Biology Test - 32

Alec Jeffreys is a British geneticist, who developed techniques for genetic fingerprinting and DNA profiling which are now used worldwide in forensic science to assist police detective work and to resolve paternity and immigration disputes. F. Sanger developed the Sanger dideoxy method of sequencing DNA and also is credited for the sequencing of fragments of automated DNA sequences called annotated DNA sequences. This was very helpful for the human genome project that could sequence the entire genetic makeup of the human being.  In 1961, Francois Jacob and Jacques Monod proposed the operon model of gene regulation in bacteria. The model was based on their study of the genes in E. coli that code for enzymes that affect the breakdown of lactose also called the Lac Operon. Avery, MacLeod and McCarty experimentally proved that DNA is the substance or the genetic material that causes transformation in bacteria. 

So, the correct option is 'A – (iii), B – (ii), C – (i), D – (iv)'.

Digestion of cell’s own component is referred to as Autophagy.

Autophagy is the self-digestion process; autophagic vacuoles contain the own components of cells, called the autophagosome, further which fuse to the lysosome where the digestion of components takes place.

Water vascular system is a characteristicfeature of the phylum Echinodermata.

The water vascular system can be defined as a hydraulic system used by echinoderms, (for example, sea stars and sea urchins) for locomotion, food and waste transportation, and respiration. The system is composed of canals connecting numerous tube feet. They move by alternately contracting muscles that force water into the tube feet, causing them to extend and push against the ground, then relaxing to allow the feet to retract.

Infrared (IR)radiation do Greenhouse gases emit.

Greenhouse gases such as methane and carbon dioxide in the atmosphere prevent the rays of the Sun reflected from the Earth's surface to escape the atmosphere thus trapping the radiations.The trapped radiations warm the Earth's atmosphere, causing increases in the global temperature. This is called the greenhouse effect.

'Biosphere Reserves' are most appropriately described as learning sites for sustainable development.

Biosphere reserves are terrestrial and coastal habitat areas that facilitate ways to balance biodiversity conservation with sustainable use.The Biosphere Conference was organized by UNESCO in 1968, which saw the beginning of the idea of a 'Biosphere Reserve'.

Bacteria having clusters of flagella at both poles of cells are known as amphitrichous.In amphitrichous, flagella occur either singly or in clusters at both cell poles. Lophotrichous refers to a cluster of polar flagella, peritrichous is surrounded by lateral flagella and monotrichous is for a single polar flagellum.

- Typhoid is caused by bacteria of the genus Salmonella.
- Elephantiasis is caused by a parasitic worm from the group Aschelminthes (specifically, filarial worms).
- Ringworm is a fungal infection caused by fungi of the genus Microsporum.
- Malaria is caused by a protozoan parasite from the genus Plasmodium.

Insulin and thyroxin arrive at an organ/tissue/cell at the same time. Thyroxine causes an effect on the organ but insulin does not because thyroxin is a lipid - soluble hormone and insulin.

• Insulin is a hormone that is produced naturally in our bodies. Its main role is to allow cells throughout the body to uptake glucose (sugar) and convert it into a form that can be used by these cells for energy. Without insulin, we cannot survive, and death from diabetes was a common occurrence until insulin was discovered in the early 1900s by Frederick Banting and Charles Best.
• Thyroxine is the primary hormone which is secreted by the thyroid gland. This medication plays an important role in controlling body metabolism and regulates the functions of the heart and the digestive tract. It also keeps the bones strong, helps in development of the brain and controls muscle growth.

Stamen is a modification of Microsporophyll.

The female reproductive organ of a flower is called a carpel. The leaf-like organ which contains microsporangia is known as microsporophyll. Modification in the microsporophyll results in the formation of stamens. Stamens are the male reproductive organ of the plant.

Please note that there are 2 sets of information given in the question. The first set (options a-e) mentions the names of compounds. The second set (options 1-4) mentions the combinations of the first set of options.

• Auxin refers to a group of plant hormones that regulate plant growth.
• Based on their origin, auxins can be divided into:
  • Natural Auxins - They occur naturally in the plant and affect physiological functions. E.g. - IAA, IBA.
  • Artificial Auxins - These are synthetically-derived chemical compounds that resemble IAA in biological activity. E.g. - NAA.
• Artificial auxins are widely used in horticultural practices, as weedicides, rooting agents, and defoliating agents.

• IPA
  • Indole-3-pyruvic acid (IPA) is an intermediate in the IAA biosynthesis pathway.
  • Hence, it is not an artificial auxin.
• PAA
  • Phenylacetic acid (PAA) is a natural auxin.
• NAA
  • Naphthalene acetic acid (NAA) is an artificial auxin that is used as a rooting agent.
• 2,4,5-T
  • 2,4,5 - Trochlorophenoxyacetic acid is an artificial auxin that is used as a herbicide.
• 2,4-D
  • 2,4 - Dichlorophenoxy acetic acid (2,4-D) is an artificial auxin that is widely used as a herbicide.