TLS Online TPP Program

#Question id: 3970


In bacteria, an operon:

#Unit 3. Fundamental Processes
  1. is a region of DNA that is transcribed as a single mRNA encoding several proteins.

  2. encodes for miRNAs.

  3. contains a promoter unique for each individual gene in the operator.

  4. none of the above

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TLS Online TPP Program

#Question id: 15409

#Unit 8. Inheritance Biology

 A heterozygous trihybrid corn plant is testcrossed and the following progeny are produced (all traits are recessive to their wildtype alternative);
          booster                              6
          booster, silkless                  137       
          booster, liguleless, silkless      291
          liguleless                          142
          liguleless, silkless                  3
          silkless                            30
          booster, liguleless                  34
          wildtype                            339
What is the order of the loci on the chromosome? 

TLS Online TPP Program

#Question id: 7256

#Unit 5. Developmental Biology

Sox9 is an autosomal gene involved in several developmental processes, most notably bone formation. In the gonadal rudiments, Sox9 induces testis formation. Expression of the Sox9 gene is specifically upregulated by the combined expression of Sry and Sf1 proteins in Sertoli cell precursors. Thus, Sry may act merely as a “switch” operating during a very short time to activate Sox9, and the Sox9 protein may initiate the conserved evolutionary pathway to testis formation. Following statements are regarding to the functions of Sox9.

A. It appears to be able to activate its own promoter, thereby allowing it to be transcribed for long periods of time.

B. It activates the ability of β-catenin to induce ovary formation, either directly or indirectly.

C. It binds to cis-regulatory regions of numerous genes necessary for testis production.

D. Sox9 binds to the promoter site on the gene for anti-Müllerian hormone, providing a critical link in the pathway toward a male phenotype.

E. Sox9 inhibits the expression of the gene encoding Fgf9, a paracrine factor.

Which of the following statements are correct?

TLS Online TPP Program

#Question id: 12277

#Unit 7. System Physiology – Animal

A 45-year-old man adds lots of high-fiber wheat and bran foods to his diet to reduce his cholesterol. He loses 30 lb on the new diet, but has undesirable side effects such as stomach cramps, flatulence, and diarrhea. His gastroenterologist diagnoses a syndrome called gluten-enteropathy or celiac sprue. Which of the following is decreased in this man?

TLS Online TPP Program

#Question id: 10791

#Unit 6. System Physiology – Plant

Following are certain statements regarding furanocoumarins;

 a) furanocoumarins have an attached furan ring

 b) These compounds are toxic until they are activated by sunlight in the ultraviolet A (UV-A) region (320–400 nm)  

 c) Light activated furanocoumarins can insert themselves into the double helix of DNA and bind to the pyrimidine bases, thus blocking transcription and repair and leading eventually to cell death   

 d) Phototoxic furanocoumarins are especially abundant in members of the Umbelliferae family, including celery, parsnip, and parsley.

 Which of the following combination from the above statements is correct?

TLS Online TPP Program

#Question id: 12508

#Unit 8. Inheritance Biology

In this pedigree I 1 and II 2 have Becker muscular dystrophy which shows X-linked recessive inheritance. III 2 has oculocutaneous albinism which shows autosomal recessive inheritance with an incidence in the general population of 1 in 10 000. The disease status for both Becker muscular dystrophy and oculocutaneous albinism is unknown for IV 1 and IV 2.
What is the probability that III 3 is a carrier of oculocutaneous albinism?