Molecular Biology S1 Module 2: DNA and Replication

During DNA polymerase activity, the entry of deoxyribonucleoside triphosphates to the enzyme active site

1

Some bases in DNA are occasionally methylated, typically C in eukaryotes and A in prokaryotes. This provides an additional ‘code’ to the information stored in DNA. How is this code maintained during DNA replication?

1

Which of the following activities is/are never associated with a DNA polymerase?

1

Is there a naturally occurring DNA polymerase that does not require a template? YES OR NO

1

שאלה #57472

		Yes
		No

This question is just nasty - but it does make you think. The enzyme TdT (Terminal deoxynucleotidyl Transferase) catalyses the addition of nucleotides onto 3' DNA ends without any template. It is therefore considered a DNA polymerase. It is found largely in B- and T-cells. Remember it as you learn about lymphocytes in Immunology. Then there is the whole issue of Translesional DNA polymerases. It's a bit of a stretch to consider the contiguous strand sitting under the active site a 'template' if there is no base there. The correct answer is: Yes.

נערך לפני 3 שנים Ido Cohen Lass

מיין לפי

Given the reactants shown, which of the images underneath is the most likely reaction product?

1

שאלה #57473

		1
		2
		3
		4

מיין לפי

Michal Horovitz 0 נקודות · יותר מ-6 חודשים

מוניטין: 1

why 2 is the correct answer?

(USMLoid) During genome replication, hydrogen-bonding between the two DNA strands is broken and the strands separated from each other. Which of the following is responsible?

1

שאלה #57474

		Primase
		No enzyme is responsible.
		Helicase
		Gyrase
		DNA polymerase
		Single-stranded DNA binding proteins

מיין לפי

The picture shown is an electron micrograph of a naturally occurring DNA structure. It is most likely:

1

שאלה #57475

		1. an initiation of translation
		2. a transcription bubble
		3. two replication forks on a plasmid
		4. a telomere
		5. a Holliday junction
		6. a nucleosome

נערך לפני שנה Ido Cohen Lass

מיין לפי

In the diagram of a replication fork shown, the circled strand

1

שאלה #57476

		1. is template
		2. is a primer
		3. is the leading strand.
		4. will be degraded
		5. is the lagging strand.

מיין לפי

(USMLoid) In human chromosomes, which of the following elements or properties works to ensure that information is not lost from the chromosome ends during cell proliferation?

1

שאלה #57477

		1. Centromeres
		2. DNA methylation
		3. Origins of replication
		4. Telomeres
		5. Nucleosomes

מיין לפי

During DNA replication the first nucleotides added are

1

שאלה #57478

		1. ribonucleotides.
		2. pyrimidines.
		3. 'A'
		4. purines.
		5. 'C'

מיין לפי

		1. is random.
		2. depends on whether it is complementary to the base of the template strand in the site.
		3. does not occur. It is nucleotides that enter the active site.
		4. is determined by hydrogen bonding to the template.
		5. depends on whether the nucleoside is a purine or pyrimidine.
		5. depends on whether the nucleoside is a purine or pyrimidine.

		1. It isn’t. The RNA polymerase holoenzyme has a demethylase activity. The methylation code is reset during DNA replication.
		2. Methyltransferases read the old strand and operate on the new strand.
		3. There is no need. Methylation is epigenetic. New methyl groups are added as needed depending on the environmental context.
		4. Since the methyl groups alter base-pairing, only correctly methylated bases will be used during DNA synthesis.

		1. Chewing gum and walking at the same time
		2. 3’ ---> 5’ polymerase
		3. 3’ ---> 5’ exonuclease
		4. 5’ ---> 3’ polymerase
		5. Endonuclease
		6. 5’ ---> 3’ exonuclease

Molecular Biology S1 Module 2: DNA and Replication

Discuss, Learn and be Happy דיון בשאלות

During DNA polymerase activity, the entry of deoxyribonucleoside triphosphates to the enzyme active site

שאלה #57469

Some bases in DNA are occasionally methylated, typically C in eukaryotes and A in prokaryotes. This provides an additional ‘code’ to the information stored in DNA. How is this code maintained during DNA replication?

שאלה #57470

Which of the following activities is/are never associated with a DNA polymerase?

שאלה #57471

Is there a naturally occurring DNA polymerase that does not require a template? YES OR NO

שאלה #57472

Given the reactants shown, which of the images underneath is the most likely reaction product?

שאלה #57473

(USMLoid) During genome replication, hydrogen-bonding between the two DNA strands is broken and the strands separated from each other. Which of the following is responsible?

שאלה #57474

The picture shown is an electron micrograph of a naturally occurring DNA structure. It is most likely:

שאלה #57475

In the diagram of a replication fork shown, the circled strand

שאלה #57476

(USMLoid) In human chromosomes, which of the following elements or properties works to ensure that information is not lost from the chromosome ends during cell proliferation?

שאלה #57477

During DNA replication the first nucleotides added are

שאלה #57478

Molecular Biology S1 Module 2: DNA and Replication

Discuss, Learn and be Happy דיון בשאלות

During DNA polymerase activity, the entry of deoxyribonucleoside triphosphates to the enzyme active site

Some bases in DNA are occasionally methylated, typically C in eukaryotes and A in prokaryotes. This provides an additional ‘code’ to the information stored in DNA. How is this code maintained during DNA replication?

Which of the following activities is/are never associated with a DNA polymerase?

Is there a naturally occurring DNA polymerase that does not require a template? YES OR NO

Given the reactants shown, which of the images underneath is the most likely reaction product?

(USMLoid) During genome replication, hydrogen-bonding between the two DNA strands is broken and the strands separated from each other. Which of the following is responsible?

The picture shown is an electron micrograph of a naturally occurring DNA structure. It is most likely:

In the diagram of a replication fork shown, the circled strand

(USMLoid) In human chromosomes, which of the following elements or properties works to ensure that information is not lost from the chromosome ends during cell proliferation?

During DNA replication the first nucleotides added are

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