Intro To Molecular Diagnostics Flashcards

1
Q

What is the central dogma of molecular biology?

A

DNA making RNA and RNA making proteins

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2
Q

An individual’s coded genetic information is hardwired into what?

A

DNA

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3
Q

What is the coded genetic information hardwired into DNA transcribed into?

A

Individual transportable pieces of messenger RNA

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4
Q

What synthesis does mRNA direct?

A

The synthesis of a particular protein based on the code it contains from transcribed genetic material

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5
Q

What is a genotype?

A

The genetic makeup of an individual.

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6
Q

Another way of saying genetic makeup

A

Primary nucleotide sequence

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7
Q

How many alleles if a gene are they! What are their sources?

A

Two. One from mother and ine from father

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8
Q

What do you understand by phenotype?

A

Phenotype is the expressed physical characteristics of a gene product and its biological function

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9
Q

What determines one’s phenotype?

A

Their genotype

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10
Q

Do alterations in genotype change phenotype?

A

They may or may not

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11
Q

What is DNA?

A

Deoxyribonucleic acid that contains genetic material

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12
Q

What is the structure of a DNA?

A

A DNA is a polymer of nucleotides

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13
Q

What does a nucleotide consist of?

A

Deoxyribose sugar
Phosphate residual
Nitrogenous base

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14
Q

What nitrogenous bases are seen in DNA?

A

A - Adenine
G - Guanine
T - Thymine
C - Cytosine

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15
Q

Identify the two bonds a DNA polymer is assembled by?

A

Intra-strand phosphodiester bond

Interstrand hydrogen bond

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16
Q

What is the purpose of intra-strand phosphodiester bond in assembling DNA polymers?

A

It links the 5’ phosphate group of one nucleotide with the 3’ hydroxyl group of the next nucleotide creating the DNA polymers sugar phosphate backbone

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17
Q

What bond is responsible for the sugar phosphate backbone of a DNA polymer?

A

Intra strand phosphodiester bond

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18
Q

What is the purpose of interstrand hydrogen bonds in assembling DNA polymer?

A

It gives DNA it’s helical conformation by joining A to T bases with 2 hydrogen bonds and G to C bases with 3 hydrogen bonds

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19
Q

How is RNA different in structure from DNA?

A
  • RNA has ribose sugar structure

- Exists in a single strand folded into complicated 3-D structure for function and integrity

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20
Q

What are the nitrogenous bases seen in RNA?

A

A - Adenine
U - Uracil
C - Cytosine
G - Guanine

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21
Q

How does RNA differ from DNA in terms of nitrogenous bases?

A

DNA has thymine that RNA doesn’t and RNA has uracil that DNA doesn’t.

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22
Q

How many pairs of chromosomes are there?

A

23 pairs, 46 chromosomes in total.

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23
Q

With the help of what are chromosomes highly condensed?

A

With the help of associated structural proteins, mainly histones.

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24
Q

What is chromatin?

A

Nuclear DNA in conjugation with associated structural proteins

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25
Q

Define a nucleosome.

A

The basic level of chromatin organization called beads on a string

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26
Q

In what phase are chromosomes in their most compact state?

A

Metaphase

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27
Q

How should DNA be during replication and gene transcription?

A

Unpacked

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28
Q

What are the 3 purposes of chromatin?

A
  • Fit long strands of DNA in nucleus
  • Protect delicate DNA from damage
  • Inactivation of genes
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29
Q

Is DNA replication conservative?

A

No, semi conservative

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30
Q

What does is the semi-conservative feature of DNA replication?

A

Each new dsDNA consists of 1 parent strand (template) and 1 daughter strand (new)

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31
Q

DNA replication is coordinated by?

A

Several DNA-binding proteins and emzymes

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32
Q

What enzyme separates the two strands of DNA?

A

Helicase

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33
Q

What is the function of the helicase?

A

Seperating the two strands of DNA

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34
Q

What enzyme participates in the underwinding of DNA?

A

Topoisomerase

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35
Q

What is the function of topoisomerase in DNA replication?

A

It underwinds DNA

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36
Q

How does ss-binding proteins help in DNA replication?

A

By preventing reannealing of ssDNA

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37
Q

What protein prevents reannealing of ssDNA?

A

Single stranded binding protein

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38
Q

What is DNA polymerase?

A

It is the enzyme that synthesizes nucleotides and links them based on template strands

39
Q

What is the rate at which DNA polymerase synthesizes nucleotides linking them based on template strands?

A

1000/s

40
Q

What is the primase in DNA replication?

A

The enzyme on lagging strand that synthesizes a starting nucleotide primer for Okazaki fragments

41
Q

DNA polymerase only synthesizes DNA from what prime ends?

A

5’ to 3’

42
Q

From what end to what end is the lagging strand?

A

3’ to 5’

43
Q

In the lagging strand, how can DNA be synthesized since it is from 3’ to 5’ and DNA polymerase synthesizes from 5’ to 3’?

A

DNA must be synthesized discontinuously in short segments

44
Q

What is the function of the ligase?

A

Enzyme on lagging strand linking Okazaki fragments together

45
Q

What the most important feature in DNA replication?

A

Integrity

46
Q

What are mutations in DNA replication?

A

Mutations are errors in nucleotide formation.

47
Q

What property does DNA polymerase have that helps counteract the mutations that happen in replication?

