Mutations Flashcards

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1
Q

Create a table contrasting gene and somatic mutation.

A

Gene mutation

  • germ line (hereditary)
  • recall: germ cell = sex cell
  • occurs to germ cell destined to become egg or sperm or zygote at sing-cell stage
  • Impacts every cell
  • Can be passed to offspring
  • e.g. Sickle Cell Anaemia

Somatic

  • recall: somatic cell = body cell
  • occurs in body cells/tissue
  • “acquired mutation” happens during lifetime
  • Ranges from localised regional impact to potential systemic effect
  • tissues that derive from mutated cell will be impacted
  • won’t be passed on to offspring
  • e.g. lung cancer from smoking
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2
Q

Describe point mutation.

A
  • “substitution”
  • nucleotide replaced with different nucleotide
  • only affects codon for single amino acid
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3
Q

Describe frameshift mutation.

A
  • “deletion”
  • removal of a nucleotide
  • alters every codon after mutation
  • “insertion”
  • adds nucleotides
  • alters every codon after mutation
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4
Q

What are three types of point mutations?

A
  1. Silent
    - nucleotide replaced but codon still produces same amino acid
  2. Missense
    - codon results in different amino acid, may or may not alter protein’s function
  3. Nonsense
    - codon now ‘stop command’
    - leads to loss protein functionality
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5
Q

What are chromosome mutations?

A
  • large-scale
  • may affect one chromosome or non-homologous pairs
  • results in entire genes or sets of genes being altered
  • often occur during crossing over meiosis (prophase 1)
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6
Q

Describe deletion.

A

(single chromosome)

- loss one of more gene(s) from parent chromosomes

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7
Q

Describe insertion.

A

(multiple chromosomes)

  • one or more gene(s) removed from one chromosome and inserted into another non-homologous chromosome
  • occur by error during prophase 1 (meiosis) when chromosomes swapping genes to increase diversity
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8
Q

Describe duplication.

A

(single chromosome)

  • addition of one or more genes
  • any repetition of a region of DNA that contains one or more genes
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9
Q

Describe inversion.

A

(single chromosome)

  • complete reversal of one or more gene(s)
  • order genes backwards from parent
  • gene is swapped “end to end”
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10
Q

Describe translocation.

A

(multiple non-homologous chromosome)

- chromosome swap one or more gene(s) within same or different chromosome

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11
Q

List large scale mutation effects.

A
  • duplication of multiple genes causes genes to be overexpressed while deletions result in missing or incomplete genes
  • lead to cells that are not viable (cell often dies)
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12
Q

What is a fusion protein?

A
  • gives cells a growth advantage, leading to tumors
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13
Q

Define aneuploidy.

A

Improper no. chromosomes in cell

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14
Q

Define autosomal aneuploidy.

A

abnormal no. autosomal chromosomes in cell e.g. 45 or 47

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15
Q

Define sexual aneuploidy.

A

abnormal no. sex chromosomes (monosomy = 1, trisomy = 3)

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16
Q

Define non-disjunction.

A

pair of chromosomes that fail to separate

17
Q

Considering non-disjunction, how doe sexual aneuploidy and autosomal aneuploidy occur?

A

Sexual aneuploidy results from non-disjunction in meiosis I and II. Autosomal aneuploidy results from non-disjunction (chromatids) mitosis

18
Q

What is a karyotype?

A
  • display of total complement of a species’ chromosomes
  • indicates no. and visual appearance of the chromosomes in cell nuclei
  • taken during mitotic metaphase with chemical interruption of anaphase
  • cell ruptured and photographs taken
  • photos examined based on centromere position, length of chromatid arms and then matched with pairs
  • anomalies then detected
19
Q

What causes mutations?

A

Mutagens -> physical or chemical agent that changes genetic material of an organism

20
Q

List examples of physical, chemical, heavy metal and biological causes of mutations.

A

Physical

  • X-rays
  • radioactive decay
  • solar radiation

Chemical

  • asbestos
  • benzopyrene
  • boric acid

Heavy metal

  • lead paint
  • nickel-cadmium batteries

Biological
- viruses