Some nerves are myelinated, and others are not. Myelinated nerves send signals faster than unmyelinated neurons. Draw two neurons of equal length, and wrap segments of myelin along one. Be careful to leave spaces for the nodes of Ranvier
Now, measure the exposed axons of each, and total up the distance. Describe why the myelinated neurons send signals faster.
It should be apparent from the drawing that myelinated neurons have less exposed axon length; thus, signals travel faster as they jump from one node to the next.
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What is one characteristic of a homeodomain?
A. It is a transmembrane protein B. It can bind to the minor groove of DNA C. It is a protein domain encoded by a homeobox D. It binds to DNA at random sequences.
At any temperature, the metabolic rates of endotherms are always higher than those of ectotherms of comparable size
1.True 2.False
Coloration in the peppered moth (Biston betularia) is determined by a single gene with two alleles showing complete dominance. Dark moths are homozygous dominant or heterozygous for the gene, light moths are homozygous recessive. In a sample of 100 moths, you determine that 64 of the moths are dark. According to the Hardy-Weinberg rule, the expected frequency of the dominant allele is ________.
A. 0.6 B. 0.64 C. 0.36 D. 0.4 E. It cannot be determined.
Vascular tissue that conducts food produced during photosynthesis is the:
A) phloem. B) ground substance. C) meristematic tissue. D) xylem.