A bacterial cell containing an F factor is a threonine prototroph. Conjugation occurs with an F– threonine auxotrophic cell. The exconjugant cell can grow on medium lacking threonine. Where was the F factor in the donor cell?
A) F plasmid
B) Hfr chromosome
C) R plasmid
D) A or B are both possible.
E) A, B, or C are all possible.
C
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A region of a protein that folds in a similar way independently of the rest of the protein is referred to as a folding ____
Help with this one please?
Plasma membrane phospholipids are labeled with a fluorescent tag and then the phospholipids in one area are bleached with a laser beamto eliminate the fluorescent signal. What would one observe after the cell is incubated for a few minutes?
A. The bleached molecules would disappear into the cell. B. The bleached molecules would diffuse laterally through the membrane and intermix with unbleached molecules. C. The bleached molecules would remain in the spot where bleaching occurred. D. All the bleached molecules would flip-flop across the cell membrane. E. The bleached molecules would be released from the cell.
This is a structure at the head of a sperm cell that allows it to penetrate an egg cell
a. acrosome b. labia c. centriole d. cortical granule e. somite
Annelids have ___.
a) a coelom b) a pseudocoelom c) no coleom d) none of the above