HSC Science Class 12 - Tamil Nadu Board of Secondary Education Question Bank Solutions for Botany

The process of recombinant DNA technology has the following steps

1. amplification of the gene
2. Insertion of recombinant DNA into the host cells
3. Cutting of DNA at a specific location using a restriction enzyme.
4. Isolation of genetic material (DNA) Picks out the correct sequence of steps for recombinant DNA technology.

Match the following:

Assertion: Agrobacterium tumifaciens is popular in genetic engineering because this bacteriumis associated with the root nodules of all cereals and pulse crops

Reason: A gene incorporated in the bacterial chromosomal genome gets automatically transferred to the cross with which bacterium is associated.

Which one of the following is not a correct statement.

How do you use the biotechnology in modern practice?

What do you know about the word pBR332?

What do you mean Embryoids? Write its application.

Read the given statements and select the correct option.

1. Hydrophytes possess aerenchyma to support themselves in water.
2. Seeds of Viscum are positively photoblastic as they germinate only in presence of light.
3. Hygroscopic water is the only soil water available to roots of plants growing in soil as it is present inside the micropores.
4. High temperature reduces use of water and solute absorption by roots.

Read the given statements and select the correct option.

1. Loamy soil is best suited for plant growth as it contains a mixture of silt, sand, and clay.
2. The process of humification is slow in the case of organic remains containing a large amount of lignin and cellulose.
3. Capillary water is the only water available to plant roots as it is present inside the micropores.
4. Leaves of shade plant have more total chlorophyll per reaction centre, low ratio of chl a and chl b are usually thinner leaves.

Read the given statements and select the correct option.

Statement A: Cattle do not graze on weeds of Calotropis.

Statement B: Calotropis have thorns and spines, as a defense against herbivores.

In soil water available for plants is

The plant of this group are adapted to live partly in water and partly above substratum and free from water

Ophrys an orchid resembling the female of an insect so as to able to get pollinated is due to phenomenon of

A free-living nitrogen-fixing cyanobacterium which can also form a symbiotic association with the water fern Azolla

In a fresh water environment like pond, rooted autotrophs are

Strong, sharp spines that get attached to animal’s feet are found in the fruits of

Sticky glands of Boerhaavia and Cleome support

Why are some organisms called as eurythermals and some others as stenohaline?

The organic horizon is generally absent from agricultural soils because tilling, e.g., plowing, buries organic matter. Why is an organic horizon generally absent in desert soils?

Soil formation can be initiated by biological organisms. Explain how?