Molecular Biology Exam quiz and
answers graded A+
RNA in cells differs from DNA in that:
a. the sugar ribose contains fewer oxygen atoms than does deoxyribose
b. it is single-stranded and cannot form base pairs.
c. it is single-stranded and can fold up into a variety of structures.
d. it contains the base uracil, which pairs with cytosine. - ANS✅✅c. it is single-stranded and can
fold up into a variety of structures.
Transcription in bacteria differs from transcription in a eukaryotic cell because:
a. the sigma subunit must associate with the appropriate type of RNA polymerase to produce
mRNAs.
b. RNA polymerase (along with its sigma subunit) requires the general transcription factors to
assemble at the promoter before polymerase can begin transcription.
c. RNA polymerase (along with its sigma subunit) can initiate transcription on its own.
d. RNA polymerase must be phosphorylated at its C-terminal tail for transcription to proceed. -
ANS✅✅c. RNA polymerase (along with its sigma subunit) can initiate transcription on its own.
Genes in eukaryotic cells often have intronic sequences coded for within the DNA. These sequences
are ultimately not translated into proteins. Why?
a. Introns are not transcribed by RNA polymerase.
b. The ribosome will skip over intron sequences when translating RNA into protein.
c. Introns are removed by catalytic RNAs in the cytoplasm.
d. Intronic sequences are removed from RNA molecules by the spliceosome, which works in the
nucleus. - ANS✅✅d. Intronic sequences are removed from RNA molecules by the spliceosome,
which works in the nucleus.
How many amino acids are commonly used in life?
a. 30
b. 15
c. >9000
d. 20 - ANS✅✅d. 20
, Tertiary bonds in proteins include:
a. Ionic bonds
b. Van der waal attraction
c. Hydrogen bonds
d. Disulfide bonds
e. All of these - ANS✅✅e. All of these
Which of the following statements is TRUE?
a. rRNA contains the catalytic activity that joins amino acids together.
b. A ribosome binds one tRNA at a time.
c. Ribosomes are large RNA structures composed solely of rRNA.
d. Ribosomes are synthesized entirely in the cytoplasm. - ANS✅✅d. Ribosomes are synthesized
entirely in the cytoplasm.
What would be the most obvious outcome of repeated cell cycles consisting of S phase and M phase
only?
a. The cells would not be able to replicate their DNA.
b. The cells would get larger and larger.
c. The mitotic spindle could not assemble.
d. The cells produced would get smaller and smaller. - ANS✅✅d. The cells produced would get
smaller and smaller.
The chromosomes condense during which phase of cell reproduction?
a. Metaphase
b. Telophase
c. Prophase
d. Anaphase - ANS✅✅c. Prophase
Cytokinesis in animal cells
a. is assisted by motor proteins that pull on microtubules attached to the cell cortex.
b. requires ATP.
answers graded A+
RNA in cells differs from DNA in that:
a. the sugar ribose contains fewer oxygen atoms than does deoxyribose
b. it is single-stranded and cannot form base pairs.
c. it is single-stranded and can fold up into a variety of structures.
d. it contains the base uracil, which pairs with cytosine. - ANS✅✅c. it is single-stranded and can
fold up into a variety of structures.
Transcription in bacteria differs from transcription in a eukaryotic cell because:
a. the sigma subunit must associate with the appropriate type of RNA polymerase to produce
mRNAs.
b. RNA polymerase (along with its sigma subunit) requires the general transcription factors to
assemble at the promoter before polymerase can begin transcription.
c. RNA polymerase (along with its sigma subunit) can initiate transcription on its own.
d. RNA polymerase must be phosphorylated at its C-terminal tail for transcription to proceed. -
ANS✅✅c. RNA polymerase (along with its sigma subunit) can initiate transcription on its own.
Genes in eukaryotic cells often have intronic sequences coded for within the DNA. These sequences
are ultimately not translated into proteins. Why?
a. Introns are not transcribed by RNA polymerase.
b. The ribosome will skip over intron sequences when translating RNA into protein.
c. Introns are removed by catalytic RNAs in the cytoplasm.
d. Intronic sequences are removed from RNA molecules by the spliceosome, which works in the
nucleus. - ANS✅✅d. Intronic sequences are removed from RNA molecules by the spliceosome,
which works in the nucleus.
How many amino acids are commonly used in life?
a. 30
b. 15
c. >9000
d. 20 - ANS✅✅d. 20
, Tertiary bonds in proteins include:
a. Ionic bonds
b. Van der waal attraction
c. Hydrogen bonds
d. Disulfide bonds
e. All of these - ANS✅✅e. All of these
Which of the following statements is TRUE?
a. rRNA contains the catalytic activity that joins amino acids together.
b. A ribosome binds one tRNA at a time.
c. Ribosomes are large RNA structures composed solely of rRNA.
d. Ribosomes are synthesized entirely in the cytoplasm. - ANS✅✅d. Ribosomes are synthesized
entirely in the cytoplasm.
What would be the most obvious outcome of repeated cell cycles consisting of S phase and M phase
only?
a. The cells would not be able to replicate their DNA.
b. The cells would get larger and larger.
c. The mitotic spindle could not assemble.
d. The cells produced would get smaller and smaller. - ANS✅✅d. The cells produced would get
smaller and smaller.
The chromosomes condense during which phase of cell reproduction?
a. Metaphase
b. Telophase
c. Prophase
d. Anaphase - ANS✅✅c. Prophase
Cytokinesis in animal cells
a. is assisted by motor proteins that pull on microtubules attached to the cell cortex.
b. requires ATP.
