Which of the following statements is true?
(a) Ribosomes are large RNA structures composed solely of rRNA.
(b) Ribosomes are synthesized entirely in the cytoplasm.
(c) rRNA contains the catalytic activity that joins amino acids together.
(d) A ribosome binds one tRNA at a time.
Choice (c) is correct. Ribosomes contain proteins as well as rRNA [choice (a)]. rRNA is synthesized in the nucleus, and ribosomes are partly assembled in the nucleus [choice (b)]. A ribosome must be able to bind two tRNAs at any one time [choice (d)].
You might also like to view...
Two amino acids that are found in some proteins due to exceptions in the universal genetic code are
A. lysine and selenocysteine. B. pyrrolysine and cysteine. C. lysine and cysteine. D. pyrrolysine and selenocysteine.
All of the petals of a flower are collectively called the
(a) corolla. (b) stamens. (c) receptacles. (d) calyx.
Some biologists argue that transposable elements provide benefits to a given species. Which of the following does not describe a potential benefit offered by transposable elements?
A. Increases genetic variation. B. Inserts into functionally important genes. C. Codes for a gene that confers antibiotic resistance. D. Codes for a gene that increases survival.
The earliest species known to reproduce sexually was a
a. cyanobacterium. b. green alga. c. fungus. d. red alga. e. archaebacterium.