Photosynthesis in Higher Plants - CBSE Notes for Class …
Notes For Class 11 Chapter 13 Photosynthesis In Higher Plants Download in pdf
Photosynthesis in Higher Plants – CBSE Notes for Class 11 Biology
The earliest photosynthetic organisms on land would have resembled modern algae, cyanobacteria, and lichens, followed by bryophytes (liverworts & mosses, which evolved from the group of green algae). Bryophytes are described as seedless, nonvascular plants. Their lack of tissue for transport of water and nutrients limits their size (most are between 2 and 20 cm high). Bryophytes don't have typical stems, leaves, or roots, but are anchored to the ground by rhizoids. They can grow in a wide range of environments and are : when the environment dries so does the plant, remaining dormant while dry but recovering rapidly when wetted. These features make them important pioneer species.
3. Even though a very few cells in a C4 plant carry out the biosynthetic – Calvin pathway, yet they are highly productive. Can you discuss why?
Ans. The productivity of a plant is measured by the rate at which it photosynthesises. The amount of carbon dioxide present in a plant is directly proportional to the rate of photosynthesis. C4 plants have a mechanism for increasing the concentration of carbon dioxide. In C4 plants, the Calvin cycle occurs in the bundle-sheath cells. The C4 compound (malic acid) from the mesophyll cells is broken down in the bundle-
sheath cells. As a result, CO2 is released. The increase in CO2 ensures that the enzyme RuBisCo does not act as an oxygenase, but as a carboxylase. This prevents photorespiration and increases the rate of photosynthesis. Thus, C4 plants are highly productive.
PHOTOSYNTHESIS IN HIGHER PLANTS notes ~ SCC …
The owe their success to the evolution of the flower. The flower's pollen and nectar encourage pollinating animals to visit, increasing the odds of fertilisation by ensuring that pollen is transferred efficiently from flower to flower. (The flowers of wind-pollinated angiosperms, e.g. grasses, are very much reduced in terms of size and complexity.) After fertilisation the carpel and other parts of the flower are used to form fruit that aid dispersal of the seeds inside the fruit. In addition, the xylem of angiosperms allow very rapid movement of water through the plant. This means that flowering plants can keep their stomata open through much of the day, achieving higher photosynthetic rates than gymnosperms; this "spare" photosynthetic capacity can support the development of fruit.
Photosynthesis occurs inside chloroplasts. Chloroplasts contain chlorophyll, a green pigment found inside the thylakoid membranes. These chlorophyll molecules are arranged in groups called photosystems. There are two types of photosystems, Photosystem II and Photosystem I. When a chlorophyll molecule absorbs light, the energy from this light raises an electron within the chlorophyll molecule to a higher energy state. The chlorophyll molecule is then said to be photoactivated. Excited electron anywhere within the photosystem are then passed on from one chlorophyll molecule to the next until they reach a special chlorophyll molecule at the reaction centre of the photosystem. This special chlorophyll molecule then passes on the excited electron to a chain of electron carriers.
Chapter 13 Photosynthesis in Higher Plants
5. Suppose there were plants that had a high concentration of Chlorophyll-b, but lacked chlorophyll-a, would it carry out photosynthesis? Then why do plants have chlorophyll-b and other accessory pigments?
Ans. Chlorophyll-a molecules act as antenna molecules. They get excited by absorbing light and emit electrons during cyclic and non-cyclic photophosphorylations. They form the reaction centres for both photosystems I and II. Chlorophyll-b and other photosynthetic pigments such as carotenoids and xanthophylls act as accessory pigments. Their role is to absorb energy and transfer it to chlorophyll-a. Carotenoids and xanthophylls also protect the chlorophyll molecule from photo-oxidation. Therefore, chlorophyll-a is essential for photosynthesis.
If any plant were to lack chlorophyll-a and contain a high concentration of chlorophyll-b, then this plant would not undergo photosynthesis.
chapter 13 photosynthesis in higher plants.
Ch 13 Photosynthesis in Higher Plants Biology 0
Photosynthesis in Higher Plants, Sample Papers & MCQ for Class 11th Biology CBSE Board, Bio Class 11th NCERT
Notes on Photosynthesis In Higher Plants - SimplyLearnt
CLASS 11 BIOLOGY CHAPTER 13 PHOTOSYNTHESIS IN HIGHER PLANTS QUESTION ANSWERS, Why is the colour of a leaf kept in …
Photosynthesis in Higher Plants
Revision Notes for the Photosynthesis In Higher Plants , CBSE Class 11-science BIOLOGY, Biology.
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