Brainscape's Knowledge GenomeTM

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


See full index

Principles > Genetics > Flashcards

Genetics Flashcards

1
Q

DNA is read and replicated in what direction?

A

5’ to 3’

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

What is the sugar backbone in DNA?

A

Deoxyribose

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

Which base pairs have a stronger bond between them?

A

CG

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

DNA strands bind with proteins to form what?

A

Chromosomes

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

Where does DNA replication take place in the cell cycle?

A

S stage

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

What are different forms of DNA damage?

A

DNA strands breaking, chemical crosslinking (DNA damage), mismatched bases

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

What is mitosis?

A

One diploid parent cell to two identical diploid daughter cells

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

What is meiosis?

A

One diploid parent cell to four haploid daughter cells

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

Where does crossing over occur?

A

Meiosis

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

What is crossing over?

A

Genes segregate independently, even if on the same chromosome

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

What are the differences of RNA compared to DNA?

A

Single stranded, ribose sugar, U instead of T

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

What part of DNA controls if the gene becomes a protein?

A

Promotor

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

Transcription and splicing takes out what part of the DNA?

A

Introns

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

The amount of protein produced is determined by what?

A

Rate of transcription
Rate of splicing
Half life of mRNA
Rate of processing of polypeptide

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

DNA is transcribed to what?

A

Pre mRNA

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

Pre mRNA is spliced to what?

A

mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

mRNA is translated to what?

A

Protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a polymorphism?

A

Any variation in the human genome that has a population frequency of > 1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a mutation?

A

A gene change which causes a genetic disorder, or any heritable change in the human genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the total number of human chromosomes?

A

46

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does it mean if the chromosomal rearrangement is balanced?

A

All the chromosomal material is present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does it mean if the chromosomal rearrangement is unbalanced?

A

There is extra or missing chromosomal material- normally 1 or 3 copies of some of the genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is aneuploidy?

A

Whole extra or missing chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are some ways the chromosomes can become different?

A

Translocations, insertions or deletions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What disease is caused by trisomy 21?

A

Down’s syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What disease is 44 + X?

A

Turner’s syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What disease is 44 + XXX?

A

Triple X

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What disease is 44 + XXY?

A

Kleinfelter’s syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Why is X chromosome aneuploidy better tolerated?

A

X inactivation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How many bases are in the human genome?

A

3 trillion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How many genes are in the human genome?

A

30, 000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are acrocentric chromosomes?

A

Where the short arm doesn’t really matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What does Robertsonian translocation involve?

A

Two acrocentric chromosomes being stuck end to end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What does Robersonian translocation increase the risk of?

A

Trisomy in a pregnancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What does trisomy 14 lead to?

A

Miscarriage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

If a first child has Down’s syndrome, what is the chance of a second child having it?

A

Approximately 1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What increases the risk of having a second child with Down’s syndrome?

A

If Robertsonian translocation is involved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does trisomy 18 give?

A

Edward’s syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Carriers of Robertsonian or reciprocal chromosomes commonly have what problem?

A

Can be infertile or have a lot of miscarriages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Modern culture and staining techniques can detect rearrangements of approximately how many base pairs?

A

5 million or more

41
Q

What is still the method of choice for analysis of very specific regions e.g. to test if a family to see if they have a mutation found in other relatives?

A

Sanger sequencing

42
Q

How does array detect chromosomal imbalance in a patient sample?

A

By comparing the patient DNA with a control sample

43
Q

In microarray, if the patient DNA is flagged up, what does this suggest?

A

Duplication of patient DNA

44
Q

In microarray, if the control DNA is flagged up, what does this suggest?

A

Deletion of patient DNA

45
Q

What technique is used to look for specific micro deletions and also for gross alterations in chromosomal number?

A

Fluorescence in situ hybridisation (FISH)

46
Q

If the DNA probe used in FISH matches a region of DNA in the genetic sequence, what happens?

A

The dye fluoresces

47
Q

If the DNA probe used in FISH does not match a region of DNA in the genetic sequence, what happens?

A

No light is emitted

48
Q

When can FISH only be used?

A

When clinical parameters have defined which region should be analysed

49
Q

What is necessary for PCR amplification and Sanger sequencing to work?

A

Identification of which gene needs to be analysed from the clinical phenotype

50
Q

If aneuploidy is a whole extra or missing chromosome, what is translocation?

A

Rearrangement of chromosomes

51
Q

What happens to acrocentric chromosomes in Robertsonian translocations?

