Biology I- chapter 15

A ________ is defined as a heritable change in the genetic material (i.e. any __________ change in the nucleotide sequence of DNA).

-Although RNA and protein molecules can be _______, they are not ________ and thus not technically considered mutations.

Not all mutations cause a ______ or significant effect on a protein.

-Ultimate effect on RNA/protein may be a gain or loss of function, altered function, or no change in function.

-Beneficial mutation(s): _________ from chimp to human.

-Detrimental mutation(s): genetic disorders and __________.

mutation, permanent, altered, heritable, change, evolution, extinction

Point mutation: a mutation that alters a ______ nucleotide (base) within the DNA.

-Can change the ____ sequence within the DNA:

-Base substitution: can be silent, ________, or nonsense.

-Can add or ______ bases to the DNA sequence:

-Addition (insertion) or deletion (loss) of a base(s): can result in a __________ mutation.

-Changes the ___________/sequence of the codons.

single, base, missense, delete, frameshift, arrangement

A base __________ is when one base is wrongly paired with another base during DNA replication.

Some base-pair substitutions have ______ or no impact on _______ function.

-Some alterations of nucleotides still indicate the ____ amino acids because of redundancy in the genetic code.

-Other changes lead to ________ from one amino acid to another with similar properties.

-Still other mutations may occur in a region where the exact amino acid sequence is not _________ for function.

Some base-pair substitutions may have a _______ effect.

-Example: sickle-cell disease.

substitution, little, protein, same, switches, essential, drastic

A ____ substitution mutation within a gene can result in _____ types of mutations to the ______ of the mRNA.

-______ mutation: does ___ alter the amino acid sequence because the new codon still __________ into the same amino acid.

-The genetic code is ___________ (Chapter 12).

-_________ mutation: codes for an amino acid but translates into a ________ amino acid (i.e. changes a single amino acid).

-Example: sickle cell disease (Chapter 3).

-________ mutation: changes a normal amino acid codon into a stop codon.

-This causes translation to be __________ prematurely and likely will _____ protein function.

base, three, codons, Silent, not, translates, degenerate, Missense, different, Nonsense, terminated, alter

A __________ mutation results from the _______ (insertion) and/or ________ (loss) of nucleotides in a gene.

-Unless these mutations occur in multiples of _____ and do not alter the order of the codons, they cause a frameshift mutation.

-These have a _________ effect on the resulting protein more often than ____ substitutions do.

-All the nucleotides downstream or after the ________ or insertion will be improperly grouped into codons.

-Results in multiple wrong amino acids and thus the production of a ____________ protein.

frameshift, addition, deletion, three, disastrous, base, deletion, nonfunctional

A mutation may alter the sequence within a ________ of a gene and affect the rate of ____________.

-May increase or _________ the rate of transcription.

Mutations may occur in other regulatory regions.

-May alter ____ processing mechanisms or ability of mRNA to be transported out of the _______ or translated.

Mutations in _______(intergenic) regions not likely to result in an effect, but still possible.

-Many intergenic regions are involved in regulation of gene ___________.

promoter, transcription, decrease, mRNA, nucleus, nongene, expression

_______ human genetic diseases are due to __________ to large segments of DNA and chromosome structure.

These can be caused by ________ sources or problems in the cell cycle (will be discussed in Chapter 16).

There are ____ categories of structural changes:

-________.

-Duplication.

-_________.

-Translocation (simple and reciprocal).

Several, alterations, external, four, Deletion, Inversion

A segment of chromosomal material is _______.

-i.e. DNA (and genes located in that region) is lost.

Most cause serious disorders or are ______.

removed, lethat

A section of chromosome occurs ___ or more times.

-Gene sequences can be ________ two or more times in a row and can occur in ______ and abnormal chromosomes.

two, repeated, normal

An ________ is a chromosomal rearrangement that results in a change of ________ of the DNA within a single chromosome.

-Occurs when a _______ of a chromosome is broken in ___ places, changes direction (reversed), and put back _______.

inversion, direction, segment, two, together

A segment of one chromosome is ______ off and becomes attached to another chromosome.

Can be simple (or nonreciprocal) or __________.

broken, reciprocal

Mutations can occur in a number of ways.

-Causes of mutations are categorized as either being ___________ or induced.

Spontaneous mutations:

-Occur as a result of _________ in natural biological processes.

-Example: DNA ___________ making an error during DNA replication that does not get corrected/_____ (Chapter 11).

-Example: normal metabolic reactions within the cell may produce _____ by-products that can alter DNA sequence.

-There is no _______ of cell influence or cause.

spontaneous, mistakes, polymerase, fixed, toxic, outside

Induced mutations:

-Occur as a result of ________ to environmental agents that can enter the cell and _____ the structure of DNA.

-_______; a chemical or ________ agents that interacts with the DNA to cause mutations.

Examples of mutagens include:

-________ agents (examples: _______ and benzo(a)pyrene).

-________ agents (examples: X-rays and __ light).

-Some _______ (examples: papilloma viruses and ________-B virus).

exposure, alter, Mutagen, physical, Chemical, nicotine, Physical, UV, viruses, hepatitis