Central Dogma

Question 1

What is “Central Dogma”?

Answer 1

Theory that explains the flow of genetic information

Question 2

Where does transcription take place?

Answer 2

nucleus (eukaryote)

Question 3

When does DNA replication happen?

Answer 3

During Interphase (S)

Question 4

How many origins do eukaryotes have?

Answer 4

multiple

Question 5

How many origins do prokaryotes have?

Answer 5

1

Question 6

What is the enzyme responsible for “building”?

Answer 6

Polymerase

Question 7

What are the polymerases? What is their function?

Answer 7

Polymerase 1: Fills in gaps at Okazaki Fragments
Polymerase 3: Main builder

Question 8

What is the Okazaki Fragments? Why does it happen?

Answer 8

They are fragments of DNA nucleotide at the lagging strand. This happens because polymerase can only build in the 5’ to 3’ direction. I.e. they can only create it in chunks.

Question 9

What enzyme seals Okazaki Fragments and mainly for damage and repair?

Answer 9

Ligase

Question 10

What is exonuclease?

Answer 10

Enzyme that removes RNA primer.

Question 11

What is the helicase?

Answer 11

enzyme that “unzips” the DNA.

Question 12

What enzyme relieves the DNA from tension/stress?

Answer 12

Topoisomerase

Question 13

What protein keeps the strands separated during replication?

Answer 13

Single-Strand binding protein

Question 14

What enzyme makes the primer?

Answer 14

Primase

Question 15

Enumerate the entire process of DNA replication.

Answer 15

1. Helicase UNZIPS DNA strands.
2. Primase make PRIMER. Strands are anti-parallel.
3. Polymerase 3 starts BUILDING. Single-strand binding protein keeps the strands separated. Topoisomerase ease tension (i.e. relaxes supercoiled DNA ahead of replication fork).
4. Leading Strand continuously builds while lagging strand builds in fragments (Okazaki Fragments).
5. Exonuclease removes RNA primase and Polymerase 1 fills in gaps.
6. Ligase seals Okazaki Fragments.

Question 16

Enumerate Protein Synthesis.

Answer 16

1. Transcription (@nucleus): DNA is copied to via RNA polymerase before releasing it outside the nucleus as mRNA.
2. Translation(@ribosome): tRNA reads codons.
3. tRNA has anti-codons which complement the codons. Codons correspond to a specific amino acid.
4. EPA site.

Question 17

What is the start codon?

Answer 17

A-U-G

Question 18

What is the stop codon?

Answer 18

1. UAG
2. UGA
3. UAA

Question 19

What does the codon at the mRNA correspond to?

Answer 19

amino acid

Question 20

What is the mRNA’s role in proteins synthesis?

Answer 20

To get a copy of a DNA gene outside of nucleus since the DNA is too big to get through the nuclear pore.

Question 21

What is the rRNA’s role in protein synthesis?

Answer 21

ensures the attachment of nucleotide at mRNA.

Question 22

What is the tRNA’s role in protein synthesis?

Answer 22

To “transfer” the amino acid that corresponds to the codons.

Question 23

The mRNA has an exon and an intron. What are they?

Answer 23

Exon: coding zone at mRNA.
Intron: non-coding zone at mRNA. This is also where Intron Splicing happens

Question 24

Explain the “EPA site”

Answer 24

This is at the ribosome.
A - “accepts” tRNA
P - tRNA “plugs in” amino acid via reading codon
E - tRNA “exits”

Explanation: tRNA binds then the previous empty one detaches. This will repeat.