Brainscape's Knowledge GenomeTM

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


See full index

MCBG > DNA + RNA > Flashcards

DNA + RNA Flashcards

1
Q

What is a nucleoside?
What is a nucleotide?
What is the difference between ribose and deoxyribose sugars?

A

Nucleoside: base and sugar
Nucleotide: base and sugar and phosphate group
Deoxyribose: Carbon-2 OH group is replaced by H
Ribose: 2 OH groups on the Carbon-2 and Carbon-3

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

What are the purines and what are the pyrimidines and what is their feature?

A

Purines (2 rings): Adenine and Guanine

Pyrimidines (1 ring): Cytosine and Thymine

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

Which bases form 3 hydrogen bonds and which form 2 hydrogen bonds?

A

3: Guanine and Cytosine
2: Adenine and Thymine

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

Where do major grooves and minor grooves arise?

A

Major: 5’ — 3’ (phosphodiester bonds above:below H-bonds)
Minor: 3’ — 5’ (phosphodiester bonds below:above H-bonds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q 
Define:
Gene
Exons
Introns
Regulatory sequence
A

Gene: Unit of DNA that codes for a protein
Exons: Coding region of DNA
Introns: Non-coding region of DNA
Regulatory sequence: Region on DNA that controls gene expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q 
Define:
Codon
Anticodon
Allele
Telomere
Kinetchore
A

Codon: Sequence of 3 bases on mRNA (Amino Acids)
Anticodon: Sequence of 3 bases on translated protein
Allele: Different form of the same gene
Telomere: Repeated Sequence coding the end of a chromosome (TTAGGG)
Kinetchore: Area on the centromere spindle fibres attach to during prometaphase of cell division

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

Where are the various locations centromeres can be found on chromosomes?

A

Metacentric: middle (50%)
Sub-metacentric: slightly above the middle (60%)
Acrocentric: above the middle (75%)
Telocentric: closer to the telomeres (85%)

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

How is DNA packaged?

A

DNA forms double helix from right-sided twist
DNA coils twice around (positively charged) histones to form Nucleosomes (with linker proteins in between)
Euchromatin (transcriptionally active) stay as histones links
Heterochromatina (transcriptionally inactive) become solenoids of histone

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

What happens to DNA packaging during cell division?

A

During prophase of cell division DNA is super-condensed into X-shaped chromosomes by scaffolding proteins

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

How does chromatin change between euchromatin and heterochromatin?

A

Euchromatin: surrounded by methyl groups (activate DNA)
Heterochromatin: surrounded by acetyl groups (inactivate DNA)
Switch between by methylation and acetylation

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

What are the three ways in which DNA accumulates damage?

A

Defective replication machinery factors (Nucleoside mis-incorporation)
Replication fork progression inhibitors (Fork slippage (can lead to repetitive DNA))
Defective response pathways (Irregular/missing cell cycle checkpoints)

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

Define DNA stress

A

Inefficient replication that leads to the replication fork slowing, stalling or breaking and consequentially further mutations

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

What is the DNA damage response?

How can this lead to cancer?

A

If DNA damage irreparable: senescence or apoptosis
If DNA damage reparable: cell cycle arrest and repair
If these pathways(senescence, apoptosis, arrest, repair) fail cell could become cancerous

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

What are the two types of DNA repair?

A

Double strand break

Mis-match Repair

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

How does double strand break repair work?

A

Non-homologous end joining:
KU70/80 dimer protects the ends of the break
Activates DNA-Pk to bridge the two stands together
Ligase joins the stands
Homology directed repair:
Resection or faulty nucleotides leaving single strand overhangs
Polymerase resynthesises missing/resected strand
Strands re-integrated into homologous pair (can cause crossing-over)

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

What is mis-match repair?

A

Works on single-strand (usually newly synthesised)

Recognition, Excision, Removal, Resynthesis, Ligation

17
Q

How does mutations in the DNA Damage Response lead to cancer evolution?

A

Mutations in the DDR lead to higher number of mutations (greater susceptibility)
Mutations cannot be corrected
Continued mutation accumulation —> heterogenous tumour

18
Q

What happens when a heterogenous tumour is exposed to therapy?

