Explore topic-wise InterviewSolutions in .

Correct option is (c) Sex chromosomal

The explanation is: In case of sex chromosome due to dosage compensation in FEMALE ONE of X chromosome is INACTIVATED. This is similar to the ABSENCE of a sex chromosome, which makes sex chromosome ANEUPLOIDY less lethal.

Correct option is (b) MONOPLOID and DIPLOID

The explanation: Anthers are the meiosis products, so the plant GENERATED from it is monoploid. Leaf is a normal diploid SOMATIC TISSUE which will give to diploid individual.

The correct choice is (a) True

To EXPLAIN: There are GREATER possibilities of SURVIVAL with deletion of GENES in sex chromosome, than that in case of autosomal deletion.

Correct answer is (a) Frame shifts

Explanation: Streisinger’s model explains that the Frame SHIFT MUTATIONS are more frequent in REPETITIVE SEQUENCES. This causes DUPLICATIVE insertion and also at times deletion.

Correct answer is (c) The flagella antigen changed

Easy explanation: In SALMONELLA, the flagellar antigen is target for immune RESPONSE. His antigen’s phase can VARY with presence of insertion sequence WITHIN the gene. In this case change of antigen could lead to a loss of SPECIFICITY by the immune system.

Right OPTION is (C) DOUBLE cross over in paracentric inversion is lethal

For EXPLANATION: In paracentric inversion there is chromosomal imbalance in products of SINGLE cross over, but double cross over products lead to normal gene balance and viable gametes.

The correct choice is (c) Both will have equal probability

The explanation is: Streisinger model WORKS on REPEATED SEQUENCES, it is not BASE specific. In this case both the AT rich and CG rich sequences should have an equal probability of getting DUPLICATED.

Correct answer is (a) Class I TRANSPOSON

For explanation: Class I transpose or retro TRANSPOSONS are those that 1^st TRANSCRIBE the transposon DNA to RNA, then USING reverse transcriptase enzyme they insert the sequence within the recipient DNA.

Right option is (d) None

Easy explanation: The chromosomal THEORY of inheritance VIOLATED none of MENDEL’s laws as the only DIFFERENCE was the genes being present in the CHROMOSOME, other than that the laws are as they were.

Right choice is (d) Tetrasomy

The best explanation: In extreme klinefelter the chromosomal constitution is 44+XXXY, there are TWO extra X CHROMOSOMES which LEADS to more severe Klinefelter condition. THUS, it is tetrasomy.

Right answer is (B) Gynandromorph

To explain: In case of sexual mosaics there is loss in one of the sex chromosomes in some cells. In case of male there will thus be a mosaic of male and female parts CORRESPONDING to XY and XO DEPENDING on which part has which COMBINATION.

Right answer is (C) 18

For explanation: Chromosome 18 TRISOMY will lead to EDWARD’s syndrome. Trisomy in chromosome 13 and 21 LEADS to Patau and Down’s syndrome RESPECTIVELY.

Correct OPTION is (b) Monosomy

The explanation is: In Turner’s syndrome one set of sex chromosmome is LOST resulting in 44+XO FEMALES who have masculine condition. This is a RESULT of monosomy.

Correct choice is (a) True

Explanation: In aneuploidy the CHANGE is in one or TWO chromosomes and not an increase or decrease of an entire set. This MAKES it different from euploidy.

Right answer is (d) It PRODUCES larger plant PARTS and products

Easiest explanation: In case of polyploid, more is the number of chromosome set more is the amount of gene PRODUCT. As a result the plant will be larger is size which is a COMMERCIAL profit.

Correct option is (d) Lack of DIVERSITY

The explanation: With the other reasons being true, lack of diversity AFFECTS at POPULATION level not at INDIVIDUAL level. It is no cause for lethality of individuals with deleterious mutation.

The CORRECT OPTION is (a) New sequence at 1 will be C—D—E—F—G

The best explanation: In reciprocal TRANSLOCATION, the PARTS are EXCHANGED between two chromosomes in same position. So, the new sequence of 1 should be F—G—C—D—E.

The correct option is (C) Two DNA strands with an inverted segment will not pair

Best explanation: Two DNA segments in inversion will pair but the pairing will be via FORMATION of a LOOP such that appropriate GENE loci can come close. Other options about inversion are TRUE.

Right choice is (d) A—O—E—D—B—F

Easy explanation: PERICENTRIC inversion is the inversion that doesn’t involve the CENTROMERE. Here in OPTION A there is no change at all, option B and C are including the centromere. Only option D doesn’t involve the centromere in the inverted SEQUENCE, so it is pericentric.

Correct choice is (b) Transposase

For explanation: RECOMBINASE such as transposase or integrase is mandatory for transposition as they HELP in RECOMBINATION at TERMINAL repeats. Branch poit A is needed in SPLICING and internal gene is not mandatory.

The correct choice is (B) Endosperm

The best EXPLANATION: MAKING a distinction on the BASIS of a number of sets of chromosome- endosperm is TRIPLOID while the rest are diploid.

The correct OPTION is (d) Notch is recessive to FACET

For explanation I would SAY: Facet is expressed only in absence of Notch gene by deletion, thus it is pseudo dominant and recessive to the notch gene. Other options are TRUE, notch is also LETHAL in hemizygous condition.

