Question 1

A codon is a three-base sequence of
A)mRNA that codes for an amino acid.
B)rRNA that codes for an amino acid.
C)tRNA that codes for an amino acid.
D)DNA that codes for an amino acid.

Accepted Answer

A codon is a sequence of three nucleotides in mRNA that specifies a particular amino acid to be incorporated into the protein being synthesized.

Question 2

RNA molecules that can act as enzymes and catalyze specific biochemical reactions are known as ________________.
A)donors
B)splice acceptors
C)ribozymes
D)tRNAs
E)restriction enzymes
Blooms Level 1: Remember

Accepted Answer

RNA molecules that can act as enzymes and catalyze specific biochemical reactions are called ribozymes. Donors and splice acceptors are involved in RNA splicing, tRNAs are involved in translation, and restriction enzymes are used in molecular biology for genetic engineering.

Question 3

Which of these is NOT a step in transcription?
A)replication
B)initiation
C)termination
D)elongation

Accepted Answer

Transcription is the process of synthesizing an RNA molecule from a DNA template. Replication, on the other hand, is the process by which DNA copies itself to form two identical DNA molecules. Therefore, replication is not a step in transcription.

Question 4

A typical example of a genetic system that employs RNA splicing is
A)the genes that code for the segments in an earthworm.
B)the genes responsible for making antibodies in humans.
C)the HIV virus genes.
D)the genes that enable RNA splicing.

Accepted Answer

Antibody genes in humans undergo RNA splicing to generate different combinations of exons, leading to the production of diverse antibodies. The other options (A, C, D) do not directly involve RNA splicing in their genetic systems.

Question 5

A sequence of DNA that reads 5' ATGCCTGAATCAGCTTTA 3' should code for ____ amino acids after all the steps of conversion into protein are complete.
A)5
B)6
C)7
D)8

Accepted Answer

The DNA sequence can be converted into mRNA by replacing thymine (T) with uracil (U) and reading from 5' to 3'. Therefore, the mRNA sequence would be 3' UACGGACUUAGUCGAAAU 5'. Using the genetic code, we can then determine that this mRNA sequence codes for 6 amino acids (Met-Pro-Asn-Gln-Leu).

Question 6

A(n) _____________ consists of proteins and small nuclear RNAs forming discrete particles that mediate splicing.
A)holoenzyme
B)splicesome
C)nucleosome
D)ribosome
E)chromosome
Blooms Level 1: Remember

Accepted Answer

A splicesome is a complex of proteins and RNA that catalyzes splicing, the process by which introns (non-coding regions) are removed from pre-mRNA and exons (coding regions) are joined together. The splicesomes are made up of small nuclear RNAs (snRNAs) and proteins, and they come together in a highly regulated process to carry out splicing. Holoenzyme refers to an enzyme that contains multiple subunits and/or cofactors. Nucleosome refers to the basic structural unit of chromatin, consisting of DNA wrapped around histone proteins. Ribosome refers to the large macromolecular machine that synthesizes proteins by translating mRNA into amino acid sequences. Chromosome refers to the condensed structure formed by DNA during cell division.

Question 7

Which of these is NOT a character of the genetic code?
A)There are the same number of codons as there are amino acids.
B)The code is used by nearly every living organism.
C)Some amino acids have multiple codons.
D)The code is degenerate.

Accepted Answer

This statement is not describing a specific character of the genetic code, but rather a relationship between codons and amino acids. The correct character of the genetic code is that each codon codes for a specific amino acid.

Question 8

In the usual flow of genetic information (often called the Central Dogma), which of the following best represents the expression of genes?
A)Protein-RNA-DNA
B)DNA-RNA-Protein
C)RNA-DNA-Protein
D)DNA-Protein-RNA

Accepted Answer

The Central Dogma states that DNA is transcribed into RNA and then translated into protein. Therefore, the correct sequence is DNA-RNA-Protein, making option B the correct choice. The other options (A, C, and D) do not follow the flow of genetic information as described by the Central Dogma.

Question 9

There are ______________ usually found in the genetic code.
A)3 start codons and 1 stop codon
B)2 start codons and 2 stop codons
C)1 start codon and 3 stop codons
D)0 start codons and 4 stop codons

Accepted Answer

The genetic code typically has 1 start codon (AUG) which codes for methionine and signals the start of protein synthesis, and 3 stop codons (UAA, UAG, UGA) which signal the termination of protein synthesis.

Question 10

The pattern or sequence in which a molecule of mRNA is deciphered by a ribosome is called the
A)synthesis platform.
B)code degeneration.
C)peptide transition.
D)reading frame.

Accepted Answer

The sequence in which an mRNA molecule is read and translated into a protein by a ribosome is called the reading frame. This is determined by the start codon (AUG) and the stop codons (UAA, UAG, and UGA) in the mRNA sequence.

Question 11

Nonsense codons are
A)codons that code for multiple amino acids.
B)codons that do not code for an amino acid.
C)codons that can be read forward or backward.
D)start codons.

Accepted Answer

Nonsense codons, also known as stop codons, do not code for an amino acid but instead signal the end of protein synthesis.

