Betaine improves the PCR amplification of GC-rich DNA sequences. Betaine reduces the formation of secondary structure caused by GC-rich regions and, therefore can be used to assist the amplification of GC rich sequences by PCR. It facilitates an isostabilizing effect on the differential thermal stability of AT and GC base pairs, which may result in a larger destabilizing effect on GC pairs and stabilzes AT rich sequence by binding with them and causing conformational change. ​

Correct Option: B

Betaine improves the PCR amplification of GC-rich DNA sequences. Betaine reduces the formation of secondary structure caused by GC-rich regions and, therefore can be used to assist the amplification of GC rich sequences by PCR. It facilitates an isostabilizing effect on the differential thermal stability of AT and GC base pairs, which may result in a larger destabilizing effect on GC pairs and stabilzes AT rich sequence by binding with them and causing conformational change. ​

Type I collagen, a fibrous protein abundant in connective tissues including tendon, ligament, dermis and blood vessel, is the major component and the primary determinant of tensile strength of the extracelluar matrix (ECM). It is widely used as a thin layer on tissue-culture surfaces to enhance the attachment and proliferation of a variety of cells including endothelial cells, fibroblasts, hepatocytes, epithelial cells and etc. In addition, collagen I can self-assemble into a 3-D superamolecular gel in vitro, making it an ideal biological scaffold to promote more in vivo-like cellular morphology and function. ​

Correct Option: B

Type I collagen, a fibrous protein abundant in connective tissues including tendon, ligament, dermis and blood vessel, is the major component and the primary determinant of tensile strength of the extracelluar matrix (ECM). It is widely used as a thin layer on tissue-culture surfaces to enhance the attachment and proliferation of a variety of cells including endothelial cells, fibroblasts, hepatocytes, epithelial cells and etc. In addition, collagen I can self-assemble into a 3-D superamolecular gel in vitro, making it an ideal biological scaffold to promote more in vivo-like cellular morphology and function. ​

Gibberellins (GAs) are plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction, and leaf and fruit senescence. ​

Correct Option: A

Gibberellins (GAs) are plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, sex expression, enzyme induction, and leaf and fruit senescence. ​

TthPlus DNA polymerase is isolated from the Thermus thermophilus strain. TthPlus DNA polymerase is a single 92 kDa polypeptide showing a 52 -32 exonuclease activity but lacking 32 -52 exonuclease activity. It catalyzes the polymerization of nucleotides into double-stranded DNA in the presence of MgCl₂. Its efficiency has been shown more particularly on large DNA fragments up to 12 kb (using lambda phage DNA as a template). TthPlus DNA polymerase is also capable of catalyzing the polymerization of DNA using a RNA template in the presence of Mn²⁺. The ability of TthPlus DNA polymerase to reverse transcribe at elevated temperatures (70 C) minimizes the problems encountered with strong secondary structures in RNA since they are unstable at higher reaction temperatures. Higher temperatures also result in increased specificity of primer hybridization and extension. In coupled RT/PCR assays, TthPlus is about 50-100 times more efficient than regular Taq DNA polymerase.

Correct Option: D

TthPlus DNA polymerase is isolated from the Thermus thermophilus strain. TthPlus DNA polymerase is a single 92 kDa polypeptide showing a 52 -32 exonuclease activity but lacking 32 -52 exonuclease activity. It catalyzes the polymerization of nucleotides into double-stranded DNA in the presence of MgCl₂. Its efficiency has been shown more particularly on large DNA fragments up to 12 kb (using lambda phage DNA as a template). TthPlus DNA polymerase is also capable of catalyzing the polymerization of DNA using a RNA template in the presence of Mn²⁺. The ability of TthPlus DNA polymerase to reverse transcribe at elevated temperatures (70 C) minimizes the problems encountered with strong secondary structures in RNA since they are unstable at higher reaction temperatures. Higher temperatures also result in increased specificity of primer hybridization and extension. In coupled RT/PCR assays, TthPlus is about 50-100 times more efficient than regular Taq DNA polymerase.

The various reasons attributed to the escape of the meristems by virus invasion are :
​​(a)​Viruses move readily in a plant body through the vascular system which in meristems is absent,
​​(b)​A high metabolite activity in the actively dividing meristematic cells does not allow virus replication and ​​
(c)​A high endogenous auxin level in shoot apices may inhibit virus multiplication.

Correct Option: A

The various reasons attributed to the escape of the meristems by virus invasion are :
​​(a)​Viruses move readily in a plant body through the vascular system which in meristems is absent,
​​(b)​A high metabolite activity in the actively dividing meristematic cells does not allow virus replication and ​​
(c)​A high endogenous auxin level in shoot apices may inhibit virus multiplication.