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Correct option is (d) 45

To explain I would say: In human cell NUCLEUS, at least 45 percent of DNA is derived from transposable ELEMENTS. More than 99% of transposable elements are incapable of moving either because they have been crippled by mutations or because their movement is suppressed by the cell.

Right answer is (b) polyploidization

The EXPLANATION: The process of polyploidization or WHOLE GENOME DUPLICATION is evident in organisms such as Xenopus laevis, which have double the number of chromosomes as their CLOS cousins Xenopus tropicalis.

Right answer is (b) False

Explanation: A nucleotide has a polarized structure: the end where phosphate is attached is CALLED the 5’end while the other is called 3’ end. All the STACKED nucleotides in the strand face the same direction; therefore the entire strand has a direction.

Right OPTION is (d) Haplotypes

Explanation: Haplotypes are the BLOCKS of DNA that have a very low frequency of RECOMBINATION. CONSEQUENTLY, they remain INTACT during transmission from one generation to the next.

Correct ANSWER is (a) HAR

The EXPLANATION is: The Human ACCELERATED region (HAR) is the region of the genome that comprises of GENES primarily INVOLVED in the development of fetal brain.

The correct answer is (a) True

The best EXPLANATION: Dark matter refers to the REGION of chromosomes, ESPECIALLY in and around the CENTROMERES of each chromosome. It consists of long STRETCHES of highly repeating DNA sequences.

Right answer is (a) 3, 2

Easy explanation: The globin gene is constructed from three exons and TWO INTRONS. FUSION of two of the exons of globin genes millions of years ago led to the formation of globin-like polypeptides leghemoglobin and MYOSIN.

The correct CHOICE is (a) True

Explanation: Gene duplication refers to duplication of a small part of single CHROMOSOME. Each gene in the genome has 1% CHANCES of being duplicated in MILLION years.

The correct choice is (B) Minisatellite DNA

The best explanation: Minisatellite DNA range from 10 to 100 base pairs in length and are found in clusters containing 3000 repeats. Because of unequal crossing over, these sequences are HIGHLY unstable and polymorphic. Because the minisatellite DNA can vary from person to person, it forms the basis of technique used for criminal or PATERNITY cases, DNA fingerprinting.

Correct choice is (a) purines

To explain I would SAY: Purines are nitrogenous BASES CONSISTING of two rings. Adenine and GUANINE are purines whereas thymine and cytosine are pyrimidines.

The correct answer is (b) False

To elaborate: There are three HYDROGEN bonds between GC pairs and two between the AT pairs. The extra hydrogen bond present leads to INCREASE stability and an overall increase in Tm when the GC (%G + %C) content is higher.

The correct choice is (a) deoxyribose

The explanation is: NUCLEOTIDE CONSISTS of five-carbon sugar deoxyribose to which one PHOSPHATE is esterified at the 5’ position of the sugar RING and one nitrogenous base is ATTACHED at 1’.

Right option is (b) amylase

For explanation I would say: The AMY1 gene encodes for starch-digesting ENZYME amylase. On comparison of HUMAN and chimpanzee genome, it was discovered that the FORMER contains only 1 copy of AMY1 gene while the latter consists many COPIES of it in the saliva.

The correct answer is (B) False

The explanation: Only about 1.5 PERCENT of the TOTAL DNA CODES for POLYPEPTIDES (proteins). Intergenic DNA refers to the DNA that resides between the genes while intronic DNA is the DNA that comprises introns, the non-coding DNA.

Right answer is (B) False

To EXPLAIN I would say: DNA transposons and RETROTRANSPOSONS are the TWO types of TRANSPOSABLE elements found in the eukaryotes. Less than 5% occur as DNA transposons which are incapable of movement.

The correct option is (a) non-functional

Explanation: Pesudogenes are GENES found in the CLUSTERS of genes that code for a specific polypeptide. Such genes are HOMOLOGOUS to functional genes in the cluster but due to accumulated mutations, are rendered nonfunctional.

Right choice is (b) 20-80

For explanation I would say: Moderately repeated DNA sequences can VARY from 20 to more than 80 PERCENT of the total DNA. They included sequences that code for known gene products like RNAS and PROTEINS.

The correct choice is (a) True

The BEST I can EXPLAIN: Circular DNAs extant in nature include mitochondrial, BACTERIAL and viral DNA. These are invariably negatively supercoiled i.e. underwound. An underwound DNA has greater number of BASEPAIRS PER turn of the helix.

The correct option is (b) sediments faster

Easy explanation: Supercoiled DNA is the molecule twisted UPON itself. It is more compact than the relaxed counterpart and OCCUPIES lesser VOLUME. CONSEQUENTLY the supercoiled DNA MOVES rapidly in response to centrifugal or electric fields.

Correct CHOICE is (c) hydrophobic, van der Waals

The explanation: The bases OCCUPY PLANES that are perpendicular to the long axis of the molecule and are stacked one on top of the other. The hydrophobic interactions and van der Waals forces between the bases stabilize the ENTIRE DNA molecule.

