cellulose cell wall and chloroplasts for photosynthesis, and they produce spores in a sporangium. They are non-vascular plants and do not have true roots.

Step 3: Analyze the Options

Evaluate each option: Option (a) cellulose cell wall, present in bryophytes; Option (b) chloroplast, present in bryophytes; Option (c) sporangium, present in bryophytes; Option (d) root, not present in bryophytes.

Step 4: Conclude the Answer

Based on the analysis, the structure not found in bryophytes is the root.

Key Concepts

non-vascular plants

Bryophytes, including mosses, liverworts, and hornworts, are non-vascular plants. This means they do not have specialized structures like xylem and phloem, which are found in vascular plants for water and nutrient transportation. Instead, bryophytes absorb water and nutrients directly through their cell walls. Because they lack vascular tissues, bryophytes are typically small and found in moist environments where water can be easily absorbed. They rely on simple diffusion and capillary action to move water and nutrients. This limitation is why bryophytes don't grow large and are usually close to the ground. Despite their simplicity, bryophytes play crucial roles in their ecosystems. They help to reduce soil erosion by stabilizing the soil with their mats of growth and forming a habitat for various microorganisms and insects.

plant cell structure

Bryophytes have a fundamental plant cell structure that is similar to other plants. Each cell has a cellulose cell wall that provides structural support and defines the shape of the cell. Inside the cell, you'll find a nucleus that controls the cell's activities and stores genetic information. There's also a vacuole, a large, fluid-filled organelle that stores nutrients and waste products and helps maintain turgor pressure. Most importantly for bryophytes, chloroplasts are present in their cells. Chloroplasts contain chlorophyll, the pigment that absorbs sunlight for photosynthesis. They convert light energy into chemical energy in the form of glucose. Additionally, bryophytes have specialized structures called sporangia, where spores are produced for reproduction. This is a key characteristic distinguishing them from plants that reproduce with seeds.

photosynthesis

Photosynthesis is the process by which bryophytes, like all green plants, convert light energy from the sun into chemical energy stored in glucose. This process primarily occurs in the chloroplasts, thanks to the pigment chlorophyll. During photosynthesis, carbon dioxide and water are converted into glucose and oxygen, with sunlight as the energy source. The general formula for photosynthesis is \[ 6CO_2 + 6H_2O + light \rightarrow C_6H_{12}O_6 + 6O_2 \]. Chloroplasts in bryophytes capture light energy and use it to split water molecules. This releases oxygen as a by-product. The energy from the light is then used to convert carbon dioxide into glucose. Despite their small size, bryophytes contribute to the carbon cycle and provide oxygen. They do not have a vascular system to transport food and water, so photosynthesis occurs in depending cells. This means that every cell needs to be close to a source of sunlight and water for effective photosynthesis. This is why bryophytes thrive in moist, shady areas where water is readily available.