06 Nucleic Acids and DNA Replication Notes 2024

A folded fork structure.

The addition of an extra nucleotide base.

In the 5' to 3' direction.

Phosphodiester bonds.

1 error per 100,000 nucleotides.

5' to 3' directionality/polarity.

Prokaryotes do not have an end replication problem because they possess circular DNA.

It may not be replaced with the correct nucleotide.

Watson and Crick.

Mostly short-lived and degraded once it has been translated.

An organic ring structure that is hydrophobic in nature.

Ribosomes consist of rRNA and ribosomal proteins, forming two subunits.

An amino acid binding site for the specific amino acid.

Ribose (for RNA) and deoxyribose (for DNA).

About 45 different tRNAs, each specific to one amino acid.

It adds free DNA nucleotides to the exposed bases on the parental DNA strand by complementary base pairing.

With each replication, DNA shortens, which may lead to the loss of critical genes after many rounds of replication.

Maurice H. F. Wilkins.

Messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).

Because it can remain at the fork after finishing the synthesis of each Okazaki fragment.

Both strands act as templates for new DNA, with parental strands re-associating to form one daughter molecule.

Through the sequence of bases that directs cell activity.

Hydrogen bonds through complementary base pairing.

In the 5’ to 3’ direction.

It may encounter a gap if there is no preceding nucleotide to extend from.

A phosphoester bond.

It breaks hydrogen bonds between complementary bases and unwinds the DNA strands.

Single-stranded DNA binding proteins.

A nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.

DNA labeled with heavy nitrogen (N-15) and light nitrogen (N-14).

It occurs when the daughter DNA strand produced is shorter than the parental template strand due to the inability to replace the RNA primer at the 3’ end.

Because there is no 3’ end available for DNA polymerase to add DNA nucleotides, preventing the replacement of the RNA primer.

Watson and Crick.

In 1953.

A purine always pairs with a pyrimidine; adenine pairs with thymine, and guanine pairs with cytosine.

DNA is the main storage molecule for genetic information.

Both strands separate and serve as templates for new strands, resulting in daughter molecules with one old and one new strand.

Purines have a two-ring structure, while pyrimidines have a one-ring structure.

Primase synthesizes primers for each Okazaki fragment.

Hydrophobic interactions between stacked bases and reduced reactivity of nitrogenous bases due to the double helix.

It seals up the gaps between newly replaced DNA and existing fragments by catalyzing the formation of phosphodiester bonds.

To differentiate between original parental DNA and newly synthesized daughter DNA.

An individual part of a chromosome that replicates as a discrete functional unit.

Polymerase accessory proteins, including a sliding clamp and a clamp loader.

To the 5’ carbon of the pentose sugar.

It is derived from phosphoric acid.

A structure formed when two replication forks move away from each other.

The parental DNA breaks into segments that act as templates, resulting in daughter strands containing a mix of old and new parts.

The 5’ end has a phosphate group, and the 3’ end has a hydroxyl group.

A nucleoside monophosphate or nucleotide.

They jointly received the Nobel Prize in Physiology or Medicine.

Meselson and Stahl’s elegant experiment.

It can remove incorrectly paired DNA nucleotides and replace them with the correct ones.

DNA is chemically stable, while RNA is chemically less stable.

In semi-conservative replication, each new DNA molecule consists of one original strand and one newly synthesized strand.

To determine the mechanism of DNA replication.

A process where a newly synthesized strand loops out, causing insertions or deletions of nucleotide bases.

That DNA replication is semi-conservative.

The 3' OH group.

It explains the directional flow of genetic information.

Nucleoside triphosphates.

They detected three primary repeating patterns in the DNA molecule: 0.34nm, 2nm, and 3.4nm.

50-100,000 replicons.

It is complementary to a specific codon on the mRNA.

With a prime (‘) symbol to distinguish them from the carbon atoms at the ring positions of the nitrogenous base.

Two daughter DNA molecules, each consisting of one parental strand and one newly synthesized daughter strand.

They synthesized new DNA incorporating the lighter 14 N isotopes.

It remains tied to the leading-strand DNA polymerase.

Short segments synthesized on the lagging strand during DNA replication.

The phosphate group.

A sequence of 3 mRNA bases that codes for a certain amino acid.

Removes the primers.

Antiparallel; the 3’ end of one strand is opposite the 5’ end of the other.

James Watson and Francis Crick.

A phosphodiester bond.

A condensation reaction.

Debate continues on who should receive credit for the discovery.

A process where each original DNA strand serves as a template for a new strand.

Single polynucleotide chain.

Maybe temporary, as it is degraded once translated.

