In a particular species of mammal black hair (B) is dominant to green hair (b) and red eyes (R) are dominant to white eyes (r). If a BbRr individual is mated with a bbrrindividual the expected phenotypic ratio of the offspring is 1 black-red : 1 black-white: 1 green-red : 1 green-white. However, when you mate these individuals you find that the phenotypic ratio of the offspring is 6 black-red :1 black-white : 1 green-red : 6 green-white. What could account for this difference?

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#Question id: 2937

#Unit 2. Cellular Organization

Separase initiates sister chromatid segregation at anaphase by cleaving:

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#Question id: 15637

#Unit 13. Methods in Biology

You have isolated two mutations in the Lac operon that cause constitutive expression of Lac genes. You designate these mutants Lac1– and Lac2–. Making use of an F' that carries the Lac operon with the LacY gene mutated, you construct strains that you test for both ß-galactosidase activity and Lac permease activity with results shown below.

     

Classify each mutation as dominant or recessive and as cis- or trans-acting, giving the experimental result that allows you to arrive at each conclusion. Finally, deduce what type of Lac mutation best fits the properties of Lac 1– and of Lac 2–.

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#Question id: 12222

#Unit 7. System Physiology – Animal

In acidosis, most of the hydrogen ions secreted by the proximal tubule are associated with which of the following processes?

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#Question id: 2269

#Unit 2. Cellular Organization

The rough ER is so named because it has an abundance of _______________ on it.

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#Question id: 4242

#Unit 3. Fundamental Processes

Which of the following properties is associated with a protein that will be secreted from a eukaryotic cell?