11.3. Causes of mutations

Causes of genetic mutations

Mutations can be spontaneous, caused by errors in replication or fortuitous DNA damage, or induced, artificially produced by mutagenic agents.

The DNA is subjected to repeated attacks of chemical or physical environment of the cell agents substances can cause natural mutations.

But in addition to nature, there are also attacks produced by unhealthy social (alcohol, tobacco,...) and eating habits that have increased the number of mutagenic agents. These mutagenic agents can be classified into:

Chemical mutagens: they are chemical compounds capable of abruptly altering DNA structures, such as:
- Alkylating agents, such as mustard gas, which alter replication by introducing radicals methyl, ethyl, ...
- Intercalating agents, such as acridine orange and benzopyrene. Benzopyrene that binds to DNA preventing base pairing.
- Deaminating agents.
- Analogs of puric and pyrimidine bases.
- Nitrous acid that accelerates the transformation of cytosine into uracil.
- Dioxins that are carcinogens.
Physical mutagens: these are radiations that can alter the sequence and structure of DNA.
- Non-ionizing radiation: For example, ultraviolet radiation that originates dimers of pyrimidine (generally thymine), which distort the double helix of DNA and prevent its replication and cell division or form free radicals.

By derivative work: Mouagip (talk)DNA_UV_mutation.gif: NASA/David HerringThis vector graphics image was created with Adobe Illustrator. (DNA_UV_mutation.gif) [Public domain], via Wikimedia Commons

Vídeo: Radiación UV y mutación del ADN.

Ionizing radiation (X-rays, gamma), break the phosphodiester bonds, altering the DNA chains. For example, gamma and alpha radiation. The ultrasound also produce structural chromosomal variations.
- - Biological mutagens: are those "living" organisms that can alter the sequences of the genetic material of their host, such as: viruses, bacteria and fungi. Examples are transposons (autonomous DNA fragments).
  - Factors that are not mutagenic agents but that determine whether or not a mutation will take place: temperature, oxygen pressure, aging.
  The 37 ºC of temperature causes, for example, that the human cells lose every day about 5000 puric bases (adenine and guanine) and the transformation of cytosine into uracil and adenine into hypoxanthine.
  - Mutagens that result from metabolized non-carcinogenic substances, for example benzopyrene is the substance resulting from liver metabolism.

Questions that have come out in University entrance exams (Selectividad, EBAU, EvAU)

Aragon. September 2018, option A, question 4. September 2014, option B, question 1.

Mutations (2.5 points)

c) Mutagens. (0.5 points)

Aragon. June 2016, option B, question 4.

Mutations: (2 points)

b) List two mutagenic agents. (0.5 points)

Andalusia, June 2017, option B, question 5.

In the radiology services of the health centers there are posters that warn of the risks of x-ray examinations to pregnant women or those who may be pregnant. What is this warning based on? Give reasons for the answer [1].

Murcia, September 2018, option B, question 5.

Answer the following questions:

a) What are mutations? (0.6 pts)

b) What is a mutagenic agent? (0.6 pts). Give an example of a physical mutagenic agent and another of a chemical agent (0.3 pts).

Extremadura, July 2020, question 6

Mutations and mutagenic agents:

A. Concept of mutation. (0.5 points)
B. Classification of mutagenic agents. Give two examples of each type. (1.5 points)

Extremadura, June 2021, question 6

6.-Regarding mutations:

A. Concept of mutation. (0.5 points)
B. Differentiate between gene and chromosomal mutation. (0.5 points)
C. List two types of mutagenic agents and give two examples for each of them. (1 point)

Navarra, June 2021, question 13

a) Cite 3 examples of mutagenic agents.

b) A person is continuously exposed to mutagenic agents in such a way that he suffers a mutation in his genome. What has happened if that mutation is hereditary?

c) What if that mutation is not hereditary?

Asturias, July 2021, question 4b

Define the concept of mutation. Name a physical and chemical mutagenic agent, indicating their action. (Maximum score 1 point)

Fundamental ideas about the causes of mutations

The causes of mutations can be:

Spontaneous, produced by errors in replication or by fortuitous DNA damage.
Induced, artificially produced by mutagenic agents.

Mutagens or mutagenic agents are chemical, physical or biological agents that alter the genetic information of an organism and this increases the frequency of mutations above the natural level.

