Question 1

Synthesis of a protein from an mRNA molecule is called ________.
A) transcription
B) translation
C) transformation
D) polymerization
E) polyadenylation

Accepted Answer

Synthesis of a protein from an mRNA molecule is called translation. Transcription refers to the synthesis of RNA from DNA, transformation is the genetic alteration of a cell by introduction of external DNA, polymerization refers to the process of joining monomers to form a polymer, and polyadenylation is the addition of a polyadenylated tail to the 3' end of an mRNA molecule.

Question 2

Nonprotein coding pieces of pre-mRNA that are removed during RNA splicing are called ________.
A) introns
B) exons
C) SNPs
D) promoters
E) poly(A) tails

Accepted Answer

Nonprotein coding pieces of pre-mRNA that are removed during RNA splicing are called introns. Exons are the protein-coding segments that remain after splicing. SNPs (single nucleotide polymorphisms) are variations in DNA sequence that occur within a population. Promoters are regions of DNA that regulate gene expression. Poly(A) tails are added to the 3' end of mRNA molecules and are important for stability and translation.

Question 3

________ is the enzyme that copies DNA during DNA replication. Thermostabile forms of this enzyme are essential for PCR.
A) RNA polymerase
B) DNA ligase
C) DNA polymerase
D) RNA primase
E) DNA helicase

Accepted Answer

DNA polymerase is the enzyme responsible for copying DNA during DNA replication, and it is also essential for PCR. The thermostabilized forms of DNA polymerase, such as Taq polymerase, are commonly used in PCR reactions. RNA polymerase, DNA ligase, RNA primase, and DNA helicase are all involved in DNA replication but are not specifically responsible for copying the DNA during replication or for PCR.

Question 4

Which of the following is a structural feature of DNA but not RNA?
A) Single-stranded
B) Containing the nitrogenous base adenine
C) Containing phosphate groups
D) Containing deoxyribose sugars
E) Containing the nitrogenous base uracil

Accepted Answer

DNA contains deoxyribose sugars, while RNA contains ribose sugars. This is a significant structural difference between the two macromolecules.

Question 5

Which of the following sequences is most commonly found at eukaryotic promoters?
A) TATAAT
B) Poly(A) tail
C) 7-methyl G cap
D) 5'-GU . . . AG-3'
E) Shine-Dalgarno sequence

Accepted Answer

The TATA box sequence (TATAAT) is the most commonly found promoter sequence in eukaryotes and is typically located about 25-35 base pairs upstream of the transcription start site.

Question 6

What is synthesis of RNA from a DNA template called?
A) Transformation
B) Reverse transcription
C) Transcription
D) Translation
E) None of these choices

Accepted Answer

Synthesis of RNA from a DNA template is called transcription.

Question 7

Which of the following is the typical start codon in most mRNA molecules?
A) UGA
B) AUG
C) AAA
D) GAA
E) CAG

Accepted Answer

The typical start codon in most mRNA molecules is AUG. This codon codes for methionine, which is commonly the first amino acid in a protein sequence.

Question 8

The complementary base that hydrogen bonds with thymine in a DNA double helix is ________.
A) uracil
B) thymine
C) guanine
D) adenine
E) cytosine

Accepted Answer

Adenine is the complementary base that hydrogen bonds with thymine in a DNA double helix. This is a specific pairing rule, where adenine always pairs with thymine and cytosine always pairs with guanine.

Question 9

Which type of point mutation creates a stop codon in a gene?
A) Nonsense
B) Frameshift
C) Silent
D) Missense
E) None of these choices

Accepted Answer

A nonsense mutation is a point mutation that changes a codon for an amino acid to a stop codon, resulting in premature termination of the protein. This can cause the protein to be truncated and non-functional.

Question 10

In a nucleotide of DNA, which carbon of the deoxyribose sugar binds to the base?
A) 1'
B) 2'
C) 3'
D) 4'
E) 5'

Accepted Answer

The base in a nucleotide of DNA is attached to the 1' carbon of the deoxyribose sugar.

Question 11

________ bind to mRNA and tRNA during translation and allow for polypeptides to be synthesized.
A) Chloroplasts
B) Ribosomes
C) Nuclei
D) RNA polymerases
E) Chromosomes

Accepted Answer

Ribosomes are the cellular organelles responsible for protein synthesis. They bind to mRNA and tRNA during translation and facilitate the assembly of amino acids into polypeptides. Chloroplasts are involved in photosynthesis, nuclei contain the cell's genetic material (DNA), RNA polymerases are enzymes that synthesize RNA from a DNA template, and chromosomes are structures composed of DNA and protein that contain genetic information.

Question 12

Which type of base-pair substitution mutation has no effect on the amino acid sequence of a protein?
A) Missense mutation
B) Nonsense mutation
C) Silent mutation
D) Frameshift mutation
E) None of these choices

Accepted Answer

A silent mutation is a type of base-pair substitution where the new codon still codes for the same amino acid, so there is no change in the resulting protein's sequence.

Question 13

Which of the following enzymes is a component of the large ribosomal subunit and catalyzes the formation of peptide bonds between an amino acid attached to a peptidyl-tRNA and an amino acid from an aminoacyl-tRNA?
A) Reverse transcriptase
B) DNA polymerase
C) Peptidyl transferase
D) DNA ligase
E) β-galactosidase

Accepted Answer

Peptidyl transferase is the enzyme that catalyzes the formation of peptide bonds between amino acids during protein synthesis in the ribosome. It is a component of the large ribosomal subunit and plays a crucial role in the elongation phase of translation. Reverse transcriptase is an enzyme that converts RNA into DNA, DNA polymerase is an enzyme that catalyzes DNA synthesis, DNA ligase is an enzyme that seals gaps in DNA strands, and β-galactosidase is an enzyme that hydrolyzes lactose. None of these enzymes are involved in peptide bond formation.

