An endosperm develops when the
a. pollen grain begins to form.
b. pollen grain sticks to a stigma.
c. sperm fertilizes the central cell.
d. sperm fertilizes an egg
C
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Chromosomes other than those involved in sex determination are known as
a. nucleosomes. b. heterosomes. c. alleles. d. autosomes. e. liposomes.
Mendel referred to the expressed trait in the F1 generation as _____. The unexpressed trait in the F1 generation was referred to as _____. For example, the purple flowering trait is dominant and the white flowering trait is recessive.
Fill in the blank(s) with the appropriate word(s).
The drug used for several protozoan infections is
A. metronidazole. B. sulfa drugs. C. griseofulvin. D. nystatin. E. amphotericin B.
The deamination of cytosine generates a uracil base. This is a naturally occurring nucleic acid base, and so does not represent a DNA lesion caused by damage due to chemicals or irradiation
Why is this base recognized as "foreign" and why is it important for cells to have a mechanism to recognize and remove uracil when it is found in the DNA duplex?