What are the components of the transport system in highly organised plants?
Transportation in plants:- There are two components for the transportation in highly organised plants. Transportation of some materials like gases, water, minerals, organic solutes in the form of food, hormones occurs by these two components- xylem and phloem.
Xylem:- transportation of water and minerals occurs through the xylem. Water and minerals are absorbs from the soil and then by the roots, transport it to the tip of growing stem in the sequential manner. This uptake of water and minerals followed by some processes like osmosis, diffusion. Water and minerals are transported through the root hair to the cortex and then to the leaves by the two pathway apoplast and symplast by the root pressure and the transpirational pull activity. This process is unidirectional.
Phloem:- Phloem helps in transportation of food in the form of organic solutes from leaves to the storage organs of the plant and to all parts of the plants, this process is known as translocation. Food is transported through the sieve elements of the phloem and needs metabolic energy to transport the food. They use this metabolic energy in the form of ATP and by the process of osmosis water enters in the sieve tubes that raise the pressure in the phloem and then the food is transported to the parts of the plants. Transportation of food movement involves along the turgor pressure gradient that is induced by maintained gradient of water potential. This process is multidirectional.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
How is the amount of urine produced regulated?
What criteria do we use to decide whether something is alive?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm. (c) chloroplast.
(b) mitochondria. (d) nucleus.
What are the differences between autotrophic nutrition and heterotrophic nutrition?
What are outside raw materials used for by an organism?
What would be the consequences of a deficiency of haemoglobin in our bodies?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Where do plants get each of the raw materials required for photosynthesis?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
Would you be able to check if water is hard by using a detergent?
Explain the following.
(a) Why is the tungsten used almost exclusively for filament of electric lamps?
(b) Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
(c) Why is the series arrangement not used for domestic circuits?
(d) How does the resistance of a wire vary with its area of cross-section?
(e) Why are copper and aluminium wires usually employed for electricity transmission?
Name a mirror that can give an erect and enlarged image of an object.
Explain the mechanism of the cleaning action of soaps.
Give an example of a double displacement reaction other than the one given in activity 1.10.
Write a balanced chemical equation with state symbols for the following reactions:
Why is vegetative propagation practised for growing some types of plants?
Why is variation beneficial to the species but not necessarily for the individual?
How do Mendel’s experiments show that traits may be dominant or recessive?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?