DNA Structure and Replication Quiz
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Questions and Answers

What are the three components that make up a nucleotide?

  • A nitrogenous base, a phosphate group, and an amino acid
  • A nitrogenous base, a deoxyribose sugar, and a lipid group
  • A nitrogenous base, a deoxyribose sugar, and a phosphate group (correct)
  • A nitrogenous base, a ribose sugar, and a phosphate group

What scientific conclusion did Avery's experiment arrive at regarding transformation?

  • RNA was responsible for genetic information
  • Carbohydrates were essential for transformation
  • Proteins caused the transformation
  • DNA was the transforming principle (correct)

According to Chargaff's rules, which bases pair correctly?

  • Adenine with Thymine and Cytosine with Guanine (correct)
  • Adenine with Guanine and Cytosine with Thymine
  • Adenine with Thymine and Guanine with Cytosine
  • Adenine with Cytosine and Guanine with Thymine

Which two bases are considered longer due to having a double ring structure?

<p>Guanine and Adenine (A)</p> Signup and view all the answers

If a DNA structure contains 35% Adenine, what is the percentage of Cytosine present?

<p>15% (A)</p> Signup and view all the answers

What is the role of Helicase during DNA replication?

<p>It unzips the double helix structure (A)</p> Signup and view all the answers

What is true about the strands resulting from DNA replication?

<p>One strand is original and the other is new (B)</p> Signup and view all the answers

What type of bonds connect the nitrogenous bases in the DNA molecule?

<p>Hydrogen bonds (A)</p> Signup and view all the answers

What role do histones play in the structure of DNA?

<p>They package chromosomal DNA inside nuclei. (D)</p> Signup and view all the answers

What is a key difference in DNA replication between prokaryotes and eukaryotes?

<p>Prokaryotic replication starts at a single point, while eukaryotic replication is more complex. (A)</p> Signup and view all the answers

Which nitrogenous base is found in RNA but not in DNA?

<p>Uracil (B)</p> Signup and view all the answers

During transcription, what function does RNA polymerase perform?

<p>It separates DNA strands and assembles RNA nucleotides. (C)</p> Signup and view all the answers

How many nucleotides are required to form codons for four amino acids?

<p>12 nucleotides (A)</p> Signup and view all the answers

What does gene expression involve?

<p>The transformation of genetic information into functional products. (A)</p> Signup and view all the answers

What is the primary function of transfer RNA (tRNA) in protein synthesis?

<p>It transports amino acids to the mRNA strand. (B)</p> Signup and view all the answers

What is the difference between exons and introns during RNA processing?

<p>Exons are spliced together, while introns are removed. (B)</p> Signup and view all the answers

What is a primary factor that differentiates gene regulation in eukaryotes from prokaryotes?

<p>Eukaryotes require additional steps of gene control. (C)</p> Signup and view all the answers

What process is responsible for the specialization of cells in multicellular organisms?

<p>Cell differentiation (D)</p> Signup and view all the answers

Flashcards

What is the monomer of DNA and RNA?

The monomer of both DNA and RNA is a nucleotide. A nucleotide is composed of three parts: a phosphate group, a sugar (deoxyribose in DNA and ribose in RNA), and a nitrogenous base.

What are the three components of a nucleotide?

A nucleotide is composed of a phosphate group, a sugar (deoxyribose in DNA and ribose in RNA), and a nitrogenous base.

What did Avery's experiment conclude?

Avery's experiment concluded that DNA is the transforming principle, meaning it is responsible for carrying genetic information from one bacterium to another.

Base Pairing Rule

Chargaff's base pairing rule states that adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C) in DNA.

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What are the differences between purines and pyrimidines?

Purines (Adenine and Guanine) have a double-ring structure, while pyrimidines (Cytosine and Thymine) have a single-ring structure.

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What is DNA replication?

DNA replication is the process by which a DNA molecule is copied, creating two identical DNA molecules. It occurs in the nucleus of a cell.

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Describe the role of helicase in DNA replication.

Helicase is an enzyme that 'unzips' the double helix structure of DNA during replication by breaking the hydrogen bonds between the nitrogenous bases.

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What are the roles of covalent and hydrogen bonds in DNA structure?

Covalent bonds connect the nucleotides within each strand of DNA, creating a strong backbone. Hydrogen bonds connect the nitrogenous bases between the two DNA strands, holding them together.

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DNA Replication in Prokaryotes

The process of copying DNA in prokaryotic cells involves a single starting point, and proceeds in both directions until the entire chromosome is duplicated.

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DNA Replication in Eukaryotes

DNA replication in eukaryotic cells involves multiple starting points and requires enzymes to facilitate the process.

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What are the 3 types of RNA?

There are three main types of RNA: mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA). Each has a specific role in protein synthesis.

