91) Which statement the most correct regarding transcription/translation?
A) : 1407212
91) Which statement is the most correct regarding transcription/translation?
A) The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.
B) The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine.
C) The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it.
D) The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it.
92) In which stage of mitosis do the identical sets of chromosomes uncoil and resume their chromatin form?
93) Which of the following is NOT a role of cell adhesion molecules:
A) transmitters of intracellular signals that direct cell migration, proliferation, and specialization
B) initiators of cell-to-cell signaling for muscle contraction
C) anchor cells to molecules in the extracellular space and to each other
D) mechanical sensors
94) Which of the following does not serve as a signal for cell division?
A) joining of cyclins and Cdks
B) loss of contact inhibition
C) repressor genes
D) shrinking surface-to-volume ratio
95) Which of the following is a principle of the fluid mosaic model of cell membrane structure?
A) Phospholipids consist of a polar head and a nonpolar tail made of three fatty acid chains.
B) Phospholipids form a bilayer that is largely impermeable to water-soluble molecules.
C) All proteins associated with the cell membrane are contained in a fluid layer on the outside of the cell.
D) The lipid bilayer is a solid at body temperature, thus protecting the cell.
96) Which of the following statements is most correct regarding the intracellular chemical signals known as "second messengers"?
A) Second messengers usually inactivate protein kinase enzymes.
B) Second messengers usually act to remove nitric oxide (NO) from the cell.
C) Second messengers act through receptors called K-proteins.
D) Cyclic AMP and calcium may be second messengers.
97) The main component of the cytosol is ________.
98) The functions of centrioles include ________.
A) organizing the mitotic spindle in cell division
B) producing ATP
C) serving as the site for ribosomal RNA synthesis
D) providing a whiplike beating motion to move substances along cell surfaces
99) A gene can best be defined as ________.
A) an RNA messenger that codes for a particular polypeptide
B) noncoding segments of DNA up to 100,000 nucleotides long
C) a three-base triplet that specifies a particular amino acid
D) a segment of DNA that carries the instructions for one polypeptide chain
100) Crenation (shrinking) is likely to occur in blood cells immersed in ________.
A) a hypertonic solution
B) a hypotonic solution
C) blood plasma
D) an isotonic solution
101) Some hormones enter cells via ________.
A) primary active transport
C) receptor-mediated endocytosis
102) If a tRNA had an AGC anticodon, it could attach to a(n) ________ mRNA codon.