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The correct option is (b) 1882

The best explanation: The term mitosis was coined in the year 1882 by German biologist Walther Flemming. The word ORIGINATES from greek word “MITOS” meaning thread. It is an important part in the life CYCLE of a cell.

The correct option is (a) 1970s

Explanation: In 1970s, an ATTEMPT was MADE by POTU Rao and Robert Johnson of the University of Colorado in a series of experiments to understand how the cell CYCLE is regulated.

Correct CHOICE is (c) G0 PHASE

The explanation: Cells that have stopped dividing either TEMPORARILY or permanently are referred to as being in the G0 state, to DISTINGUISH them from cells in the G1 phase that are about to enter the synthesis phase.

Correct answer is (d) Cytoplasm

The explanation is: After the process of MITOSIS, the following process is that of CYTOKINESIS. It is the division of a CELL into two by partitioning of the cytoplasm of the cell. The two daughter cells RESEMBLE each other and also the parent cell.

Right answer is (a) True

For explanation I WOULD say: Meiosis ensures a haploid phase in the LIFE CYCLE and leads to a reduction in the GENETIC material. Fertilization ensures a DIPLOID phase and leads to doubling of the chromosomal content.

Right answer is (d) conformation

To explain I would SAY: Cyclin binding leads to a change in the conformation of catalytic SUBUNIT of kinase enzyme by binding to its catalytic SITE. This binding allows the cyclin dependent kinase (CDK) to PHOSPHORYLATE its SUBSTRATES.

Correct answer is (a) fungi

To ELABORATE: ZYGOTIC meiosis or initial meiosis OCCURS only in protists and fungi. In these organisms the meiotic divisions OCCUR just after fertilization to facilitate the production of spores.

The correct ANSWER is (a) 1950s

To explain I would say: In 1950s, the proposal made by Douglas Marsland known as the contractile ring theory is responsible for the CURRENT understanding of mechanism behind CYTOKINESIS. He proposed that the force required to cleave the cell resides in the cortex, just BENEATH the furrow of dividing cell.

Correct choice is (a) skin cells

For EXPLANATION I would say: Only highly specialized cells of the body such as nerve cells, muscle cells and RED blood cells LACK the ability to DIVIDE, once they have differentiated they remain in that state till the end of their LIFE cycles.

Right choice is (a) True

For explanation I would say: There are two types of cell divisions in eukaryotes – meiosis and mitosis. Mitosis produces CELLS identical to the parent cells while meiosis produces cells that contain half the GENETIC content as PRESENT in their parents.

The correct ANSWER is (c) XP V

To explain: Patients afflicted with a variant of Xeroderma pigmentosum, XP V are susceptible to developing SKIN cancer due to sun exposure. It is discovered that the GENE encoding replicative polymerase Η.

The correct choice is (a) premature CHROMOSOME COMPACTION

Explanation: If a G1 cell and M phase cell are FUSED together, premature chromosome compaction takes place. If G2 and M phase cell are fused together G2 chromosomes will appear visibly doubled and undergone premature gene compaction.

The correct OPTION is (c) 3

For explanation: Three types of cancer – basal cell CARCINOMA, squamous cell carcinoma and malignant melanoma. The first two types are the most common and can be excised in a clinic, while the THIRD type is a POTENTIAL killer.

Right option is (b) Reiji Okazaki

The explanation: Reiji Okazaki of NAGOYA UNIVERSITY, Japan; made the discovery that one of the strands during DNA replication is synthesized discontinuously (TERMED the LAGGING strand) in SHORT fragments – Okazaki fragments.

Right option is (c) Interphase

The best EXPLANATION: The period between cell divisions is TERMED as interphase. It is the TIME in which a cell prepares for cell division, grows and performs metabolic activities. Interphase is a long period and may last for DAYS, WEEKS or longer.

The CORRECT choice is (d) 4

Easiest EXPLANATION: One round of meiotic division gives RISE to 4 haploid cells. In the process of MEIOSIS, there are two sequential ROUNDS of division without an intervening round of replication.

The CORRECT ANSWER is (c) 3

To explain I would say: THREE models of DNA replication were considered before the semiconservative nature of DNA replication was CONFIRMED. These included the semiconservative, conservative and DISPERSIVE replication.

The correct option is (a) HUMAN males

For EXPLANATION: KLINEFELTER syndrome is associated with human males who have one extra copy of the FEMALE sex chromosome (XXY), characterized by mental RETARDATION, underdevelopment of genitalia and development of female characteristics.

