Year 12 ATAR Human Biology - Mutations

Flashcards on mutations, types, causes, and effects for Year 12 ATAR Human Biology.

What is a mutation?

A permanent change in a gene or chromosome that can lead to new characteristics in an organism or its offspring.

What are induced mutations?

Mutations caused by damage from mutagens in the environment.

What is a mutation?

A permanent change in a gene or chromosome that can lead to new characteristics in an organism or its offspring.

What are induced mutations?

Mutations caused by damage from mutagens in the environment.

What are spontaneous mutations?

Mutations that occur due to random errors in biological processes like DNA replication or cell division.

What is a germ-line mutation?

A mutation that occurs in reproductive cells/gametes; inheritable by offspring.

What is a somatic mutation?

A mutation that occurs in body cells; not inheritable by offspring.

What are gene mutations?

Changes in a single gene, often resulting in changes or removal of the traits produced by the gene.

What are chromosomal mutations?

Changes to all or part of a chromosome (i.e., multiple genes can be affected).

What is a point mutation?

Changes to a single nucleotide in the DNA sequence.

What is a substitution mutation?

An existing nucleotide is replaced with a nucleotide with a different base.

What is an insertion mutation?

A new nucleotide is added into the DNA sequence.

What is a deletion mutation?

An existing nucleotide is removed from the DNA sequence.

What is a frameshift mutation?

Occurs when nucleotides are added (insertion) or removed (deletion) from a section of code, resulting in new codons/codes for different amino acids.

What is a missense mutation?

Causes a change in amino acid, which changes the protein produced.

What is a nonsense mutation?

Changes the base sequence to a STOP codon, causing protein synthesis to stop and producing a shorter, likely non-functional protein.

What is a silent mutation?

No change in the amino acid sequence, resulting in no change in the protein produced.

What is a neutral mutation?

A change in amino acid that results in a similar type of amino acid being produced, which is not enough to change protein structure/function.

What is chromosome insertion?

Extra base pairs added into the chromosome.

What is chromosome deletion?

A section of chromosome is removed/lost.

What is chromosome duplication?

A section of chromosome (or whole chromosome) is repeated.

What is chromosome inversion?

Breaks occur in the chromosome; the broken segment is reversed and reinserted into the chromosome.

What is chromosome translocation?

Part of a chromosome breaks off and attaches to another chromosome.

What is non-disjunction?

During meiosis, a chromosome pair does not separate, resulting in daughter cells with an extra chromosome or one less than the normal number.

What is aneuploidy?

Change in chromosome number, resulting from non-disjunction.

Why can mutations occur during DNA replication?

Even though there are built-in repair mechanisms, a small number of errors are expected during DNA replication.

What are mutagens?

Substances known to increase the rate at which mutations occur.

Give physical examples of mutagens.

Temperature, X-rays, and nuclear radiation (ionizing radiation) can cause breaks in bonds in the sugar-phosphate backbone. UV radiation can cause cross-linking between bases.

Give chemical examples of mutagens.

Chemicals that resemble DNA nucleotides and intercalate (stick) between the bases of DNA, disrupting its structure (e.g., ethidium bromide). Nitrous acid deaminates adenine and cytosine.

Give biological examples of mutagens.

Viruses can bind to a host cell and insert their DNA into the host DNA, thus permanently changing the DNA (e.g., HPV).