Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Mutations > Flashcards

Mutations Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Aneuploidy

A

○Gain/loss of one or more chromosomes, but not a whole set.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Nullisomy

A

○Loss of a chromosomal pair (2n-2).
○Lethal in early embryogenesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Monosomy

A

○Loss of a single chromosome (2n-1).

○Lethal in autosomes.

○Unmasks recessive lethals & causes haploinsufficiency, where a single recessive allele is not enough for normal function (Klug et al., 2020, pp.152-163).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Trisomy

A

○Gain of a single chromosome (2n+1).

○Addition of a small chromosome can produce viable individuals, but addition of a large autosome has severe effects & can be lethal (Klug, et al., 2020, pp.152-163).

○Causes gene dosage effects (Klug et al., 2020, pp. 153).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give an example of a genetic disorder caused by a monosomy mutation.

A

○45, X Turner syndrome is caused by monosomy (loss) of X chromosome (Klug, et al., 2020, pp.152-163).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Give an example of genetic disorders caused by trisomy mutation.

A

○Trisomy 21: Down syndrome caused by failure of homologous chromosomes to separate during meiosis, producing trisomic condition after fertilisation (zygote has three chromosomes) (Klug, et al., 2020, pp.152-163).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Euploidy

A

○Organism gains the whole haploid chromosome set.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Polyploidy

A

Organism has more than two sets of chromosomes.
This could arise when chromosomes replicate but the cell doesn’t divide, and instead re-enters interphase (Klug, et al., 2020, pp.152-163).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Autopolyploidy

A

Extra chromosome sets are identical to parent species.

Failure of chromosomal segregation produces a diploid gamete (Klug et al., 2020, pp.152-163).
Fertilisation with a haploid gamete forms a zygote which has three sets of chromosomes (Klug et al., 2020, pp.152-163).

Can also be caused by multiple sperms fertilising an ovum (Klug et al., 2020, pp.152-163).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Frameshift mutation

A

○Change in the reading frame of triplets during translation (Klug et al., 2020, pp.361-383).
○Every triplet/protein coded will be incorrect after the frameshift mutation (Klug, et al., 2020, pp.361-383).

○Insertion - addition of a nucleotide (Klug, et al., 2020, pp.361-383).

○Deletion - loss of a nucleotide due to chromosome breakage (Klug, et al., 2020, pp.152-163).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe a genetic disorder caused by deletion mutation.

A

○Cri du chat syndrome is caused by the deletion of a small part of chromosome 5 (Klug, et al., 2020, pp.152-163).

○Several phenotypic effects:
□Anatomic malformations.
□Gastrointestinal & cardiac compilations.
□Abnormal development of glottis & larynx, causing characteristic cat-like cry.
□Intellectual disability (Klug et al., 2020, pp.152-163).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Point mutation/base substitution

A

Substitution of one base pair to another (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe missense mutation and give an example of a genetic disorder caused by this type of mutation.

A

Change in nucleotide changes the coding triplet & so a different amino acid is produced (Klug, et al., 2020, pp.361-383).

Sickle cell anaemia is caused by a mutation which changes base 17 of haemoglobins beta chain from adenine to thymine.
This causes codon 6 to change from GAG to GTG, which produces valine instead of glutamic acid.

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe nonsense mutation.

A

Change in nucleotide changes the coding triplet, but the changed triplet codes for a stop codon, causing protein translation to terminate quicker.

Produces a non-functioning gene product.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the genetic disorder phenylketonuria (PKU).

A

PKU is a metabolic disorder and an autosomal recessive disease (Klug, et al., 2020, pp.361-383).
The mutation occurs at the gene which encodes phenylalanine hydroxylase (Klug, et al., 2020 pp.361-383).
At the 5’-GU splice donor site of intron 12, a guanine base changes to adenine.
This causes the splice machinery to use the intron 11 donor site instead of the intron 12 donor site as it doesn’t recognise the intron 12 donor site anymore.
The mutation inactivates phenylalanine hydroxylase, preventing conversion of phenylalanine to tyrosine (Klug, et al., 2020, pp.361-383).
This results in a build-up of phenylalanine, and so it is converted to other derivatives such as phenylpyruvic acid (Klug et al., 2020, pp.361-383).
However, the derivatives are excreted in the urine more quickly than phenylalanine as they are less efficiently reabsorbed by the kidneys (Klug et al., 2020, pp.361-383).
Increased levels of phenylalanine and its derivatives in the brain causes intellectual disability (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe neutral mutation.