Licensed under the Creative Commons Attribution Share Alike License 4.0

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Skip navigation Biology 2nd Baccalaureate Biology 2nd Bac. 1. Bioelements and biomolecules. Water and mineral salts 1.1. Chemical bonds in biology 1.1.1. Intramolecular bonds 1.1.1.1. Covalent bond 1.1.1.2. Ionic bond 1.1.2. Intermolecular bonds 1.1.2.1. Van der Waals forces 1.1.2.2. Hydrogen bonds 1.2. The chemical basis of life: inorganic and organic components 1.2.1. Primary bioelements 1.2.2. Secondary bioelements 1.2.3. Trace elements 1.3. The immediate principles or biomolecules 1.3.1. Water 1.3.1.1. Chemical structure of water 1.3.1.2. Properties and functions of water 1.3.2. Mineral salts 1.3.2.1. Functions of salts in solution 1.3.2.2. Colloidal solutions and dispersions 1.3.2.3. Properties of colloidal dispersions 1.3.2.4. Diffusion, osmosis and dialysis 1.3.2.4.1. Diffusion 1.3.2.4.2. Osmosis 1.3.2.4.3. Dialysis 1.4. Bibliography 2. Glucides 2.1. Glucid concept 2.2. Classification of carbohydrates 2.3. Monosaccharides 2.3.1. Trioses 2.3.1.1. Spatial isomerism or stereoisomerism 2.3.2. Tetroses 2.3.3. Pentoses 2.3.3.1. Monosaccharide cyclization 2.3.4. Hexoses 2.4. The N-glucosidic and O-glucosidic bonds 2.4.1. Substances derived from monosaccharides 2.5. Disaccharides 2.6. Polysaccharides 2.6.1. Homopolysaccharides 2.6.1.1. Reserve homopolysaccharides 2.6.1.2. Structural homopolysaccharides 2.6.2. Heteropolysaccharides 2.6.3. Heterosides 2.7. General functions of glucides 2.8. Bibliography 3. Lipids 3.1. Lipid concept 3.2. Classification of lipids 3.2.1. Fatty acids 3.2.1.1. Saturated and unsaturated fatty acids 3.2.1.2. Chemical properties of fatty acids 3.2.1.3. Physical properties of fatty acids 3.2.1.4. Fatty Acid Functions 3.2.2. Saponifiable lipids or with fatty acids 3.2.2.1. Simple lipids 3.2.2.1.1. Acylglycerides 3.2.2.1.2. Cerides 3.2.2.2. Complex lipids 3.2.2.2.1. Phospholipids 3.2.2.2.2. Glycolipids 3.2.3. Unsaponifiable lipids or without fatty acids 3.3. Lipid functions 3.4. Bibliography 4. Proteins 4.1. Introduction to proteins 4.2. Amino acids 4.2.1. Classification of amino acids 4.2.2. Properties of amino acids 4.3. The peptide bond 4.4. Protein 4.4.1. Protein structure 4.4.1.1. Primary structure of proteins 4.4.1.2. Secondary structure of proteins 4.4.1.3. Tertiary structure of proteins 4.4.1.4. Quaternary structure of proteins 4.4.2. Protein properties 4.4.3. Classification of proteins 4.4.3.1. Holoproteins 4.4.3.2. Heteroproteins 4.4.4. Protein functions 4.5. Enzymes 4.5.1. Structure of enzymes 4.5.2. The active center of enzymes 4.5.3. General Mechanism of Enzyme Catalysis 4.5.4. Regulation of enzyme activity 4.5.5. Allosteric enzymes 4.5.6. Nomenclature and classification of enzymes 4.6. The vitamins 4.6.1. Fat-soluble vitamins 4.6.2. Water soluble vitamins 4.7. Bibliography 5. Nucleotides and nucleic acids 5.1. The chemical composition of nucleic acids 5.1.1. Components of nucleic acids 5.1.2. Concept, types and functions of nucleic acids 5.1.3. Nucleosides 5.1.4. Nucleotides 5.1.4.1. Nucleotide functions 5.1.5. Nucleic acids 5.2. Deoxyribonucleic acid (DNA) 5.2.1. DNA structure 5.2.1.1. Primary structure of DNA 5.2.1.2. Secondary structure of DNA 5.2.1.3. Tertiary structure of DNA 5.2.1.3.1. Tertiary structure of DNA in prokaryotes 5.2.1.3.2. Tertiary structure of DNA in eukaryotes 5.2.1.4. Quaternary structure of DNA 5.2.2. DNA types 5.2.3. Genetic material: chromatin and chromosomes 5.2.3.1. Karyotype and karyogram 5.3. Ribonucleic acid (RNA) 5.3.1. RNA types 5.3.1.1. Transfer RNA 5.3.1.2. Messenger RNA 5.3.1.3. Ribosomal RNA 5.3.1.4. Nucleolar RNA 5.3.1.5. Small nuclear RNA 5.3.2. Functions of ribonucleic acids 5.4. Bibliography 6. Cell morphology 6.1. Cell concept 6.1.1. Cell history 6.1.2. Cell theory 6.2. Levels