Meiotic division of the secondary oocyte is completed:

NEET-(Sept)2020 Human-Reproduction [class-xii ]

• Prior to ovulation
• At the time of copulation
• After zygote formation
• At the time of fusion of a sperm with an ovum
Correct Option: D  [ At the time of fusion of a sperm with an ovum ]

Remark:

Select the option including all sexually transmitted diseases.

NEET-(Sept)2020 Reproductive-Health [class-xii ]

• Gonorrhoea, Syphilis, Genital herpes
• Gonorrhoea, Malaria, Genital herpes
• AIDS, Malaria, Filaria
• Cancer, AIDS, Syphilis
Correct Option: A  [ Gonorrhoea, Syphilis, Genital herpes ]

Remark:

In which of the following techniques, the embryos are transferred to assist those females who cannot conceive?

NEET-(Sept)2020 Reproductive-Health [class-xii ]

• ZIFT and IUT
• GIFT and ZIFT
• ICSI and ZIFT
• GIFT and ICSI
Correct Option: A  [ ZIFT and IUT ]

Remark:

How many true breeding pea plant varieties did Mendel select as pairs, which were similar except in one character with contrasting traits?

NEET-(Sept)2020 Principles-of-Inheritance-and-Variation [class-xii ]

• 4
• 2
• 14
• 8
Correct Option: C  [ 14 ]

Remark:

Identify the wrong statement with reference to the gene 'I' that controls ABO blood groups.

NEET-(Sept)2020 Principles-of-Inheritance-and-Variation [class-xii ]

• The gene (I) has three alleles.
• A person will have only two of the three alleles.
• When I^A and I^B are present together, they express same type of sugar.
• Allele 'i' does not produce any sugar.
Correct Option: C  [ When I^A and I^B are present together, they express same type of sugar. ]

Remark:

Experimental verification of the chromosomal theory of inheritance was done by:

NEET-(Sept)2020 Principles-of-Inheritance-and-Variation [class-xii ]

• Mendel
• Sutton
• Boveri
• Morgan
Correct Option: D  [ Morgan ]

Remark:

Select the correct match.

NEET-(Sept)2020 Principles-of-Inheritance-and-Variation [class-xii ]

• Haemophilia -

  Y linked

• Phenylketonuria -

  Autosomal dominant trait

• Sickle cell anaemia -

  Autosomal recessive trait, chromosome-11

• Thalassemia -

  X linked

Correct Option: C  [
Sickle cell anaemia -

Autosomal recessive trait, chromosome-11
]

Remark:

Name the enzyme that facilitates opening of DNA helix during transcription.

NEET-(Sept)2020 Molecular-Basis-of-Inheritance [class-xii ]

• DNA ligase
• DNA helicase
• DNA polymerase
• RNA polymerase
Correct Option: D  [ RNA polymerase ]

Remark:

Which of the following statements is correct?

NEET-(Sept)2020 Molecular-Basis-of-Inheritance [class-xii ]

• Adenine pairs with thymine through two H-bonds.
• Adenine pairs with thymine through one H-bond.
• Adenine pairs with thymine through three H-bonds.
• Adenine does not pair with thymine.
Correct Option: A  [ Adenine pairs with thymine through two H-bonds. ]

Remark:

If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is 6.6×10⁹ bp, then the length of the DNA is approximately:

NEET-(Sept)2020 Molecular-Basis-of-Inheritance [class-xii ]

• 2.0 meters
• 2.5 meters
• 2.2 meters
• 2.7 meters
Correct Option: C  [ 2.2 meters ]

Remark: