Write short notes.
a. Meristematic tissue.
b. Xylem
c. Striated muscles.
d. Agro-complementary business.
e. Genetic engineering
f. Sericulture
a. Meristematic tissue.
a. Meristematic tissues: Meristematic tissues are the cells or group of cells that have the ability to divide. These cells divide continuously and thus helps in increasing the length and thickness of the plant. Depending upon the position, meristematic tissues can be classified as:
• Apical Meristem: It is present at the growing tips of stem and roots. It increases the length of the plant body. The apical meristems produce three kinds of primary meristems i.e., protoderm, ground meristem and procambium.
• Intercalary Meristem: It is present at the base of the leaves. This meristem helps in the elongation of internodes.
• Lateral Meristem: It is present at the lateral regions of the stems and roots which bring about an increase in the width of the plant body. These are of two types: cork cambium and vascular cambium.
b. Xylem: Xylem is the complex tissue as it consists of both parenchymatous and sclerenchymatous cells. It is composed of four elements:
(a) Tracheids: It is a non-living, elongated cell with tapering ends. The wall is highly thickened with lignin, except at certain circular spots known as pits.
(b) Vessel: It is a non-living cell with lignified walls. Tracheids and vessels are the main conducting elements in the xylem.
(c) Xylem parenchyma: It consists of living cell and performs the function of storage.
(d) Xylem fibre: It is a non-living, thick walled cell which provides mechanical support.
c. Striated muscles: Striated muscles are also known as skeletal muscle fibres. Skeletal muscle fibres are striated and are bundled together in a parallel manner by a sheath of tough connective tissues. These are attached to the skeletal bones and are voluntary in nature (because their actions are directly under the control of person’s will).
d. Agro-complementary business: The complementary good or services that are used in conjunction with agriculture are referred to as agro-complementary business. Agro complementary business are mainly carried out to produce high yielding breed, desirable quality and for economic benefit. It includes animal husbandry, poultry farming and sericulture. Animal husbandry is practiced for milk production and the cattle is used for farming, poultry farming is done for the rearing of eggs and meat and sericulture is done for rearing of silk.
e. Genetic engineering: Genetic engineering which is also known as gene manipulation/recombinant DNA technology involves the modification of the genetic information of living organisms by manipulation of DNA. This manipulation can be done by adding, removing or repairing a part of DNA. This manipulation results in the change in phenotype of an organism.
For example, it is used in the synthesis human insulin and interferons.
There are various applications of genetic engineering:
(i) Producing enzymes, proteins, vaccines and antibiotics by bioprocess technology
(ii) Developing pest-resistant and disease-resistant crops
(iii) Identifying and correcting genetic defects by gene therapy
(iv) Forensic application, in the identification of criminals using restriction fragment length polymorphism (RFLP)
f. Sericulture: The rearing of silkworms to obtain silk fibre is known as sericulture. The methodology of sericulture includes five steps:
-
Collection of eggs − The ripened cocoons are collected and adult moths are allowed to come out of them and mate. The females are then collected and kept in a bag with mouth sealed and within some time, they die after laying their eggs, which are recovered for further process.
-
Incubation of eggs − The obtained eggs are spread evenly on tray and kept in incubator at 65°F. The temperature is slowly increased day after day and eggs hatch at 77°F. Larvae are recovered from the incubator.
-
Rearing of larvae − Larvae are reared in special rooms maintained at 77°F. They feed on mulberry leaves and become double their size in 4-5 days. During this 40 days larval period, 4 cycles of sleep followed by moulting is encountered.
-
Recovery of silk from cocoon − The larva is then transferred to the spinning trays where silk is released from the silk glands of larvae to form a cocoon. It takes 9-10 days for spinning to complete. Cocoons are preserved and are passed on to steam treatment. On steam treatment, the pupa inside the cocoon dies. Thereafter, drying treatment is done, which dries up the pupa.
