Nucleic Acids and DNA Replication

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which of the following base pairing rules did Erwin Chargaff establish?

[A] = [G] and [C] ≡ [T]

[A] = [C] and [T] ≡ [G]

[G] = [T] and [A] ≡ [C]

[A] = [T] and [C] ≡ [G] (correct)

Which type of DNA is characterized as a right-handed double helix and is the most common form?

Z DNA

A DNA

X DNA

B DNA (correct)

Under what conditions is A DNA typically found?

In acidic solutions only

Low salt concentration with no alcohol

High salt concentration or with alcohol added (correct)

At room temperature without any additives

What is the structural characteristic of Z DNA?

Its bases seem to zigzag Signup and view all the answers

What feature of B DNA relates to the orientation of its strands?

Strands are anti-parallel Signup and view all the answers

Which statement correctly describes the structure of nucleotides?

Nucleotides are the basic units of nucleic acids, consisting of three covalently-linked units. Signup and view all the answers

Which of the following pairs of bases are correctly matched as complementary base pairs in DNA?

Adenine and Thymine Signup and view all the answers

What characterizes purine bases compared to pyrimidine bases?

Purines have two hydrogen-carbon rings while pyrimidines have one. Signup and view all the answers

Which sugar is found in RNA, and how does it differ from the sugar in DNA?

Ribose; it has an oxygen atom at carbon 2. Signup and view all the answers

How many pairs of chromosomes are present in a typical human genome?

22 autosome pairs and 1 sex chromosome pair. Signup and view all the answers

What accurately describes the function of the phosphate group in nucleotide structure?

It contributes to the formation of the DNA backbone. Signup and view all the answers

Which of the following correctly identifies the number of phosphate groups that can be present in a nucleotide?

Nucleotides can have up to three phosphate groups. Signup and view all the answers

Which best describes the overall construction of DNA?

DNA is a double-stranded helix made of nucleotides with a consistent backbone. Signup and view all the answers

How many hydrogen bonds are formed between adenine and thymine?

2 Signup and view all the answers

What is the distance covered by one full helical turn of DNA?

3.4 nm Signup and view all the answers

Which nitrogenous base forms three hydrogen bonds with its complementary base?

Guanine Signup and view all the answers

What is the complementary sequence of 5’-GTAGCCTA-3’?

3’-CATCGGAT-5’ Signup and view all the answers

How many base pairs per turn of the DNA helix are observed?

10 bp's Signup and view all the answers

What is the chemical composition of deoxyadenosine monophosphate (dAMP)?

Deoxyribose, Adenine, 1 Phosphate Signup and view all the answers

What type of proteins do histones represent in DNA packaging?

Structural Proteins Signup and view all the answers

What is the correct numbering for the nitrogenous base pairing where adenine pairs with thymine?

N6 to N3 Signup and view all the answers

What is the primary function of topoisomerase in the context of DNA?

Prevents tangling of DNA strands. Signup and view all the answers

Which component of chromatin is directly associated with the DNA-protein complex structure?

Nucleosomes Signup and view all the answers

In eukaryotic cells, where does transcription occur?

In the nucleus Signup and view all the answers

What role do condensins play during cell division?

They compact chromosomes. Signup and view all the answers

What is the correct sequence of the central dogma of molecular biology?

DNA → RNA → Protein Signup and view all the answers

Which type of chromatin is characterized as tight and inactive?

Heterochromatin Signup and view all the answers

What is the primary role of linker DNA in the context of chromatin?

To connect nucleosomes. Signup and view all the answers

What is the function of messenger RNA (mRNA) in the central dogma?

To serve as a template for protein synthesis. Signup and view all the answers

What initiates protein synthesis in the process of translation?

AUG codon Signup and view all the answers

In which cellular component does translation occur?

Ribosome Signup and view all the answers

Which of the following statements is true regarding prokaryotic transcription and translation?

They occur simultaneously. Signup and view all the answers

What characterizes the transcriptional region of a gene?

