Brainscape's Knowledge GenomeTM

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


See full index

BioTech Martin Edwards > Lecture 1 > Flashcards

Lecture 1 Flashcards

1
Q

What are the five broad classes of enzymes?

A

1) Nucleases
2) Ligases
3) Polymerases
4) Modifying enzymes
5) Topoisomers

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

What are the two kinds of nucleases?

A

Exonucleases and Endonucleases

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

What do endonucleases do?

A

Break internal phosphodiester bonds within a DNA molecule e.g. S1 Nuclease

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

What do exonucleases do?

A

Remove nucleases one at a time from the end of a DNA molecule

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

What is the mode of action for nucleases?

A

Degrade a DNA molecule by breaking the phosphodiester bonds that link one nucleotide to the next in a DNA strand.

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

What does RNAseA do?

A

Endoribonuclease that specifically degrades ss RNA

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

What does RNAseH do?

A

Endoribonuclease that digests the RNA of an RNA-DNA hybrid?

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

What is the mode of action for ligases?

A

Catalyses the formation of phosphodiester bond between adjacent 3’-OH and 5’-P termini in DNA

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

What do polymerases do?

A

Synthesise a new strand of DNA complementary to an existing DNA or RNA template.

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

What are the four types of DNA polymerases routinely used in molecular biology techniques?

A

1) DNA polymerase I
2) Klenow fragment DNA polymerase
3) RNA-dependent DNA polymerase
4) Taq DNA polymerase

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

What does DNA polymerase I do?

A

Usually from E.coli and T4 phage

  • DNA dependent
  • Has 5’-3’ action and 3’ to 5’ (so dual function DNA polymerisation and degradation)
  • Commonly used in Nick Translation, Probe preparation, repairing DNA fragments, producing blunt end DNA from sticky end DNA.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does Klenow Fragment DNA polymerase do?

A
  • DNA dependent
  • 5’-3’ polymerase activity
  • 3’-5’ exonuclease activity
  • Can only synthesise a complementary DNA strand on a single stranded template
  • Used in Sanger dideoxy sequencing, filling of 3’ recessed termini created by digeston od DNA with RE/.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does RNA-dependent DNA polymerase do?

A
  • Needs RNA as template
  • 5’-3’ polymerase
  • 5-3’ riboexonuclease
  • 3-5’ exoribonouclease activity
  • used in synthesis of cDNA for cloning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does TaqDNA polymerase do? (PCR enzyme)

A
  • 5’-3’ polymerase activity
  • NO 3’-5’ exonuclease (no proof reading)
  • Widely used in PCR reaction
  • High polymerase activity
  • Latest version of Taq has proofreading activities with higher polymerisation activities.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do DNA modifying enzymes do?

A

Can modify DNA molecules through addition or removal of specific chemical groups.

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

What are the four DNA modifying enzymes?

A

1) Alkaline phosphatase (AP)
2) Terminal deoxynucleotidyl transferase
3) DNA methylases (dam and dcm)
4) Polynucleotide Kinase

17
Q

What does polynucleotide kinase do?

A

Adding phosphate groups on to free 5’ termini

reverse of AP

18
Q

What does AP do?

A

Removes the phosphate group from 5’ terminus of DNA molecule

19
Q

What does Terminal deoxynucleotidyl transferase do?

A

Adds 1 or more deoxynucleotides onto the 3’ terminus of a DNA molecule

20
Q

What does DNA methylase do?

A

Transfer of methyl group to internal A or C residues in the specific sequences to produce methylated duplex DNA.

21
Q

What do class I endonucleases do?

A

Recognise some specific sequences BUT are not useful in gene manipulation since their cleavage site is non-specific.

22
Q

What do class II endonucleases do?

A

They are mg2+ dependant with a highly specific recognition site. Very useful for DNA manipulation

23
Q

What do class III endonucleases do?

A

Recognition site not symmetrical, contain nuclease and methylase activity.

24
Q

What do restriction enzymes do? (Class II endonucleases)

A
  • Cut DNA in a very precise and reproducible manner
  • They cut both strands of DS DNA within a recognition site
  • Hydrolyse sugar phosphate backbone to give 5’-P on one side and 3’-OH on the other = sticky ends.
25
Q

What are isoschizomers?

A

RE that recognise the same sequence, the first example is called a prototype and all subsequent enzymes that recognise the same sequence are called isoschizomers.
Hpall (recognition site C/CGG)
Mspl (recognition site C/CGG) = isoschizomers

26
Q

What are neoschizomers?

A

Recognise the same sequence but cleave at different positions from the prototype.
AatII (GACGT/C)
Zral (GAC/GTC) = neoschizmers

BioTech Martin Edwards (3 decks)

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