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HUMAN BIOLOGY - Evidence of evolution > Mutations > Flashcards

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a group of organisms of the same species living together in a particular place at a particular time


Gene pool

The sum of all the alleles in a given population


Allele frequencies

how often each allele of a gene occurs in the gene pool for that population



A change in a gene or a chromosome leading to a new characteristic in an organism - a permanent change in the DNA.



A characteristics resulting from a mutation


Two types of Mutations

Chromosome; when all or part of a chromosome is affected.

Gene mutation; Changes in a single gene so that traits normally produced by that genes are changed or destroyed.


Mutagenic agents

Known to increase the rate of which mutations occur. E.g. X-rays, mustard gas etc.


Gene mutations

A change in the bases of the DNA could change the amino acid and could alter the protein. Could have no affect or prevent the protein from being produced.


Types of mutation

Induced; a mutation caused by a mutagenic agent

Spontaneous; A mutation that occurs due to an error in the natural biological process


Heritability of the mutation

Somatic; A change occurring in the gene in the body cell.

Germline; a change in the heredity material in the egg or sperm that becomes incorporated into the DNA of every cell in the body


Effects of Mutation

Missense Mutation; A change in the amino acid and therefore the protein that is produced

Non-sense Mutation; A change in the base sequence that results in a STOP of the code. Therefore synthesis will stop and shorter proteins are produced.

Neural Mutation; A mutation that causes a change in the amino acid, however does not cause a change in the overall protein produced

Silent Mutation; A mutation that does not change the sequence of the amino acid


Extent of mutations

Chromosomes mutations affect a whole number of genes whereas Gene mutations only affect a singular gene.


Change in DNA (Nucleotide)

1. insertion - A new nucleotide is added to the DNA strand
2. Substitution - An existing nucleotide is replaced with another
3. Deletion - A nucleotide is removed from the DNA strand


Point mutations

A change in just one of the bases in a DNA molecule


Frame shift mutation

Occurs when bases have been added or removed. This results in a series of bases that codes for an amino acid starting at a different base. They affect the outcome for all the DNA from that point on.


Change in DNA (DNA strands)

1. Duplication - a section of chromosome occurs twice
2. Deletion - A piece of DNA is removed
3. Inversion - Breaks occur in the Chromosome and is rejoined the wrong way around
4. Translocation - part of the chromosome breaks off and is rejoined to the wrong chromosome
5. Non-disjunction - During meiosis, a chromosome part does not separate and so one daughter has an extra chromosome and one daughter has one less chromosome


Conditions due to mutations (Gene)

Gene mutations;
1. Duchenne Muscular dystrophy
2. Cystic fibrosis


Conditions due to mutations (Chromosomal)

Chromosol mutations;
1. Down syndrome or trisomy 21.
2. Partial trisomy
3. Patau syndrome