Molecular Biology Overview
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Questions and Answers

How many pairs of chromosomes are present in every somatic cell of humans?

  • 23 pairs (correct)
  • 24 pairs
  • 46 pairs
  • 22 pairs

    • What term describes a gene that is present in two loci of homologous chromosomes?

  • Homologous
  • Heterozygous
  • Chromatid
  • Allele (correct)

    • Which part of a gene serves as the binding site for RNA polymerase and transcription factors?

  • Exon
  • Enhancer
  • Intron
  • Promoter (correct)

    • What are the segments of coding sequences within a gene called?

    <p>Exons</p> Signup and view all the answers

    What defines a homozygous allele?

    <p>When the alleles are identical</p> Signup and view all the answers

    What best describes the primary characteristic of eukaryotic cells?

    <p>They contain a true nucleus surrounded by a nuclear membrane.</p> Signup and view all the answers

    How is the genetic material in prokaryotic cells typically organized?

    <p>It consists of a single circular DNA molecule dispersed in the cytoplasm.</p> Signup and view all the answers

    What is true about the human genome?

    <p>Only about 10% of human genes have defined functions.</p> Signup and view all the answers

    What distinguishes eukaryotic DNA from prokaryotic DNA?

    <p>Eukaryotic DNA is linear and associated with proteins.</p> Signup and view all the answers

    Which of the following statements about cell division is correct?

    <p>Eukaryotic cells undergo mitosis for cell division.</p> Signup and view all the answers

    What aspect of eukaryotic genomes is more complex compared to prokaryotic genomes?

    <p>The number of chromosomes present.</p> Signup and view all the answers

    Which type of cells is characterized by having no nuclear membrane?

    <p>Prokaryotic cells</p> Signup and view all the answers

    What is the arrangement of chromosomes in the human genome?

    <p>One pair of sex chromosomes and 22 pairs of autosomes.</p> Signup and view all the answers

    What is the primary role of ribosomal RNA (rRNA) in protein synthesis?

    <p>It provides a framework for ribosome structure.</p> Signup and view all the answers

    What process is involved in the addition of a poly (A) tail to RNA?

    <p>Cleavage of the 3' end followed by addition of adenine residues.</p> Signup and view all the answers

    Which statement accurately describes transfer RNA (tRNA)?

    <p>It carries amino acids to the ribosome for protein assembly.</p> Signup and view all the answers

    Which of the following is NOT a minor class of RNA mentioned?

    <p>Micro RNA</p> Signup and view all the answers

    In the context of molecular biology, which application does NOT relate to rRNA?

    <p>Paternity analysis</p> Signup and view all the answers

    What is the primary function of messenger RNA (mRNA)?

    <p>To synthesize proteins through translation</p> Signup and view all the answers

    Which of the following best describes microsatellites?

    <p>Sequences that consist of short repeated sequences of 2-8 bp</p> Signup and view all the answers

    What is the purpose of splicing in mRNA processing?

    <p>To remove introns and join exons</p> Signup and view all the answers

    Where are telomeres located and what is their primary function?

    <p>At the ends of chromosomes, providing protection and maintaining integrity</p> Signup and view all the answers

    Which type of RNA carries amino acids to ribosomes during protein synthesis?

    <p>Transfer RNA (tRNA)</p> Signup and view all the answers

    What distinguishes hypervariable minisatellites from other types of DNA sequences?

    <p>They are located around centromeres and are used in forensic and paternity testing</p> Signup and view all the answers

    What are tandem repeats classified based on?

    <p>The number of nucleotide bases in the repeated sequences</p> Signup and view all the answers

    Which of the following statements about RNA is true?

    <p>RNA uses ribose sugar as opposed to deoxyribose</p> Signup and view all the answers

    Which nitrogenous bases in DNA form 2 hydrogen bonds with each other?

    <p>Adenine and Thymine</p> Signup and view all the answers

    What is the role of hydrogen bonds in the double helix structure of DNA?

    <p>They stabilize the double helix.</p> Signup and view all the answers

    What is the direction of the DNA chain?

    <p>5’ to 3’</p> Signup and view all the answers

    Which of the following is not a component of a nucleotide in DNA?

