VITEEE Biology Test - 5 - JEE MCQ

Mitosis is the type of cell division that ensures equal distribution of genetic material in daughter cells. Mitosis can occur both in diploid and haploid cells.
The main function of mitosis is to make copies of cells for growth and regeneration.

• The polymerase chain reaction is a technology in molecular biology used to amplify a single copy or a few copies of a piece of DNA.
• Calcium ions is not required in PCR technology.

At prophase I, DNA replication has already occurred, and the original amount of DNA has been doubled to x. At anaphase I, the amount of DNA in the cell remains the same because no cytokinesis has occurred yet to separate the cytoplasm.

Ribozymes are RNA molecules that have catalytic activity, meaning they can catalyze reactions like protein enzymes.

In plants, cytokinesis or division of cytoplasm occurs due to the formation of the cell plate.

In animals, cytokinesis occurs due to the formation of constriction in the middle cell membrane.

Filtration occurs through 3 layers: the endothelium of blood capillaries, the basement membrane of the epithelium and the filtration slits of the renal capsule. The endothelium ofblood capillaries contains large pores which donot filter out larger molecules, The basement membrane consists of a meshwork of collagen fibres that are able to filter them out. The filtration silts are formed by the podocytes and do not hinder the passage of large molecules.

Genetic engineering is the artificial synthesis, isolation, modification, combination, addition and repair of the genetic material (DNA) to alter the phenotype of the host organism to suit human needs. It is the manipulation of genes by man in vitro. Restriction endonucleases play major role in genetic engineering as they can cut DNA at specific sites.

Soil bacterium, Bacillus thuringiensis (Bt) produces proteins that kill certain insects like lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes). Bacillus thuringiensis forms some intracellular protein crystals. These crystals contain a toxic insecticidal protein. The Bt toxin protein exists as inactive toxin and is converted into an active form due to the alkaline pH of the alimentary canal that solubilises the crystals. The activated toxin binds to the surface of midgut epithelial cells and create pores which cause cell swelling and lysis and finally cause death of the insect.

- Statement (i): The instrument used for recording the heart's electrical events is indeed named an electrocardiograph.

- Statement (ii): In any ECG, the part of the baseline between any two deflections is actually called a segment, not an interval. Therefore, this statement is incorrect.

- Statement (iii): Abnormalities in the working of the heart can indeed change the wave pattern of an ECG. This is because different heart conditions can affect the electrical activity of the heart, leading to changes in the ECG wave pattern.

Therefore, the correct option is C

The chlorophyll pigments which are excited give up their electrons and to compensate for the loss of electrons, water is split to release four H⁺ ions and four electrons and O². The electrons that are lost from the PSII enter into an electron transfer chain or ETC.

Photosystem (PS) - I and II are two pigments system of light reaction. Non-cyclic photophosphorylation is the light-requiring part of photosynthesis in higher plants, in which an electron donor is required, and oxygen is produced as a waste product. It consists of two photoreactions, resulting in the synthesis of ATP and NADPH₂. The hydrogen needed for the reduction of NADP (nicotinamide adenine dinucleotide phosphate) is made available from the breakdown of water.

When the external intercostal muscles and diaphragm relax, the ribs move downward and inward and diaphragm becomes convex (dome shaped), thus decreasing the volume of thoracic cavity and increasing the pressure inside as compared to the atmospheric pressure outside. This will cause the air to move out (expiration).

Genetic engineering involves:
(i) Identifying DNA with desirable genes.
(ii) Introduction of identified DNA into the host.
(iii) Maintenance of introduced DNA in the host.
(iv) Transfer of DNA in its progeny.

Hence, option C is correct.

The algae groups are correctly matched with their distinct characteristics as follows:

• 1-B (Chlorophyceae - Green Algae): Characterized by chlorophyll a and b, cell walls made of cellulose and pectose, and reproduces asexually by flagellated zoospores.
• 2-A (Phaeophyceae - Brown Algae): Noted for being found primarily in marine habitats, contains chlorophyll a and c, and stores food as complex carbohydrates like laminarin or mannitol.
• 3-C (Rhodophyceae - Red Algae): Known for being predominantly in warmer marine areas, stores food as floridean starch, and reproduces sexually by non-motile gametes which are oogamous.

