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Life Science > Mutations > Flashcards

Mutations Flashcards

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Biology 101 flashcards
1
Q

What are mutations?

A

Any change in the genetic composition of an organism.

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2
Q

Why does a mutation occur

A

-could occur by chance
-could occur as a result of mutagens

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3
Q

What are mutagens

A

-physical or chemical agents that cause mutations.

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4
Q

When can gene mutations be transferred to children

A

Only mutations that occur in the sexual organs can be passed on

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5
Q

What are the 2 types of mutations

A

-Gene mutations
-chromosomal mutations

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6
Q

What are gene mutations?

A

-A change in the nucleotide sequence

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7
Q

When can gene mutations occur?

A

They can occur during:
- DNA replication
- Transcription of DNA and RNA
- Crossing over during prophase of meiosis

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8
Q

What are the four types of gene mutations?

A

-Substitution
-deletion
-insertion
-inversion

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9
Q

A change in the nucleotide sequence.
As a result…

A

As a result the code for protein synthesis changes and forms a faulty protein.

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10
Q

What happens in substitution?

A

-One nitrogenous base is replaced by another
-results in the alterations of one amino acid
-point mutation

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11
Q

What happens in deletion?

A

-one or more nitrogenous bases are lost
-results in a frame shift
- all base triplets are altered and consequently all the amino acids are

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12
Q

What happens during insertions?

A

-one or more nitrogenous bases are inserted
-all base triplets are altered and consequently also the amino acids.
-frame shift

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13
Q

How does a chromosomal mutation occur?

A
  • it occurs when Meiosis doesn’t proceed properly which results in changes in one chromosome number or structure.
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14
Q

What is Aneuploidy?

A
  • extra chromosomes or missing chromosomes in a cell.
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15
Q

Give examples of Aneuploidy.

A
  • Down syndrome - 47 chromosomes.
  • Turner Syndrome - only one sex chromosomes (XO)
  • Klinefelter syndrome- extra sex chromosomes (XXY)
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16
Q

How does Down syndrome occur?

A

Occurs during the production of eggs during Meiosis when chromosomes number 21 doesn’t separate during Anophase 1

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17
Q

What is a zygote?

A

It is a fertilised egg cell that is formed when a female gamete and a male gamete join.

18
Q

What is trisomy 21?

A

A genetic chromosome 21 disorder causing developmental and intellectual delays.

-Also known as Down syndrome.

19
Q

What are the characteristics of Down syndrome? (9)

A
  • small almond eyes
  • ears situated lower down the head
  • flat forehead
  • short, stubby toes
  • poor muscle tone
  • flat nose bridge
  • large tongue
  • predisposed to heart disease
  • mental retardation
20
Q

What is the Maternal Age Effect?

A
  • After the age of 35 the risk of complications like miscarriage, congenital disorders and high blood pressure.
21
Q

What gender does the turner syndrome effect and what happens with the chromosomes?

A
  • effects the development of females
  • only one X chromosome (XO)
22
Q

How many people develop turner syndrome?

A

1 out of 40 zygotes develop turner syndrome

23
Q

What are the characteristics of turner syndrome? (7)

A
  • abnormal growth - short in stature
  • lack of female secondary sexual characteristics.
  • sterile
  • slight mental retardation
  • webbed neck
  • heart defects
  • low hairline
24
Q

What are Somatic Mutations.

A

They are mutations that occur in body cells and are not transmitted to the next generation. It can cause cells to become malignant.

25
Q

Definition malignant.

A
  • Cancerous
26
Q

What gender does klinerfelter syndrome effect.

A

Males
- it causes men to have 2 or more X chromosomes ( XXY )

27
Q

What are the characteristics of Klinefelter syndrome? (5)

A
  • Abnormal development of the Tetris
  • Infertile
  • often tall
  • produce a small amount of testosterone
  • develop some female characteristics
28
Q

What may reduce effects of klinefelter syndrome symptoms?

A

Testosterone treatment may reduce symptoms caused by Klinefelter syndrome.

29
Q

What are Gametic Mutations?

A
  • gametic mutations are mutations that occur in reproductive organs and they produce change in gametes. They are transmitted to the next generation.
30
Q

Examples of reproductive organs. (4)

A
  • ovaries
  • testes
  • anthers
  • embryo sacs
31
Q

Gametic Mutations may lead to…

A

Gametic mutations may lead to hereditary diseases.

32
Q

What are the 3 different types of Gametic Mutations?

A
  • lethal/harmful
  • Beneficial
  • neutral
33
Q

How does a beneficial mutation occur?

A

If the mutation results in organisms adapting better to new or unfavourable conditions, they will survive and reproduce beneficial mutations.

34
Q

What is Nature Selections?

A
  • Nature “selects” the better adapted feature/ability and then this is passed to the next generation until all individual have it.
35
Q

Where do small mutations occur?

A

Small mutations occur in the phenotype

36
Q

What are some examples of beneficial mutations?

A
  • Antibiotics resistant bacteria
  • Peppered Moths in industrial Great Britain
37
Q

What are Neutral Mutations.

A

Mutations that don’t affect the phenotype or they have no survival effect on the organism

38
Q

What are some examples of Neutral Mutations?

A
  • attached vs unattractive earlobes
  • Heterochromia, a mutation that causes two different colored eyes
39
Q

What is an example of Harmful Mutations?

A
  • Albinism
    -colour blindness.
40
Q

Harmful mutations usually have

A

Usually autosomal recessive traits

41
Q

What’s is Heterozygous and homozygous?

A

Heterozygous- having two different versions of a gene.

Homozygous- having two identical versions of the same gene

Life Science (5 decks)

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