A current leading hypothesis about the first system of inheritance in the earliest life-forms involves
A) self-replicating DNA molecules.
B) self-replicating RNA molecules aided by ribozymes.
C) proteins that served as templates for RNA molecules, leading to the formation of DNA.
D) self-replicating polypeptides aided by ribosomes.
Answer: B
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Why might a point mutation in DNA make a difference in the level of a protein's activity?
A) It might result in a chromosomal translocation. B) It might exchange one stop codon for another stop codon. C) It might delay the rate of DNA replication. D) It might substitute a different amino acid in the active site. E) It might substitute the N-terminus of the polypeptide for the C-terminus.
Segmented genomes in negative-strand RNA viruses may include two to eight segments each coding for a unique protein.
Answer the following statement true (T) or false (F)
Genetically, Methanococcus is most closely related to ____
a. bacteria b. fungi c. plants d. both bacterial and eukaryotic cells, although not closely related to either. e. animals
What is the mechanism by which synthetic auxins are routinely used to control weeds?
A. They cause the plant cell wall to disintegrate. B. They interfere with DNA synthesis in the cell. C. They interfere with protein synthesis in the cell. D. They cause weeds to grow so fast they reduce their ATP production, so no energy is left for other essential plant functions. E. They disrupt the plasma membrane of plant cells, causing them to leak and die.