MODULE 6:GENETIC CHANGE Flashcards

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1
Q

Define a mutagen

A

an agent such as electromagnetic radiation or chemicals that can cause genetic mutation

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2
Q

Define mutation

A

a permanent change in the nucleotide sequence of an organism’s genome

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3
Q

Give the Effect of electromagnetic radiation, how they operate
Cause:X-Rays and Gamma Rays

A

Effect: classed as ionising radiation because when they strike an atom/mlcle they, ‘bump off’ an eletron leaving an ion

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4
Q

What is the outcome of ionising radiation

A

It can break DNA molecules
Damage bases and cause chromosomal deletion
It also causes cross-linking of DNA to itself and proteins

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5
Q

Give the Effect of electromagnetic radiation, how they operate
Cause:UV light

A

Effect: short wavelength and high energy ways are absorbed by DNA
Which excite adjacent prymidine (C and T) to form covalent bonds

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6
Q

Outcome of UV light exposure

A

pyrimidine dimers to form possible translation and transcription errors

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7
Q

Give the Effect of chemicals and how they operate

Cause: Nitrogen mustard

A

Effect: alkylating agents produce mutations by adding small hydrocarbon groups to either bases or backbone of DNA

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8
Q

Outcome of : Nitrogen mustard

Possible source

A

Bone marrow suppression === anemia

Side effects of chemotherapy

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9
Q

Give the Effect of chemicals and how they operate

Cause: dimethyl nitrosamine

A

removes amine groups from bases such as converting C bases to U and producing mutations

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10
Q

Outcome of dimethyl nitrosamine

Possible source

A

Lung Cancer

Source: produced in the stomach of animals after eating foods containing nitrous acid

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11
Q

Give the Effect of chemicals and how they operate

Cause: proflavin

A

Insert themselves into DNA stretching it and causing frameshift mutations

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12
Q

Outcome of Proflavin

Possible source

A

Tumors

used labs as dyes

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13
Q

Define frameshift mutations

A

mutations that result the way we read codons in mRNA

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14
Q

Give the Effect of naturally occuring mutagens and how they operate
Cause: VIRUS HPV

A

HPV hits the genome, disrupting and rearranging nearby host-cell genes “This can lead to overexpression of cancer-causing genes in some cases, or it can disrupt protective tumor-suppressor genes in others. Both kinds of damage likely promote the development of cancer.”

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15
Q

Outcome of HPV

A

This can lead to overexpression of cancer-causing genes in some cases eg brca gene which can result in Cancer

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16
Q

Give the Effect of naturally occuring mutagens and how they operate
Cause: metals such as mercury

A

can induce chromosomal variation or abnormal cell divisions in animals or plant cells

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17
Q

Outcome of mercury

A

Cancer

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18
Q

Give the Effect of naturally occuring mutagens and how they operate
Cause: Reactive Oxygen Species (ROS)

A

result in mutagens attached to nitrogenous bases as well as DNA strand breaks and crosslinks

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19
Q

What are the different types of point mutations

A

Silent, nonsense and missense, frameshift insertion and deletion

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20
Q

Normal DNA LEVEL: TTC
mRNA LEVEL: AAG
Protein: Lys

Example 
DNA LEVEL:  TTT
mRNA: AAA
protein: Lys
what type of mutation is that ?
A

point mutation, silent mutation

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21
Q

Normal DNA LEVEL: TTC
mRNA LEVEL: AAG
Protein: Lys

Example 
DNA LEVEL: ATC
mRNA: UAG
protein: STOP
what type of mutation is that ?
A

Nonsense point mutation

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22
Q

Normal DNA LEVEL: TTC
mRNA LEVEL: AAG
Protein: Lys

Example 
DNA LEVEL: TCC
mRNA: AGG
protein: Arg
what type of mutation is that ?
A

Missense, point mutation

23
Q

missense is equal to

A

changed amino acid in polypeprtide chain

24
Q

When does chromosomal mutation occur

A

when a cell in undergoing cell division

25
Q

What causes mutations

A

Mutagens

26
Q

What are the four main types of chromosomal mutations

A

Deletion
Inversion
Translocation
Duplication

27
Q

Explain what happens during deletion chromosomal mutation

A

Chromosome breaks and a section of DNA is lost

28
Q

Explain what happens during inversion chromosomal mutation

A

The chromosomal DNA breaks free, reorients and rejoins in the reverse order

29
Q

Explain what happens during translocation chromosomal mutation

A

section of the chromosome breaks off and rejoins the non-homologous chromosome

30
Q

Explain what happens during duplication of chromosomal mutation

A

a section of the chromosome is copied and added

31
Q

When homologous chromosomes pairs fail to segregate during cell division is called

A

non-disjunction

32
Q

What does non-disjunction result in

A

aneuploidy - offspring may have an extra or missing chromosomes

33
Q

What is the difference between germline and somatic mutation

A

Somatic - future generations are not affected

Germline- 50% of the offspring may inherit the disease

34
Q

What are the effects of point mutation

A

New alleles are formed in germline and somatic cells

35
Q

what are the effects of chromosomal mutation

A

Chromosomal mutations cause- abnormalities such as Trisomy 21
Cell death, malfunction and cancer in somatic

36
Q

How significant are DNA mutations in the coding segments of DNA

A

May result in no effect or failure to produce a functional polypeptide

37
Q

How significant are DNA mutations in the coding segments of DNA

A

May have no impact or result in changes in gene expressions eg Huntington’s Disease

38
Q

Define a gene pool

A

A gene pool is a collection of genes within an interbreeding population at a particular time

39
Q

define gene/allele frequency

A

How often different alleles occur in the gene pool of a population is known as the allele frequency
(number yawo haichinje)

40
Q

What causes genetic variation

A

meiosis, fertilisation and mutation

41
Q

What causes allele frequency

A

mutation

42
Q

What increases the gene pool

A

meiosis

43
Q

how does fertilisation cause genetic variation and what is the effect on the gene pool

A

allows new combinations of alleles and natural selection may play a role in selecting fit parents

44
Q

how does meiosis cause genetic variation

A

Random segregation -causes new combinations of chromosomes and hence alleles
crossing over- new combinations along chromosomes

45
Q

how does meiosis cause genetic variation

A

produces new alleles and changes in gene regulation and expression or chromosome number and arrangement

46
Q

Random chance effects on allele frequency in gametes and populations esp if population is smallis the definition for

A

genetic drift

47
Q

Define gene flow

A

movement of genes between populations because of migration == genetic variation

48
Q

What is the effect of mutation on gene pool

A

initially mutation increases the variety of alleles in the gene pool

49
Q

What is the evaluation of mutation on the gene pool

A

most significant change. Mutation impact can be positive, negative or neutral

50
Q

What is the effect of genetic drift on a gene pool

A

Increases or decreases in alleles frequency by chance

51
Q

Evaluate the effect of genetic drift on a gene pool

A

less likely to alter the gene pool

52
Q

What is the effect of gene flow on gene pool

A

increases genetic diversity due to gene flow

53
Q

Evaluation of gene flow on a gene pool

A

Generally positive impact by increasing the diversity of the gene pool