High School Biology : Understanding Mutation and Evolution

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #1 : Understanding Mutation And Evolution

What distinguishes mutations from evolution?

Possible Answers:

Mutation and evolution are synonymous

Mutations do not get passed onto offspring, but evolution is inherited

Mutations happen to individuals while evolution happens to a species

Evolution affects organisms on a short term basis, while mutations are long term

Evolution happens to individuals while mutations happen to a species

Correct answer:

Mutations happen to individuals while evolution happens to a species

Explanation:

Mutations and evolution must be distinctly defined. Mutations happen to individuals. To acquire a mutation, a single event will cause the DNA of a single individual to become altered. If the result is a positive mutation, meaning the change helps increase the fitness of the individual (ability to reproduce), then it will get passed on to the next generation.

Evolution affects a population when mutations change the genetic variety of individuals. As a mutation spreads through the population by reproduction and inheritance it changes the genome of the species. As more and more mutations are acquired in the population, speciation can eventually occur.

Example Question #2 : Understanding Mutation And Evolution

Which of the following statements is incorrect?

Possible Answers:

Mutations happen when there is a need for a new trait in a population

Mutations create diversity among life-forms

Radiation and chemical damage can cause mutations

Mutations are the source of new alleles

Without mutations, there would be no evolution

Correct answer:

Mutations happen when there is a need for a new trait in a population

Explanation:

Mutations are not goal-directed. A mutation simply happens, and does not arise as a result of environmental necessities.

Alleles are different nucleotide sequences at a given gene's location. Different alleles generate different forms of the same protein product. Repair flaws caused by radiation and chemical damage change the nucleotide sequence, causing mutations. Mutations alter the gene pool, and are therefore the source of new alleles. These mutations are the foundation of evolutionary change and diversity among life-forms. 

Example Question #3 : Understanding Mutation And Evolution

Which of the following mutations would be least detrimental to the function of a protein?

Possible Answers:

Nonsense

Deletion of two nucleotides

Frameshift

Silent

Missense

Correct answer:

Silent

Explanation:

Silent mutations change the nucleotide sequence of the DNA, yet the protein sequence is unchanged. This is due to the redundancy of the genetic code. Missense mutations involve substitution of one amino acid instead of another, which could change the folding pattern of the polypeptide. Nonsense mutations involve substitution of a nucleotide that results in a stop codon rather than the appropriate amino acid. This results in a truncated protein, which is nonfunctional. Frameshift mutations involve insertions, deletions and/or duplications of nucleotides. This shifts the reading frame on the mRNA, resulting in a nonfunctional protein. Note that frameshift mutations in which multiples of three nucleotides are inserted, deleted and/or duplicated are do not change the reading frame, and may still yield a functional protein. However, for example, a deletion of two nucleotides does change the reading frame and would lead to a nonfunctional protein.

Example Question #2 : Understanding Mutation And Evolution

Sickle cell anemia is a blood disorder in which the red blood cells are not shaped correctly and cannot carry oxygen as well as regular blood cells.

Sickle cell anemia is known to be caused by a single base mutation. What type of mutation is sickle cell anemia most probably caused by?

Possible Answers:

A nondisjunction

An insertion

A deletion

A missense mutation

A nonsense mutation

Correct answer:

A missense mutation

Explanation:

The red blood cells are still made, but their shape is different. This can be caused by a missense mutation, the replacement of one amino acid by another. A nonsense mutation would produce a truncated protein, which most likely would not be functional at all. An insertion or deletion could cause a frameshift mutation which could produce a completely different protein. Nondisjunction refers to meiosis, not DNA replication.

Example Question #3 : Understanding Mutation And Evolution

Which of the following is most likely to drive evolution?

Possible Answers:

An insertion mutation

A point mutation

All of these

A frameshift mutation

A missense mutation

Correct answer:

All of these

Explanation:

Evolution relies on genetic diversity. One source of genetic diversity is spontaneous mutation. One spontaneous mutation may be beneficial to an organism's fitness, increasing the chance of that mutation being passed to the next generation.

Example Question #4 : Understanding Mutation And Evolution

Which is incorrect regarding mutations? 

Possible Answers:

Mutations lead to genetic variation

Mutations are always harmful 

Mutations can be beneficial 

Mutation is a process that produces new alleles and genes

Many mutations are due to error in DNA replication 

Correct answer:

Mutations are always harmful 

Explanation:

Mutations are not always harmful as they can also be beneficial. Keep in mind mutations are also not always beneficial. Mutation simply is a process that produces new alleles in genes due to mistakes made during recombination, DNA replication or repair. 

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