BABS1201 Lecture Notes - Lecture 13: Semiconservative Replication, Primase, Thymidine

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scarletdolphin313

18 Nov 2018

School

UNSW, UNSW Sydney

Department

Biotechnology & Biomolecular Sciences

Course

BABS1201

Professor

john

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Describe the basic steps involved in the process of dna replication. Parental dna molecule; each base is paired with its specific partner. The first step is the separation of the two dna strands. Each parental strand serves as a template for the order of nucleotides along the new complementary strand. The nucleotides are connected to form the sugar-phosphate backbone of the new strands. Multiple origins are needed so that all the dna in a cell can be replicated in a short time. Human cells contain 6 billion bases which are all copied within a few hours. The two dna strands are antiparallel; they run in opposite directions with respect to the sugar- phosphate backbone. Dna is replicated from the 5" to the 3" end. The two new strands are formed in different ways. Describe the function of the major enzymes involved in dna replication. Dna polymerase catalyses the addition of new nucleotides.

Related Questions

What step in DNA replication precedes the pairing of complementary bases?

	A.	polymerization of DNA.
	B.	formation of the histone core.
	C.	mitotic division.
	D.	separation of the two strands.
	E.	joining of the two strands.

In eukaryotes, transcription occurs in the

	A.	ribosome.
	B.	mitochondria.
	C.	cell membrane.
	D.	cytoplasm.
	E.	nucleus.

Normal human body cells contain how many chromosomes?

	A.	46
	B.	22
	C.	23
	D.	44
	E.	42

Hershey and Chase performed an experiment in which they used radioactive isotopes to phosphorus and sulfur to label different components of bacterial viruses. Their results clearly showed that

	A.	the viruses did not contain protein.
	B.	genetic material normally contains radioactive isotopes.
	C.	the viruses did not contain DNA.
	D.	protein was entering into the infected bacteria.
	E.	DNA was entering into the infected bacteria.

A package of histones with DNA wrapped around them forms spherical structures called

	A.	nucleosomes.
	B.	lysosomes.
	C.	ribosomes.
	D.	nucleoli.
	E.	chromatin.

DNA replication

	A.	does not require proteins.
	B.	is constantly happening in a cell.
	C.	occurs in G1 of interphase.
	D.	takes place in the nucleus of the cell.
	E.	occurs in the cytoplasm of the cell.

The two subunits of the ribosome join during

	A.	promotion of transcription.
	B.	initiation of translation.
	C.	termination of transcription.
	D.	termination of translation.
	E.	elongation.

DNA replication of a single DNA molecule is referred to as semiconservative because

	A.	each of the two DNA molecules will consist of one parental strand and one newly synthesized strand.
	B.	all the DNA strands in the two DNA molecules will have both parental and newly synthesized DNA.
	C.	it results in two nonidentical DNA molecules.
	D.	of the two DNA molecules, one is made up totally of parental DNA, while the other is entirely newly synthesized DNA.
	E.	one DNA strand is replicated continuously, while the other must be replicated discontinuously.

The bases are bonded to what part of the backbone of the DNA molecule?

	A.	the 4â carbon atom of the sugar molecule.
	B.	the 3â carbon atom of the sugar molecule.
	C.	the 5â carbon atom of the sugar molecule.
	D.	the 1â carbon atom of the sugar molecule.
	E.	the 2â carbon atom of the sugar molecule.

1.When a protein binds to DNA at a site defined by a particular nucleotide sequence, with which parts of the DNA does the protein primarily interact?

