A student uses restriction enzymes to cut a DNA molecule into fragments. The digested DNA is loaded into the wells of an agarose gel and the gel is subjected to an electric current. Upon completion of the run, the gel is stained. The type and density of the gel are important because
(A) they influence the rate of migration of the fragments
(B) they may cause some DNA molecules to replicate
(C) some DNA nucleotides may be lost due to chemical reactions with the gel
(D) some DNA molecules may sink to the bottom and not migrate
(E) some DNA molecules may cross-link
Ans: (A) they influence the rate of migration of the fragments
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A. prokaryotic cell wall. B. capsomere. C. eukaryotic cellular membrane. D. cytoplasm.
When comparing the genetic characteristics between embryonic and adult stem cells, embryonic stem cells
A. are collected from the testes and ovaries, while adult stem cells are collected from other tissues. B. are produced naturally in human development, while adult stem cells are from cloning. C. There is no real genetic difference between embryonic and adult stem cells, except how they were collected. D. can't differentiate into any specialized cells, while adult stem cells can. E. can differentiate into any specialized cells, while adult stem cells can't.
The rate of eukaryotic transcription after initiation is increased by:
a. upstream promoter elements. b. the order of gene arrangement in operons. c. the action of catabolite activator proteins. d. how fast 5’ caps and 3’ tails can be added to pre-mRNA. e. enhancers.
The stem apical meristem gives rise to:
a. leaf primordia. b. lateral meristems. c. root caps. d. root hairs. e. cork cells.