A

Clonal expansion of resistant tumour cells

Therapy induced mutagenecity (DNA damage —> mutations that resist therapy)

19
Q

What are the molecular techniques used to detect DNA nucleotide mutations?

A

DNA sequencing
DNA gel electrophoresis
PCR

20
Q

What are the molecular techniques used to detect DNA gene mutations?

A 
Electrophoresis
Southern blot
Microarray
DNA fingerprinting
Northern blot
Reverse Transcriptase PCR
Gene Cloning
21
Q

What are the molecular techniques used to detect DNA chromosome mutations?

A

Karyotyping

FISH

22
Q

What are the molecular techniques used to detect protein mutations?

A

Electrophoresis
Western blot
Enzyme assays
ELISA

23
Q

How does DNA sequencing work?

A

Sanger-Chain termination:
Dideoxy-NTP’s with fluorescent markers are used to anneal to replicating DNA strand (no elongation of strand - cannot form phosphodiester bonds)
Mixture of strands produced each dd-NTP’s binds at different point resulting in strands of different length
Electrophoresis separates strands and DNA sequence can be read

24
Q

How does DNA gel electrophoresis work?

A

DNA is separated into fragments by endonucleases and placed into a gel (buffered: constant pH)
An electric field is placed over the gel and the fragments move to the anode separating based on their size

25
Q

How does Polymerase Chain Reaction work?

A

DNA strands are separated with extreme heating
Complementary primers form H-bonds with the target sequence (taq-polymerase joins primers)
Strands are cooled and reseal with the primers annealed to the target strand
Repeated with the number of strands of the target sequence doubled each time

26
Q

How does southern blot work?

A

After gel electrophoresis, the DNA fragments are denatured with an alkaline solution (separating strands)
Strands are placed onto a nylon membrane and fluorescent probes complementary to the target sequence are added

27
Q

How does a microarray work?

A

RT-PCR produces cDNA from the case and control
The cDNA are hybridised with different coloured fluorescent probes and superimposed
The colour of the microarray indicates the expression of genes

28
Q

How does DNA fingerprinting work?

A

PCR is used to amplify mini-satellites (non-coding regions in different amounts on different chromosomes)
Southern blot is used to separate the strands (each strand is identical to a maternal or paternal strand)

29
Q

How does Northern blot work?

A

After gel electrophoresis, the RNA fragments

Strands are placed onto a nylon membrane and fluorescent probes (DNA) complementary to the target sequence are added

30
Q

How does Reverse Trascriptase PCR work?

A 
Generates cDNA (single-strand) from mRNA using primer and DNA nucleotides
PCR on the fragment of cDNA will then amplify the sequence
31
Q

How does gene cloning work?

A

Isolate relevant gene from mRNA using endonucleases and insert into a plasmid vector
Plasmid vector is transported to a bacteria that produces relevant protein from the DNA

32
Q

How does karyotyping work?

A

Chromosomes are stained during metaphase and evaluated

Chromosome size, shape and number are compared

33
Q

How does FISH work?

A

Probes for a whole chromosome or gene are introduced in situ and can be visualised

34
Q

How does protein electrophoresis work?

A

SDS: proteins are denatured and separate based on size (toward anode)
Isoelectric focussing: proteins separate based on their Isoelectric point
2D: combines isoelectric focussing and SDS to separate proteins based on their charge and size

35
Q

How does western blotting work?

A

After SDS electrophoresis, proteins are transferred onto a solid support
Antibodies bind to specific protein on one strand and secondary antibodies allow us to visualise where protein strand is

36
Q

How do enzyme assays work?

A

Activity of Enzymes in solution are measured

Rate of change of reaction (Substrate to Product) = amount of gene expression and therefore protein

37
Q

How do ELISA work?

A

Enzyme Linked Immunoassays
Measure the amount of antibodies or antigens in solution
Antibodies and antigens bind to one another
Amount of binding is determined by secondary antibody which also binds but can be detected

38
Q

What properties do probes have?

A

Do not have to be 100% complementary
Do not have to completely align
Do not affect the position of target during electrophoresis

MCBG (9 decks)

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