A

Two of them get stuck together

52
Q

What will be the outcome of around 50% of reciprocal translocations?

A

Normal chromosomes or a balances translocation

53
Q

Unbalanced reciprocal translocations have what outcomes?

A

Miscarriage or a dysmorphic, delayed child

54
Q

What is the first line chromosome test?

A

Array CGH

55
Q

What is the treatment for someone with a HER2 amplifications?

A

Monoclonal antibody

56
Q

What is the treatment for someone with a problem with the Philadelphia chromosome?

A

Tyrosine kinase inhibitor

57
Q

How much of the genome is exons?

A

2-3%

58
Q

What type of DNA analysis shows big genetic changes?

A

Array CGH

59
Q

What types of DNA analysis show small genetic changes?

A

PCR, Sanger and next generation sequencing

60
Q

What is the commonest mutation of bases?

A

Cytosine becomes thymine

61
Q

What does a promotor mutation cause?

A

No or little transcription, hence no or little protein

62
Q

What do splice consensus altered mutations affect?

A

Translation

63
Q

What does a base change causing a new stop codon result in?

A

Shortened or absent protein

64
Q

What do nonsense mutations result in?

A

Single point mutation causing early stop codon

65
Q

What do missense mutations result in?

A

Single point mutation causing a different or non-functioning protein

66
Q

What is penetrance?

A

The likelihood of having a disease if you have a gene mutation

67
Q

What does 100% penetrance mean?

A

If you have the mutation, you will definitely have the disease

68
Q

What are types of Mendelian disorders?

A

Autosomal dominant/recessive or X linked

69
Q

In terms of families, how often are autosomal dominant diseases seen?

A

In every generation

70
Q

If one parent is affected with an autosomal dominant condition, what is the chance of a child having it?

A

50%

71
Q

What is the male to female ratio in autosomal dominant diseases?

A

Have the same risk

72
Q

In terms of families, how often are autosomal recessive conditions seen?

A

Often only 1 generation

73
Q

If parents are both carriers, what is the risk of a child having an autosomal recessive condition?

A

25%

74
Q

What is a caveat?

A

A female carrier showing mild features of an X linked condition

75
Q

What causes some female carries to show features of an X linked condition?

A

X inactivation

76
Q

Why does X inactivation occur?

A

Provide gene dosage compensation in females

77
Q

What are single nucleotide polymorphisms?

A

Alterations in DNA sequence which occur every 100-300 base pair

78
Q

How many SNPs are there?

A

Over 10 million possible

79
Q

What are copy number variations?

A

Extra or missing stretches of DNA

80
Q

What is a genetic change in multifactorial disease?

A

Just another risk factor

81
Q

How many genes do monozygotic twins share?

A

About 100%

82
Q

How many genes do dizygotic twins share?

A

About 50%

83
Q

What does P < 0.05 in a statistical test suggest?

A

1 in 20 probability that the data seen has happened by chance

84
Q

What are the 4 types of non-mendelian inheritance?

A

Mitochondrial, mociacism, multi-factorial, imprinting

85
Q

What does DNA methylation lead to?

A

Modification of histones which represses transcription

86
Q

What causes imprinting?

A

DNA methylation

87
Q

Mitochondrial DNA is inherited almost exclusively from who?

A

Mother

88
Q

Are sons and daughters equally affected by mitochondrial inheritance?

A

Yes

89
Q

When do most of the mutations causing cancer occur?

A

Post-zygotic

90
Q

What are driver mutations?

A

Mutations that drive carcinogenesis

91
Q

What are passenger mutations?

A

Incidental mutations which happen because a tumour is unstable

92
Q

How many copies of retinoblastoma must be mutated for a tumour to develop?

A

two

93
Q

Carriers of a BRCA1 mutation have what lifetime risk of cancer?

A

80%

94
Q

What is symptomatic testing?

A

A test to find the cause of a disease in a person

95
Q

What is pre-symptomatic testing?

A

Testing in a patient who has a relative with a mutation

96
Q

When can FISH only be used initially?

A

If the geneticist knows roughly what they are looking for

97
Q

What does it mean if you have more than 36 CAG repeats?

A

At high risk for Huntington’s

98
Q

What does it mean if you have more than 40 CAG repeats?

A

Will definitely develop Huntington’s

99
Q

What does anticipation mean?

A

A genetic disease gets more severe with succeeding generations

Principles (11 decks)

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