TLS Online TPP Program

#Question id: 341


 Which force can stabilize a DNA double-helix?

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. Hydrophobic bases are found in the interior of the helix where each base-pair is stabilized by the same number of hydrogen bonds.

  2. Hydrophilic sugar-phosphate groups are found on the exterior of the helix where they can interact with water.

  3. Non-covalent N-glycosidic bonds can form between nitrogenous bases in opposite strands in the helix.

  4. Covalent base-stacking interactions can occur between adjacent bases within the same strand in the helix.

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TLS Online TPP Program

#Question id: 10289

#Unit 6. System Physiology – Plant

If C6 of glucose is radiolabelled, which carbon of Dihydroxyacetone phosphate and glyceraldehyde 3-phosphate  is radiolabelled?

TLS Online TPP Program

#Question id: 15155

#Unit 8. Inheritance Biology

In this problem we will explore some of the many ways that mutations in two different genes can interact to produce different Mendelian ratios. Consider a hypothetical insect species that has red eyes. Imagine mutations in two different unlinked genes that can, in certain combinations, block the formation of red eye pigment yielding mutants with white eyes. In principle, there are two different possible arrangements for two biochemical steps responsible for the formation of red eye pigment. The two genes might act in series such that a mutation in either gene would block the formation of red pigment. Alternatively, the two genes could act in parallel such that mutations in both genes would be required to block the formation of red pigment.

Further complexity arises from the possibility that mutations in either gene that lead to a block in enzymatic activity could be either dominant or recessive. If the crosses between a wild type insect with red eyes and a true breeding white eyed strain with mutations in both genes. Such considerations yield the Pathways in parallel with dominant mutations in both genes, determine the phenotype of the F1 progeny and the expected phenotypic ratio of red to white eyed insects in the F2.

TLS Online TPP Program

#Question id: 128

#Unit 1. Molecules and their Interaction Relevant to Biology

Amino acids with non-ionizable side chains are zwitterions when they are ________.

TLS Online TPP Program

#Question id: 7751

#Unit 5. Developmental Biology

Ultrastructural studies have led to the characterization of two distinctive cytological
pathways of PCD in plants;
I) Vacuolar-type PCD
II) Hypersensitive response-type (HR-type) PCD
a) cytosol and all its organelles, including the plasma membrane, are completely brokendown
b) The vacuole loses water, resulting in marked cell shrinkage, contraction from the cell wall,
and nuclear DNA degradation
c) PCD occurs in leaves in response to microbial attack
d) cell wall is either partially or completely digested as well, as in endosperm tissue
e) Continued water loss from the cytosol leads to the breakdown of the plasma membrane
and the release of residual cellular contents into the apoplast
Given characterization of PCD pathway match with its type PCD?

TLS Online TPP Program

#Question id: 31102

#Unit 2. Cellular Organization

Which of the following statements are correct regarding the actin polymerization?

a) the concentration of G-actin is above the Cc, the filament end will grow
b) the concentration of G-actin is below the Cc, the filament end will grow
c) (+) end of microfilament polymerization is much faster than the (-) end
d) D form that adds to the filament and the T form that leaves