-
Reeling and spinning − The process of removing the silk thread from the killed cocoon is called reeling. The silk so obtained is the raw silk, which is boiled and purified by acids to bring lustre.
a. Meristematic tissues: Meristematic tissues are the cells or group of cells that have the ability to divide. These cells divide continuously and thus helps in increasing the length and thickness of the plant. Depending upon the position, meristematic tissues can be classified as:
• Apical Meristem: It is present at the growing tips of stem and roots. It increases the length of the plant body. The apical meristems produce three kinds of primary meristems i.e., protoderm, ground meristem and procambium.
• Intercalary Meristem: It is present at the base of the leaves. This meristem helps in the elongation of internodes.
• Lateral Meristem: It is present at the lateral regions of the stems and roots which bring about an increase in the width of the plant body. These are of two types: cork cambium and vascular cambium.
b. Xylem: Xylem is the complex tissue as it consists of both parenchymatous and sclerenchymatous cells. It is composed of four elements:
(a) Tracheids: It is a non-living, elongated cell with tapering ends. The wall is highly thickened with lignin, except at certain circular spots known as pits.
(b) Vessel: It is a non-living cell with lignified walls. Tracheids and vessels are the main conducting elements in the xylem.
(c) Xylem parenchyma: It consists of living cell and performs the function of storage.
(d) Xylem fibre: It is a non-living, thick walled cell which provides mechanical support.
c. Striated muscles: Striated muscles are also known as skeletal muscle fibres. Skeletal muscle fibres are striated and are bundled together in a parallel manner by a sheath of tough connective tissues. These are attached to the skeletal bones and are voluntary in nature (because their actions are directly under the control of person’s will).
d. Agro-complementary business: The complementary good or services that are used in conjunction with agriculture are referred to as agro-complementary business. Agro complementary business are mainly carried out to produce high yielding breed, desirable quality and for economic benefit. It includes animal husbandry, poultry farming and sericulture. Animal husbandry is practiced for milk production and the cattle is used for farming, poultry farming is done for the rearing of eggs and meat and sericulture is done for rearing of silk.
e. Genetic engineering: Genetic engineering which is also known as gene manipulation/recombinant DNA technology involves the modification of the genetic information of living organisms by manipulation of DNA. This manipulation can be done by adding, removing or repairing a part of DNA. This manipulation results in the change in phenotype of an organism.
For example, it is used in the synthesis human insulin and interferons.
There are various applications of genetic engineering:
(i) Producing enzymes, proteins, vaccines and antibiotics by bioprocess technology
(ii) Developing pest-resistant and disease-resistant crops
(iii) Identifying and correcting genetic defects by gene therapy
(iv) Forensic application, in the identification of criminals using restriction fragment length polymorphism (RFLP)
f. Sericulture: The rearing of silkworms to obtain silk fibre is known as sericulture. The methodology of sericulture includes five steps:
-
Collection of eggs − The ripened cocoons are collected and adult moths are allowed to come out of them and mate. The females are then collected and kept in a bag with mouth sealed and within some time, they die after laying their eggs, which are recovered for further process.
-
Incubation of eggs − The obtained eggs are spread evenly on tray and kept in incubator at 65°F. The temperature is slowly increased day after day and eggs hatch at 77°F. Larvae are recovered from the incubator.
-
Rearing of larvae − Larvae are reared in special rooms maintained at 77°F. They feed on mulberry leaves and become double their size in 4-5 days. During this 40 days larval period, 4 cycles of sleep followed by moulting is encountered.
-
Recovery of silk from cocoon − The larva is then transferred to the spinning trays where silk is released from the silk glands of larvae to form a cocoon. It takes 9-10 days for spinning to complete. Cocoons are preserved and are passed on to steam treatment. On steam treatment, the pupa inside the cocoon dies. Thereafter, drying treatment is done, which dries up the pupa.
-
Reeling and spinning − The process of removing the silk thread from the killed cocoon is called reeling. The silk so obtained is the raw silk, which is boiled and purified by acids to bring lustre.
