TLS Online TPP Program

#Question id: 4352


How does extracellular glucose inhibit transcription of the lac operon?

#Unit 3. Fundamental Processes
  1. by strengthening the binding of the repressor to the operator

  2. by weakening the binding of the repressor to the operator

  3. by inhibiting RNA polymerase from opening the strands of DNA to initiate transcription

  4. by reducing the levels of intracellular cAMP

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TLS Online TPP Program

#Question id: 11490

#Unit 2. Cellular Organization

Valinomycin, which is one of the best characterized ionophores, specifically transports

TLS Online TPP Program

#Question id: 31111

#Unit 2. Cellular Organization

Arp2/3 needs to be activated by interacting with a nucleation promoting factor (NPF). Although there are many different NPFs, The major NPF family is characterized by the presence of a region called:

TLS Online TPP Program

#Question id: 4862

#Unit 8. Inheritance Biology

In guinea pigs, white coat (w) is recessive to black coat (W) and wavy hair (v) is recessive to straight hair (V). A breeder crosses a guinea pig that is homozygous for white coat and wavy hair with a guinea pig that is black with straight hair. The F1 are then crossed with guinea pigs having white coats and wavy hair in a series of testcrosses. The following progeny are produced from these testcrosses:

black, straight  -   220             black, wavy  -30

white, straight  -30                   white, wavy- 220

If the genes are not assorting independently, what is the distance between coat color and hair shape governing gene

TLS Online TPP Program

#Question id: 1772

#Unit 4. Cell Communication and Cell Signaling

J chain is present in?

TLS Online TPP Program

#Question id: 804

#Unit 1. Molecules and their Interaction Relevant to Biology

With respect to microRNAs, which, if any, of the following statements, is false?

a) A microRNA normally works by binding to perfectly complementary sequences within an RNA transcript, usually an mRNA.

b) Like the great majority of mRNAs an miRNA is usually produced as a larger precursor RNA that is capped and has a 3’ poly(A) tail.

c) The precursor miRNA undergoes different types of post-transcriptional cleavage by endoribonucleases that are specific for double-stranded target sequences.

d) A nuclear endoribonuclease called dicer cleaves the miRNA precursor so that it forms a stem-loop RNA.