Genetic Material and DNA Structure
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Questions and Answers

What is the sugar molecule found in DNA?

  • Glucose
  • Ribose
  • Deoxyribose (correct)
  • Fructose
  • What is the function of promoters in DNA?

  • To regulate gene expression (correct)
  • To transcribe genes
  • To translate proteins
  • To replicate DNA
  • What is the main difference between DNA and RNA?

  • DNA contains uracil, while RNA contains thymine
  • DNA is composed of nucleotides with deoxyribose, while RNA is composed of nucleotides with ribose (correct)
  • DNA is single-stranded, while RNA is double-stranded
  • DNA is found in the nucleus, while RNA is found in the cytoplasm
  • What is the function of histones in eukaryotic cells?

    <p>To store DNA in the nucleus</p> Signup and view all the answers

    What is the name of the segments of DNA that can move throughout the genome?

    <p>Transposable elements</p> Signup and view all the answers

    What is the main purpose of meiosis?

    <p>To produce gametes that are genetically unique from one another</p> Signup and view all the answers

    What is the term for the process of an egg and a sperm combining their genetic material?

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

    What is the result of crossing-over during meiosis I?

    <p>Chromosomes with genetically unique allele combinations</p> Signup and view all the answers

    What is the number of cell divisions involved in meiosis?

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

    What is the term for the type of cell division that results in two identical diploid cells?

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

    What is the primary function of DNA in eukaryotic cells?

    <p>Providing instructions for protein synthesis</p> Signup and view all the answers

    What is the role of lactase in the human body?

    <p>Breaking down lactose</p> Signup and view all the answers

    What is the result of a damaged p53 protein?

    <p>Uncontrolled cell growth</p> Signup and view all the answers

    What is the function of hemoglobin in the human body?

    <p>Carrying oxygen from the lungs around the body</p> Signup and view all the answers

    What is the purpose of cell differentiation?

    <p>To create diversity in life on Earth and within the cells of our body</p> Signup and view all the answers

    What is the process by which undifferentiated cells become specialized cells with a specific structure and function?

    <p>Cellular differentiation</p> Signup and view all the answers

    What is the main reason why somatic cells look and behave differently from each other despite having the same genome?

    <p>Different genes are expressed in the nuclei of different cells</p> Signup and view all the answers

    What is the role of transcription factors in cell differentiation?

    <p>They cause changes in proteins that control gene expression</p> Signup and view all the answers

    What is the purpose of differential gene expression analysis in the study of cellular differentiation?

    <p>To determine which genes are expressed in a cell</p> Signup and view all the answers

    What is the function of enhancers and promoters in gene expression?

    <p>They guide gene expression into proteins</p> Signup and view all the answers

    Study Notes

    Genetic Material

    • Genetic material is the hereditary material of the cell, holding the information needed for all cell structure and function.
    • There are two main types of genetic material: DNA and RNA.
    • In eukaryotic cells, DNA is stored in the nucleus, wrapped around proteins called histones.
    • In prokaryotic cells, DNA exists in the cytoplasm.

    DNA Structure

    • DNA is a double helix made of two strands of nucleotides twisted together.
    • Each nucleotide consists of a sugar, a phosphate, and a base.
    • There are four bases in DNA: adenine (A), guanine (G), cytosine (C), and thymine (T).

    RNA

    • RNA is made of nucleotides but has ribose sugar instead of deoxyribose.
    • RNA is single-stranded, and different bases are used, including adenine (A), guanine (G), cytosine (C), and uracil (U).

    Human Genome

    • The human genome is made up of many different types of DNA sequences, including:
      • Introns (intervening sequences)
      • Exons (expressed regions that encode amino acids)
      • Unique noncoding DNA (pseudogenes, segments of inactive DNA)
      • Regulatory sequences (promoters, which delineate where gene transcription begins)
      • Repetitive DNA (sequences repeated throughout the genome, related to transposable elements)

    Protein Synthesis

    • Deoxyribonucleic acid (DNA) is a double helix structure composed of nucleotides.
    • Nucleotides are composed of a phosphate group, a deoxyribose sugar, and a nitrogen-containing base.
    • Nitrogen-containing bases form hydrogen bonds to form the double helix.
    • DNA resides in the nucleus of eukaryotic cells or floats freely in the cytoplasm of prokaryotic cells.
    • DNA provides instructions for protein synthesis through transcription and translation.

    Protein Functions

    • Proteins serve many functions in the cell, including:
      • Providing structure
      • Regulating body processes
      • Transporting materials
      • Balancing fluids
      • Helping with immunity
      • Providing energy
    • Examples of proteins include:
      • Keratin (found in hair and skin)
      • Collagen (found in connective tissues)
      • Hormones (regulate body processes and cell activity)
      • Enzymes (speed up chemical processes)
      • Hemoglobin (transports oxygen from the lungs)

    Cell Division

    • Cell division is essential in all living organisms.
    • In eukaryotes, cell division occurs via:
      • Mitosis (produces new somatic, or body, cells)
      • Meiosis (produces gametes, like sperm and ova)
    • Mitosis has five stages:
      • Prophase (chromosome condensation, break-down of nuclear envelope)
      • Metaphase (chromosomes aligned at metaphase plate)
      • Anaphase (sister chromatids pulled to each end of the cell)
      • Telophase (nuclear envelope forms again)
      • Cytokinesis (cleavage furrow separates daughter cells in animal cells, cell plate separates daughter cells in plant cells)

    Cell Differentiation

    • Cell differentiation is the process of stem cells becoming more specialized.
    • Cell differentiation creates diversity in life on Earth, within the cells of our body, and allows cells to create unique structures that fit their individualized functions.

    Somatic Cells

    • Somatic cells are specialized cells with a fixed structure and function.
    • Examples of somatic cells include liver cells, skin cells, kidney cells, and brain cells.
    • Before somatic cells became specialized, they were undifferentiated cells called stem cells in the fetus.
    • Cellular differentiation is the process that triggers cellular differentiation, and it is triggered by differential gene expression.

    Genes

    • Genes are the basic unit of inheritance, composed of DNA.
    • Genes reside in the nucleus of eukaryotic cells, wrapped around proteins called histones.
    • In prokaryotes, genes are present on chromosomes floating free in the cytoplasm.
    • Gene expression into proteins is guided by extrinsic factors such as enhancers and promoters.

    Chromosomes

    • Chromosomes are structures containing DNA wrapped around histones to form nucleosomes.
    • There are 46 human chromosomes, forming 22 pairs of autosomal chromosomes and one pair of sex chromosomes.
    • Chromosomes represent a pair of sister chromatids, each containing the same genetic information, joined by a common centromere.
    • There are four main types of chromosomes:
      • Metacentric chromosomes (centromere located at the center)
      • Submetacentric chromosomes (centromere slightly off-center)
      • Acrocentric chromosomes (centromere significantly off-center)
      • Telocentric chromosomes (centromere located at the end of the chromosome)

    Meiosis

    • Meiosis is a process in which a gamete-producing cell undergoes two cell divisions, known as meiosis I and meiosis II, to produce four gametes (sperm or egg cells).
    • Meiosis allows for genetic variations in offspring during sexual reproduction.
    • Meiosis has two main divisions: meiosis I and meiosis II.
    • During meiosis I, homologous pairs of chromosomes combine to form a tetrad, and chromatids exchange alleles, resulting in genetically unique allele combinations.

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    Description

    This quiz covers the basics of genetic material, including DNA and RNA, their storage in eukaryotic and prokaryotic cells, and the structure of DNA as a double helix.

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