In this problem we will explore some of the many ways that mutations in two different genes can interact to produce different Mendelian ratios. Consider a hypothetical insect species that has red eyes. Imagine mutations in two different unlinked genes that can, in certain combinations, block the formation of red eye pigment yielding mutants with white eyes. In principle, there are two different possible arrangements for two biochemical steps responsible for the formation of red eye pigment. The two genes might act in series such that a mutation in either gene would block the formation of red pigment. Alternatively, the two genes could act in parallel such that mutations in both genes would be required to block the formation of red pigment.

Further complexity arises from the possibility that mutations in either gene that lead to a block in enzymatic activity could be either dominant or recessive. If the crosses is made between a wild type insect with red eyes and a true breeding white eyed strain with mutations in both genes. Such considerations yield the Pathways in parallel with recessive mutations in both genes, determine the phenotype of the F1 progeny and the expected phenotypic ratio of red to white eyed insects in the F2.

#Question id: 2971

#SCPH28 | Zoology

Which one of the following is the most appropriate match?

#Question id: 2972

#I Life Science/ Life Sciences Group – I-V

Match the following attachment (Column I) with definition(Column II).

Which of the following is correct?

#Question id: 2972

#SCPH06 I Botany

Match the following attachment (Column I) with definition(Column II).

Which of the following is correct?

#Question id: 2973

#I Life Science/ Life Sciences Group – I-V

Following statements are regarding to the spindle position checkpoint pathway in budding yeast.

A. During interphase and early mitosis, Cdc14 is sequestered and inactivated in the nucleolus. Inactive Tem1-GDP associates with the spindle pole body (SPB) nearest to the bud as soon as the mitotic spindle forms.

B. If chromosome segregation occurs properly, extension of the spindle microtubules inserts the daughter SPB into the bud, causing Tem1 to be activated by an unknown mechanism.

C. Tem1-GDP activates a protein kinase cascade, which then promotes the release of active Cdc14 from the nucleolus and exit from mitosis.

D. If the spindle apparatus fails to place the daughter SPB in the bud, Kin4 (cyan), an inhibitor of Tem1, is recruited from the parent cell cortex to the parent-cell-located SPB and maintains Tem1 in the GTP-bound form, and mitotic exit does not occur.

Which of the following are correct?

#Question id: 2973

#SCPH06 I Botany

Following statements are regarding to the spindle position checkpoint pathway in budding yeast.

A. During interphase and early mitosis, Cdc14 is sequestered and inactivated in the nucleolus. Inactive Tem1-GDP associates with the spindle pole body (SPB) nearest to the bud as soon as the mitotic spindle forms.

B. If chromosome segregation occurs properly, extension of the spindle microtubules inserts the daughter SPB into the bud, causing Tem1 to be activated by an unknown mechanism.

C. Tem1-GDP activates a protein kinase cascade, which then promotes the release of active Cdc14 from the nucleolus and exit from mitosis.

D. If the spindle apparatus fails to place the daughter SPB in the bud, Kin4 (cyan), an inhibitor of Tem1, is recruited from the parent cell cortex to the parent-cell-located SPB and maintains Tem1 in the GTP-bound form, and mitotic exit does not occur.

Which of the following are correct?

#Question id: 2974

#I Life Science/ Life Sciences Group – I-V

Following statements are regarding to control of the G1–S phase transition in budding yeast.

A. G1 cyclin-CDK complexes stimulate the formation of G1/S phase cyclin-CDKs, which then initiate bud formation, centrosome duplication, and DNA replication. In yeast, the G1 cyclin gene is called CLN3.

B. Once sufficient Cln3 is synthesized from its mRNA, Cln3-CDK complexes phosphorylate and activate the transcriptional repressor Whi5.

C. Phosphorylation of Whi5 promotes its export out of the nucleus, allowing the transcription factor complex SBF to induce transcription of the G1/S phase cyclin genes CLN1 and CLN2 as well as other genes important for DNA replication.

D. Once produced, Cln1/2-CDKs contribute to further Whi5 phosphorylation. This positive feedback loop ensures the rapid accumulation of G1/S phase cyclin-CDKs.

Which of the following statements are correct?