Molecular Genetics Flashcards
(30 cards)
1
Q
enzymatic tools
A
- restriction endonuclease
- modifying enzymes
2
Q
restriction endonucleases
A
- enzymes that cut double stranded DNA at specific sequences
- cleaves DNA at palindromic recognition sequences = restriction sites
- creates either blunt ends or complementary overhangs
= sticky ends - 2 DNA molecules w/ complementary sticky can form H bonds
3
Q
methyltransferases
A
- catalyse transfer of a methyl group (CH3) to DNA bases
- block restriction sites
- approx 1% DNA bases undergo methylation
4
Q
nucleases
A
- enzymes that randomly cleave nucleic acids
5
Q
deoxyribonucleases
A
- nucleases that cleave single stranded or double stranded DNA
6
Q
endonucleases
A
- cut DNA inside the sequences
7
Q
exonucleases
A
- cut DNA from the extremities
8
Q
ribonucleases
A
- nucleases that’s cut RNA
9
Q
DNA ligases
A
- catalyse formation of covalent phosphodiester bonds between 5’ phosphate of one fragment and 3’ hydroxyl of another
two types: - ATP-dependant
- NAD-dependant
10
Q
DNA polymerases
A
- copy a DNA strand into another DNA strand
- C-ter or N-ter
11
Q
C-ter polymerase
A
- larger fragment
- Klenow fragment
- DNA polymerisation, base extension in the 5’ to 3’ direction
- sequence editing & proofreading
12
Q
N-ter polymerase
A
- small fragment
- 5’ to 3’ exonuclease actiity
13
Q
3 main types of DNA polymerase in bacteria
A
- DNA pol 1 = main enzyme for DNA replication in bacteria, the ones used in PCR
- DNA pol 2 = involved in DNA repair
- DNA pol 3 = involved in DNA replication
14
Q
processivity
A
- no. of nucleotides added to the new strand per second
15
Q
fidelity
A
- rate of errors
16
Q
RNA polymerase
A
- transcribe single stranded DNA to RNA
17
Q
reverse transcriptases
A
- RNA = dependant DNA polymerases
- transcribe single-stranded RNA into single-stranded complimentary DNA
- used mainly by retroviruses
18
Q
eukaryote RNA polymerases
A
- RNA polymerase 1 = large ribosomal RNAs
- RNA polymerase 2 = messenger RNA
- RNA polymerase 3 = transfer RNA & small RNA
19
Q
molecular tools
A
- vectors
- molecular probes
- oligonucleotides
20
Q
biological tools
A
- bacterial cells
- yeast cells
- insect cells
- plant cells
- bacteriophages
- viruses
21
Q
vectors
A
- small DNA molecules having regulatory & coding sequences
- foreign DNA can be inserted into them
- used as carriers of foreign DNA into host cells
22
Q
vector characteristics
A
- origin of replication = replication of vector, with foreign DNA fragment inserted into it
- genetic markers = selection of cells which have been taken up the plasmid DNA
- multiple cloning site = a site where DNA is inserted
23
Q
transfer DNA
A
- transfer a gene into a target genome, vector DNA can be used as a DNA vaccine
24
Q
plasmids
A
- a vector
- double stranded circular bacterial DNA
- used for molecular cloning to amplify or express insert DNA into bacterial hosts
25
phagemids
- DNA cloning vectors
- derived from phage DNA & containing an origin of replication
- used to amplify insert DNA via bacteriophage replication into host cells
26
cosmids
- minimal phage vectors lacking the origin of replication
27
bacterial artificial chromosome /BAC
- large DNA vectors engineered from F plasmid, behaves like chromosome
- used to carry large insert DNA up to 300Kb
- used to create & store genomic libraries
28
yeast artificial chromosome/YAC
- act like real chromosomes in yeast
- can store very long DNA fragments
- used in genomic studies
29
molecular probes
- labelled polynucleotide DNA or RNA fragments
- variable in size
- natural or synthetic
- used for detection of DNA & RNA targets in complex samples
- usually have som fluorescence
30
oligonucleotides
- short sequences
- single strand oglios = used as primers for DNA & RNA amplification
- double strand ogles = used as adapters that are ligated to DNA fragments to facilitate cloning and other applications
