Now extinct, ____ appear in the fossil record from the late Ordovician through the Permian periods
These jawed fishes, also called spiny sharks, had streamlined bodies, large jaws, and numerous teeth.
a. acanthodians
b. conodonts
c. osteolepiforms
d. placoderms
e. ostracoderms
A
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An organism whose genetic makeup is 50% C-G bonds would have a(n) _________ melting temperature (Tm), compared with an organism with 20% C-G bonds
a. higher b. lower c. equal d. similar
An enzyme synthesized in the laboratory is found to have little activity when compared to the enzyme extracted from cell culture. Both enzymes were examined and have identical amino acid composition
What is the best explanation for the lack of activity of the synthesized enzyme? A) The van der Waals radius was altered during laboratory synthesis. B) The synthetic enzyme was not made of amino acids. C) The ATP required for self-assembly was present in the cell extract but not in the laboratory synthesis. D) Denaturation of the synthesized enzyme was not complete. E) The synthesized enzyme was not folded correctly because molecular chaperones were not present.
The cephalochordates possess an atrium that is used to filter microscopic food particles out of the water.
Answer the following statement true (T) or false (F)
Which statement is correct about all organisms that are eukaryotes?
A) They consist of many cells. B) They have organelles such as a nucleus. C) They consist of cells that are surrounded by a cell wall. D) They can be seen without a microscope.