Question 12

Experiments that are done outside a living cell are describe by the Latin term
A)in vino.
B)in vito.
C)in vivo.
D)in vitro.

Accepted Answer

The correct term for experiments done outside a living cell is "in vitro," which means "in glass" in Latin.

Question 13

Charles Yanofsky helped decipher the genetic code working with the _____ biosynthesis genes in _______.
A)leucine Salmonella enteritidis
B)phenylalanine Klebsiella pneumoniae
C)tryptophan Escherichia coli
D)glycine Serratia marcescens

Accepted Answer

Charles Yanofsky worked with the tryptophan biosynthesis genes in Escherichia coli, which helped him decipher the genetic code.

Question 14

The (expressed) sequences within mRNA that code for gene products are called
A)extremes.
B)exons.
C)inclusions.
D)introns.

Accepted Answer

The sequences within mRNA that code for gene products are called exons. Introns are non-coding sequences within genes that are transcribed into mRNA but are later removed during post-transcriptional processing. Extremes and inclusions do not relate to gene expression.

Question 15

The cellular organelle responsible for protein synthesis is the
A)nucleus.
B)mitochondria.
C)centrioles.
D)ribosome.

Accepted Answer

Ribosomes are the cellular organelles responsible for protein synthesis. They are composed of RNA and protein, and are found in large numbers in cells that produce a lot of proteins. The process of protein synthesis takes place on the ribosomes, where the mRNA (messenger RNA) is translated into a sequence of amino acids to form a protein.

Question 16

The retroviruses, including HIV, are unique because they do reverse
A)replication.
B)transcription.
C)splicing.
D)translation.

Accepted Answer

Retroviruses are unique in that they carry an RNA genome that must be reverse transcribed into DNA before it can be integrated into the host cell genome. Reverse transcription is the process of creating DNA from an RNA template, which is the opposite of the normal process of transcription that occurs in cells, where RNA is synthesized from DNA. Therefore, the correct answer is B) transcription.

Question 17

Which of these terms is NOT used as a nickname for a stop codon?
A)emerald
B)amber
C)opal
D)ochre

Accepted Answer

The three stop codons in the genetic code are often referred to by their colors: amber, opal, and ochre. 'Emerald' is not used as a nickname for any of the stop codons.

Question 18

The sequences within mRNA that are spliced out (removed) are called
A)extremes.
B)exons.
C)inclusions.
D)introns.

Accepted Answer

The sequences within mRNA that are spliced out (removed) before the mRNA leaves the nucleus are called introns. Exons are the sequences that remain intact and are eventually translated into protein. Extremes and inclusions are not accurate terms for describing these sequences.

Question 19

The scientists credited with postulating the basis for the genetic code are
A)Hershey and Chase.
B)Griffith and Avery.
C)Watson and Crick.
D)Cohen and Boyer.

Accepted Answer

Watson and Crick are credited with discovering the structure of DNA, but they also played a role in postulating the basis for the genetic code. They proposed that groups of three nucleotides, called codons, corresponded to specific amino acids. This was later confirmed through experiments by other scientists. Hershey and Chase demonstrated that DNA, not protein, was the genetic material; Griffith and Avery showed that DNA carried genetic information; and Cohen and Boyer were pioneers in genetic engineering.

Question 20

How many different amino acids could be coded for using the synthetic mRNA sequence of (5' UGCUGCUGC 3')?
A)0
B)1
C)2
D)3

Accepted Answer

The sequence UGC can code for cysteine (Cys), and the sequence GCU can code for alanine (Ala). Therefore, the repeating sequence UGCUGCUGC can code for two different amino acids, Cys and Ala, depending on the reading frame.

Quiz 8: Gene Expression: The Flow of Information From DNA to RNA to Protein

A codon is a three-base sequence of

RNA molecules that can act as enzymes and catalyze specific biochemical reactions are known as ________________.

Which of these is NOT a step in transcription?

A typical example of a genetic system that employs RNA splicing is

A sequence of DNA that reads 5' ATGCCTGAATCAGCTTTA 3' should code for ____ amino acids after all the steps of conversion into protein are complete.

A(n) _____________ consists of proteins and small nuclear RNAs forming discrete particles that mediate splicing.

Which of these is NOT a character of the genetic code?

In the usual flow of genetic information (often called the Central Dogma) , which of the following best represents the expression of genes?

There are ______________ usually found in the genetic code.

The pattern or sequence in which a molecule of mRNA is deciphered by a ribosome is called the

Nonsense codons are

Experiments that are done outside a living cell are describe by the Latin term

Charles Yanofsky helped decipher the genetic code working with the _ biosynthesis genes in ___.

The (expressed) sequences within mRNA that code for gene products are called

The cellular organelle responsible for protein synthesis is the

The retroviruses, including HIV, are unique because they do reverse

Which of these terms is NOT used as a nickname for a stop codon?

The sequences within mRNA that are spliced out (removed) are called

The scientists credited with postulating the basis for the genetic code are

How many different amino acids could be coded for using the synthetic mRNA sequence of (5' UGCUGCUGC 3') ?