Mutations 2 Flashcards

1
Q

What are the types of mutations in terms of cell type?

A

Germ line/hereditary

Somatic

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2
Q

What type of cells are affected by germ line mutations?

A

Sperm

Eggs

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3
Q

What type of cells are affected by somatic mutations?

A

Body cells

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4
Q

Are germ line mutations or somatic mutations passed on to offspring?

A

Germ line mutations

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5
Q

Germ line mutations that have passed on to the offspring affect which cells of the offspring?

A

All of them!

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6
Q

Are DNA replication errors or transcription errors more common? Why?

A

Transcription errors

RNA polymerase doesn’t proof-read like DNA polymerase does

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7
Q

Do DNA replication errors or transcription errors have shorter-term effects? Why?

A

Transcription errors

  • Not all copies of RNA will contain errors
  • RNA molecules not inherited
  • RNA molecules quickly degraded
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8
Q

Germ line mutations in mitochondrial DNA that have passed on to the offspring affect which organs the most? Why?

A

Brain
Heart
Muscles

Because require most energy

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9
Q

What are the symptoms and signs of mitochondrial disease?

A

Dementia

Heart disease

Muscle weakness, wasting

Hearing loss

Abnormalities of vision

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10
Q

What type of mutation builds up in mitochondrial DNA? Why?

A

Somatic mutations

because mitochondrial DNA has limited ability to repair itself

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11
Q

What is a build up of somatic mutations in mitochondrial DNA associated with?

A

Ageing

Age-related disorders

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12
Q

What are some examples of age-related disorders?

A

Neurodegenerative diseases

Heart disease

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13
Q

What are the types of mutations in terms of heridity?

A

Spontaneous

Inherited

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14
Q

What are spontaneous mutations?

A

Newly arising mutation

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15
Q

What is an inherited mutation?

A

Mutation carried from parents to offspring

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16
Q

If a cell has trisomy for a chromosome that contains genes which slow down growth, what may this lead to?

A

Cell death

17
Q

If a cell has trisomy for a chromosome that contains genes which increase growth, what may this lead to?

A

Uncontrollable cell growth and division

leading to cancer

18
Q

What is a primordial follicle?

A

Primary oocyte surrounded by squamous epithelium

19
Q

How do numbers of primary oocytes change with age?

A

Decrease signifiantly from birth to puberty

20
Q

By what process are primary oocytes decreased in number from birth to puberty?

21
Q

How does the mutation rate change with age? Why?

A

Increases with age

  • Spermatogonium been exposed to mutagens for longer
  • Primary oocytes spent longer in meiosis arrest
22
Q

Is the mutation rate in male or female gametes higher? Why?

A

Male gametes

  • More mitotic divisions in spermatogenesis than oogenesis
  • Spermatogonium continue dividing by mitosis throughout life
23
Q

The IVF embryo mutation rate is higher or lower than in vivo rate? Why?

A

Higher

No selection of fittest sperm to fertilise egg as occurs in vivo

24
Q

Why do primary oocytes decrease in number from birth to puberty?

A

Have defective genomes

Dying primary oocytes act as nurse cells for surviving primary oocytes

25
What would happen to an embryo if it was exposed to mutagens?
Teratogenesis Death
26
What are the conditions of a germ line mutation to be inheritable?
Must not impair fertilisation Must not impair gamete function Allows production of adult who can reproduce as normal
27
What do recessive mutations generally cause?
Loss of function
28
What do recessive mutations generally affect?
Biochemical pathways
29
What do dominant mutations generally cause?
Increased function
30
What do dominnt mutations generally affect?
Structure - give structural abnormalities
31
Are most mutations more likely to deactivate a protein or activate it? Why?
Deactivate protein many more ways to do this than to do activate one
32
Why do recessive alleles require the individual to be homozygous to be expressed in phenotype?
Because loss of function can be compensated by other allele being normal no overall effect
33
Why are dominant alleles expressed in phenotype in heterozygous individuals?
Increased function cannot be compensated for by other allele being normal will have an effect
34
What are miscarriages commonly caused by?
Chromosomal abnormalities - structural - numerical