    <p>Ribose sugar</p> Signup and view all the answers

    What classifies nuclear DNA?

    <p>Linear double-stranded DNA</p> Signup and view all the answers

    How many hydrogen bonds do guanine and cytosine form?

    <p>3</p> Signup and view all the answers

    Which type of DNA contains 37 genes coding for proteins involved in oxidative phosphorylation?

    <p>Mitochondrial DNA</p> Signup and view all the answers

    Which of the following best describes the structure of deoxyribonucleotides?

    <p>They include a phosphate and nitrogenous base.</p> Signup and view all the answers

    What characterizes the major and minor grooves of DNA?

    <p>They are regions for protein binding.</p> Signup and view all the answers

    Which element is found in the phosphate backbone of a DNA molecule?

    <p>Oxygen</p> Signup and view all the answers

    Which of the following statements about purines and pyrimidines is false?

    <p>Purines have a single-ring structure.</p> Signup and view all the answers

    What is the functional significance of phosphodiester linkages in DNA?

    <p>They create the sugar-phosphate backbone.</p> Signup and view all the answers

    How many base pairs are typically present in one turn of the DNA double helix?

    <p>10 bp</p> Signup and view all the answers

    Study Notes

    Molecular Biology Overview

    • Focuses on macromolecules essential for life: nucleic acids and proteins.
    • Overlaps with genetics and biochemistry.

    Eukaryotic and Prokaryotic Cells

    • Eukaryotic cells: found in animals, plants, fungi; true nucleus with nuclear membrane.
    • Prokaryotic cells: unicellular organisms like bacteria; genetic material dispersed in cytoplasm, no nuclear membrane.
    • Eukaryotic genome: complex, distributed among multiple chromosomes; DNA is linear complexed with proteins (nucleoproteins).
    • Prokaryotic DNA: circular molecule, naked (without proteins).

    Cell Division

    • Eukaryotic division: mitosis.
    • Prokaryotic division: binary fission.

    Genome and Genes

    • Genome: total genetic material of an organism, encoded primarily in DNA (or RNA for some viruses).
    • Human genome: 23 pairs of chromosomes (22 autosomes, 1 sex chromosome).
    • Germ cells have half the chromosome number of somatic cells.
    • Gene: segment of DNA or RNA coding for protein; basic unit of heredity located at specific points called loci.

    Alleles and Gene Structure

    • Alleles: variations of a gene, present in homologous chromosomes; they can be homozygous (identical) or heterozygous (different).
    • Most genes consist of exons (coding sequences) and introns (noncoding sequences), with promoter regions for RNA polymerase binding.

    Nucleic Acids

    • Nucleic acids are polymers of nucleotides; DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid).
    • DNA structure includes:
      • Double helix stabilized by hydrogen bonds.
      • 4 bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
      • 5’ to 3’ directional chain.

    Types of DNA Sequences

    • Nuclear DNA: includes genes and extragenic DNA (active and inactive).
    • Mitochondrial DNA: circular double strand DNA with 37 genes for oxidative phosphorylation.

    Extragenic DNA

    • Tandem repeats: repetitive sequences located together; classified into:
      • Satellite DNA: large nucleotide repeats.
      • Minisatellite: 10-60 bp repeats.
      • Microsatellite: 2-8 bp repeats; associated with hereditary disorders.

    RNA Classes

    • Three major RNA types:
      • Messenger RNA (mRNA): encodes protein synthesis; undergoes splicing, capping, and polyadenylation.
      • Transfer RNA (tRNA): carries amino acids to ribosomes for polypeptide chain assembly.
      • Ribosomal RNA (rRNA): structural and functional component of ribosomes, essential for protein synthesis.

    Applications of Molecular Biology

    • Research: foundational for genetic studies.
    • Diagnosis: assists in identifying genetic diseases.
    • Transplantation: compatibility testing.
    • Forensic analysis: DNA profiling for criminal justice.
    • Gene therapy: seeks to treat genetic disorders.
    • Drug design: innovates pharmaceuticals based on molecular mechanisms.

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    Description

    This quiz covers the essential concepts of molecular biology, focusing on the formation, structure, and function of vital macromolecules like nucleic acids and proteins. Test your knowledge and understanding of the fundamental aspects of life at the molecular level.

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