Ecosystem And Biosphere

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Sclerenchyma cells are the permanent tissues present in the plants. They provide hardness and stiffness to the plant and are composed of dead cells. This tissue is present in stems around vascular bundles in the veins of leaves and in hard covering of seeds and nuts.

Details

Details

Details

Details

Xylem is one of the two types of transport tissue in vascular plants, phloem being the other. The basic function of xylem is to transport water from roots to stems and leaves, but it also transports nutrients.

Phototropism is one of the many plant tropisms or movements which respond to external stimuli. Growth towards a light source is called positive phototropism, while growth away from light is called negative phototropism (skototropism).

Plant have cellulose while animals lack it.

We know that, proteins are polymers of amino acids. So, plants are also used to synthesise protein from amino acids. Hence, plants synthesis protein from amino acids in the presence of ATP by specific synthetases.

The plant cells absorb nitrates from the soil and convert them into ammonia which ultimately reduced to ammonium ions (NH4+). These ammonium ions are then combined with organic compounds to form amino acids such as glutamine i.e., free nitrogen. This process of conversion is known as nitrogen fixation.

Cellular respiration occurs in the double-membrane organelle called the mitochondrion.

Unit membrane is the basic structure found in all membranes such as those of mitochondria and chloroplasts.

Pollen grains in plants are produced in flower.

Plants are killed in winter by frost as there is desiccation and mechanical damage to the tissues. Desiccation is the state of extreme dryness, or the process of extreme drying.