A cell fails to detoxify the waste substances produced in it because it does not possesses enough………
a) SER
b) lysosomes
c) RER
d) ribosomes
Ribosome is composed of ………
a) 50% RNA, 20% lipids, 30% protein
b) 30% RNA, 20% lipids, 50% protein
c) 50% RNA, 50% protein
d) 50% DNA, 50% protein
Explanation: hence they are called ribonucleoprotein particles
On the basis of sedimentation, there are…….types of ribosomes.
a) two
b) three
c) four
d) five
Explanation: 80S and 70S, (S= Svedberg unit used in ultracentrifugation)
In which of the following, 70S ribosomes are found?
a) mitochondria
b) chloroplast
c) prokaryotes
d) all of these
Explanation: ribosomal similarity shows that both mitochondria and chloroplast are of prokaryotic
Which of the following is true about prokaryotic ribosomes?
Which of the following is true about eukaryotic ribosomes?
Explanation: The large sub-unit
sediments at 50s, the small sub-unit sediments at 30s, but the two together
(that is, the whole ribosome) sediments at 70s, not 80s. The same way a
eukaryotic ribosome has a large sub-unit that sediments at 60s, a small one
that sediments at 40s, but the whole structure sediments at 80s, not 100s.
Which of the
following ions are required for the binding of ribosomal subunits?
a) H+
b) Mg++
c) Ca++
d) Na
Explanation: ribosome was discovered by Palade