A. the phosphate and deoxyribose groups in the DNA backbone

B. the phosphate and deoxyribose groups in the DNA backbone, and hydrophobic interactions with the nucleotide bases

C. nucleotide bases within the major grooves of the DNA

D. nucleotide bases within the major and minor grooves of the DNA

E. none of the above

2. Which of the following proteins binds to DNA with sequence specificity?

A. POI Ill holoenzyme

B. DnaA

C. DnaB

D. Dam methylase

E. Both B and D

3. Which of the following is NOT a functional parallel among all known cellular systems of DNA replication?

A. Replication is initiated at specific sites

B. Replication is continuous on the leading strand and discontinuous on the lagging strand

C. DNA replication is semiconservative

D. Replication forks move away from the origin in one direction

E. Nucleases, polymerases and ligases replace RNA primers with DNA and seal the remaining nick

4. A DNA polymerase cannot synthesize a DNA strand de novo (from the beginning) from a mixture of dNTPs. Which of the following explains the role of the primer in the reaction promoted by this enzyme?

A. The primer is an initiation protein with attached nucleotides that binds to the template and to which new nucleotides are added to the 3 ' end.

B. The primer is an initiation protein with attached nucleotides that binds to the template and to which new nucleotides are added to the 5' end.

C. The primer is a preexisting strand of RNA or DNA to which new nucleotides are added to the 3' end.

D. The primer is a preexisting strand of RNA or DNA to which new nucleotides are added to the 5' end.

E. The primer is a preexisting strand of DNA synthesized by DNA pol I, prior to replicative DNA synthesis by DNA pol Ill.

5. Universal features of DNA polymerases include:

A. 5'-3' exonuclease function.

B. Formation of an 'closed' conformation of the polymerase when the template-nucleotide base pair is correct.

C. Use of a single magnesium ion to orient reacting molecules and assist in dissipation of the negative charge that develops during nucleotidyl transfer.

D. Alignment of conserved residues in the active site for attack of the DNA primer by the 3 'OH on the incoming nucleotide.

E. Continuous unbinding and rebinding of the polymerase to the DNA template as each nucleotide is added.

byzantiumscorpion425

1. _________________________ is the name of the process that produces proteins using RNA molecules.

a.Transcription

b Translation

c. Replication

d. Mutagenesis

2. The peptide bonding site on the ribosome:

a. A site

b. P site

c. E site

d. D site

3. The name given to the bond formed between two amino acids.

a. Hydrogen bond

b. Double bond

c. Peptide bond

d. Negative bond

4. __________________________ is the movement of the mRNA molecule on the ribosome to open up the A-site for the new incoming amino acid.

a. Transformation

b. Mutation

c. Translocation

d. Initiation

5. What does the term semi-conservative mean.

a. Replication of RNA is semi-conservative, each new strand consists of one old strand of RNA and one new strand of RNA.

b. Replication of DNA is semi-conservative, each new strand consists of one old strand of DNA and one new strand of DNA.

c. Replication of DNA is semi-conservative, each new strand consists of new strands of nucleotides.

d. Transcription of RNA is semi conservative.

6. This molecule functions during protein synthesis to recognize the codon and bring the proper amino acid back to the ribosome for translation.

a. mRNA

b. tRNA

c. rRNA

d. DNA polymerase

7. What is meant by the base-pairing rule.

a. Bases on a single strand of DNA are always found as pairs

b. Adenine always base pairs with guanine; cytosine with thymine

c. Adenine always base pairs with thymine; cytosine with guanine

d. Bases on a single strand of RNA are found in pair.

8. In this step of protein synthesis, amino acids are added to a growing polypeptide chain.

a. Initiation.

b. Elongation.

c. Termination.

d. Transpiration.

9. Three complementary bases found in a mRNA are called ____________________.

a. Anti-codon.

b. Triplet.

c. Doublet.

d. Codons.

10. Which statement best describes the job or function of the messenger RNA.

a. Carries the map of the gene sequence in the form of codons to the cytoplasm

for translation of the protein.

b. It transfers amino acids to the ribosome for protein synthesis.

c. It forms the ribosomes.

d. It helps replicate DNA.

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BABS1201 Lecture Notes - Lecture 13: Semiconservative Replication, Primase, Thymidine

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