A

Exonuclease activity

48
Q

What does the exonuclease activity of DNA polymerase achieve?

A
  • Recognizes and cuts out wrong nucleotide. (Proof-reading)
49
Q

How are mutations reduced after proof reading function of DNA polymerase?

A

One nucleotide error happens every 10^5 nucleotide incorporated, but with proof reading of DNA polymerase, one error happens per 10^9/10 nucleotides replicated

50
Q

How many errors are seen per cycle after proof reading?

A

0.3 to 3

51
Q

Why are mutations dangerous?

A

Mutations of important genes like GI,or surprises or genes or proto-oncogenes may lead to cancer

52
Q

What cells are prone to grow cancer? And why?

A

Cells with increased exposure to carcinogens. They have a high turnover rate, so more cell cycles and more chance for errors to happen

53
Q

What is PCR?

A

Polymerase chain reaction. An artificial replication technique that is fast and inexpensive used to copy and amplify specific DNA fragments

54
Q

This fast and inexpensive technique is used to copy and amplify specific DNA fragments.

A

PCR

55
Q

What are the components in PCR system?

A

DNA polymerase
Primers
dNTPs

56
Q

What component of the PCR systems makes it require high levels of heat to function?

A

DNA polymerase which is heat resistant

57
Q

What are primers in PCR and what is their use?

A

Short, manufactured single strings of nucleotides used to define a specific DNA segment for amplification

58
Q

What is the use of dNTPs?

A

Nucleotide building blocks used to synthesize new DNA

59
Q

How many cycles does the PCR system have? How many steps?

A

30-40 cycles. 3 steps

60
Q

Describe the three steps in PCR?

A

Denaturation: separating double strand at high temp (94-98)
Annealing: primers binding to single strand template (50-65)
Extension: DNA polymerase makes new DNA strands (70-80)

61
Q

What is the end product of PCR?

A

Large amount f specific DNA fragments of target

62
Q

What is the difference between DNA and protein that calls for transcription?

A

DNA stored genetic information but protein carries out the function

63
Q

How is RNA necessary for transcription?

A

RNA is a necessary intermediate messenger carrying specific instructions to the factories that synthesize proteins

64
Q

Define transcription.

A

Transcription is the provess of transferring sequence information from DNA to RNA

65
Q

How is transcription initiated?

A

Transcription starts by binding transcription factors to promoter regions

66
Q

What are promotors?

A

Regulatory region of a gene where transcriptional factors bind to activate gene transcription

67
Q

What is the regulatory region of a gene where transcription factors bind to activate gene transcription?

A

Promoter region

68
Q

What are transcription factors?

A

Series of protein cofactors that bind to promotors and RNA polymerase II and start transcription from DNA to mRNA

69
Q

What is the difference between an exon and intron?

A

An exon is the coding region of a gene that contributes to AA sequence while an intron is the no coding sequence between exams of a gene

70
Q

What is the expressed sequence of a gene

A

Exon

71
Q

What is the intervening sequence of a gene?

A

Intron

72
Q

The 5’ end of RNA is modified with what!

A

A protective cap

73
Q

What does the cap do aside replacing the 5’ end of RNA?

A

Initiates recognition and protein synthesis later on

74
Q

The 3’ end of RNA is modified by addition of what?

A

Multiple adenine bases. Poly (A) tail

75
Q

What is the necessity of the poly (A) tail I’m mRNA transcripts?

A

Translation and protecting mRNA from degradation

76
Q

What us RNA slicing?

A

This is the process of converting a newly transcribed RNA (pre mRNA) into a mature mRNA

77
Q

In what process are intron sequences sequences removed and exon sequences connected together?

A

RNA splicing

78
Q

What does a mature RNA consist of?

A

5’ cap
3’ poly (A) tail
Spliced sequence

79
Q

What is translation?

A

It is the process in which mRNA sequences direct the amino acid sequences to synthesize proteins

80
Q

Where does translation take place?

A

On ribosomes (rRNA) using tRNA to match mRNA

81
Q

A codon is a how many nucleotide sequence?

A

3 nucleotide sequence a

82
Q

Each amino acids have how many codons!

A

At least one

83
Q

What is the initial codon where protein synthesis begins?

A

AUG

84
Q

Identify the stop codons

A

UGA
UAG
UAA

85
Q

Specific amino acids are delivered to mRNA by

A

tRNA

86
Q

What are genetic events related to?

A

Changes in actual DNA sequences

87
Q

Identify some genetic events

A

Gene mutation
Translocation
Deletions etc

88
Q

Epigenetic events are related to what?

A

Processes that don’t alter DNA sequences but still have effects in gene function

89
Q

What is the difference between genetic and epigenetic events?

A

In genetic events, there’s actual change in DNA sequence but in epigenetic events, processes alter gene function without a,tearing DNA sequence

90
Q

List some epigenetic events

A

DNA methylation
Histone modification
ncRNA regulation (non-coding RNA)
Chromatin remodeling

91
Q

These events affect the access to genetic code without affecting genetic code itself

A

Epigenetic events

92
Q

What is DNA methylation?

A

A biological process by which methyl groups are added to a DNA molecule by binding it to cytosine

93
Q

How does DNA methylation inhibit transcription?

A

Methylated cytosine prevents binding of RNA polymerase II to get access to DNA sequence