SRMJEEE Biology Mock Test - 2 - JEE MCQ

Chiru or the Tibetan antelope (Pantholops hodgsoni) is medium-sized bovid, which is about 1.2 m in height. It's coat is grey to reddish brown, with a white underside. The Chiru’s wool, known as shahtoosh, is worm, soft and fine. Shahtoosh is very warmest, lightest and most expensive wool. The wool can only be obtained by killing the animal. It is listed as endangered by the world conservation union and the 'United States Fish and Wildlife Service' due to commercial poaching for its wool. 

Extracts of Aconitum species have been given orally in traditional medicine to reduce fever associated with colds, pneumonia, laryngitis, croup, and asthma; for pain, inflammation, and high blood pressure; as a diuretic; to cause sweating; to slow heart rate; and for sedation.

Valley of Flowers National Park is an Indian national park, located in North Chamoli, and  in the West Himalayas in the state of Uttarakhand and is known for its meadows of endemic alpine flowers and the variety of flora.

Both haemophilia and colour blindness skips generations; the unaffected parents have diseased progeny which means that the traits are present in recessive condition in parents. Males are more affected than females which means that traits are dependent on sex of individual; both are sex linked traits. Colour blindness and haemophilia are X-linked recessive disorders. One copy of the affected gene in males in each cell is sufficient to cause the disorder (X^cY or X^hY ). Females with two copies of the affected gene show the disorder (X^cX^c or X^hX^h). The heterozygous females serve as the carrier for the disease. 

A unit of red blood cells (RBCs) expires in 35 or 42 days because of the type of anticoagulant in the bag. But in real life RBCs live about 120 days (except for Scarlett O'Negative, she's immortal)

Enamel is the hardest part of not only tooth but even of the body. It’s harder than bones.

Enamel is a dead tissue as its forming cells Ameloblasts retract away from the surface after laying down it. That’s why it lacks the quality to heal, remodel or repair.

Meroblastic cleavage is a type of cleavage that occurs in very yolky eggs like birds in which the egg cytoplasm and not the yolk divides (incomplete division). There are two types of meroblastic cleavage  discoidal and superficial. Discoidal usually occurs in birds, reptiles, fishes etc. which have telolecithal eggs and superficial cleavage occurs in insects which have centrolecithal eggs. 

RNA contains all the bases of DNA except thymine.
Instead of thymine, Uracil is present in RNA.
So, bases present in RNA are adenine, guanine cytosine and uracil.

In presence of lactose, allolactose; an isomer of lactose binds to the repressor and causes an allosteric shift. The altered repressor cannot bind to the operator, allowing RNA polymerase to transcribe the lac genes. The repressor, encoded by the regulator gene, bind to the operator region which is located just upstream the binding site of the RNA polymerase and hence, prevent the binding of the RNA polymerase and transcription of structural genes is turned off. The lac Z, lacY and lac A genes in lac operon are the structural genes that code for β-galactosidase (converts lactose into glucose and galactose), β-galactoside permease (transports lactose into the cell) and β-galactoside transacetylase respectively. Binding of the repressor to RNA polymerase turns the gene expression off and hence, none of the above-mentioned enzymes are synthesized.

Thus, the correct answer is option D.

Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (without regard to sequence), while many, typically called restriction endonucleases or restriction enzymes, cleave only at very specific nucleotide sequences. These enzymes are often used in genetic engineering to make recombinant DNA for introduction into bacterial, plant, or animal cells, as well as in synthetic biology

Another feature of of independent assortment is recombination. Recombination occurs during meiosis and is a process that breaks and recombines pieces of DNA to produce new combinations of genes.

9:3:3:1 is the phenotypic ratio obtained in the F2 generation of a dihybrid cross. Where the values 9 and 1 represent parental phenotypes, the other two values represent new combination. This is because of independent assortment of alleles belonging to the characters considered in the cross.

The ductus reuniens also the canalis reuniens of Hensen is part of the human inner ear. It connects the lower part of the saccule to the cochlear duct near its vestibular extremity.

The Involuntary muscular could traction of a group of muscle fibres or heart is called as muscle spasm.
It is mainly caused due to overuse I mean over working,muscle fatigue (making us slow and causing pain while doing exercise for longer time),dehydration and electrolyte abnormalities.

Muscle fatigue is caused due to accumulation of lactic acid in them. This occurs because of the need for high energy, fluctuation of energy need and insufficient supply of oxygen. Higher level of lactic acid can cause pain in the muscles.

Photosynthesis in plants converts solar energy into chemical energy using electrons and protons from water. The process of photosynthesis in plants involves a series of steps and reactions that use solar energy, water, and carbon dioxide to produce organic compounds and oxygen.

Mineral nutrition of plants includes various diseases and disorders like chlorosis, stunted plant growth, premature leaves abscission, internode shortening, cell division inhibition. Etiolation is seen in flowering plants when they are grown in partial or complete absence of light. They have pale yellow leaves and long internodes.

Thus, the correct answer is option D.

The xylem is the principal water-conducting tissue of vascular plants. It consists of tracheary elements, tracheids and wood vessels and of additional xylem fibres. Bordered pits are typical for tracheids, while wood vessels are marked by perforated or completely dissolved final walls. The principal conductive cells of the xylem are tracheary elements, of which there are two types, tracheids and wood vessels. 

Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids. Some governments have made efforts since the 1970s to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere with positive results.

 Option ( b)... Interstitial cells is the correct answer. 

The interstitial cells are found adjacent to seminiferous tubules in testicle. They produce testosterone in presence of (LH) luteinizing hormone.