Polymorphisms & Genes
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Questions and Answers

What is a single base change in DNA called?

  • Chromosomal variation
  • Genetic drift
  • Single nucleotide polymorphism (SNP) (correct)
  • Short tandem repeat polymorphism (STR)
  • How much of your DNA do you share with other humans?

  • 99.0%
  • 97.5%
  • 98.5%
  • 99.5% (correct)
  • Which of the following describes short tandem repeat polymorphisms (STR)?

  • They involve substitutions of entire genes.
  • They are variations involving a single base pair.
  • They are long sections of DNA over 100 base pairs.
  • They are short sections of DNA that are repeated multiple times. (correct)
  • What percentage of DNA do humans share with chimpanzees?

    <p>98.5%</p> Signup and view all the answers

    What structure within cells contains the majority of human genes?

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

    What type of variations are commonly found in intron sequences among humans?

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

    How many chromosomes do humans typically have?

    <p>46</p> Signup and view all the answers

    What is the total number of base pairs in the human genome?

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

    What are gene regulators responsible for?

    <p>Turning different genes on and off</p> Signup and view all the answers

    What is a common characteristic of most single nucleotide polymorphisms (SNPs)?

    <p>They account for many genetic differences among people.</p> Signup and view all the answers

    What percentage of the human genome is made up of exons that encode proteins?

    <p>1%</p> Signup and view all the answers

    What are polymorphisms primarily associated with?

    <p>Inherited non-coding DNA variations</p> Signup and view all the answers

    Which of the following is NOT a characteristic of introns?

    <p>Introns are mostly responsible for genetic diseases.</p> Signup and view all the answers

    What is the main risk associated with mutations occurring in exons?

    <p>They may result in genetic diseases.</p> Signup and view all the answers

    How do mutations in introns affect an individual?

    <p>They usually have no effect on function.</p> Signup and view all the answers

    What was the early perception of noncoding DNA often referred to as?

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

    What is the main reason mutations in exons are less likely to be passed on compared to those in introns?

    <p>Exon mutations often lead to a decrease in reproductive success.</p> Signup and view all the answers

    Which genetic diseases are primarily caused by mutations in exons?

    <p>Cystic fibrosis and sickle cell disease</p> Signup and view all the answers

    Which factor contributes to the uniqueness of individuals in the population?

    <p>Differences in noncoding DNA</p> Signup and view all the answers

    What is the role of introns in the gene structure?

    <p>They contribute to chromosome structure.</p> Signup and view all the answers

    The portion of Eukaryotic DNA that encodes proteins comprises about 50% of the genome.

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

    Introns are responsible for the majority of known genetic diseases due to mutations.

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

    Polymorphisms are variations found in non-coding DNA that can act as genetic fingerprints.

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

    Mutations in introns have a higher likelihood of being passed down through generations than mutations in exons.

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

    Scientists originally viewed noncoding DNA as having significant functional roles within the cell.

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

    Random mutations are more likely to occur in exons since they are crucial for protein function.

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

    Mutations occurring in an exon can lead to serious health issues in an individual.

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

    Introns are considered filler DNA that may contribute to the structural integrity of chromosomes.

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

    The differences passed down through generations due to random mutations in exons often lead to genetic variation between individuals.

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

    The majority of human genetic variation arises from mutations in coding regions of DNA.

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

    Polymorphisms specifically refer to variations in the exon sequences of DNA.

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

    Single nucleotide polymorphisms (SNPs) are the most common type of genetic variation.

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

    Humans typically possess 23 pairs of chromosomes.

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

    The human genome consists of approximately 3 million base pairs.

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

    Most SNPs have observable differences that can affect an individual’s appearance or health.

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

    You share 98.5% of your DNA with chimpanzees.

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

    Introns are primarily responsible for coding proteins in genes.

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

    Gene regulators are proteins that help to express the appropriate traits in an organism.

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

    Short tandem repeat polymorphisms (STRs) consist of longer sections of DNA than SNPs.

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

    The majority of your genes are located in your mitochondria.

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

    Study Notes

    Human Genes and DNA

    • Humans have approximately 20,000-25,000 genes.
    • Only about 1% of DNA codes for proteins (exons).
    • Introns are non-coding DNA regions interspersed with exons; not used for protein synthesis, but may affect chromosome structure.
    • Originally, non-coding regions were called "junk DNA," but evidence shows some have important functions like gene regulation.
    • Human genetic differences are mainly found in non-coding regions.

    Polymorphisms

    • Polymorphisms are inherited segments of non-coding DNA, acting as genetic fingerprints.
    • Population variations form the basis of polymorphisms.
    • Non-coding DNA mutations are more likely to be passed down due to no direct effect on protein function.
    • Polymorphisms can involve single base changes (SNPs) or repeated sections (STRs).

    Mutations and Genetic Diseases

    • Random mutations can occur anywhere in the genome.
    • Exon mutations are often harmful, causing genetic diseases (e.g., cystic fibrosis, sickle cell disease, Huntington's disease).
    • Exon mutations negatively impact cell function and are less likely to be passed on.
    • Intron mutations generally have no effect on cell function and are easily inherited.
    • Exons responsible for nearly identical sequences between humans, while introns show variation among individuals.

    Relatedness and DNA

    • Humans share around 99.9% of their genes.
    • Variations in introns (polymorphisms) provide insights into shared ancestry.
    • Single nucleotide polymorphisms (SNPs) are the most common type, involving single base-pair changes.
    • Short tandem repeat polymorphisms (STRPs) involve repeated short DNA sequences.

    DNA Structure and Function

    • DNA is a double-stranded molecule composed of sugar, phosphate, and four bases (adenine, thymine, cytosine, guanine).
    • The order of these bases determines genetic traits.
    • Genes are recipes for making proteins, and these recipes are inherited.
    • Genes function through protein production; cells express specific traits using genes.
    • A cell's function is orchestrated by Gene Regulators turning on or off specific genes based on the need.
    • The full set of 23 human chromosomes constitutes a human genome.
    • Variation in a single base pair is a single nucleotide polymorphism (SNP).

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    Description

    Explore the fascinating world of human genetics through this quiz covering DNA, genes, polymorphisms, and mutations. Learn the essentials of coding and non-coding DNA, their roles, and how mutations can lead to genetic diseases. Test your understanding of genetic variations and their implications in human health.

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