Which of the following is involved in muscle relaxation?
a. Acetylcholinesterase removes ACh and the muscle cell returns to resting potential.
b. Ca2+ is actively taken up by the lateral sacs when there is no longer an action potential.
c. The cross bridges pull the filaments back to their original resting positions.
d. Both a and b
e. Both b and c
D
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The defecation reflex involves
A) sympathetic nerves. B) relaxation of both the internal and external anal sphincters. C) conscious control of both the internal and external anal sphincters. D) relaxation of the ileocecal valve to move feces into the rectum. E) parasympathetic nerve control from sacral nerves.
Match the following:
A) Messenger RNA B) Synthetase enzymes C) Transfer RNA D) ATP E) Ribosomal RNA 1) Forms part of the protein synthesis site in the cytoplasm. 2) Act as "interpreter" molecules that recognize specific amino acids and nucleotide base sequences. 3) Attaches the correct amino acid to its transfer RNA. 4) Provides the energy needed for synthesis reactions. 5) Found in the cytoplasm, this structure specifies the exact sequence of amino acids of the protein to be made.
Using the figure below, identify the labeled part.
1) Label A: ______________________________
2) Label B: ______________________________
3) Label C: ______________________________
4) Label D: ______________________________
5) Label E: ______________________________
6) Label F: ______________________________
7) Label G: ______________________________
8) Label H: ______________________________
9) Label I: ______________________________
10) Label J: ______________________________
11) Label K: ______________________________
12) Label L: ______________________________
13) Label M: ______________________________
14) Label N: ______________________________
15) Label O: ______________________________
Which statement is true?
a. diploid cells contain 23 chromosomes b. sperm and egg are haploid cells c. sperm and egg are produced by mitosis d. each human cells has 22 pairs of sex chromosomes e. genetic males have two of the same sex chromosomes