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Transcription

The process of creating RNA from a DNA template.

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Translation

The process of converting the genetic code carried by mRNA into a protein.

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Codon

A three-nucleotide sequence in mRNA that codes for a specific amino acid.

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Gene Expression

The process by which the information encoded in a gene is used to create a functional product, typically a protein.

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Cell Differentiation

The process by which cells become specialized in structure and function.

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Gene Regulation

The control of gene expression, ensuring that genes are expressed only when and where they are needed.

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Introns vs. Exons

Introns are non-coding regions of DNA that are removed from the pre-mRNA during RNA splicing. Exons are coding regions that are spliced together to form the final mRNA.

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Study Notes

DNA Structure and Replication

  • Monomer of DNA/RNA: Nucleotides
  • Nucleotide components: Nitrogenous base, phosphate group, sugar molecule (deoxyribose)
  • Avery's experiment conclusion: DNA caused transformation.
  • Chronological order of DNA discovery: Chargaff's rules, Franklin's X-ray diffraction, Watson and Crick's structure elucidation.
  • Scientist roles:
    • Griffith: Discovered transformation and the chemical nature of genes.
    • Avery: Determined DNA's role in transformation.
    • Hershey and Chase: Confirmed DNA as the genetic material of bacteriophages.
  • Chargaff's base pairing rule: A with T; C with G
  • Longer bases: Guanine, Adenine (double-ring)
  • Shorter bases: Cytosine, Thymine (single-ring)
  • Complementary strand for CGTTAGCAT: GCAATCGTA
  • Base percentages (35% Adenine): Guanine-35%, Cytosine-15%, Thymine-15%
  • Base percentages (21.5% Guanine): Adenine-21.5%, Cytosine-28.5%, Thymine-28.5%
  • DNA replication: Occurs at origins of replication. Helicase unzips the double helix.
  • Replication strands: New and original strands (semiconservative)
  • Covalent vs. hydrogen bonds in DNA: Covalent bonds connect nucleotides; hydrogen bonds connect bases.
  • Nucleotide structure and DNA function: Weak hydrogen bonds allow for DNA to separate for replication while maintaining structure.
  • DNA, histones, chromosomes, and nucleosomes: DNA is packaged with histones into nucleosomes, which form chromosomes.

DNA Replication - Prokaryotes vs. Eukaryotes

  • Prokaryotic DNA replication: Starts at a single origin, replicates in both directions until complete.
  • Eukaryotic DNA replication: Replication occurs multiple times from multiple origins on chromosomes simultaneously. Enzymes assist.

DNA and RNA Comparison

  • DNA vs RNA Differences: DNA is double-stranded; RNA is single-stranded. DNA uses thymine; RNA uses uracil. DNA has deoxyribose; RNA has ribose.
  • Types of RNA and functions:
    • mRNA (messenger): Carries genetic code for protein synthesis.
    • tRNA (transfer): Carries amino acids to ribosomes.
    • rRNA (ribosomal): Component of ribosomes, facilitates protein synthesis.

Transcription and Translation

  • Transcription location: Nucleus
  • Transcription steps:
    1. RNA polymerase binds to DNA promoters.
    2. DNA strands separate.
    3. RNA polymerase assembles complementary RNA.
  • Translation location: Cytoplasm
  • Translation steps:
    1. mRNA leaves nucleus.
    2. mRNA codons are matched with tRNA anticodons, which bring the corresponding amino acids.
  • Protein synthesis molecules: mRNA, tRNA, rRNA
  • Codons/Amino acids: 3 nucleotides form a codon; 12 nucleotides specify 4 amino acids.
  • mRNA to amino acid translation: Use a codon chart to identify amino acids.
  • Transcription of ATGTGCGCATGCATC: UACACGCGUACGUAG
  • Translation of ATGTGCGCATGCATC: AUGAGCGCAUGCAUC

Gene Expression and Regulation

  • Gene expression: Gene information becomes functional product.
  • Gene expression sequence: Initiation, elongation, termination
  • Cell differentiation: Cells specialize in shape, structure, and function.
  • Gene regulation eukaryotes vs. prokaryotes: Eukaryotes have an additional layer of regulation than prokaryotes. Prokaryotes have simple regulatory mechanisms.
  • Gene regulation importance: Specialized cells regulate genes to express only needed functions.
  • Introns vs. exons: Exons code for protein; introns are removed through RNA splicing.
  • Mutation effect: Most mutations have significant effects.
  • Homeotic genes (Hox genes): Determine body segment identities.

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Description

Test your knowledge on the structure and replication of DNA! This quiz covers essential concepts such as nucleotide components, key experiments in genetics, and the chronological discovery of DNA. Challenge yourself with questions on base pairing and complementary strands.

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