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TLS Online TPP Program

#Question id: 12482

The Rb protein has been called the “master brake” of the cell cycle. How the Rb protein acts as a cell cycle brake?

#Unit 2. Cellular Organization
  1. Rb bound to E2F and function as transcriptional repressors because Rb recruits chromatin-modifying enzymes that promote deacetylation and methylation of specific histone lysines, causing chromatin to assume a condensed, transcriptionally inactive form.
  2. S phase CDKs and mitotic CDKs maintain Rb protein in the phosphorylated state throughout the S, G2, and early M phases.
  3. Rb bound to E2F and promotes ubiquitinylation of E2F and inhibits chromosomal segregation.
  4. Rb bound to E2F and promotes acetylation which prevents unloading of cohesins.
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TLS Online TPP Program

#Question id: 12490

#Unit 8. Inheritance Biology

Tay-Sachs disease shows autosomal recessive inheritance. Parents of a newly diagnosed affected child are referred for genetic counselling. It would be correct to tell them that:
TLS Online TPP Program

#Question id: 12491

#Unit 8. Inheritance Biology

Phenylketonuria shows autosomal recessive inheritance with an incidence of 1 in 10000. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?
TLS Online TPP Program

#Question id: 12492

#Unit 8. Inheritance Biology

A young man with phenylketonuria, who was successfully treated following diagnosis on newborn screening, is planning to start a family with his healthy, unaffected, and unrelated partner, who has no family history of phenylketonuria . Phenylketonuria shows autosomal recessive inheritance with an incidence of 1 in 10 000. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?
TLS Online TPP Program

#Question id: 12493

#Unit 8. Inheritance Biology

Cystic fibrosis shows autosomal recessive inheritance with an incidence of 1 in 2500. The unaffected brother of an affected girl is referred for genetic counseling. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?
TLS Online TPP Program

#Question id: 12494

#Unit 8. Inheritance Biology

Hunter syndrome is a rare form of mucopolysacchararidosis that differs from all other forms in that it shows X-linked recessive inheritance. A woman with two affected brothers is referred for genetic counselling. Which of the following is correct?
TLS Online TPP Program

#Question id: 12495

#Unit 8. Inheritance Biology

Haemophilia A is a severe coagulation disorder that shows X-linked recessive inheritance. Red-green colour blindness also shows X-linked recessive inheritance. A man with both haemophilia A and colour blindness is referred for genetic counseling. Assume that his partner is not a carrier of either of these conditions. Which of the following is correct?