Chapter 15 - Gene Mutations

Question 1

What term refers to a heritable change in the genetic material?

Answer 1

Mutation

Question 2

What is the positive side of Allelic variations provided by mutations?

Answer 2

They are the foundation for evolutionary change and necessary for a species to adapt to changes in the environment

Question 3

What is the negative side of Allelic variations provided by mutations?

Answer 3

New mutations are more likely to be harmful that beneficial and are often the cause of diseases

Question 4

What is a point mutation?

Answer 4

A change in a single base pair

Question 5

What is the change of a pyrimidine (C, T) to another pyrimidine or a purine (A, G) to another purine called?

Answer 5

Transition

Question 6

What is the change of a pyrimidine (C, T) to a purine (A, G) or vice versa called?

Answer 6

Transversion

Question 7

Which is more common? A Transversion or a Transition?

Answer 7

A Transition

Question 8

What else can mutations involve?

Answer 8

Deletion or Addition

Question 9

What type of mutation is a base substitution that does not alter the amino acid sequence of the polypeptide? (AGT to AGC = both code for serine)

Answer 9

Silent Mutation

Question 10

What type of mutation is a base substitution in which an amino acid change does occur? (GAG to GTG = Glutamic Acid to Valine)

Answer 10

Missense Mutation

Question 11

What type of mutation is Sickle-Cell Anemia?

Answer 11

Missense Mutation

Question 12

What type of mutation is a base substitutions that change a normal codon to a stop codon?

Answer 12

Nonsense Mutation

Question 13

What type of mutation involves the addition or deletion of a number of nucleotides that is not divisible by three?

Answer 13

Frameshift Mutation

Question 14

Where can mutations change levels of gene expression?

Answer 14

In the Core Promoter

Question 15

What type of mutation increases expression?

Answer 15

Up mutations

Question 16

What type of mutation decreases expression?

Answer 16

Down mutations

Question 17

What is the possible effect of a mutation on the Promoter?

Answer 17

It may increase or decrease the rate of transcription

Question 18

What is the possible effect of a mutation on the Regulatory Element/Operator Site?

Answer 18

It may disrupt the ability of the gene to be properly regulated

Question 19

What is the possible effect of a mutation on the 5’-UTR/3’-UTR?

Answer 19

It may alter the ability of mRNA to be translated; may alter mRNA stability

Question 20

What is the possible effect of a mutation on the Splice Recognition Sequence?

Answer 20

It may alter the ability of pre-mRNA to be properly spliced

Question 21

What is the relatively prevalent genotype called in a natural population?

Answer 21

The wild-type genotype

Question 22

What type of mutation changes a wild-type genotype into some new variation?

Answer 22

A Forward Mutation

Question 23

What type of mutation changes a mutant allele back to the wild-type genotype?

Answer 23

A Reverse Mutation (reversion)

Question 24

What type of mutation decreases the chance of survival?

Answer 24

Deleterious Mutations

Question 25

What is the most extreme Deleterious Mutation?

Answer 25

Lethal Mutations

Question 26

What type of mutation enhances the survival or reproductive success of an organism?

Answer 26

Beneficial Mutations

Question 27

What can affect the whether a given mutation is deleterious or beneficial?

Answer 27

The environment

Question 28

What is it called when mutations affect the phenotype only under a defined set of conditions? (Ex. Temperature-Sensitive mutation)

Answer 28

Conditional Mutations

Question 29

What is a second-site mutation that can counteract the effects of a first mutation?

Answer 29

Suppressor Mutation or Suppressors

Question 30

What is a second mutant site within the same gene as the first mutation?

Answer 30

Intragenic Supressor

Question 31

What is a second mutant site in a different gene from the first mutation?

Answer 31

Intergenic Suppressor

Question 32

What are the two types of Animal Cell classifications?

Answer 32

Germ-line cells and Somatic Cells

Question 33

What type of cells that give rise to gametes such as eggs and sperm?

Answer 33

Germ-line Cells

Question 34

What type of cells are all other cells?

Answer 34

Somatic Cells

Question 35

What type of mutations occur directly in a sperm or egg cell, or in one of their precursor cells?

Answer 35

Germ-line Mutations

Question 36

What type of mutations occur directly in a body cell, or one of its precursor cells?

Answer 36

Somatic Mutations

Question 37

What type of mutations result form abnormalities in cellular/biological processes?

Answer 37

Spontaneous Mutations

Question 38

What type of mutations are caused by environmental agents?

Answer 38

Induced Mutations

Question 39

What are the agents known to alter DNA structure?

Answer 39

Mutagens

Question 40

What is the abnormal crossing over that may cause deletions, duplications, translocations, and inversions called?

Answer 40

Aberrant Recombination (Spontaneous)

Question 41

What is the abnormal chromosomal segregation that may cause aneuploidy or polyploidy?

Answer 41

Aberrant Segregation (Spontaneous)

Question 42

What is a mistake by DNA polymerase that may cause a point mutation?

Answer 42

Errors in DNA Replication (Spontaneous)

Question 43

What are elements that can insert themselves into the sequence of a gene?

Answer 43

Transposable Elements (Spontaneous)

Question 44

What is the linkage between purines (Adenine and Guanine) and deoxyribose that can spontaneously break? If not repaired, this can lead to mutation.

Answer 44

Depurination (Spontaneous)

Question 45

What is it called when Cytosine and 5-methylcytosine can spontaneously deaminate to create uracil or thymine?

Answer 45

Deamination (Spontaneous)

Question 46

What is a spontaneous change in base structure that can cause mutations if they occur immediately prior to DNA replication?

Answer 46

Tautomeric Shifts (Spontaneous)

Question 47

What are the products of normal metabolic processes, such as reactive oxygen species, it may be chemically reactive agents that can alter the structure of DNA?

Answer 47

Toxic Metabolic Products (Spontaneous)

Question 48

What are chemical substances that may cause changes in the structure of DNA?

Answer 48

Chemical Agents (Induced)

Question 49

What are physical phenomena such as UV light and X-rays that can damage the DNA?

Answer 49

Physical Agents (Induced)

Question 50

What is the likelihood that a gene will be altered by a new mutation?

Answer 50

Mutation Rate

Question 51

What is the range of a mutation rate

Answer 51

10^(-5) to 10^(-6) per generation

Question 52

What are the three types of spontaneous mutations that can arise by three types of chemical changes?

Answer 52

1. Depurination 2. Deamination 3. Tautomeric Shift

Question 53

What is the term for a covalent bond between deoxyribose and a purine base that undergoes a spontaneous reaction with water that releases the base from the sugar?

Answer 53

Apurinic Site

Question 54

What type of bases tend to create hot spots for mutation in Deamination?

Answer 54

Methylated Cytosine Bases

Question 55

What is the common, stable form of thymine and guanine?

Answer 55

The Keto form

Question 56

What is the form that thymine and guanine can interconvert into at a low rate?

Answer 56

The Enol form

Question 57

What is the common, stable form of adenine and cytosine?

Answer 57

The Amino form

Question 58

When must a mutation occur for a tautomeric shift to be the cause?

Answer 58

Prior to DNA replication

Question 59

What is an unusual form of mutation that causes several human genetic diseases called?

Answer 59

Trinucleotide Repeat Expansion (TNRE)