Part of DNA that is transcribed to mRNA Signup and view all the answers

What is the role of tRNA during translation?

To match amino acids with corresponding codons Signup and view all the answers

Which of the following modifications can occur after protein synthesis?

Glycosylation Signup and view all the answers

How many protein-coding genes are estimated to exist in the human genome?

20,000 Signup and view all the answers

Which sequence is classified as a stop codon?

UGA Signup and view all the answers

What is the primary characteristic of semi-conservative DNA replication?

Each new DNA molecule contains one original and one new strand. Signup and view all the answers

In DNA replication, what is the role of specific enzymes?

They assist in the separation of DNA strands. Signup and view all the answers

During the Meselsohn-Stahl experiment, what was observed after one round of replication in the presence of heavy nitrogen?

The DNA exhibited an intermediate density. Signup and view all the answers

Which model of DNA replication suggests both strands contain mixed old and new DNA?

Dispersive model Signup and view all the answers

What defines the specific start point of DNA replication?

Designated origins in the chromosome. Signup and view all the answers

What was a key finding in the Meselsohn-Stahl experiment regarding the DNA of E.coli after switching from heavy to light nitrogen?

One strand contained heavy nitrogen and the other light nitrogen. Signup and view all the answers

In which direction does DNA replication occur at the replication fork?

Bidirectionally from the origin. Signup and view all the answers

What is DNA polymerase primarily responsible for during DNA replication?

Driving the synthesis of the new DNA strand. Signup and view all the answers

Study Notes

Nucleic Acids

Nucleic acids are the genetic material
Found in all living organisms
Consist of nucleotides
Nucleotides are composed of three parts: nitrogenous base, pentose sugar, and phosphate group.
Nitrogenous bases can be either purines (Adenine, Guanine) or pyrimidines (Cytosine, Thymine, Uracil).
Pentose sugar is either ribose (in RNA) or deoxyribose (in DNA)
DNA is a double helix made of two strands of nucleotides paired in a specific manner (A with T, and C with G).
RNA is a single stranded structure.
Chromosomes are long strands of DNA
DNA and RNA carry the instructions for creating and maintaining life.
Genes are segments of DNA that carry hereditary information.
DNA replication: creates a new double-stranded DNA molecule from an existing one.
Transcription: produces an RNA (mRNA) molecule from a DNA template.
Translation: uses mRNA to create a protein.

DNA Replication

DNA replication happens during cell division
Using semi-conservative principle (one original strand and one new strand)
Process involves several enzymes and proteins to unwind, separate, copy and assemble new strands.
Starts at specific sites on DNA called origins of replication.
Proceeds bidirectionally away from the origin, creating replication forks, to copy the entire DNA molecule.
DNA polymerase is the main enzyme responsible for synthesizing new DNA strands.
Replication occurs in a 5' to 3' direction.
Leading strand is synthesized continuously; lagging strand is synthesized in short fragments (Okazaki fragments), joined by DNA ligase

DNA Transcription

DNA transcription uses the information in a DNA strand to create an RNA molecule
RNA polymerase is the main enzyme that performs DNA transcription.
The process initiates at specific DNA regions called promoters , with the enzyme starting at the 3' → 5'.
During transcription, a DNA strand serves as a template, which gets copied into an RNA molecule, one nucleotide at a time (5' →3').
After transcription, the enzyme detaches from the DNA molecule.

DNA Translation

DNA translation is the synthesis of proteins from the information encoded in an mRNA molecule, using ribosomes and transfer RNA molecules, to read the language of mRNA.
The mRNA molecule is a transcript for the DNA molecule.
Ribosomes read three nucleotides on the mRNA , translating into amino acids.
tRNAs bring the needed amino acids to the ribosome, using the mRNA as a guide, to assemble into a protein.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the essential concepts of nucleic acids, including their structure and function, as well as the processes of DNA replication. It explores the components of nucleotides, the roles of DNA and RNA, and the mechanisms of transcription and translation. Test your understanding of how genetic material is preserved and expressed in living organisms.