Biology Test - 34

Western Ghats area in India has the largest number of endemic plant species.

The Western Ghats (Sahyadri) covers a total area of 140,000 sq km. It is a part of the states of Karnataka, Tamil Nadu, Kerala, Goa, Maharashtra and Gujarat. The largest numbers of endemic plant species are found here. It was declared a UNESCO World Heritage Site and a hot-spot of biological diversity.

The vaccines prepared by recombinant DNA technology are called second-generation vaccines. These vaccines do not contain the whole organism instead, they contain a part of the organism. Examples of second-generation vaccines are the Hepatitis B virus, Herpes virus, pneumonia vaccine, etc.

Abscisic acid is not required for the initiation and maintenance of plant tissue culture.

Plant tissue culture is a collection of techniques used to maintain or grow plant cells, tissues, or organs under sterile conditions on a nutrient culture medium of known composition. It is widely used to produce clones of a plant in a method known as micropropagation.

• During plant tissue culture growth sucrose acts as a fuel source for sustaining photomixotrophic metabolism (organisms can use different sources of energy and carbon), ensuring optimal development, although other important roles such as carbon precursor or signaling metabolite have more recently been highlighted.
• Kinetin is required for the initiation and maintenance of plant tissue culture.
• Auxins are responsible for the initiation and promotion of cell division in the cambium. This effect of auxin is particularly important in the secondary growth of stem and differentiation of xylem and phloem tissues. Cell Division in Tissue Culture.

The figure is identified as salivary gland. It is multicellular and is lined with glandular epithelium cells. These types of cells are specialized in production and release of particular kind of digestive juices or sweat or oil. Salivary gland secretes alkaline fluid called saliva.

Microfilaments are composed of the protein actin.

Microfilaments are fine, thread-like protein fibers, 3-6 nm in diameter. They are composed predominantly of a contractile protein called actin, which is the most abundant cellular protein. Microfilaments' association with the protein myosin is responsible for muscle contraction.

The antiviral action of purine analogues is primarily related to theInhibition of DNA polymerase.

The purine analogues used as antineoplastic agents are a group of agents with similar structures, but somewhat different mechanisms of action, pharmacokinetics, indications and adverse effects. These agents are nucleoside analogues and are considered antimetabolites, interfering or competing with nucleoside triphosphates in the synthesis of DNA or RNA or both. The agents are analogues of adenine or guanine and generally have excellent activity against leukemias and lymphomas, perhaps because of their preferential uptake, activation and effects in lymphoid tissue.

Pseudomureincell wall component can effectively defend against lysozyme.

Pseudomurein otherwise known as pseudopeptidoglycan is one of the cell wall components of archaea bacteria. They resemble peptidoglycan layer in function and structure but differ in chemical composition. Lysozyme is a defense mechanism in higher animals and they cannot defend against bacteria containing pseudomurein cell wall.

Cells become variable in morphology and functions in different region of the embryo, this process is called differentiation.

After formation of three primary germ layers (i.e., ectoderm, mesoderm and endoderm), cells of these three layers become variable in mprphology, shape, size and more specified to form organs so as to meet out the future functional needs of the foetus, this process is called differentiation.

Cork cambiumis a secondary meristem.

Secondary meristem develops from permanent tissues during secondary growth and gives rise to secondary tissues. Cork cambium is the secondary meristem. It is found in many vascular plants. It is a part of the periderm. The cork cambium is involved in the secondary growth of the plant.