Question 1

What is the effect of a nonsense mutation in a gene?

Accepted Answer

A)  It changes an amino acid in the encoded protein. 
B)  It has no effect on the amino acid sequence of the encoded protein. 
C)  It introduces a premature stop codon into the mRNA. 
D)  It alters the reading frame of the mRNA. 
E)  It prevents introns from being excised. 
A)  It changes an amino acid in the encoded protein. 
B)  It has no effect on the amino acid sequence of the encoded protein. 
C)  It introduces a premature stop codon into the mRNA. 
D)  It alters the reading frame of the mRNA. 
E)  It prevents introns from being excised.

Question 2

Use the following information to answer the next few questions.
A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) already in the ribosome.
-Which component of the complex described enters the exit tunnel through the large subunit of the ribosome?

Accepted Answer

A)  tRNA with attached lysine (#1) 
B)  tRNA with polypeptide (#2) 
C)  tRNA that no longer has attached amino acid 
D)  newly formed polypeptide 
E)  initiation and elongation factors 
A)  tRNA with attached lysine (#1) 
B)  tRNA with polypeptide (#2) 
C)  tRNA that no longer has attached amino acid 
D)  newly formed polypeptide 
E)  initiation and elongation factors

Question 3

Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?

Accepted Answer

A)  a deletion of a codon 
B)  a deletion of two nucleotides 
C)  a substitution of the third nucleotide in an ACC codon 
D)  a substitution of the first nucleotide of a GGG codon 
E)  an insertion of a codon 
A)  a deletion of a codon 
B)  a deletion of two nucleotides 
C)  a substitution of the third nucleotide in an ACC codon 
D)  a substitution of the first nucleotide of a GGG codon 
E)  an insertion of a codon

Exam 14: Gene Expression: From Gene to Protein

What is the effect of a nonsense mutation in a gene?

Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Regulation of Gene Expression

Development, Stem Cells, and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition, Nutrition, and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons, Synapses, and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

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