Question 14

Which of the following is a characteristic of smooth endoplasmic reticulum (SER) but not rough endoplasmic reticulum (RER)? A) Protein synthesis B) Sending vesicles to the Golgi that contain proteins that are either secreted or become part of the plasma membrane C) Steroid synthesis D) Drug and alcohol detoxification E) Steroid synthesis and drug and alcohol detoxification

Accepted Answer

Smooth endoplasmic reticulum (SER) is involved in lipid and steroid synthesis, metabolism of carbohydrates, and detoxification of drugs and poisons, distinguishing it from rough endoplasmic reticulum (RER), which is primarily involved in protein synthesis.

Question 15

Which organelles form the site of ATP production by aerobic cellular respiration?
A) Lysosomes
B) Mitochondria
C) Ribosomes
D) Golgi
E) Rough endoplasmic reticulum

Accepted Answer

Mitochondria are the organelles that form the site of ATP production by aerobic cellular respiration.

Question 16

Addition of a poly(A) tail to an mRNA molecule ________.
A) allows the mRNA to be recognized by ribosomes during translation
B) allows mRNA molecules to be more stable in the cytoplasm
C) results in removal of introns
D) only occurs in bacteria
E) is an important step in translation

Accepted Answer

The addition of a poly(A) tail to an mRNA molecule enables the molecule to be more stable in the cytoplasm. This tail protects the mRNA from degradation by exonucleases. It does not directly aid in translation by ribosomes, nor does it result in intron removal. Although some prokaryotes do add poly(A) tails to their mRNA, it is much more common in eukaryotes.

Question 17

Which type of RNA molecules transport amino acids to the ribosome during translation?
A) rRNA
B) tRNA
C) siRNA
D) mRNA
E) miRNA

Accepted Answer

tRNA (transfer RNA) molecules transport amino acids to the ribosome during translation. They have an anticodon sequence that binds to the complementary codon sequence on the mRNA, allowing the correct amino acid to be added to the growing protein chain. rRNA (ribosomal RNA) is a component of the ribosome itself and helps to catalyze peptide bond formation during translation. siRNA and miRNA are involved in gene regulation, not translation. mRNA (messenger RNA) carries the genetic information from DNA to the ribosome and is translated into protein by tRNA molecules.

Question 18

Which type of RNA molecule contains the genetic code of a gene that is read by ribosomes during translation?
A) rRNA
B) tRNA
C) siRNA
D) mRNA
E) miRNA

Accepted Answer

The mRNA (messenger RNA) molecule contains the genetic code of a gene that is read by ribosomes during translation. It carries the genetic information from DNA in the nucleus to the ribosomes in the cytoplasm, where it is used as a template to synthesize a protein.

Question 19

What enzyme separates strands of DNA during DNA replication to make DNA single-stranded so it can be copied?
A) DNA primase
B) DNA polymerase
C) DNA helicase
D) DNA ligase
E) Reverse transcriptase

Accepted Answer

DNA helicase is the enzyme responsible for separating the strands of DNA during replication. It uses energy to unwind the double helix and separate the two strands so that the DNA polymerase can copy each strand.

Question 20

Which of the following is the most commonly used stop codon in most mRNA molecules?
A) UGA
B) AUG
C) AAA
D) GAA
E) CAG

Accepted Answer

UGA is the most commonly used stop codon in most mRNA molecules. It signals the end of protein synthesis and initiates release of the newly synthesized protein. AUG is actually the start codon, while AAA, GAA, and CAG are all codons for amino acids (lysine, glutamic acid, and glutamine, respectively).

Quiz 2: An Introduction to Genes and Genomes

Synthesis of a protein from an mRNA molecule is called ________.

Nonprotein coding pieces of pre-mRNA that are removed during RNA splicing are called ________.

________ is the enzyme that copies DNA during DNA replication. Thermostabile forms of this enzyme are essential for PCR.

Which of the following is a structural feature of DNA but not RNA?

Which of the following sequences is most commonly found at eukaryotic promoters?

What is synthesis of RNA from a DNA template called?

Which of the following is the typical start codon in most mRNA molecules?

The complementary base that hydrogen bonds with thymine in a DNA double helix is ________.

Which type of point mutation creates a stop codon in a gene?

In a nucleotide of DNA, which carbon of the deoxyribose sugar binds to the base?

________ bind to mRNA and tRNA during translation and allow for polypeptides to be synthesized.

Which type of base-pair substitution mutation has no effect on the amino acid sequence of a protein?

Which of the following enzymes is a component of the large ribosomal subunit and catalyzes the formation of peptide bonds between an amino acid attached to a peptidyl-tRNA and an amino acid from an aminoacyl-tRNA?

Which of the following is a characteristic of smooth endoplasmic reticulum (SER) but not rough endoplasmic reticulum (RER) ?

Which organelles form the site of ATP production by aerobic cellular respiration?

Addition of a poly(A) tail to an mRNA molecule ________.

Which type of RNA molecules transport amino acids to the ribosome during translation?

Which type of RNA molecule contains the genetic code of a gene that is read by ribosomes during translation?

What enzyme separates strands of DNA during DNA replication to make DNA single-stranded so it can be copied?

Which of the following is the most commonly used stop codon in most mRNA molecules?