Molecular techniques Flashcards

(52 cards)

1
Q

How can the sample affect the DNA/RNA purification method

A

Some tissues are easy to access with high RNA/DNA content, some tissues have high protein/fat content, some DNA sources affect the quality of DNA/RNA (faecal and urine samples)

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

What are the 5 major steps in studying DNA and RNA

A

Sample selection, extraction/purification, amplification, analysis, interpretation

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

Why is sample selection of DNA and RNA important (2 reasons)

A

DNA/RNA can vary between tissues and the sample can affect the extraction/purification method

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

Why is DNA extraction and purification important

A

DNA must be isolated and purified from source material contaminants e.g. RNA, proteins, fats

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

What is the DNA extraction/purification steps (5)

A

Break up source, break open cells, separate DNA, purify DNA, stock for analysis

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

What is Isolation/amplification of a target extracted DNA sample

A

Analysis off a particular part of DNA by PCR and visualisation, quantitative PCR and cloning

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

What is PCR

A

The amplification of a specific region/gene of DNA from the DNA pool

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

What is included in the PCR mix

A

Template, primer, nucleotides, polymerase, buffer

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

What happens in the denaturation stage of PCR

A

DNA template strands are opened

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

What happens in the annealing stage of PCR

A

Primers bind to region of interest

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

What happens in the extension stage of PCR

A

Region of interest is copied (polymerised)

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

Why does PCR have an exponential increase

A

Copies of DNA doubles each time until limited by nucleotides

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

At what temperature does denaturation occur in PCR

A

94

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

At what temperature does priming occur in PCR

A

55 >68

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

At what temperature does extension occur in PCR

A

72

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

What is DNA visulisation

A

Visualisation of stained DNA through a gel matrix where DNA is separated by size and pulled through a porous medium (agarose) by an electrochemical gradient

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

What does almost every DNA/RNA based technique begin with

A

PCR

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

What is PCR used for

A

Preparation of DNA for sequencing for medical diagnosis, DNA fingerprinting and paternity testing

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

When is quantitative PCR used

A

If we want to measure the amount of nucleic acid in given sample

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

What is quantitative PCR

A

Extremely sensitive real time monitoring of PCR amplification using fluorescent dyes which counts DNA molecules/measures copies of DNA

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

How is DNA quantity assessed in quantitative PCR

A

As reaction progresses using a DNA labelling dye,

22
Q

What are the practical applications of quantitative/ qPCR

A

Anything where DNA abundance is of interest e.g. copy number variation to measure the amount of a specific DNA molecule such as to detect chromosomal abnormalities

23
Q

How is the effect of mutation or a specific gene studied

24
Q

What is DNA cloning

A

Recombinant DNA technology

25
What are the 3 steps of DNA cloning
1) DNA target is inserted into plasmid 2) plasmid is transferred into a host organism 3) host organism replicates the target DNA
26
What is a plasmid
Small piece of DNA that contains the genes necessary to replicate or express the DNA target
27
What are the 3 practical applications of DNA cloning
Biological factory for bulk production of DNA/RNA/protein Study of the expression of a target in other organisms to understand it’s function (transgenic) To give an organism a new trait/feature e.g resistance crops
28
What 4 processes are involved in analysis of extracted/purified and amplified DNA
Sanger sequencing, gene expression, metagenomics and next generation sequencing
29
What is DNA sequencing
Visualisation and determination of DNA sequence, analysis of exact sequence of DNA you’re observing to detect variations using chain termination
30
Describe DNA sequencing
standard PCR mix and 2 types of nucleotide (DNTPs and diDNTPs) are used to synthesise every possible length of PCR product with a dye label as when diDNTP is incorporated (labelled nucleotide) the chain is terminated
31
What is the difference between Deoxyribosenucelotides and Di-deoxyribosenucelotides
DNTPS can bind to the next base pair in the DNA chain, diDNTPS are dye labelled and cannot bind to the next base pair in DNA as have a H instead of OH group on C3
32
What are the practical applications of DNA sequencing
Diagnostic testing for disease, forensics, paternity testing, public health/viral and infection tracing
33
How are the products of DNA studied (what is expressed)
RNA arrays ans RNAseq
34
What is a micro array
Simultaneous analysis of thousands of genes in one experiment
35
What are the 4 steps of a micro array
1) RNA is extracted and converted to stable cDNA 2) cDNA is loaded onto an array with many probes for different genes 3) cDNA can bind to each probe 4) Successful binding release a fluorescent signal, signal intensity =amount of cDNA/RNA (genes are present in sample and can be quantified)
36
What is RNA sequencing
Alternative to array expression analysis to record the RNA sequence and amount in a sample
37
What are the 4 steps of RNA sequencing
1) RNA is extracted and converted to cDNA 2) cDNA molecules are fragmented into smaller parts and sequenced many times 3) Each fragments is aligned to a reference 4) amount of fragment is equal to amount of RNA in sample
38
What are the practical applications of arrays and RNAseq
Study of transcriptomics (assigning function to genetic variation), studying the effect of a mutation on different cells/tissues
39
What is next generation sequencing
The study of all DNA in a sample at the same time
40
What is whole genome sequencing
Sequencing of introns and exons
41
What is whole exome sequencing
Exons only
42
Describe the 4 steps of next generation sequencing
1) DNA is sheared into smaller fragments 2) exaggerated fragment is sequenced (only exons in whole exome sequencing using probes and arrays) 3) software aligns each fragment to a reference version of genome 4) comparisons are made between sample and reference to identify changes
43
What are the practical applications of next generation sequencing
Diagnostic testing for disease (unbiased as all genes), novel gene identification, personalised medicine
44
What is the difference between NGS and DNA sequencing
NGS is faster, on a larger scale and more economical
45
What is Metabiomics
Studying DNA that isn’t ours (microbiomics)
46
What is metabiomics used for
To study the DNA of the gut microbiome
47
What type of sequencing is used in metabiomics
Next generation sequencing
48
What 4 steps are involved in metabiomics
1) sample microbes from source (skin, gut etc.) 2) extract DNA and sequence by NGS to determine Volans number of different microbes in sample 3) microbial abundance= sequence amount 4) analysis
49
What are the two types of analysis used to metabiomics
Taxonomy profiling and functional profiling
50
What is taxonomy profiling
Comparing what should be present to what is present
51
What is functional profiling
Comparing what is there under different conditions e.g, diet changes, disease
52
What are the practical applications of metabiomics/microbiomics
Microbiome in human health, disease, infection, drug discovery, agriculture, agrifood, environment, veterinary