What is the right sequence of steps during infection of plants by nitrogen-fixing bacteria?
A) Nodule forms; infection thread grows into the root cortex; rhizobia proliferate inside of root
hair; rhizobia release flavonoids and Nod factors.
B) Rhizobia release Nod factors; roots release flavonoids; rhizobia proliferate inside of root hair;
infection thread grows into the root cortex; nodule forms.
C) Roots release flavonoids; rhizobia release Nod factors; rhizobia proliferate inside of root hair; infection thread grows into the root cortex; nodule forms.
D) Rhizobia release flavonoids; roots release Nod factors; rhizobia proliferate inside of root hair;
infection thread grows into the root cortex; nodule forms.
E) Roots release flavonoids; rhizobia release Nod factors; rhizobia proliferate inside of root hair; nodule forms; infection thread grows into the root cortex.
Ans: C) Roots release flavonoids; rhizobia release Nod factors; rhizobia proliferate inside of root hair; infection thread grows into the root cortex; nodule forms.
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Compared with 31P, the radioactive isotope 32P has
A) a different atomic number. B) one more proton. C) one more electron. D) one more neutron.
Which of the following reactions is an example of dehydration synthesis?
A) Fat ? fatty acids + glycerol B) Glucose + galactose ? lactose C) Peptide ? alanine + glycine D) Cellulose ? glucose E) Glycogen ? glucose subunits
In an infected cell, new viruses arise via:
A. Logarithmic growth B. Growth and division of the infecting virus particle C. Cell division D. Binary fission E. De novo assembly of newly synthesized viral proteins with newly synthesized viral genomes
True or false: All changes in gene sequence are mutations, but not all mutations decrease or increase in frequency over time
A. true B. false