Paper : AIPMT 2007 Biology Screening (Part - 5)
All India Pre-Medical / Pre-Dental Entrance Examination

Q. 81. During transcription, RNA polymerase holoenzyme binds to a gene promoter and assumes a saddle - like structure. What is it’s DNA-binding sequence?

1. TATA
2. TTAA
3. AATT
4. CACC

Sol. The DNA binding sequence for RNA polymerase is called TATA box. Correct choice: (1)

Q. 82. Two genes R and Y are located very close on the chromosomal linkage map of maize plant. When RRYY and rryy genotypes are hybridized, the F2 segregation will show:

1. Higher number of the parental types.
2. Higher number of the recombinant types.
3. Segregation in the expected 9: 3: 3: 1 ratio.
4. Segregation in 3:1 ratio.

Sol. When the linked genes are situated quite close, the chances of crossing over are highly reduced. Due to this, large number of parental gametes are formed and only few recombinant gametes are formed. This results in higher number of parental types in F₂ generation as compared to recombinants.
Correct choice: (1)

Q. 83. In maize, hybrid vigour is exploited by:

1. Inducing mutations.
2. Bombarding the seeds with DNA.
3. Crossing of two inbred parental lines.
4. Harvesting seeds from the most productive plants.

Sol. Correct choice: (3)

Q. 84. Differentiation of organs and tissues in a developing organism, is associated with:

1. Deletion of genes
2. Developmental mutations
3. Differential expression of genes
4. Lethal mutations

Sol. Correct choice: (3)

Q. 85. In pea plants, yellow seeds are dominant to green. If a heterozygous yellow seeded plant is crossed with a green seeded plant, what ratio of yellow and green seeded plants would you expect in F1 generation?

1. 3 : 1
2. 50 : 50
3. 9 : 1
4. 1 : 3

Sol. This is a monohybrid test cross. Correct choice: (2)

Q. 86. The length of DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cells. How is this DNA accommodated?

1. Through elimination of repetitive DNA.
2. Deletion of non-essential genes.
3. Super-coiling in nucleosomes.
4. DNAse digestion.

Sol. The nucleosome model explains the packaging of histone proteins and DNA in the chromatin material which forms the chromosome. Correct choice: (3)

Q. 87. In cloning of cattle a fertilized egg is taken out of the mother’s womb and:

1. from this upto eight identical twins can be produced
2. the egg is divided into 4 pairs of cells which are implanted into the womb of others cows
3. in the eight cell stage, cells are separated and cultured until small embryos are formed which are implanted into the womb other cows.
4. in the eight cell stage the individual cells are separated under electrical field for further development in culture media.

Sol. As per the experiment performed by the scientist from Japan. Correct choice: (3)

Q. 88. Which one of the following statements is correct?

1. At present it is not possible to grow maize without chemical fertilizers.
2. Extensive use of chemical fertilizers may lead to eutrophication of nearby water bodies.
3. Both Azotobacter and Rhizobium fix atmospheric nitrogen in root nodules of plants.
4. Cyanobacteria such as Anabaena and Nostoc are important mobilizers of phosphates and potassium for plant nutrition in soil.

Sol. The Agricultural run off contains high concentration of chemical fertilizers. Which is discharge in near by lakes causes nutrient enrichment of lakes called eutrophication. Correct choice: (2)

Q. 89. The population of an insect species shows an explosive increase in numbers during rainy season followed by its disappearance at the end of the season. What does this show?

1. The population of its predators increases enormously.
2. S-shaped or sigmoid growth of this insect.
3. The food plants mature and die at the end of the rainy season.
4. Its population growth curve is of J-type.

Sol. A population which grows exponentially and crashes suddenly exhibits J-type growth curve. Correct choice: (4)

Q. 90. The two polynucleotide chains in DNA are:

1. semiconservative
2. parallel
3. discontinuous
4. antiparallel

Sol. The two chains in a dsDNA run in opposite direction one while other in opposite direction.

Q. 91. A plant requires magnesium for:

1. Cell wall development
2. Holdin g cells together
3. Protein synthesis
4. Chlorophyll synthesis

Q. 92. Probiotics are:

1. Live microbial food supplement
2. Safe antibiotics
3. Cancer inducing microbes
4. New kind of food allergens

Sol. Live microbial food supplements are called probiotics (e.g., curd). Correct choice: (1)

Q. 93. Bowman’s glands are located in the:

1. olfactory epithelium of our nose
2. proximal end of uriniferous tubules
3. anterior pituitary
4. female reproductive system of cockroach

Sol. Correct choice: (1)

Q. 94. Increased asthamatic attacks in certain seasons are related to:

1. Low temperature
2. Hot and humid environment
3. Eating fruits preserved in tin containers
4. Inhalation of seasonal pollen

Sol. Correct choice: (4)

Q. 95. A human male produces sperms with genotypes AB, Ab, aB and ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?

1. AABB
2. AaBb
3. AaBB
4. AABb

Sol. The formula for gamete formation is 2n where n stands for number of heterozygous pairs. AaBb has 2 heterozygous pairs so it will form 4 types of gametes. Correct choice: (2)

Q. 96. Which one of the following pairs is wrongly matched?

Sol. Coliforms are bacteria found in colon e.g. E. coli. For the preparation of vinegar Acetobacter aceti is employed. Correct choice: (1)

Q. 97. Which one of the following pairs is mismatched?

Sol. Pinctada vulgaris is a bivalve from which pearl is obtained. Correct choice: (2)

Q. 98. Which one of the following is viral disease of poultry?

1. Pasteurellosis
2. Salmonellosis
3. Coryza
4. New Castle disease

Sol. Correct choice: (4)

Q. 99. Ultrasound of how much frequency is beamed into human body for sonography?

1. 45 - 70 MHz
2. 30 - 45 MHz
3. 15 - 30 MHz
4. 1 - 15 MHz

Sol. Correct choice: (4)

Q. 100. Lysozyme that is present in perspiration, saliva and tears, destroys:

1. most virus-infected cells
2. certain fungi
3. certain types of bacteria
4. all viruses

Sol. Correct choice: (3)

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