A

Mutation in the noncoding DNA which doesn’t affect gene product or gene expression.

17
Q

What is transition?

A

Transition is when a pyrimidine replaces a pyrimidine, or a purine replaces a purine in a point mutation (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

18
Q

What is transversion?

A

When a pyrimidine replaces a purine, or vice versa, in a point mutation (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

19
Q

Loss-of-function mutations

A

Mutations that decrease or remove the gene products function.

20
Q

Describe recessive loss-of-function mutation.

A

Mutation caused by recessive alleles which results in the decrease of gene products function (Klug, et al., 2020, pp.361-383).

Wild-type allele masks expression of recessive allele, and wild-type phenotype is expressed (Klug et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

21
Q

Describe dominant loss-of-function mutation.

A

Mutation caused by dominant allele which results in the decrease of gene products function (Klug, et al., 2020, pp.361-383).

Mutant phenotype is expressed even if the other allele is wild-type (Klug, et al., 2020, pp.361-383).

The gene product of one allele could be inactive and interfering the gene products of the other allele (Klug et al., 2020, pp.361-383).

Haploinsufficiency, when mutation inactivates one allele, and the other active allele doesn’t produce enough gene products to cause a wild type phenotype (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

22
Q

Give an example of a genetic disorder caused by a dominant loss-of-function mutation.

A

Marfan syndrome is caused by loss-of-function in one copy of fibrillin-1 gene, causing haploinsufficiency (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

23
Q

Gain-of-function mutation.

A

Mutations that increase the gene products function, or cause it to have negative or new functions (Klug, et al., 2020, pp.361-383).
This is due to increased gene expression at high levels or abnormal times or places, due to mutation in regulatory region in gene (Klug, et al., 2020, pp.361-383).
New function can arise from altered amino acid sequence (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

24
Q

Suppressor mutation

A

Mutation which changes or remove the effects of a previous mutation (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

25
Q

Describe intragenic mutations.

A

Mutations occurring in the same gene that had a previous mutation (Klug, et al., 2020, pp.361-383).

For example, converting a frameshift mutation (Klug, et al., 2020, pp.361-383).
If the first mutation was caused by deletion of a base, a second mutation which inserts a base near the first mutation location could change the reading frame back to original (Klug, et al., 2020, pp.361-383).

Restoring a mutated gene products function by coding for a correct amino acid (Klug, et al., 2020, pp.361-383).
For example, changing a mutated codon to another codon which codes for the same amino acid as the original (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

26
Q

Describe intergenic mutation.

A

A mutation occurring elsewhere on the genome, not in the same gene (Klug, et al., 2020, pp.361-383).

For example, first mutation changes structure of protein so it can’t interact with another protein which it normally interacts with, but a second mutation occurs in the other protein which changes its structure, allowing it to interact with the first mutated protein (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

27
Q

Somatic mosaicism

A

A somatic mutation of a cell which occurs very early in development, that could contribute to a large section of an adult organism (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

28
Q

Describe the difference between spontaneous mutations and induced mutations.

A

Spontaneous mutations are caused by alteration of nucleotide sequence of genes that occur naturally (Klug, et al., 2020, pp.361-383).

Induced mutations arise due to the influence of exogenic factors (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

29
Q

What are X-linked and Y-linked mutations, and how do they differ from autosomal mutations?

A

Mutations on the X or Y chromosome respectively (Klug, et al., 2020, pp.361-383).

Autosomal mutations occur in autosomal genes (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

30
Q

Describe the difference between somatic and germ-line mutations.

A

Somatic mutations occur in any body cells except germ cells (Klug, et al., 2020, pp.361-383).

Germ-line mutations occur only in germ cells (Klug, et al., 2020, pp.361-383).

References: Klug, W.S., Cummings, M.R., Spencer, C.A., Palladino, M.A., Killian, D.J. (2020) Concepts of Genetics. 12th rev. edn. Harlow: Pearson Education.

Microbiology (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions