Practice Questions

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#Question id: 13142

The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years.
Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.
Fitness is a measure of the reproductive success of a particular genotype. The highest fitness is 1.00.
There is a substantial number of heterozygotes in the population. Which of the following is the best explanation of this observation?

#Unit 10. Ecological Principles

Heterozygotes (Rr) have a selective advantage over both homozygotes (RR and rr).
The gene for susceptibility (r) is increasing rapidly each generation.
The gene for susceptibility (r) is being lost by chance each generation.
Dominant homozygotes (RR) enjoy a reproductive advantage over heterozygotes

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TLS Online TPP Program

#Question id: 12643

#Unit 6. System Physiology – Plant

Which of the following is the first polypeptide hormone discovered in plants?

TLS Online TPP Program

#Question id: 12642

#Unit 6. System Physiology – Plant

The systemic production of proteinase inhibitors in young tomato plants is triggered by a complex sequence of events such as;

1) Prosystemin is proteolytically processed to produce the short polypeptide called systemin

2) Systemin is then transported out of the wounded leaf via the phloem.

3) systemin is believed to bind to a site on the plasma membrane and initiate the biosynthesis of jasmonic acid

4) Wounded tomato leaves synthesize prosystemin, a large recursor protein

5) Systemin is released from damaged cells into the apoplast

6) Jasmonic acid eventually activates the expression of genes that encode proteinase inhibitors

Arrange the correct sequence of given above following statements ;

TLS Online TPP Program

#Question id: 12641

#Unit 6. System Physiology – Plant

Among the diverse components of plant defense arsenals are proteins that interfere with herbivore digestion, Given some defense compound of plants in column I with its given action in column II

Column I	column II
I) α-amylase inhibitors	a) Antidigestive proteins, block the action of herbivore proteolytic enzymes. After entering the herbivore’s digestive tract, they hinder protein digestion by binding tightly and specifically to the active site of protein-hydrolyzing enzymes such as trypsin and chymotrypsin
II) Lectins	b) block the action of the starch-digesting enzyme
III) proteinase inhibitors	c) A defensive proteins that bind to carbohydrates or carbohydrate-containing proteins. After being ingested by an herbivore, bind to the epithelial cells lining the digestive tract and interfere with nutrient absorption

Correctly match the defence compound withits action on herbivore;

TLS Online TPP Program

#Question id: 12530

#Unit 6. System Physiology – Plant

Some given hormones is also called a ubiquitous hormone?

c) Abscisic acid

d) Brassinosteroids

TLS Online TPP Program

#Question id: 12519

#Unit 6. System Physiology – Plant

Some given statements about biosynthesis of Abscisic acid ;

a) ABA is synthesized in almost all cells that contain chloroplasts or amyloplasts

b) ABA is a 15-carbon terpenoid, or sesquiterpenoid, which is synthesized in plants by an indirect pathway via 40-carbon carotenoid intermediates

c) Cleavage of the carotenoid by the enzyme NCED (9-cis-epoxycarotenoid dioxygenase) is a rate-limiting

d) Oxidation by ABA-8′-hydroxylases lead to ABA inactivation, ABA can also be inactivated by conjugation, but this is irreversible. Both types of inactivation are also tightly regulated.

Which of the following combination from the above statements is correct?

TLS Online TPP Program

#Question id: 12516

#Unit 6. System Physiology – Plant

ABA Is Synthesized from a Carotenoid Intermediate is takes place in___