TOPIC 2 - Central Dogma : DNA Relplication, Transcription, Translation

Question 1

What is the Central Dogma of Molecular Cell Biology?

Answer 1

Concept that Genetic Information FLOWS from DNA to RNA to Proteins.

Question 2

DNA Replication

Answer 2

Process of producing 2 identical replicas from 1 original DNA molecule. This biological process occurs in all living organisms and is the basis for biological inheritance. DNA is made up of 2 strands and each strand of the original DNA molecule serves as a template for the production of the Complementary strand, a process referred to as semiconservative replication. Cellular proofreading and error-checking mechanisms ensure near perfect fidelity for DNA replication.

Question 3

RNA Transcription

Answer 3

Synthesis of an RNA molecule from a DNA template

Question 4

mRNA Processing

Answer 4

Protein Processing ?

Question 5

Protein Translation

Answer 5

Synthesis of Polypeptide chain from mRNA Template.

Question 6

DNA Polymerase

Answer 6

Catalyzes DNA Synthesis.

Question 7

What is the REACTION Catalyzed by DNA Polymerase?

Answer 7

ALL (known) of this type of Enzyme ADD a Deoxyribonucleoside 5’-Triphosphate to the 3’-Hydroxyl group of a growing DNA chain (the Primer strand; see Fig 6.1).

Question 8

ALL known DNA Polymerases share 2 Fundamental Properties w/ Critical Implications for DNA Replication. What are these Properties?

Answer 8

(1st) . ALL Polymerases Synthesize DNA only in the 5’ to 3’ direction, ADDING a dNTP to the 3’-Hydroxyl group of the Growing chain.
(2nd) . DNA Polymerases can ADD a New Deoxyribonucleotide ONLY to a Pre-formed Primer Strand that is H-bonded to the Template.

Question 9

Can DNA Polymerase initiate DNA synthesis de novo by catalyzing the Polymerization of Free dNTPs.

Answer 9

NOPE!

DNA Polymerase CANNOT initiate DNA Synthesis by Catalyzing the Polymerization of Free dNTPs.

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Question 10

Replication Fork

Answer 10

Region of DNA synthesis where Parental Strands separate & 2 new Daughter Strands Elongate.

Question 11

Okazaki Fragments

Answer 11

Short DNA segment synthesized to Form the Lagging Strand of DNA.

Question 12

DNA Ligase

Answer 12

Enzyme that SEALS Breaks in DNA strands.

Question 13

Leading Strand

Answer 13

Strand of DNA synthesized CONTINUOUSLY in the direction of movement towards Replication Fork.

Question 14

Lagging Strand

Answer 14

Strand of DNA synthesized OPPOSITE to the direction of the movement of Replication Fork by LIGATION of Okazaki Fragments.

Question 15

Primase

Answer 15

RNA Polymerase used to Initiate DNA Synthesis

Question 16

Exonuclease

Answer 16

Enzyme that Hydrolyzes DNA molecules in either the 5’ —> 3’ or 3’ —> 5’ direction,

Question 17

RNase H

Answer 17

Enzyme that Degrades the RNA strand of RNA-DNA Hybrid molecules.

Question 18

Helicases

Answer 18

Catalyze the UNWINDING of Parental DNA, COUPLED to the Hydrolysis of ATP, ahead of the Replication Fork

Question 19

Single-Stranded Binding Proteins

SSBPs

Answer 19

Proteins that STABILIZES unwound DNA by Binding to Single-Stranded regions.

Question 20

Topoisomeras

Answer 20

Catalyze the REVERSIBLE Breakage + Rejoining of DNA strands.

Question 21

SUMMARIZE: The Fidelity of Replication

Answer 21

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Question 22

Proofreading

Answer 22

One of Major Mechanisms responsible for Accuracy of DNA Replication (activity of DNA Polymerase).

Question 23

SUMMARIZE: Origins & the Initiation of Replication

Answer 23

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Question 24

Origins of Replication

Answer 24

Specific DNA sequence that serves as Binding site for Proteins that Initiate the Replication process.

Question 25

Figure 6.3 - Replication Origins in Eukaryotic Chromosomes.

Answer 25

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Question 26

Autonomously Replicating Sequences

ARSs

Answer 26

Origin of DNA Replication in Yeast

Question 27

Origin of Replication Complex

ORC

Answer 27

Req’d for the Initiation of DNA Replication @ Eukaryotic origins.

Question 28

SUMMARIZE: Telomeres + Telomerase: Maintaining the Ends of Chromosomes

Answer 28

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Question 29

Telomeres

Answer 29

Repeat, Simple-sequence DNA that Maintains the Ends of Linear Chromosomes.

Question 30

Telomerase

Answer 30

Is a REVERSE Transcriptase that Synthesizes Telomeric repeat sequences at the Ends of Chromosomes FROM its OWN —> RNA Template.

Question 31

Reverse Transcriptase

Answer 31

DNA Polymerase that USES an RNA Template.

Question 32

What is Reverse Transcription?

Answer 32

The Synthesis of DNA from an RNA Template

Question 33

Semiconservative Replication

Answer 33

Process of DNA Replication in which 2 Parental Strands separate + serve as Templates for 2 new progeny strands.

Question 34

Nucleosome

Answer 34

Basic Structural unit of Chromatin consisting of DNA wrapped around a Histone Core