Lac & Trp Operon / Mutations

Question 1

Missense Mutation

Answer 1

• Occurs when single substitution of one amino acid takes place and results in a polypeptide

Question 2

Nonsense Mutation

Answer 2

• When a normal codon is altered into a termination codon

Question 3

Substitution

Answer 3

The replacement of one base in a DNA sequence

Question 4

Deletion

Answer 4

The elimination of a base pair or group of base pairs from DNA sequence

Question 5

Insertion

Answer 5

The placement of an extra nucleotide In a DNA sequence

Question 6

Frameshift Mutation

Answer 6

A mutation that causes reading frame to change, usually resulting in different amino acids being incorporated into the polypeptide

Question 7

Point Mutation

Answer 7

Mutation at a specific base pair in the genome (silent, insertion, deletion)

Question 8

Translocation

Answer 8

Transfer of a fragment of DNA from one site in the genome to another location

Question 9

Transposable Elements

Answer 9

• Also known as jumping genes

- Segments of DNA that are replicated as a unit from one location to another on chromosomal DNA

Question 10

Inversion

Answer 10

The reversal of a segment of DNA within a chromosome. Depending on where the break is, a gene may be disrupted

Question 11

Spontaneous Mutations

Answer 11

Mutations that occur as a result of errors made in the DNA replication. D A polymerase rereads for errors but sometimes misses a base or two which results in point mutation

Question 12

Mutagenic Agents

Answer 12

Things that can cause a mutation

Question 13

Induced Mutations

Answer 13

Mutations caused by a chemical agent or radiation

Question 14

4 Characteristics of a Lac Operon

Answer 14

1. Regulates production of B-galactosidase and other proteins in in the metabolism of Lactose
2. Cluster of 3 genes under the control of one promoter and one operator
3. Lacl repressor protein binds to the operator when Lactose levels are low
4. High levels of Lactose induce the Operon

Question 15

4 Characteristics of the Trp Operon

Answer 15

1. Regulates the production of the amino acid Tryptophan
2. Cluster of 5 genes under control of one promoter and one operator
3. The corereppressor tryptophan binds to the Trp repressor protein, and the complex binds to the operator when tryptophan levels are high
4. High levels of Tryptophan repress the Operon

Question 16

3 types of Point Mutation

Answer 16

1. Substitution
2. Deletion
3. Addition/Insertion

Question 17

Silent Mutation

Answer 17

• Takes place in noncoding regions like the introns of DNA

- Since introns get cut out during transcription, the mutation has no effect on the cell

Question 18

6 steps of Lac Operon

Answer 18

1. Promoter attracts RNA polymerase
2. When there is a decrease in [Lactose], the Lacl protein attaches to operator and acts like a roadblock for RNA polymerase