TLS Online TPP Program

#Question id: 4364


A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. One of her colleagues suggested she try increased methylation of cytosine (C) nucleotides in the DNA of promoters of a mammalian system. Which of the following results would she most likely see?

#Unit 3. Fundamental Processes
  1. decreased chromatin condensation

  2. activation of histone tails for enzymatic function

  3. higher levels of transcription of certain genes

  4. inactivation of the selected genes

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TLS Online TPP Program

#Question id: 8911

#Unit 9. Diversity of Life Forms

The larvae of some insects are merely small versions of the adult, whereas the larvae of other insects look completely different from adults, eat different foods, and may live in different habitats. Which of the following most directly favors the evolution of the latter, more radical, kind of metamorphosis?

TLS Online TPP Program

#Question id: 10305

#Unit 6. System Physiology – Plant

Pyruvate dehydrogenase complex Consists of three Distinct enzymes and it requires Coenzymes, these are;

TLS Online TPP Program

#Question id: 33229

#Unit 1. Molecules and their Interaction Relevant to Biology

The effects of pH on enzymes depends on a combination of factors: 
(a) Most enzymes are active within only a narrow pH range, typically 5 to 9. 
(b) the ionization states of the amino acid residues involved in the catalytic activity of the enzyme
(c) the variation of protein structure (usually significant only at extremes of pH).
Which of the above is correct

TLS Online TPP Program

#Question id: 10917

#Unit 6. System Physiology – Plant

Photosynthetic sugar molecules are transported via phloem to other parts of the plants. The following aspects are associated with sucrose unloading in phloem and its transport;

a) The presence of plasmodesmata is assumed to provide apoplastic transport. An absence of plasmodesmata between cells indicates an nonfunctional symplastic continuity

b) Phloem unloading and short-distance transport can occur via symplastic as well as apoplastic pathways

c) Both unloading and the short-distance pathway appear to be completely symplastic in some young eudicot leaves, such as sugar beet and tobacco

d) An apoplastic step is required in developing seeds because there are no symplastic connections between the maternal tissues and the tissues of the embryo

Which of the following combination is INCORRECT?

TLS Online TPP Program

#Question id: 5673

#Unit 5. Developmental Biology

Species-specific sperm attraction has been documented in numerous species. In echinoderms, sperm are attracted toward eggs of their species by chemotaxis. Following statements are about chemoattraction-

A. In this process Sperm follows a gradient of a chemical secreted by the egg.

B. These oocytes control only the type of sperm they attract, but not the time at which they attract them.

C. Releasing the chemotactic factor only when the sea urchin egg has completed all of its meiotic divisions .

D. Releasing the chemotactic factor only when the sea urchin egg is in second metaphase of its meiotic division.

E. The mechanisms of chemotaxis differ among species and chemotactic molecules are different even in closely related species.

Which of the following statement are incorrect about this process?