Lesson 8

Question 1

It occurs when a DNA gene is damaged or changed in such way as to alter the genetic message carried by that gene

Answer 1

Mutation

Question 2

Refers to the process of altering a DNA sequence

Answer 2

Mutate

Question 3

Mutation range in magnitude from substitution of a single DNA base to ____

Answer 3

deletion/ duplication of bases and to/of entire chromosomes

Question 4

Does mutation affect any part of the genome?

Answer 4

Yes, the sequences that encode proteins or control transcription, introns, repeats, and sites critical to intron removal and exon splicing

Question 5

Refers to the phenotype and also describes an allele

Answer 5

Mutant

Question 6

Are all DNA sequences likely to mutate?

Answer 6

NO

Question 7

A Mutant’s nature depends upon _____

Answer 7

how the mutation affects the gene’s product/activity, and usually connotes an abnormal/ unusual characteristic

Question 8

Can a mutant phenotype be normal?

Answer 8

Yes, it may also be a rare variant that is nevertheless “normal” (such as red hair)

Question 9

Two kinds of Mutations

Answer 9

Germline and Somatic

Question 10

What mutation is when the change occurs during the DNA replication that PRECEDES MEIOSIS?

Answer 10

Germline

Question 11

The resulting gamete and all cells that descend after a Germline Mutation are (transmitted/not)

Answer 11

Transmitted to the next generation

Question 12

What mutation happens during DNA replication BEFORE MITOSIS?

Answer 12

Somatic

Question 13

How is a Somatic Mutation passed to the next generation?

Answer 13

All cells that descend from the original changed cell are altered but they might only compromise a small part of the body.

Question 14

Effects of mutation

Answer 14

Vary

Question 15

Mutations may ___

Answer 15

Impair function
Have no effect
Beneficial

Question 16

Can stop or slow production of a protein, overproduce it, or impair the protein’s function (altering its secretion, location, or interaction w/ another protein)

Answer 16

Deleterious (harmful) mutation

Question 17

When the gene’s product is reduced or absent

Answer 17

“loss-of-function”

Question 18

When the gene’s activity changes

Answer 18

“gain-of-function”

Question 19

What most mutations are

Answer 19

Recessive and cause a loss of function

Question 20

When mutations tend to be dominant

Answer 20

“toxic”

Question 21

An agent of substance that can bring about a permanent alteration to the physical composition of a DNA gene such that the genetic message is changed

Answer 21

Mutagen

Question 22

Causes of Mutation

Answer 22

Chemical and Physical Mutagens

Question 23

Mutagen that changes the sequence of bases in a DNA gene in a number of ways

Answer 23

Chemical

Question 24

Chemical mutagenic agents

Answer 24

1. Base analogs
2. Alkylating agents
3. Intercalating agents
4. Metal ions
5. Other chemical mutagens

Question 25

Chemicals like the bases of DNA or structurally resemble them
(bromouracil and aminopurine)

Answer 25

base analogs

Question 26

They add alkyl radical to the DNA and damages it (poison gas, vinyl chloride)

Answer 26

alkylating agents

Question 27

The molecules intercalate between the bases of DNA and disrupt its structure; can cause frameshift mutation; blocks transcription
(proflavine, acridine orange)

Answer 27

intercalating agents

Question 28

Work by producing reactive oxygen species, hindering the DNA repair pathway, causing DNA hypermethylation, or may directly damage the DNA
(nickel, iron, cobalt)

Answer 28

metal ions

Question 29

Can be sunlight or radiation

Answer 29

Physical mutagen

Question 30

It is high energy radiation from a radioactive material or from X-rays is absorbed by the atoms in water molecules surrounding the DNA

Answer 30

Radiation

Question 31

How does Radiation alter DNA?

Answer 31

High energy radiation from a radioactive material is transferred to the electrons leaving behind a free radical, which is highly dangerous and highly reactive molecule that attacks DNA molecule and alters it in many ways; it also cause double strand breaks (unrepairable)

Question 32

It contains ultraviolet radiation which, when absorbed by the DNA causes a cross link to form between certain adjacent bases

Answer 32

Sunlight

Question 33

Is Sunlight mutagen repairable?

Answer 33

In normal cases, yes. But unrepaired dimers of this sort can cause the replicating system to skip over (leaving a gap)

Question 34

This mutation occurs without exposure to any obvious mutagenic agent when DNA nucleotides shift without warning

Answer 34

Spontaneous mutation

Question 35

Three types of Mutations

Answer 35

1. Point (least harmful)
2. Frameshift (more serious/deadly)
3. Expanding repeats (add stretches)

Question 36

A change in a single nitrogen base in a DNA sequence

Answer 36

Point Mutation

Question 37

When a base in a codon is changed, the amino acid won’t be affected, and mutation does not change the organism

Answer 37

Wobble effect

Question 38

What does a point mutation cause?

Answer 38

A change in a single amino acid of a protein that may alter the protein’s folding pattern

Question 39

Example of Point Mutation

Answer 39

Sickle cell anemia

Question 40

Types of Point Mutations

Answer 40

• transition
• transversion
• missense
• nonsense
• silent

Question 41

Point mutation that replaces a purine with a purine or a pyrimidine with a pyrimidine

Answer 41

transition

Question 42

Point mutation that replaces purine with a pyrimidine and vice versa

Answer 42

transversion

Question 43

Point mutation that the change in a codon normally specifies a PARTICULAR amino acid into one that codes for a DIFFERENT amino acid

Answer 43

missense

Question 44

Point mutation that the change in a codon specifies an amino acid into a STOP (AUG, UAA, UGA)

Answer 44

nonsense

Question 45

Point mutation that a change in the sequence of nucleotide bases WITHOUT a subsequent change in the amino acid/ function of the overall protein

Answer 45

silent

Question 46

Only a single nitrogen base is affected (completely DELETED or an EXTRA one is inserted into the middle of the DNA sequence)

Answer 46

Frameshift Mutation

Question 47

How does a frameshift mutation alter the sequence?

Answer 47

The deletion or insertion causes the reading frame to shift, changing the three-letter codon sequence for mRNA to transcribe and translate

Question 48

Types of Frameshift Mutation

Answer 48

1. Insertion (added in the middle)
2. Deletion (nitrogen base is taken out)

Question 49

This mutation when a DNA repeats expand because they attract each other

Answer 49

Expanding repeats (trinucleotide repeat) Mutation