Practice Questions

  1. Home
  2. Free Resources
  3. Practice Questions
  4. 5225
TLS Online TPP Program

#Question id: 5438

Which of the following statement is incorrect?

#Unit 8. Inheritance Biology

  1. Discontinuous characteristics exhibit few distinct phenotypes

  2. Continuous characteristics exhibit a wide range of phenotypes

  3. Continuous characteristics are frequently produced by effects of many genes

  4. Discontinuous characteristics are frequently produced effect of many genes

More Questions
TLS Online TPP Program

#Question id: 15154

#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 a recessive mutation in one gene and a dominant mutation in the other, 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: 26898

#Unit 10. Ecological Principles

Which of the following characteristics is incorrect consider in Hot desert?
TLS Online TPP Program

#Question id: 10813

#Unit 6. System Physiology – Plant

A living cytoplasmic connection penetrate the walls between sieve tube elements and their companion cells; which are often complex and branched on the companion cell side, known as
TLS Online TPP Program

#Question id: 12084

#Unit 10. Ecological Principles

In bottom sediments of lakes and streams, organic matter is broken down by heterotrophic microorganisms and ammonia is released. Under aerobic conditions, specialized bacteria convert ammonia to nitrate (nitrification). This nitrate, together with nitrate from other sources, diffuses into the deeper sediments, where it may undergo anaerobic conversion to nitrogen gas (denitrification). These sediments typically contain oligochaete worms that live with their heads buried and their tails waving back and forth in the overlying water. Plastic columns were packed with freshly collected  stream  sediments  and  then  covered  with  layers  of  nitrate enriched  water.  A  similar  set  of  columns  was packed with sediment that had been sterilized and then covered with either nitrate-enriched water or distilled water. Oligochaete  worms  were  collected  and  acclimated  to  20°(C)Following  acclimation,  worms  were  rinsed  in  distilled water and then added to three sediment columns. The columns were incubated in the dark at 20°C and monitored every three days for changes in the concentration of nitrate in the overlying water. Nitrate concentrations in each of the experimental treatments were plotted against time, as shown in the graph below.


The best explanation for the increase in nitrate concentration in one treatment is that
TLS Online TPP Program

#Question id: 4958

#Unit 11. Evolution and Behavior

What is true of the fossil record of mammalian origins?