If a long-day plant has a critical night length of 9 hours, which 24-hour cycle would prevent flowering? (SS)

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#Question id: 5435

#Unit 8. Inheritance Biology

A polygenic trait is controlled by three genes-A, B and C. In a cross, AaBbCc x AaBbCc, what is a probability of intermediate phenotype offspring?

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#Question id: 15525

#Unit 4. Cell Communication and Cell Signaling

In the instructive model, TCR/CD4 and TCR/CD8 coengagement generates unique signals, if a thymocyte randomly generated a TCR with an affinity for MHC Class I. which thymocyte would bind with MHC class I?

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#Question id: 27392

#Unit 1. Molecules and their Interaction Relevant to Biology

Match the following

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#Question id: 15154

#Unit 8. Inheritance Biology

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 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 a recessive mutation in one gene and a dominant mutation in the other, determine the phenotype of the F1 progeny and the expected phenotypic ratio of red to white eyed insects in the F2.

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#Question id: 15383

#Unit 8. Inheritance Biology

You are trying to develop true breeding blue hydrangeas, but the plants in one corner of your plot consistently turn pink regardless of your mating strategy. Which of the following would you suspect?