Molecular Biology & DNA

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The NIH Genetics Home Reference Handbook explains that mutations are passed to offspring if these mutations are present in germ line (sperm or egg) cells. Germ line mutations can occur early in the parent's development so that they affect all of the cells in the parent's body, including eventual gametes. These mutations can also occur in gametes alone and therefore only affect offspring.

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  • Why did Gregor Mendel use pea plants in his research?

    Q: Why did Gregor Mendel use pea plants in his research?

    A: Gregor Mendel used pea plants in his research on heredity because they had characteristics that were consistent and easy to recognize. Pea plants had other qualities that also made them ideal for cross-pollination.
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  • What is the main function of nucleic acids?

    Q: What is the main function of nucleic acids?

    A: Nucleic acids are biochemical macromolecules that store and transfer genetic information in the cell. They use their stored genetic information to direct the synthesis of new proteins in the cell. New proteins can be synthesized by the ribosomes from the DNA and genes held in the nucleic acids.
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  • What is a codon and where is it found?

    Q: What is a codon and where is it found?

    A: A codon is a sequence of three nucleotides in DNA or RNA that either codes for a particular amino acid or tells the cellular machinery to start or stop using the code. A group of codons starts with the initiation codon. It then has codons in sequence that gives instructions on the amino acids to use to build a protein, and it then has a stop codon to signal when the protein assembly is complete. Normally, there is one initiation codon and three stop codons, and most amino acids are represented by more than one codon.
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  • What is RNA primase?

    Q: What is RNA primase?

    A: According to Scitable, RNA primase is an enzyme involved in the replication of DNA strands during cell division. It goes over a single DNA strand and creates RNA sequences called primers, which transcribe DNA into RNA. These short sequences of RNA are complementary to the DNA strand they were hovering over, and serve as a template for a new strand of DNA.
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  • Why is DNA called the blueprint of life?

    Q: Why is DNA called the blueprint of life?

    A: Just as blueprints direct the building of a house, DNA molecules contain the genetic instructions used in the development and functioning of a living organism. The DNA of eukaryotic organisms such as plants and animals is organized into linear chromosomes and stored within the nucleus of every cell.
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  • Under what circumstances can an atom emit a photon?

    Q: Under what circumstances can an atom emit a photon?

    A: Atoms emit a photon when an electron falls from a high-energy state to a low-energy state. The conditions under which this process occurs happen in two ways. According to the Cornell Center for Materials Research, electrons either absorb the energy from a photon and jump to a higher energy level or a photon collides with an electron that is already in an excited state.
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  • What is the Mitochondrial Eve?

    Q: What is the Mitochondrial Eve?

    A: Mitochondrial Eve is a concept in molecular biology that refers to a common ancestor of all of the currently living anatomically modern human beings. The concept describes a maternal lineage of mitochondrial DNA that originated approximately 100,000 to 200,000 years ago.
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  • Where is genetic information stored?

    Q: Where is genetic information stored?

    A: Genetic information is stored in several places, which are DNA molecules, genes, chromosomes, mitochondria and the genome. Different amounts and types of genetic information are stored in these locations. The majority of genetic information is stored within individual DNA molecules, although it is found in other cellular locations as well.
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  • What is an example of mutualism in the rainforest?

    Q: What is an example of mutualism in the rainforest?

    A: An example of mutualism in the rainforest is the pollination of the Durian tree by bats. However, there are many other examples of mutualism in this type of ecosystem.
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  • Why must DNA be able to make copies of itself?

    Q: Why must DNA be able to make copies of itself?

    A: The University of Illinois at Chicago explains that DNA must replicate itself so that during cell division, both daughter cells receive the same genetic information. DNA replication is necessary during the process by which somatic cells divide, called mitosis, as well as during meiosis, the process by which organisms produce gametes, or sex cells.
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  • Is parthenogenesis possible in humans?

    Q: Is parthenogenesis possible in humans?

    A: Parthenogenesis is possible in humans but very unlikely to result in a viable baby. In order for an embryo to develop from an unfertilized egg, the egg would have to sense a spike in calcium, skip meiosis and then lose at least two specific maternal genes.
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  • What is a gene chip?

    Q: What is a gene chip?

    A: A DNA microchip or gene chip is a tiny chip that has many single strands of the DNA from a specific gene attached to it. Sometimes a microchip has more than one gene's DNA on it or different variations of a gene. It is used to test for gene mutations, such as the ones that are thought to be responsible for a larger percentage of hereditary breast cancer cases.
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  • What is the function of chromosomes?

    Q: What is the function of chromosomes?

    A: Reference.com says that the function of chromosomes is to carry hereditary information. Chromosomes are located in the nucleus of a cell, and when a cell divides, so do the chromosomes.
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  • What happens during DNA replication?

    Q: What happens during DNA replication?

    A: During DNA replication, two strands of DNA separate, and each separate strand forms a template to make a new strand. The replication process results in the formation of two identical molecules, containing one strand from the original piece of DNA and one newly synthesized strand.
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  • What is chromatin made of?

    Q: What is chromatin made of?

    A: Chromatin is made of nucleic acids, such as DNA or RNA, and proteins. During cell division, chromatin condenses to form chromosomes. Eukaryotic and prokaryotic cells differ in where chromatin is housed. In eukaryotes, it is located in the nucleus and in prokaryotes, it is located in the nucleoid.
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  • What makes up the rungs of the DNA molecule?

    Q: What makes up the rungs of the DNA molecule?

    A: As shown on the NIH Genetics Home Reference site, when DNA molecules are represented as ladders, the rungs represent the base pairs of the DNA. The bases in DNA are often represented as G, A, T and C, which stand for guanine, adenine, thymine and cytosine. When two strands of DNA form a double-strand helix, the bases pair up in the middle of the molecule.
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  • What class of macromolecules does DNA belong to?

    Q: What class of macromolecules does DNA belong to?

    A: DNA, also known as deoxyribonucleic acid, belongs to a class of polymeric organic macromolecules called nucleic acids. The only other member of this class is ribonucleic acid, or RNA. Nucleic acids were first discovered in 1869 by the Swiss scientist Friedrich Miescher.
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  • What is the difference between dominant and recessive alleles?

    Q: What is the difference between dominant and recessive alleles?

    A: Dominant alleles are always expressed in the organism, while recessive traits tend to be expressed only when the dominant allele is not present. The relationship between dominant and recessive genes is described by the Law of Segregation. As related by About.com, Gregor Mendel observed nine different traits among his pea plants and found that certain traits, such as pod color, bred true only when two recessive alleles were present.
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  • What is genetic splicing?

    Q: What is genetic splicing?

    A: Genetic splicing is the process in which an organism's DNA is cut and another gene is added. It is used so single-celled organisms can produce certain products, such as insulin, and produces genetically altered organisms.
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  • What is the chemical composition of carbohydrates?

    Q: What is the chemical composition of carbohydrates?

    A: All carbohydrates are made from carbon, hydrogen and oxygen. They have twice as many hydrogen atoms as oxygen atoms. The word "carbohydrate" is a combination of the names of these elements and means "watered carbon." The presence of carbon makes carbohydrates organic, rather than inorganic, compounds.
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  • What is the difference between chromatin vs. chromosome?

    Q: What is the difference between chromatin vs. chromosome?

    A: Chromatin and chromosomes are both structures of DNA, but chromosomes are condensed chromatin. DNA exists as chromatin a majority of the time so that the DNA is accessible to proteins for transcription and proteins can be made during the process of translation. Chromatin is condensed into chromosomes during mitosis to ensure that replicated genetic information is divided equally between the two resulting daughter cells.
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