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TLS Online TPP Program

#Question id: 7097

What property of the mammalian embryo permits the production of chimeric mice?

#Unit 5. Developmental Biology
  1. The inner cell mass is highly regulative, so that extra cells derived from the inner cell mass of a different embryo are incorporated without causing defects.
  2. f half of the cells of the inner cell mass are removed and replaced with cells from half of a different embryo's inner cell mass, the embryo will heal and develop normally.
  3. The embryo can develop outside the womb, making surgical manipulations possible
  4. Blastomeres separated at the two-cell stage will regulate and each forms a normal embryo.
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TLS Online TPP Program

#Question id: 2877

#Unit 2. Cellular Organization

What is the superhelical density of a closed-circular DNA with a length of 4,200 bp and a linking number (Lk) of 374? What is the superhelical density of the same DNA when Lk = 412? Are these molecules negatively or positively supercoiled?

A. The molecule is getting negatively supercoiled.

B. The molecule is getting positively supercoiled.

C. The superhelical density is positive.

D. The superhelical density is negative.

Which of the combinations of the above statements are correct?
TLS Online TPP Program

#Question id: 2878

#Unit 2. Cellular Organization

Match the following types of Transposable elements with their respective types and examples found in various organisms.

Transposon

Type

Example

1. F and G element

a. DNA-mediated

 i. Drosophila

2. Ty elements

b. RNA-mediated

 ii. Humans

3. Alu sequences

c. Poly-A retrotransposons

 iii. Yeast

4. P-elements

d. Virus-like retrotransposons

 iv. Mammals

TLS Online TPP Program

#Question id: 2879

#Unit 2. Cellular Organization

Hybridization between mature mRNA and DNA can identify introns in eukaryotic genes. When mature mRNA produced by the insulin gene is hybridized with denatured chromosomal DNA, which of the following will most likely be observed?
TLS Online TPP Program

#Question id: 2880

#Unit 2. Cellular Organization

According to the manner in which they work, three main classes of proteins that modify chromatin are recognized. Match the following classes of proteins given in COLUMN I with their respective examples in COLUMN II.

COLUMN I

COLUMN II

1. Writers

a) DNA demethylases

2. Erasers

b) Histone acetyltransferases

3. Readers

c) meCG-binding proteins

 

d) Histone kinases

 

e) Chromatin remodelers

 

f) Histone deacetylases

TLS Online TPP Program

#Question id: 2881

#Unit 2. Cellular Organization

Depletion of a 2.2-kb noncoding RNA expressed from the HOXC locus by siRNA unexpectedly led to derepression of the HOXD locus on another chromosome encoding several Hox proteins and multiple other noncoding RNAs, in these cells. Assays similar to chromatin immunoprecipitation showed that this noncoding RNA, named HOTAIR, associates with the HOXD loci and with PRC2 complexes. This association results in

i. Histone H3K9 di- and trimethylation

ii. H2B monoubiquitinylation

iii. Histone H3K4 demethylation

iv. H2A monoubiquitinylation

v. Histone H3K4 methylation

vi. Histone H3K27 di- and trimethylation

Which of the following results is CORRECT regarding this association?
TLS Online TPP Program

#Question id: 2882

#Unit 2. Cellular Organization

SUMO (small ubiquitin-related modifier) proteins are ∼10-kD polypeptides that function as reversible post-translational protein modifiers. They form isopeptide bonds with ɛ-amino groups of acceptor Lys residues in hundreds of target proteins in a process termed as sumoylation. Which of the following statements is correct regarding this modification?