MOLECULAR BIOLOGY EXAM 1
QUESTIONS 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. - ANSWER-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. - ANSWER-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. - ANSWER-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 - ANSWER-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 - ANSWER-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. - ANSWER-d. Ribosomes are
synthesized entirely in the cytoplasm.
Organisms that reproduce sexually
a. must be haploid, unlike organisms that reproduce asexually.
b. can reproduce only with a partner that carries the same alleles.
c. create zygotes that are genetically identical to each other.
d. undergo a sexual reproductive cycle that involves an alternation of haploid cells with
the generation of diploid cells. - ANSWER-d. undergo a sexual reproductive cycle that
involves an alternation of haploid cells with the generation of diploid cells.
Which of the following statements most correctly describes meiosis?
a. Meiosis involves two rounds of DNA replication followed by a single cell division.
b. Meiosis involves a single round of DNA replication followed by four successive cell
divisions.
c. Meiosis involves four rounds of DNA replication followed by two successive cell
divisions.
d. Meiosis involves a single round of DNA replication followed by two successive cell
divisions. - ANSWER-d. Meiosis involves a single round of DNA replication followed by
two successive cell divisions.
Which of the following statements about Mendel's experiments is FALSE?
a. The pea plants could undergo both cross-fertilization and self-fertilization.
b. The true-breeding strains were homozygous for the traits that Mendel examined.
c. The egg can carry either the allele from the maternal or the paternal chromosome.
d. All traits that Mendel studied were recessive. - ANSWER-d. All traits that Mendel
studied were recessive.
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. - ANSWER-d. The cells produced
would get smaller and smaller.
The chromosomes condense during which phase of cell reproduction?
a. Metaphase
b. Telophase
c. Prophase
QUESTIONS 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. - ANSWER-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. - ANSWER-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. - ANSWER-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 - ANSWER-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 - ANSWER-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. - ANSWER-d. Ribosomes are
synthesized entirely in the cytoplasm.
Organisms that reproduce sexually
a. must be haploid, unlike organisms that reproduce asexually.
b. can reproduce only with a partner that carries the same alleles.
c. create zygotes that are genetically identical to each other.
d. undergo a sexual reproductive cycle that involves an alternation of haploid cells with
the generation of diploid cells. - ANSWER-d. undergo a sexual reproductive cycle that
involves an alternation of haploid cells with the generation of diploid cells.
Which of the following statements most correctly describes meiosis?
a. Meiosis involves two rounds of DNA replication followed by a single cell division.
b. Meiosis involves a single round of DNA replication followed by four successive cell
divisions.
c. Meiosis involves four rounds of DNA replication followed by two successive cell
divisions.
d. Meiosis involves a single round of DNA replication followed by two successive cell
divisions. - ANSWER-d. Meiosis involves a single round of DNA replication followed by
two successive cell divisions.
Which of the following statements about Mendel's experiments is FALSE?
a. The pea plants could undergo both cross-fertilization and self-fertilization.
b. The true-breeding strains were homozygous for the traits that Mendel examined.
c. The egg can carry either the allele from the maternal or the paternal chromosome.
d. All traits that Mendel studied were recessive. - ANSWER-d. All traits that Mendel
studied were recessive.
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. - ANSWER-d. The cells produced
would get smaller and smaller.
The chromosomes condense during which phase of cell reproduction?
a. Metaphase
b. Telophase
c. Prophase
