Practice Questions

TLS Online TPP Program

#Question id: 12083

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
It can be concluded from the figure that

#Unit 10. Ecological Principles

The presence of o1igochaete worms increases the rate of denitrification
The presence of oligochaete worms decreases the rate of denitrification
The presence of sediment microorganisms decreases the rate of denitrification
Oligochaete worms carry out denitrification in the absence of sediment microorganisms

More Questions

TLS Online TPP Program

#Question id: 12671

#Unit 6. System Physiology – Plant

When genetic changes in an entire plant population have been fixed over many generations by selective environmental pressure, those changes are referred to as,

TLS Online TPP Program

#Question id: 12711

#Unit 6. System Physiology – Plant

Various sensors monitor ROS levels in cells; an increase in ROS activates a signal transduction network. ROS scavenging is carried out by antioxidant molecules ____X_________and by antioxidant enzymes such as____Z_________

TLS Online TPP Program

#Question id: 12713

#Unit 6. System Physiology – Plant

Following are certain statements related to plants water deficit condition;

a) Inhibits Leaf Abscission

b) Enhances Root Extension into Deeper, Moist Soil

c) Limits Photosynthesis within the Chloroplast

d) decreases Resistance to Liquid-Phase Water Flow

e) Increases Wax Deposition on the Leaf Surface

f) Alters Energy Dissipation from Leaves

Which of the following combination given statements is correct

TLS Online TPP Program

#Question id: 12714

#Unit 6. System Physiology – Plant

Physiological and biochemical perturbations in plants caused by fluctuations in the abiotic environment, given column I with environmental factor and with its effects in the form of primary effects in column II and secondary effects in column III

COLUMN I

(environmental factor )

COLUMN II

(primary effects)

COLUMN III

(secondary effects)

A) Water deficit

i) Hypoxia, Anoxia

a) Membrane dysfunction

B) High temperature

ii) ROS production

b) Reduced cellular and metabolic activities,

Leaf abscission,

Ion cytotoxicity and Cavitation

C) Trace element toxicity

iii) Photo inhibition

c) Reduced respiration,

Fermentative metabolism, Inadequate ATP production ,

ROS production and

Stomatal closure

D) Flooding and soil compaction

iv) Membrane destabilization

d) Inhibition of PSII repair

E) Chilling

v) Cell dehydration and Hydraulic resistance

e) Disruption of metabolism

F) High light intensity

f) Photosynthetic and respiratory inhibition, ROS production

Find out the correct combination of given above column;

TLS Online TPP Program

#Question id: 12716

#Unit 6. System Physiology – Plant

Some cis-elements of target genes, which are involved in the Signal perception of stress (Drought/salinity and cold) to activating tolerance,

These cis-elements are____

TLS Online TPP Program

#Question id: 12717

#Unit 6. System Physiology – Plant

During drought /salinity and cold tolerance performing Signal perception via signal transduction pathway in

(1) ABA-dependent and (2) ABA-independent manner and activating various transcriptional factor such as