Standard 9 Science and Technology - 17. Introduction to Biotechnology

Question 1:

Each of the following statements is wrong. Rewrite them correctly by changing either one or two words.

a. Simple squamous epithelium is present in respiratory tract.

b.  Glandular epithelium is present in kidneys.

c.  Chlorenchyma helps the plant to float in water.

d.  Striated muscles are also called involuntary muscles.

e.  Chloroplast is present in permanent tissue.

Answer 1:

a. Simple squamous epithelium is present in oesophagous.

b.  Glandular epithelium is present in inner layer of skin.

c.  Chlorenchyma helps the plant to perform photosynthesis.

d.  Striated muscles are also called voluntary muscles.

e.  Chloroplast is present in simple permanent tissue.

Question 2:

Identify the odd word and explain why it is odd.

a.  Xylem, phloem, permanent tissue, meristematic tissue.

b. Epithelium, Muscle fibre, nerve fibre, epidermis.

c. Cartilage, bone, tendon, cardiac muscle.

Answer 2:

a.  Xylem, phloem, permanent tissue, meristematic tissue- Meristematic tissue is the odd one out because xylem and phloem are types of permanent tissues.

b. Epithelium, Muscle fibre, nerve fibre, epidermis- Epidermis is the odd one out because all the other three are different types of tissues. Epidermis is an outer layer of cells found in plants.

c. Cartilage, bone, tendon, cardiac muscle- Cardiac muscle is the odd one out because rest of the three are connective tissues while cardiac muscle is a type of muscular tissue.

Question 3:

Write the names of the following tissues.

a. Tissue lining inner surface of mouth.

b.  Tissue joining muscles and bones.

c.  Tissue responsible for increasing height of plants.

d.  Tissue responsible for increasing girth of stem.

Answer 3:

a. Tissue lining inner surface of mouth-  squamous epithelium

b.  Tissue joining muscles and bones- tendons

c.  Tissue responsible for increasing height of plants- apical meristem

d.  Tissue responsible for increasing girth of stem- lateral meristem

Question 4:

Write the differences.

Simple tissue and complex tissues in plants.

Answer 4:

Simple tissue	Complex tissue
1. Simple tissues are made up of single type of cells.	Complex tissues are made up of different type of cells.
2. Simple tissue consists of  parenchyma, collenchyma and sclernchyma.	Complex tissue consists of  xylem and phloem.
3. It occurs in all parts of plant.	It occurs only in vascular region.
4. They perform various functions like storage, protection etc.	Their main function is to acrry out conduction or transportation.

Question 5:

Write short notes.

a.  Meristematic tissue.

b. Xylem

c.  Striated muscles.

d.  Agro-complementary business.

e.  Genetic engineering

f. Sericulture

Answer 5:

 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:

1. 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.
2. 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.
3. 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.
4. 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.
5. 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.

Question 6:

Explain the meaning of biotechnology and its impact on agricultural management with suitable examples.

Answer 6:

Biotechnology is the branch of biology that involves application of technology in utilising the living organisms or their parts to produce products useful for humans. Biotechnology can be used in agricultural management in the following ways:

• Biotechnological procedures have enabled us to produce genetically modified crops which have various useful characteristics which are not present in the original varieties.
• Pest-resistant crop can be produced by this process which also reduces the load of chemical pesticides and thus protects the environment, example, Bt cotton.
• Disease-resistant crops can be produced by this method which are capable of handling environmental stress like drought, changing temperature etc.
• High-yielding crops with better shelf life can be produced.

Question 7:

Which two main techniques are used in biotechnology? Why?

Answer 7:

The two main techniques which are used in biotechnology are tissue culture and genetic engineering.

Plant tissue culture is the production of new plants from small amounts of plant tissue under carefully controlled laboratory conditions. In this method, some plant tissues are taken under sterile conditions and are kept in test tubes containing culture medium, which allows these cells to grow fast and form an unorganised mass of cells called callus. This callus is transferred into another medium containing proper growth hormones for differentiation and organ formation. As a result, small plantlets are formed in the test tubes. These can be later placed in soil where they can grow into mature plants. This technique is called micro-propagation.

Tissue culture

Tissue culture has various applications like:

(i) It is used to produce disease resistant and high yielding varieties of plants.

(ii) Tissue culture is helpful to produce new varieties of plants by fusing two different cells through a technique called germplasm hybridisation and then growing the fused cells through tissue culture. For example: Pomato.

(iii) Tissue culture along with recombinant DNA technology has made it possible to transfer nitrogen fixing genes from bacteria into plants. This has helped these plants to fix atmospheric nitrogen.

(iv) It helps to produce large number of plants in short duration of time and in limited space.

(v) It has made it possible to preserve characteristics of the parent plants.

Genetic engineering:

Genetic engineering is the process in which gene(s) for a particular character is/ are introduced inside the chromosome of the cell of an individual. When the gene for a particular character is introduced in a plant cell, transgenic plants are produced. Genetic engineering finds applications like:

(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)

Question 8:

Discuss ‘Agritourism’ in the class and write a project on an agro-tourism centre nearby. Present it in the class in groups.

Answer 8:

It is a project. Kindly do it yourself.

Question 9:

Define the term tissue and explain the concept of tissue culture.

Answer 9:

Groups of cells performing the same function are known as tissues. 

Plant tissue culture is the production of new plants from small amounts of plant tissue under carefully controlled laboratory conditions. In this method, some plant tissues are taken under sterile conditions and are kept in test tubes containing culture medium, which allows these cells to grow fast and form an unorganised mass of cells called callus. This callus is transferred into another medium containing proper growth hormones for differentiation and organ formation. As a result, small plantlets are formed in the test tubes. These can be later placed in soil where they can grow into mature plants. This technique is called micro-propagation.
 

Tissue culture

Tissue culture has various applications like:

(i) It is used to produce disease resistant and high yielding varieties of plants.

(ii) Tissue culture is helpful to produce new varieties of plants by fusing two different cells through a technique called germplasm hybridisation and then growing the fused cells through tissue culture. For example: Pomato.

(iii) Tissue culture along with recombinant DNA technology has made it possible to transfer nitrogen fixing genes from bacteria into plants. This has helped these plants to fix atmospheric nitrogen.

(iv) It helps to produce large number of plants in short duration of time and in limited space.

(v) It has made it possible to preserve characteristics of the parent plants.

Question 10:

‘Rearing of sheep is a livestock’. Justify this statement.

Answer 10:

Rearing of sheeps refers to farming of sheeps for various purposes. It is among the traditional business and occupations of the people of some countries around the world. From the ancient time, sheeps have been reared as a domestic animal. Sheeps are reared for their milk, meat and wool production.