Thus, Option A is the correct answer providing the precise matching of algae groups with their respective characteristics.

• They are the 3 mature cells in the embryo sac present opposite to the micropylar end.
• The function of the antipodal cells is to provide nutrition and nourishment to the embryo sac.

Xenogamy is the cross-pollination between the flowers of different plants. Cross pollination is the transfer of pollen grains from the anther of one flower to the stigma of a genetically different flower. Cross pollination is performed with the help of an external agency.

• Insertional inactivation is the inactivation of a gene upon insertion of another gene inside in its place or within its coding sequence.
• It help in identification of recombinant clones.

Amphibians are particularly vulnerable to extinction due to their sensitive skin, environmental requirements, and the impact of habitat loss, climate change, and diseases.

The original statement that neurons regulate endocrine activity is not entirely correct. Both the nervous system and the endocrine system interact with and regulate each other.

• The nervous system can influence endocrine glands through nerves, such as the hypothalamus controlling the pituitary gland.
• Conversely, hormones produced by endocrine glands can affect neural activity, demonstrating a two-way interaction.

Therefore, the idea that only one system regulates the other is inaccurate. The correct statement reflects the mutual regulation between these systems.

• PCR is the short form for polymerase chain reaction which is the phenomenon which is used for amplification of the part-specific region of DNA as per our interest.
• The final step of PCR is extension, wherein Taq DNA polymerase (isolated from a thermophilic bacterium Thermus aquaticus) synthesises the DNA region between the primers, using dNTPs (denoxynucleoside triphosphates) and Mg²⁺.
• The primers are extended towards each other so that the optimum temperature for this
  polymerisation step is 72^∘C. Taq polymerase remains active during high temperature induced denaturation of double stranded DNA.

In agarose gel electrophoresis, the DNA fragments separate out (resolve) according to their size or length because of the sieving property of agarose gel. It means, the smaller the fragment size, the farther it will move.

A centriole is a barrel - shaped cell structure found in most animal eukaryotic cells, though absent in higher plants and most fungi.

Bt toxin gene has been closed from the bacteria and expressed in plants to provide resistance to insects without the need for insecticides. Examples are Bt cotton, Bt corn, rice, tomato, potato and soybean, etc.

Autogamy (Gk. autos-self, gamos-marriage) is a type of self-pollination in which an intersexual or perfect flower is pollinated by its own pollen.

Geitonogamy is a type of pollination in which pollen grains of one flower are transferred to the stigma of another flower belonging to either the same plant or a genetically similar plant. In geitonogamy, the flowers often show modifications similar to ones found in xenogamy or cross-pollination.

Xenogamy or cross-pollination is the transfer of pollen grains from the anther of one flower to the stigma of a genetically different flower.

Based on the number of axon and dendrites, the neurons are divided into three types, i.e., multipolar (with one axon and two or more dendrites; found in the cerebral cortex), bipolar (with one axon and one dendrite, found in the retina of eye) and unipolar (cell body with one axon only; found usually in the embryonic stage).

A DNA triplet of CGT would yield an mRNA codon of GCA. The complementary tRNA anticodon would therefore he CGU.

• The arteries carry blood from the heart to all over body parts. Hence, statement (i) is correct.
• The vessels which carry blood from the heart to the lungs is the pulmonary artery but it carries deoxygenated blood. Hence, statement (ii) is correct.

(A) Cellular level
(B) Radial symmetry
(C) Bilateral symmetry
(D) Pseudocoelomates
(E) Coelomates

The globular head of a meromyosin molecule functions as an active ATPase enzyme. This enzyme has specific binding sites for ATP and actin, playing a crucial role in muscle contraction by enabling the interaction of myosin with actin filaments, thereby converting chemical energy into mechanical energy.
 

RNA polymerase synthesizes RNA in the 5' → 3' direction and follows the template-strand direction. In prokaryotes, translation can begin while mRNA is still being transcribed.