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

1
Q

What is the Central Dogma of Molecular Cell Biology?

A

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

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2
Q

DNA Replication

A

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.

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3
Q

RNA Transcription

A

Synthesis of an RNA molecule from a DNA template

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4
Q

mRNA Processing

A

Protein Processing ?

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5
Q

Protein Translation

A

Synthesis of Polypeptide chain from mRNA Template.

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6
Q

DNA Polymerase

A

Catalyzes DNA Synthesis.

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7
Q

What is the REACTION Catalyzed by DNA Polymerase?

A

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).

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8
Q

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

A

(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.

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9
Q

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

A

NOPE!

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

∵ ???

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10
Q

Replication Fork

A

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

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11
Q

Okazaki Fragments

A

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

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12
Q

DNA Ligase

A

Enzyme that SEALS Breaks in DNA strands.

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13
Q

Leading Strand

A

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

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14
Q

Lagging Strand

A

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

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15
Q

Primase

A

RNA Polymerase used to Initiate DNA Synthesis

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16
Q

Exonuclease

A

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

17
Q

RNase H

A

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

18
Q

Helicases

A

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

19
Q

Single-Stranded Binding Proteins

SSBPs

A

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

20
Q

Topoisomeras

A

Catalyze the REVERSIBLE Breakage + Rejoining of DNA strands.

21
Q

SUMMARIZE: The Fidelity of Replication

A

.

22
Q

Proofreading

A

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

23
Q

SUMMARIZE: Origins & the Initiation of Replication

A

.

24
Q

Origins of Replication

A

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

25
Q

Figure 6.3 - Replication Origins in Eukaryotic Chromosomes.

A

.

26
Q

Autonomously Replicating Sequences

ARSs

A

Origin of DNA Replication in Yeast

27
Q

Origin of Replication Complex

ORC

A

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

28
Q

SUMMARIZE: Telomeres + Telomerase: Maintaining the Ends of Chromosomes

A

k

29
Q

Telomeres

A

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

30
Q

Telomerase

A

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

31
Q

Reverse Transcriptase

A

DNA Polymerase that USES an RNA Template.

32
Q

What is Reverse Transcription?

A

The Synthesis of DNA from an RNA Template

33
Q

Semiconservative Replication

A

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

34
Q

Nucleosome

A

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