Right option is (b) topoisomerase II

Easy EXPLANATION: Both these drugs are TARGET DNA in Cancer cells. They bind to topoisomerase II enzyme which prevents the DNA STANDS from re-ligating and THUS causes it to BREAK.

Correct option is (a) Linus PAULING

Best explanation: Linus Carl Pauling was an American chemist, BIOCHEMIST, peace activist and author. He made an erroneous proposal by suggesting that DNA consists of THREE nucleotide STRANDS.

The correct answer is (a) moderately repeating sequences

Best explanation: Moderately repeating sequences arise DUE to TRANSPOSITION of elements in the genome. These sequences are interspersed throughout the genome; examples INCLUDE the L1 and ALU families.

Right answer is (c) NUCLEIC acid hybridization

The best explanation: Reannealing is the process of RESTORATION of DNA helical structure after they have been DENATURED. This characteristic of the genetic MATERIAL forms the basis of nucleic acid hybdridization.

Right choice is (a) 2R hypothesis

The BEST explanation: In 1971, Susuma Ohno proposed the 2R hypothesis, in which he proposed that the VERTEBRATES have evolved from INVERTEBRATES following two ROUNDS of whole genome MULTIPLICATION.

The correct OPTION is (B) 2

Easy explanation: In a nucleotide, nitrogenous base is attached at the 1’ site. There are TWO types of nitrogenous base: PYRIMIDINES, which consist of one ring, and purines, which contain two rings.

Correct choice is (c) genetic polymorphisms

For explanation I would SAY: No two individuals have the same DNA sequence throughout the GENOME. The sites where this diversity arises, where the genome varies amongst individuals is KNOWN as genetic polymorphisms.

The correct choice is (a) regulation of gene EXPRESSION

The BEST EXPLANATION: Some of the fastest evolving genes are the ones that encode for the regulation of gene expression, the TRANSCRIPTION factors.

Right OPTION is (a) 1-10 %

Explanation: The HIGHLY repeated fraction consists of SEQUENCES that are present in at least 105 copies per genome. Such sequences MAKE up about 1 to 10% of the total DNA.

Right option is (b) 1953

Best explanation: The STRUCTURE of DNA was investigated and elucidated in the year 1953 by James WATSON and FRANCIS CRICK at Cambridge University.

The correct CHOICE is (d) Microsatellite DNA

To explain I would say: Also called short tandem repeats, Microsatellites are short repeats of 2-6 bp of DNA that are PRESENT throughout the genome and have variability among populations. They are therefore USED in DNA FINGERPRINTING.

Correct answer is (b) marine animal

For explanation: Amphioxus is a marine animal lacking a BACKBONE but having CERTAIN other FEATURES that are common to vertebrates. It has been found out that homologous genes from vertebrates are DOUBLE in NUMBER than that present in the amphioxi.

The correct answer is (C) 1960

Easy explanation: In the year 1960 Julius MARMUR and co-workers at the HARVARD University found that slowly cooling the solution of bacterial DNA that had been THERMALLY denatured, the DNA renatures and the properties of a double helix are restored.

The correct option is (B) retrotransposons

Easiest explanation: Alu SEQUENCES are short INTERSPERSED nuclear elements (SINEs) about 300 base PAIRS in length, which are retrotransposons.

Correct choice is (a) intron

Explanation: The part of gene which CODES for AMINO acids in a polypeptide (gene PRODUCT) is CALLED exon. The intervening sequences which do not code for a gene product are called introns.

The correct answer is (a) satellite DNA

To EXPLAIN: In 1969 Mary Lou Pardue and Joseph Gall of Yale University DEVELOPED the technique of in situ hybridization to determine the LOCATION of satellite DNA.

Right ANSWER is (c) 24

For explanation I WOULD say: The human genome is ESSENTIALLY equivalent to all the genetic information that is present in a single haploid set of CHROMOSOMES, CONTAINING 22 autosomes and 2 sex chromosomes X and Y.

Correct choice is (a) ETHIDIUM bromide

For explanation: In the technique of gel electrophoresis, to view DNA MOLECULES on a gel ethidium bromide is USED. EtBr is a fluorescent intercalating AGENT that INSERTS itself into the double helix.

Right OPTION is (b) misalignment

For explanation I WOULD say: Unequal crossing over takes place due to misalignment of chromosomes during meiosis. As a RESULT one CHROMOSOME receives and extra SEGMENT of DNA (duplication) and the other chromosome loses a segment of DNA (deletion).

Right answer is (b) 2 nm

To explain: The distance from the PHOSPHORUS ATOM of the backbone to the center of the axis of molecule is 1 NANOMETER (1 nm = 10^-9m). The entire width of the double HELIX is 2 nm.

The correct CHOICE is (a) base COMPOSITION

To elaborate: Erwin Chargaff of Columbia University in the year 1950 DETERMINED the amounts of each base in various samples of DNA, which is the base composition of samples.

Right answer is (a) absorbance

For explanation I would say: DNA MELTING is the process where DNA is dissolved in saline solution and the temperature is increased to initiate the process of SEPARATION. When DNA separates into its component STRANDS, the absorbance of dissolved DNA increases and this serves as a parameter for MONITORING the process.