Discuss how mutations that eliminate or alter the activity of an enzyme can cause phenotypic effects. What will be an ideal response?
ANSWER: The substrate for the blocked reaction may build up and reach toxic levels, causing an
abnormal phenotype. In addition, the enzyme may control a reaction that produces a
molecule needed for some cellular function. If this product is not made, a mutant phenotype
may result. Mutations that affect enzymes can produce many different phenotypes, ranging
from inconsequential to lethal.
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Neural transmission across a mammalian synapse is accomplished by _____
A) the movement of sodium and potassium ions from the presynaptic neuron into the postsynaptic neuron B) impulses traveling as electrical currents across the synapse C) impulses causing the release of a chemical signal and its diffusion across the synapse D) impulses ricocheting back and forth across the synapse E) the movement of calcium ions from the presynaptic into the postsynaptic neuron
________ is the process by which close ecological interactions cause two species to evolve jointly
a. Coevolution b. Adaptive radiation c. Exaptation d. Extinction
F. acidarmanus, a species of bacteria that lives in California copper mines, has adapted to its environment by altering
the ____ at which its enzymes function.
a. temperature b. pH c. light levels d. substrate concentration e. salt concentration
The size of a population is affected by all of the
following EXCEPT a. biotic potential. b. trophic level. c. carrying capacity of the environment. d. death rate. e. birth rate.