TLS Online TPP Program

#Question id: 4742


In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A recessive lethal allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele and a normal female?

#Unit 8. Inheritance Biology
  1. 2:1 male to female

  2. 1:2 male to female

  3. 1:1 male to female

  4. 3:1 male to female

More Questions
TLS Online TPP Program

#Question id: 12097

#Unit 10. Ecological Principles

The herbaceous plant Achillea lanulosa is widespread in the Northern Hemisphere. Phenotypic variation in the species has been extensively studied along an altitudinal gradient from sea level to over 3,000 meters. In California there is conspicuous variation in  height; alpine plants are only several centimeters tall  while  those in  the San Joaquin Valley may reach a height of 1.8 meters. Adaptation to different local environments also results in variation in physiological processes such as photosynthetic rate, resistance to cold, and the timing of dormancy.


Which of the following methods would be best to determine whether the phenotypic variation in Achillea lanulosa is due to genotypic variation?

TLS Online TPP Program

#Question id: 11795

#Unit 1. Molecules and their Interaction Relevant to Biology

_________ residue in a tetrasaccharide linker connects a glycosaminoglycan such as chondroitin 4-sulfate to _______ residue in the core protein. The residue at the reducing end of the linker is joined by its anomeric carbon to the hydroxyl of this residue.

TLS Online TPP Program

#Question id: 11732

#Unit 6. System Physiology – Plant

Cytokinins are defined as compounds that have biological activities similar to those of trans-zeatin. These activities include the ability to do the following:

a) Induce cell division in callus cells in the presence of an auxin

b) Promote bud or root formation from callus cultures when in the appropriate molar ratios to auxin

c) promote senescence of leaves

d) Promote expansion of dicot cotyledons

Which one of the following activities are incorrect?

TLS Online TPP Program

#Question id: 5689

#Unit 8. Inheritance Biology

What kind of aneuploidy gamete will be generated if meiotic nondisjuction in second division (n represent haploid number of chromosome )

TLS Online TPP Program

#Question id: 5846

#Unit 8. Inheritance Biology

The bacteriophage can lysogenize after infecting a bacterium, i.e. integrate into the host bacterial chromosome by site-specific recombination, and may reside there for many generations before an excision event regenerates the viral genome in an infective form.  Which one of the following is not a component of these events?