The correct option is (a) Two normal, one dicentric and one acentric CHROMOSOME

The EXPLANATION: RECOMBINATION in the paracentric region will take place between only two STRANDS, so the other two strands will be normal. This recombination will RESULT in one dicentric chromosome and another acentric chromosome.

Correct option is (b) The chromosome will be torn apart while segregation

To explain: The CHROMOSOMES will not join as in CASE of inversion, so the chromosome will not SNAP at the anaphase. But the distribution of the gene will be UNEQUAL.

Correct choice is (b) INCREASE in size is not appreciable

For explanation I would say: The other options being true, in animals there is a more strict regulation of GENE PRODUCT formation than in the CASE of PLANTS. In animals with an increase in cell size there would be a decrease in cell number keeping the ultimate animal sizes same. It is thus not profitable at all.

The correct ANSWER is (b) Normal phenotype

The best I can explain: In this case as the product of the 2^nd copy is mutated and not AFFECTING the phenotype, only one copy is producing the required product in normal quantity. This is SIMILAR to the DUPLICATION being silenced.

The correct option is (d) Pleiotropy

The best I can explain: In case of Pleiotropy one gene effects SEVERAL CHARACTER; this may be due to mutations of the initial DUPLICATED SEQUENCES.

Right option is (d) 4

The best I can EXPLAIN: In PERICENTRIC INVERSION there will be 4 strands in the inversion LOOP although only 2 will undergo recombination to give the recombination products. This is because the sister chromatids are bound by the centromere.

Right answer is (b) Y linked

Best explanation: If the gene has a sex bias it is CERTAINLY sex linked. In this CASE, it is a common OCCURANCE in the MALES only in a pedigree so it must be Y linked gene. There is no dominant recessive as Y is always hemizygous.

The CORRECT answer is (b) 14 and 21

The best explanation: In Down’s SYNDROME a part of the 21^st chromosome’s long ARM duplicates and TRANSFERS to chromosome 14’s long arm.

Correct choice is (b) PAIRINGS at dichtyotene stages are gradually lost

The explanation: The CHROMOSOMES with AGE tend to lose the proper pairings that existed when they were in dictyotene stage as this is PROLONGED over decades. This LEADS to improper segregation causing trisomy.

Correct option is (c) Chromosome 3 will be inactivated

For explanation: XIC is responsible for SILENCING one of the X chromosomes in a female for dosage compensation. If an XIC is PRESENT within the chromosome 3 it will be considered SIMILAR to an X chromosome and it MAY as well be inactivated.

Right option is (c) TANDEM

The explanation is: Simple translocation is the transfer of a BROKEN piece of one chromosome to the END of another. Reciprocal is the exchange of parts between the two chromosomes intercalary is translocation to an INTERMEDIATE LOCATION. There is no tandem translocation.

The CORRECT OPTION is (c) Grand father

Explanation: A male BEE is produced from the unfertilized EGGS by parthenogenesis, thus it will have a mother but not a father. The female mother was produced by FERTILIZATION so there is a grandfather and grandmother.

The correct ANSWER is (a) The LTR

To EXPLAIN: The long terminal repeats or LTR is present in both ends of TRANSLOCATING regions which are responsible for RECOMBINATION.

The correct choice is (d) Daughters with red eye and sons with white eyes

To elaborate: Eye colour is a sex linked trait. In this following case, the F1 male PROGENY was red eyed, as the father only gave the Y chromosome and not X which DETERMINES eye colour. Then similarly the F2 sons would be white eyed by allele from their mother, female will be red eyed as they GET both ALLELS.

Right answer is (b) Klinefelter

To explain I would say: Klinefelter syndrome results from trisomy in sex chromosome PRODUCING 44+ XXY. Turner is due to MONOSOMY, ENDOSPERM is triploid i.e. the complete set of chromosome is increased and XP is due to mutation or deletion in gene not entire chromosome.

Correct ANSWER is (b) False

The explanation is: In euploidy there is an INCREASE in chromosomal SET due to duplication of originally existing set and not due to blending of chromosomes of TWO organisms. Thus it is AUTOPLOIDY and not Alloploidy.

The correct CHOICE is (b) Pseudo DOMINANCE

For explanation: Pseudo dominance is the condition when the recessive allele is expressed in deletion mutation of dominant. Hemi-dominance is the condition when only one COPY of the gene is supposed to be PRESENT, as in genes of Y chromosomes. Co-dominance and imperfect dominance are different.

Correct option is (d) 64

Easiest explanation: There are 32 chromosomes but they are in duplicate chromatids so 64 is the number of chromatids before anaphase 1.

Correct option is (b) One bivalent and two UNIVALENT

For EXPLANATION I would say: In normal pairing all available chromosomes with complimentary are paired, so the existence of two univalent which are free to pair is not possible. HOWEVER in case of trivalent and univalent as one of the other SET is not available univalent exists.

Correct choice is (B) Deletion

For explanation I would say: Here the agouti allele which is to be EXPRESSED only in certain tissues is brought under the control of RALLY gene promoter which is expressed in all tissues, by deletion of Rally gene and agouti promoter in between the TWO. The strong promoter over expresses Agouty gene leading to the COLOR.

The correct choice is (c) Regulator of gene X is deleted

Explanation: In this case over EXPRESSION of gene X is due to deletion of some negative regulator like OPERON, insulator, silencer ETC.