Bio Unit 5

True or false A purine to purine, or a pyrimidine to pyrimidine change is called Transition

True

True or false Most mutations are neither harmful nor helpful

True

True or false Mutations are best described as changes in DNA or RNA

True

Mutations increase genetic ______ and the potential for individuals to differ.

Variation

Examples of potentially dangerous mutagens include which of the following? (1) cigarette smoke (2) chemicals in processed meats (3) overexposure to sunlight (4) certain viruses -1 only -1 and 3 -2 and 4 -1, 2, 3, and 4

1, 2, 3, and 4

Examine the following mutation: ACGGGCAAACGATTG to ACGGGCAACGATTG. The mutation is -A frameshift mutation -An insertion of a single nucleotide -A nonsense mutation -A duplication mutation

A frameshift mutation

Distinguish between mutation and mutagen.

A mutation is the base or chromosomal change in the DNA sequence, either spontaneous or induced. A mutagen is the environmental factor that induces a mutation to occur. A mutagen causes mutation.

Types of point mutations include -Missense mutations -Nonsense mutation -Silent mutations -All of the above

All of the above

True or false Single base substitutions are not considered to be mutations

False

Which of the following types of mutations would most likely result in a genetic disorder -Somatic mutation -Silent mutation -Frameshift mutation -All of the above

Frameshirt mutation

Why are mutations essential for evolution to occur?

Mutations are essential for evolution to occur because they increase an organism's chance of surviving and reproducing, so they are likely to become more common over time.

Compare and contrast spontaneous mutations and induced mutations.

Spontaneous mutations occur under natural conditions and are random changes in teh DNA. Induced mutations are changes in DNA caused by mutagens. Mutagens are environmental factors that induced a mutation to occur.

Examine the following mutations: AUG-GUC-CCU-AAA to AUG-AGU-CCC-UAA-A. Describe how this mutation affects the encodon amino acid sequence.

The base A was inserted into the mRNA sequence after the first G. This causes a frameshift mutation, where the reading frame is moved over one base. When the reading frame is changed, the following codon sequence shifts and now codes for different amino acids, resulting in a protein that does not function properly or at all.

Assume that a point mutation changes the codon AUU to AUC. Explain why is this a neutral mutation.

This point mutation is a neutral mutation because the codon AUU and AUC both code for the same amino acid, isoleucine. This mutation has no effect on the final polypeptide chain.

True or false Cystic Fibrosis is a genetic disorder

True

True or false The two major categories of mutations are germline mutations and somatic mutations

True

Which of the following statements are correct concerning mutation? -Mutations are essential for evolution to occur -A mutation is change in the sequence of bases in DNA or RNA -Most mutations have no effect on the organism in which they occur -All of the above

all of the above

______ is a disease in which cells grow out of control and form abnormal masses of cells

cancer

Ultraviolet radiation, X-ray radiation, and other chemicals are all: -causes of mutations -used in barbecuing -used in labs -none of these

causes of mutations

True or false Beneficial mutations may become more common through artificial selection

false

A ______ is a disease caused by a mutation in one or a few genes. -evolution -natural selection -genetic disorder -mutagen

genetic disorder

True or false A mutation always causes a mutant phenotype.

False

True or false Somatic mutations occur in gametes

False

______ mutations may become more common through natural selection.

Beneficial

Spontaneous mutations occur due to errors in ______. -telemerase -DNA replication -RNA replication -All of these

DNA replication

A ______ mutation changes the reading frame of the mRNA

Frameshift

Induced mutations are caused by ______.

Mutagens

A ______ mutation codes for the same amino acid.

Silent

Distinguish between silent, missense, and nonsense mutations

Silent, missense, and nonsense mutations are all point mutations. Silent mutations code for the same amino acid and have no effect on the resulting protein.

Types of chromosomal alterations include -Translocation -Frameshift mutations -Point mutations -All of the above

Translocations

Mutations are essential for evolution to occur because they increase ______. -genetic variation -potential for individuals to differ -survivability of the species - all of the above

all of the above

Many mutations cause ______. -cancer -mutagens -chemotherapy -all of the above

cancer

Down Syndrome is due to trisomy of the 21st chromosome caused by: -non-disjunction during egg formation -non-disjunction during sperm formation -addition of the extra chromosome -either A or B

either A or B

Anything in the ______ that can cause a mutation is known as a mutagen.

environment

What is a mutagen? -cancer-causing agent -factor that immediately kills the organism -inherited mutations -environmental factors that cause mutations

environmental factors that cause mutations

Mutations that have neither a negative nor positive effect on the organism is called a ______ mutation.

neutral