Correct CHOICE is (a) MEIOSIS

The EXPLANATION is: It is estimated that about 20 to 25 percent of human oocytes are aneuploid, which is much higher than the human spermatozoa. It is hence believed that meiosis in males occurs with a much lower frequency of CHROMOSOMAL ABNORMALITIES than in females.

Correct answer is (b) LIVER cells

To explain I would say: Liver cells do not USUALLY grow and divide but can be MADE to do so under specific conditions such as liver surgery. LYMPHOCYTES can also be induced to regrow and divide by interaction with a proper antigen.

The correct answer is (b) double-strand breaks

For EXPLANATION I WOULD say: The nonhomologous end JOINING pathway (NHEJ) is a pathway to repair double-strand breaks in the DNA. These are introduced by agents such as ionization radiations, CANCER DRUGS etc.

Correct choice is (a) X

Easy explanation: Chiasmata (SINGULAR chiasma) are X-shaped structures located at the sites on CHROMOSOMES where crossing over between two DNA molecules of the two chromosomes has OCCURRED in the PAST.

Correct option is (a) translesion synthesis

Easiest EXPLANATION: The POLYMERASE Η was discovered in 1999, it is a member of family of DNA POLYMERASES having the function of incorporating NUCLEOTIDES opposite particular types of DNA lesions in the template STRAND.

Right answer is (a) multiprotein complex

To EXPLAIN I would say: Condensin is a multiprotein complex BELIEVED to play a major ROLE in CHROMOSOME compaction. The PROTEINS of condensing were discovered by incubating nuclei in frog egg extracts.

Right option is (b) cyclin

Easy EXPLANATION: The regulatory SUBUNIT of maturation-promoting factor (MPF) is called cyclin. The CONCENTRATION of this regulatory protein CHANGES in a predictable pattern. When the cyclin concentration is low, the ENZYME is inactive.

Correct OPTION is (a) True

The EXPLANATION: Certain mutant strains of BACTERIA can not replicate their genetic MATERIAL (chromosomes) at elevated TEMPERATURES, termed nonpermissive (or restrictive) temperatures.

Correct option is (c) Stem cells

The EXPLANATION: HEPATOCYTES and EPITHELIAL cells undergo symmetric cell division which is UNIVERSAL in cell division. Stem cells are an EXCEPTION as they can produce asymmetric cells and neurons do not undergo division.

Correct CHOICE is (a) S PHASE

Explanation: DNA replication OCCURS during the synthesis (S) phase of the cycle. During this phase additional histones are also synthesized that will be needed as the CELL doubles the number of nucleosomes in its chromosomes.

Correct choice is (b) prophase II

Explanation: Leptotene and zygotene are the stages that OCCUR during prophase II in the meiosis. During the leptotene, the chromosomes BECOME microscopically VISIBLE and during zygotene visible association of homologues can be SEEN.

The CORRECT ANSWER is (b) meiosis

To elaborate: Vertebrate eggs typically fertilize at a stage before the completion of meiosis, usually the metaphase II. Meiosis is completed after fertilization, when sperm is ALREADY RESIDING in the egg.

Right CHOICE is (d) 5

The explanation is: Mitosis has five phases – PROPHASE, prometaphase, metaphase, ANAPHASE and telophase; that constitute different SEGMENTS of a continuous process that mitosis is. The morphology of chromosomes changes during these phases.

Correct CHOICE is (b) 2

Easiest explanation: Nucleotide excision repair (NER) operates by excising the lesions and then repairing it. There are two pathways of this repair SYSTEM – transcription coupled pathway and global GENOMIC pathway.

Right choice is (a) Nitrogen

Easiest explanation: In 1957, researchers used the Nitrogen isotopes to confirm the semiconservative nature of DNA replication. At the California Institute of TECHNOLOGY, the researches GREW bacteria in TWO subsequent mediums containing ^15N and ^14N isotopes.

Right CHOICE is (c) plants

For explanation: Cell plate is a simple precursor, the CONSTRUCTION of which INITIATES the formation of a new cell. PLANT cells are enclosed by inextensible cell walls and therefore undergo cytokinesis by a DIFFERENT mechanism.

Correct OPTION is (a) Prophase

Easy explanation: The cytoskeleton is disassembled in the prophase of MITOSIS, and mitotic SPINDLE is ASSEMBLED following condensation of chromosomal material to form COMPACT chromatids.

Right CHOICE is (d) gyrase

Easiest explanation: DNA gyrase is an enzyme BELONGING to the topoisomerase-II type of ENZYMES. The basic function of DNA gyrase is to relieve the mechanical stress and the POSITIVE supercoils that BUILD up during replication.