In humans, albinism (unpigmented skin, hair, and eyes) is due to an enzymatic deficiency, and it is an autosomal recessive trait. Suppose that in a small country of one million people (“Generation 1”), there are 500 aa albinos and 9000 Aa heterozygous carriers. Estimate p, the frequency of allele A, in Generation 1?

#Question id: 7063

#Unit 5. Developmental Biology

The avian embryo comes entirely from

#Question id: 10599

#Unit 10. Ecological Principles

In a type I survivorship curve characterized by:

#Question id: 11800

#Unit 6. System Physiology – Plant

There are at least three different types of companion cells in the minor veins of mature, exporting leaves. Which of the following statements about these companion cells is CORRECT?

 a.) transfer cells are transport sugars enter the apoplast during the movement of sugars from mesophyll cells to sieve elements. Transfer cells transport sugars from the apoplast to the symplast of the sieve elements and companion cells in the source.

 b.) the numerous mitochondria in companion cells may supply energy as ATP to the sieve elements

 c.) Ordinary companion cells can function in either symplastic or apoplastic short-distance transport in source leaves, depending in part on plasmodesmatal frequencies

 d.) Intermediary cells, by contrast, function in symplastic transport of sugars from mesophyll cells to sieve elements

#Question id: 23851

#Unit 13. Methods in Biology

#Question id: 19721

#Unit 3. Fundamental Processes