DNA Structure and Function Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which of the following experimental findings provided crucial evidence that DNA, rather than protein, is the primary carrier of genetic information?

Chargaff's rules demonstrating equal ratios of adenine to thymine and guanine to cytosine.
The Avery-MacLeod-McCarty experiment demonstrating that DNA from virulent bacteria could transform non-virulent bacteria.
The observation that DNA is primarily located within the nucleus of eukaryotic cells.
Hershey and Chase's experiment showing that bacteriophage inject DNA, not protein, into bacteria to program them. (correct)

How does the Watson-Crick model of DNA structure explain Chargaff's rules regarding the ratios of nitrogenous bases?

The model incorporates a triple helix structure, allowing for more variation of base pairing between purines and pyrimidines.
The model demonstrates that adenine always pairs with thymine, and guanine always pairs with cytosine, due to hydrogen bonding, ensuring A=T and G=C. (correct)
The model suggests that the total number of purines should equal the total number of pyrimidines, because of the sugar-phosphate backbone.
The model proposes that adenine always pairs with guanine and cytosine always pairs with thymine to maintain a consistent helix width.

During DNA replication, the enzyme DNA gyrase (a type of topoisomerase) plays a critical role. What is its primary function?

To relieve the torsional stress caused by unwinding DNA at the replication fork by introducing negative supercoils. (correct)
To prevent the re-annealing of separated DNA strands during replication.
To synthesize RNA primers on the lagging strand.
To add nucleotides to the 3' end of the growing DNA strand.

Consider a PCR reaction designed to amplify a specific gene from a DNA sample. After several cycles, the amplification reaches a plateau where the amount of amplified DNA no longer increases exponentially. Which factor is MOST likely responsible for this plateau effect?

<p>The concentration of primers becomes limiting, preventing further amplification. (C)</p> Signup and view all the answers

Telomerase, a specialized DNA polymerase, is crucial for maintaining the integrity of linear chromosomes in eukaryotic cells. What specific function does telomerase perform that addresses the end-replication problem?

<p>Telomerase adds a repeating sequence of DNA to the 3' end of chromosomes, compensating for the shortening that occurs during replication. (D)</p> Signup and view all the answers

Flashcards

DNA as genetic material

DNA was proven to be the genetic material through various experiments, including those by Avery, MacLeod, and McCarty using transformational bacteria.

Watson-Crick model

The Watson-Crick model describes DNA’s double helix structure, supporting Chargaff’s rules and utilizing Franklin’s X-ray diffraction data.

DNA denaturation factors

Factors influencing DNA denaturation include temperature, pH, and chemical agents such as urea that affect hydrogen bonding.

PCR (Polymerase Chain Reaction)

A technique used to amplify specific DNA sequences, allowing for detection and quantification of DNA or RNA.

Signup and view all the flashcards

Semiconservative replication

DNA replication is semiconservative, meaning each new double helix contains one original and one new strand, proven by BrdU labeling experiments.

Signup and view all the flashcards

Study Notes

DNA Structure and Function

DNA is the genetic material of cells
The Watson-Crick model incorporates Chargaff's rules and Franklin's X-ray diffraction data
Watson-Crick DNA structure features a double helix with a sugar-phosphate backbone and nitrogenous bases in the interior
The defining characteristics of this structure include base pairing (A with T, and G with C), antiparallel orientation of strands, and a specific diameter.
Genome and proteome size correlate with organism complexity. Larger genomes and proteomes are often associated with more complex organisms.

DNA Replication and Analysis

PCR (Polymerase Chain Reaction) is a technique for amplifying specific DNA sequences
PCR can be used to quantify mRNA and identify individuals.
DNA is packaged into nucleosomes in eukaryotic cells and organized further into metaphase chromosomes.
Metaphase chromosomes are well-structured, compact structures of DNA.
Euchromatin is less condensed and actively transcribed, while heterochromatin is dense and inactive transcriptionally.

DNA Types and Denaturation

There are three major types of DNA which are distinguished by their structure and function.
Factors influencing DNA denaturation include temperature, pH, and salt concentration.
FISH (Fluorescent in situ hybridization) is a technique used to visualize and locate specific DNA sequences on chromosomes.
FISH is performed by labeling a DNA sequence with a fluorescent tag, then hybridizing the probe to the DNA on a chromosome.
The information obtained from FISH includes the physical location of a specific DNA sequence on a chromosome.

Studying That Suits You

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

Description

Test your knowledge on the structure and role of DNA, including the Watson-Crick model and the process of DNA replication. This quiz covers key concepts such as base pairing, genome size, and PCR techniques. Challenge yourself with questions that span the fundamental aspects of genetics.