In 2009, which of the following did scientists discover was possible on early Earth?
A. gram-positive bacteria with outer membranes that contain lipopolysaccharides
B. abiotic synthesis of RNA monomers
C. gram-negative bacteria with cell walls composed of a thick layer of peptidoglycan
D. bacterial cell walls made mainly of chitin
Answer: B. abiotic synthesis of RNA monomers
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Hematopoietic stem cells are _________
A. Pluripotent B. Totipotent C. Unipotent D. Multipotent
Before Mendel began his pea plant experiments he wondered if traits in offspring result from blending of parental traits or it they are inherited as ____________________ units
Fill in the blank(s) with correct word
The hypothesis that certain eukaryotic cell structures may have evolved from a prokaryotic cell being engulfed by a eukaryotic cell is called the
A) endosymbiont hypothesis. B) prebiotic evolution hypothesis. C) living intermediate hypothesis. D) spontaneous generation hypothesis. E) protocell hypothesis.
A researcher studying a member of the Conus genus of cone snails discovers that there are many dozens of slightly different variants of venom proteins coded by closely related genes. What is the most likely explanation for this great variation? [Hint: The compounds likely diversified in a similar way as the multiple globin proteins in mammals did.]
A. Concerted evolution resulted in the production of many venom genes, scattered throughout the genome. B. Hybridization between two snail species has left the offspring with multiple orthologous genes. C. Multiple gene duplication events have led to the production of a paralogous multigene family. D. Duplicated genes underwent incomplete gene conversion, leading to many errors in sequence. E. The last common ancestor of all cone snails had a diverse set of venom genes that have been inherited by all cone snails.