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TLS Online TPP Program

#Question id: 4605

Over long periods of time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?

#Zoology

  1. Natural selection cannot account for losses, but accounts only for new structures and functions.

  2. Natural selection accounts for these losses by the principle of use and disuse.

  3. Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

  4. The ancestors of these organisms experienced harmful mutations that forced them to lose these structures.

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TLS Online TPP Program

#Question id: 38741

#Plant Biotechnology

Q. Which enzyme combination is MOST appropriate for complete degradation of primary plant cell wall during protoplast isolation?
TLS Online TPP Program

#Question id: 38742

#Plant Biotechnology

Q: Which of the following combinations of statements is entirely CORRECT?
I. Cell wall components include cellulose, hemicellulose, and pectin.
II. The optimal temperature range for isolation is 25-30°C.
III. Barley aleurone cells are treated with Zymolyase to form sphaeroplasts.
IV. The one-step method involves using an enzyme mixture together simultaneously.
TLS Online TPP Program

#Question id: 38744

#Plant Biotechnology

Match the following enzymes commonly used in plant tissue maceration with their sources:

List IList II
A. Zymolyase1. Rhizopus arrhizus
B. Pectolyase2. Arthrobacter luteus
C. Macerase3. Aspergillus japonicus
D. Macerozyme R-104. Helix pomatia
Select the correct option:
TLS Online TPP Program

#Question id: 38745

#Plant Biotechnology

Q: Assertion (A): An osmoticum must be added to the medium during the isolation of protoplasts.
Reason (R): Protoplasts lack a cell wall and are prone to bursting without osmotic stabilization.
TLS Online TPP Program

#Question id: 38747

#Plant Biotechnology

Q. Assertion (A): Co-culturing is a vital technique for the regeneration of recalcitrant protoplasts. 
Reason (R): Fast-growing protoplasts in the medium secrete diffusible substances that stimulate cell wall synthesis in neighboring cells.
TLS Online TPP Program

#Question id: 38748

#Plant Biotechnology

Q. Assertion (A): In a co-culture system, the two types of protoplasts must be in direct physical contact to exchange nutrients.
 Reason (R): Growth factors provided by "nurse" cells are diffusible and can move through the liquid or semi-solid culture medium.