The colonial flagellate hypothesis states that animals descended from a hollow spherical colony of flagellated cells. Place the probable steps in the order which this would occur.
A. Step 3
B. Step 4
C. Step 1
D. Step 2
A. Individual cells become specialized for reproduction.
B. Infolding of certain cells creates tissue layers.
C. A few flagellated cells form an aggregate.
D. The colony of aggregated cells forms a hollow sphere.
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How do viability stains usually distinguish between living cells and dead cells?
A) The chemical fluoresces only when bound to ribosomes that are actively synthesizing proteins. B) The chemical stain is taken up by living cells and once metabolized becomes fluorescent. C) The dye specifically targets intact cytoplasmic membranes. D) The dye's fluorescence is quenched by dead cells.
Which of the following occurs when ribosome encounters either UAA or UAG?
a. Ribosomal subunits leave the mRNA. b. Ribosomal subunits bind to the mRNA. c. The mRNA template initiates translation. d. Amino acids form on the mRNA template.
Observing a patient who has been given an experimental drug, you notice that it constricts blood vessels and slows digestion, making its effects similar to those of
A. calcitonin. B. epinephrine. C. insulin. D. glucagon. E. testosterone.
If an Arabidopsis plant does not express homeotic genes during flower development
A. the plant will only develop to the heart stage. B. the plant will not develop cotyledons. C. the plant will develop leaves instead of flowers. D. the plant will develop flowers instead of leaves. E. the plant will die.