A free hydroxyl (-OH) group attached to the 3' carbon of the pentose sugar.

It may loop out, resulting in the deletion of a nucleotide base in the newly synthesized strand.

Each new DNA molecule consists of one original strand and one newly synthesized strand.

Two DNA polymerase molecules are active at the fork at any one time.

Most RNA molecules are single-stranded.

Telomeres help protect chromosomes from shortening during replication, which is linked to the end replication problem.

The double-helix model.

It showed many features of scientific inquiry in action.

By hydrogen bonds between nitrogenous bases.

Leading strand and lagging strand.

DNA replication, transcription, and translation.

2 nm.

Code for and store genetic information, and replicate accurately.

A characteristic 'clover-leaf' shape.

ATP.

5' end always ends in G and 3' end always ends in CCA.

Deoxy-.

The work by Meselson and Stahl.

It is single-stranded but may fold into different shapes.

They provide stability, allowing heritable changes to occur rarely.

Primase catalyzes the synthesis of an RNA primer complementary to DNA nucleotides on the template.

It cannot synthesize DNA from scratch; it can only add new nucleotides to a pre-existing 3' hydroxyl (-OH) end provided by RNA primers.

To bring the appropriate amino acid to the ribosome for protein synthesis.

Condensation reactions.

In the 5' to 3' direction with respect to the growing chain.

They are removed and replaced with corresponding DNA nucleotides by DNA polymerase I.

DNA is double-stranded, made up of two polynucleotide strands.

Nucleic acids, like proteins, are essential for life and DNA forms the genetic material of all living organisms.

In the 1800s.

They are removed in the process.

In the nucleolus region of the nucleus.

Watson and Crick.

In the 5’ to 3’ direction.

Major groove and minor groove.

A nucleoside.

It moves along the template away from the replication fork.

A free phosphate group (5' end).

A, U, C, G.

Using the intact complementary strand as a template to guide the repair.

Using ultracentrifugation based on different densities.

Complementary base pairing.

A double helical structure.

Conservative, dispersive, and semiconservative mechanisms.

Matthew Meselson and Franklin Stahl.

That DNA from any cell of all organisms has a 1:1 ratio of pyrimidine and purine bases, specifically that cytosine equals guanine and adenine equals thymine.

Monomers that make up nucleic acids, arranged to form long molecules called polynucleotides.

Because it is a long polymer with a linear sequence of bases.

Short fragments of nucleotides synthesized discontinuously on the lagging strand.

They strengthen the strands of DNA nucleotides.

At a site known as the origin of replication.

A, T, C, G.

15 N.

The structure of DNA allows it to store genetic information and facilitate replication.

The semiconservative mechanism.

Carries information from DNA out of the nucleus to ribosomes in the cytoplasm.

Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

0.34 nm.

There is only one origin of replication where DNA replication initiates.

Pentose sugar, inorganic phosphate, and nitrogenous base.

Each unwound strand acts as a template for synthesizing a new daughter strand.

Two daughter DNA molecules, each containing one parental and one newly synthesized strand.

DNA strands base pair to create copies without loss of information.

Via phosphodiester bonds between the 5’ and 3’ carbons of the pentose sugars.

Meselson and Stahl in 1958.

tRNA, rRNA, and mRNA.

Ribose.

All bases in the DNA incorporated the 15 N element, making it heavier than normal DNA.

DNA is double-stranded and contains deoxyribose sugar, while RNA is single-stranded and contains ribose sugar.

Towards the replication fork.

They can lead to new stable forms of a gene, contributing to genetic variation.

It links two adjacent DNA nucleotides together.

A replication bubble with a replication fork at each end.

Semi-conservative replication.

Double nucleotide chains forming a double helix.

A Y-shaped structure formed when the double-stranded DNA unwinds to expose single-stranded templates.

Deoxyribose.

A nutrient medium containing the heavy isotope of nitrogen, 15 N.

DNA replication is the process by which a DNA molecule makes a copy of itself.

The end replication problem arises because DNA polymerase cannot fully replicate the ends of linear chromosomes.

They supported the semi-conservative mode of DNA replication.

Two bands of equal thickness: one of the intermediate type and one of the light density type (50% 15N 14N, 50% 14N 14N).

Experiments such as those by Meselson and Stahl provide evidence for semi-conservative replication.

Grown in 14N for 1 generation.

One band, all of the intermediate density type (100% 15N 14N).

Dinucleotides are formed from two nucleotides, while polynucleotides are long chains of nucleotides, such as DNA and RNA.

One band, all of the heavy type (100% 15N 15N).

Grown in 15N for 14 generations.

Ultracentrifugation.

Grown in 14N for 2 generations.