Question 1

What is polycistronic mRNA?

Accepted Answer

Polycistronic mRNA is seen primarily among prokaryotes in which one mRNA carries coding information and internal punctuation for the translation of more than one protein.

Question 2

Describe the function of N -formylmethionine in prokaryotes.

Accepted Answer

N -formylmethionine is a modified amino acid, which serves as the starting amino acid in protein synthesis.

Question 3

List four base triplets that are clearly responsible for punctuation (initiation, termination).

Accepted Answer

AUG (rarely GUG) for initiation; UAA, UGA, and UAG for termination

Question 4

Describe the direction of information flow in living systems. Use appropriate, scientific terms in your description.

Accepted Answer

DNA is replicated and passed to offsprin

Question 5

When examining the genetic code, it is apparent that _.

Accepted Answer

A)  there can be more than one amino acid for a particular codon 
B)  the code is ambiguous in that the same codon can code for two or more amino acids 
C)  AUG is a terminating codon 
D)  there can be more than one codon for a particular amino acid 
E)  there are 44 stop codons because there are only 20 amino acids 
A)  there can be more than one amino acid for a particular codon 
B)  the code is ambiguous in that the same codon can code for two or more amino acids 
C)  AUG is a terminating codon 
D)  there can be more than one codon for a particular amino acid 
E)  there are 44 stop codons because there are only 20 amino acids

Question 6

The triplet AUG is commonly used as a start codon during translation.

Accepted Answer

A) True 
 B)False

Question 7

When scientists were attempting to determine the structure of the genetic code, Crick and coworkers found that when three base additions or three base deletions occurred in a single gene, the wild -type phenotype was sometimes restored. These data supported the hypothesis
That _.

Accepted Answer

A)  the code contains internal punctuation 
B)  there are three amino acids per base 
C)  the code is triplet 
D)  AUG is the initiating triplet 
E)  the code is overlapping 
A)  the code contains internal punctuation 
B)  there are three amino acids per base 
C)  the code is triplet 
D)  AUG is the initiating triplet 
E)  the code is overlapping

Question 8

Messenger RNA is usually polycistronic in eukaryotes.

Accepted Answer

A) True 
 B)False

Question 9

Introns are known to contain termination codons (UAA, UGA, or UAG), yet these codons do not interrupt the coding of a particular protein. Why?

Accepted Answer

A)  More than one termination codon is needed to stop translation. 
B)  These triplets cause frameshift mutations, but not termination. 
C)  Introns are removed from mRNA before translation. 
D)  UAA, UGA, and UAG are initiator codons, not termination codons. 
E)  Exons are spliced out of mRNA before translation. 
A)  More than one termination codon is needed to stop translation. 
B)  These triplets cause frameshift mutations, but not termination. 
C)  Introns are removed from mRNA before translation. 
D)  UAA, UGA, and UAG are initiator codons, not termination codons. 
E)  Exons are spliced out of mRNA before translation.

Question 10

In the context of molecular genetics, how does one reconcile the terms overlapping genes
and nonoverlapping code?

Accepted Answer

The genetic code contains codons that ar

Question 11

RNA processing occurs when amino acids are removed from nascent proteins.

Accepted Answer

A) True 
 B)False

Question 12

An intron is a section of an RNA that gets spliced out.

Accepted Answer

A) True 
 B)False

Question 13

A 5' -cap describes the addition of a base, usually thymine, to the 5' end of a completed peptide.

Accepted Answer

A) True 
 B)False

Question 14

When considering the initiation of transcription, one often finds consensus sequences located in the region of the DNA where RNA polymerase(s) binds. Which of the following is a common consensus sequence?

Accepted Answer

A)  any trinucleotide repeat 
B)  TTTTAAAA 
C)  satellite DNAs 
D)  GGTTC 
E)  TATA 
A)  any trinucleotide repeat 
B)  TTTTAAAA 
C)  satellite DNAs 
D)  GGTTC 
E)  TATA

Question 15

In eukaryotes, which three factors appear to encourage the specific association of RNA polymerase(s) to a specific region of DNA?

Accepted Answer

promoters,

Question 16

Transcription factors function to help move ribosomes along the mRNA.

Accepted Answer

A) True 
 B)False

Question 17

The code is nonoverlapping, meaning that, assuming "standard translation," a given base participates in the specification of one and only one amino acid.

Accepted Answer

A) True 
 B)False

Question 18

The relationship between codon and anticodon can be characterized as involving
________.

Accepted Answer

hydrogen bonds betwe

Question 19

Heterogeneous nuclear RNA is a primary transcript in eukaryotes that is processed prior to involvement in translation.

Accepted Answer

A) True 
 B)False

Question 20

"Breaking the genetic code" has been referred to as one of the most significant scientific achievements in modern times. Describe (in outline or brief statement form) the
procedures used to break the code.

Accepted Answer

- use of polynucleotide phosphorylase fo

Exam 12: The Genetic Code and Transcription

What is polycistronic mRNA?

Describe the function of N -formylmethionine in prokaryotes.

List four base triplets that are clearly responsible for punctuation (initiation, termination).

Describe the direction of information flow in living systems. Use appropriate, scientific terms in your description.

When examining the genetic code, it is apparent that _.

The triplet AUG is commonly used as a start codon during translation.

When scientists were attempting to determine the structure of the genetic code, Crick and coworkers found that when three base additions or three base deletions occurred in a single gene, the wild -type phenotype was sometimes restored. These data supported the hypothesis That _.

Messenger RNA is usually polycistronic in eukaryotes.

Introns are known to contain termination codons (UAA, UGA, or UAG), yet these codons do not interrupt the coding of a particular protein. Why?

In the context of molecular genetics, how does one reconcile the terms overlapping genes and nonoverlapping code?

RNA processing occurs when amino acids are removed from nascent proteins.

An intron is a section of an RNA that gets spliced out.

A 5' -cap describes the addition of a base, usually thymine, to the 5' end of a completed peptide.

When considering the initiation of transcription, one often finds consensus sequences located in the region of the DNA where RNA polymerase(s) binds. Which of the following is a common consensus sequence?

In eukaryotes, which three factors appear to encourage the specific association of RNA polymerase(s) to a specific region of DNA?

Transcription factors function to help move ribosomes along the mRNA.

The code is nonoverlapping, meaning that, assuming "standard translation," a given base participates in the specification of one and only one amino acid.

The relationship between codon and anticodon can be characterized as involving ________.

Heterogeneous nuclear RNA is a primary transcript in eukaryotes that is processed prior to involvement in translation.

"Breaking the genetic code" has been referred to as one of the most significant scientific achievements in modern times. Describe (in outline or brief statement form) the procedures used to break the code.

Introduction to Genetics

Mitosis and Meiosis

Mendelian Genetics

Modifications of Mendelian Ratios

Sex Determination and Sex Chromosomes

Chromosome Mutations: Variation in Number and Arrangement

Linkage and Chromosome Mapping in Eukaryotes

Genetic Analysis and Mapping in Bacteria and Bactierophages

DNA Structure and Analysis

DNA Replication and Recombination

Chromosome Structure and Dna Sequence Organization

Translation and Proteins

Gene Mutation, Dna Repair, and Transposition

Regulation of Gene Expression

The Genetics of Cancer

Recombinant Dna Technology

Genomics and Proteomics

Applications and Ethics of Genetic Engineering and Biotechnology

Developmental Genetics

Quantitative Genetics and Multifactorial Traits

Population and Evolutionary Genetics

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