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Molecular Biology > Central Dogma, Continued > Flashcards

Flashcards in Central Dogma, Continued Deck (17):
1

What are the 5 enzymes that are used in DNA replication in order of use?

1) DNA Helicase : unwinds DNA
2) DNA Topoisomerase :relieves supercoil strain on DNA
3) RNA primase: Is a RNA polymerase that adds RNA primer
4) DNA polymerase: adds DNA nucleotides
5) DNA Ligase : ligates Okazaki fragments together

2

What is the overall process of DNA replication?

Replication starts when Helicase unwinds the DNA at a spot where the origin of replication is

Topoisomerase relieves strain by cutting the DNA which was supercoiled.

RNA primase adds primer on the leading strands on each "side" of the origin

DNA polymerase then starts adding nucleotides to the complementary strand.

On lagging strand, RNA primase has to constantly add new primers as the strand is elongating. DNA polymerase does its job too in gap sequences.

Afterwards, Ligase "glues" together the strands in the lagging strand

3

In prokaryotes, why is another name for "DNA Replication"?

Theta Replication

4

In prokaryotes, what are the 5 types of DNA polymerases and their functions?:

DNA polymerase 3:
Is a very fast polymerase with very high processivity.
It is the main polymerase used in replication
Has a 5'-3' replication and 3'-5' exonuclease activity
has no known function for DNA repair

DNA polymerase 1:
is a slower polymerase
Has a 5' -3' replication and 3'-5' exonuclease activity, and 5'-3' exonuclease activity which removes the primer
Functions in Excision repair pathway

DNA polymerase 2:

5' to 3' polymerase and a backup to DNA pol 3
is involved in DNA repair

DNA pol 4 and 5
error prone 5' to 3' activity
involved in DNA repair

5

What is a core difference in origin of replication between Eukaryotes and Prokaryotes?

Eukaryotes have multiple origins of replications.

6

What is a unique problem that Eukaryotic DNA comes to face towards the end of replication?

The ends of the lagging strand cannot be replicated fully, as towards the end, there is nowhere to put in the last primer to do the last DNA polymerase activity.

This causes there to be shortened strands in the end.

7

What is one way to work around the problems of having shortened telomeres in the end of DNA replication?

You have telomerase activity that uses it's reverse transcriptase activity and built in RNA primer, template for TTAGGG, and reverse transcriptase activity that can add ends to the cells.

8

What are some differences between DNA and RNA?

1) RNA uses Uracil vs. Thymine
2)You have more than 1 kind of RNA, in fact you have 5 types of RNA

9

What are the 5 kinds of RNA and what is their purpose?

The 5 kinds of RNA are
1) mRNA( precursor to proteins)
2) rRNA (makes up Ribosomes)
3) tRNA (carries amino acids)
4) hnRNA (pre-processed mRNA)
5) hiRNA
6) miRNA
4) and 5) are responsible for regulating gene expression

10

What are differences between transcription and translation?

1) Transcription has a stop codon, while translation does not
2) Transcription does not have a primer
3) Transcription does not have editing/ looking for mutations on the RNA transcript

11

What is the strand that is Transcribed called?

The template strand/ the Anti -sense strand

12

What is the strand that is opposite of the transcribed strand?

It is called the coding strand/the sense strand

13

What is the main point of regulation for the translation?

Transcription

14

What are 2 of the main ways that transcription is regulated?

It is regulated by
1) Promoters
2) DNA binding proteins

15

What are promoters? And how do they regulate transcription?

Promoters are RNA polymerase binding domains. they regulate transcription by having relative levels of affinity to RNA polymerase.

16

What are DNA binding proteins? How do they regulate transcription?

DNA binding proteins are proteins which bind to DNA. They regulate transcription by being either enhancers or repressors.

17

What are the differences between prokaryotic and eukaryotic transcription?

Prokaryotic Transcription
1) Polycistrionic
2) Translation and transcription happen at the same time
3) mRNA does not have to be modifies
4) Only one kind of RNA polymerase

Eukaryotic translation
1) Monocistrionic
2) Translation occurs in nucleus, while transcription occurs in the cytosol
3) mRNA has to be processed before being translated
4) 3 types of RNA Polymerase
RNA polymerase 1 : creates rRNA
RNA polymerase 2: creates mRNA
RNA polymerase 3 : creates tRNA