In mammalian development, the embryo will form from which population of cells?

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#Question id: 9269

#Unit 6. System Physiology – Plant

The distribution of electrons in the excited molecule is somewhat different from the distribution in the groundstate molecule, Absorption of blue light excites the chlorophyll to a higher energy state than absorption of red light because

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#Question id: 23279

#Unit 13. Methods in Biology

What will be the value of D if sin angle is 90o and oil immersion is used at λ=700?

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#Question id: 10908

#Unit 6. System Physiology – Plant

The energy is necessary to move photosynthate from producing cells into the sieve elements. This movement of photosynthate is called

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#Question id: 7275

#Unit 5. Developmental Biology

The following experiment is designed to study the role of several hormones in the regulation of metamorphosis in frogs.

Group #	Treatment	Days to Metamorphosis
1	Saline	30
2	Prolactin	> 100
3	TSH	15
4	Thyroxine	10
5	Corticosterone	30
6	Thyroxine + Corticosterone	5
7	Prolactin + TSH	30
8	Thyroid gland removed	> 100

 

If the thyroid gland were removed from the tadpoles in Group 4, metamorphosis would

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#Question id: 15153

#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 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.