of cellular organization 6.2.1. General characteristics of cells 6.2.2. Prokaryotic cells 6.2.2.1. Prokaryotic cell morphology 6.2.2.2. Structure of prokaryotes 6.2.2.2.1. Bacterial capsule 6.2.2.2.2. Bacterial wall 6.2.2.2.3. Plasma membrane 6.2.2.2.4. Cytoplasm-Ribosomes-Inclusions 6.2.2.2.5. Bacterial DNA 6.2.2.2.6. Bacterial appendages 6.2.2.3. Bacteria Physiology 6.2.3. Eukaryotic cells 6.2.3.1. Animal and plant cell 6.2.3.1.1. Animal eukaryotic cell 6.2.3.1.2. Plant eukaryotic cell 6.2.3.2. Cell Evolution: Endosymbiont Theory 6.3. Size, shape and quantity 6.4. The plasma membrane 6.4.1. Chemical composition of the membrane 6.4.2. The structure of the membrane. The fluid mosaic model 6.4.3. Functions of the plasma membrane 6.4.4. Transport across the membrane 6.4.4.1. Small molecule transport 6.4.4.2. Macromolecule transport 6.4.5. Plasma membrane differentiations 6.5. The cell wall of plant cells 6.5.1. Chemical composition of the cell wall 6.5.2. Cell wall structure 6.5.3. Cell wall differentiations 6.5.4. Cell wall functions 6.6. Extracellular matrix or glucocalyx 6.7. Cytosol or hyaloplasm 6.8. The cytoskeleton 6.8.1. Microfilaments or actin filaments 6.8.2. Intermediate filaments 6.8.3. Microtubules 6.9. Cell membrane and organelle systems 6.9.1. Membrane systems 6.9.1.1. The endoplasmic reticulum 6.9.1.2. Golgi apparatus 6.9.2. Cell organelles 6.9.2.1. Lysosomes 6.9.2.2. Peroxisomes 6.9.2.3. Vacuoles 6.9.2.4. Mitochondria 6.9.2.4.1. Functions of the mitochondria 6.9.2.5. Plastids 6.9.2.5.1. Chloroplasts 6.9.2.6. Ribosomes 6.9.2.7. Centrosome 6.9.2.8. Cilia and flagella 6.10. Cell motility 6.11. The cell nucleus 6.11.1. Characteristics of the cell nucleus 6.11.2. The interphase nucleus 6.11.3. The mitotic nucleus or nucleus in division 6.12. Bibliography 7. Metabolism 7.1. Metabolism 7.1.1. Energetic Aspects of Cellular Chemical Reactions 7.2. Catabolism 7.2.1. Catabolism and obtaining energy 7.2.2. Carbohydrate catabolism 7.2.2.1. Glycolysis 7.2.2.2. Cellular respiration 7.2.2.2.1. Oxidative decarboxylation 7.2.2.2.2. Krebs cycle 7.2.2.2.3. Electron transport chain 7.2.2.2.4. Energy balance of cellular respiration 7.2.2.3. Fermentations 7.2.2.3.1. Alcoholic or ethyl fermentation 7.2.2.3.2. Lactic fermentation 7.2.2.3.3. Other types of fermentations 7.3. Anabolism 7.3.1. Autotrophic anabolism 7.3.2. Photosynthesis 7.3.2.1. Photochemical or light phase 7.3.2.1.1. Photosystems 7.3.2.1.2. Photophosphorylation 7.3.2.1.2.1. Non cyclic photophosphorylation 7.3.2.1.2.2. Cyclic photophosphorylation 7.3.2.2. Biosynthetic or dark phase 7.3.2.3. Factors influencing photosynthesis 7.3.2.4. Products of photosynthesis 7.3.3. Chemosynthesis 7.4. Bibliography 8. Cell reproduction 8.1. The cell cycle 8.1.1. Interphase 8.1.2. Cellular division 8.2. Cellular division 8.2.1. Mitosis 8.2.1.1. Prophase 8.2.1.2. Metaphase 8.2.1.3. Anaphase 8.2.1.4. Telophase 8.2.1.5. Cytokinesis 8.2.1.6. More on mitosis 8.2.2. Meiosis 8.2.2.1. Meiosis I 8.2.2.2. Meiosis II 8.2.3. Meiosis and sexual reproduction 8.2.4. Meiosis and life cycle 8.2.5. Biological importance of meiosis 8.3. Differences and similarities between mitosis and meiosis 8.4. Bibliography 9. Classical genetics 9.1. Genetics basics 9.2. Mendelian genetics 9.2.1. The method 9.2.2. Mendel's Laws 9.2.2.1. Mendel's first law or principle of uniformity in the first generation 9.2.2.2. Mendel's second law or principle of segregation 9.2.2.2.1. Backcross and test crossover 9.2.2.3. Mendel's third law or principle of independent combination 9.3. Gene interaction 9.3.1. Gene interaction between allelic genes 9.3.2. Gene interaction between non-allelic genes that influence for the same trait 9.4. Chromosomal theory of heredity 9.5. Ligation and recombination 9.6. Complex mendelism 9.6.1. Multiple allelism 9.6.1.1. Lethal genes 9.6.2. Pleiotropy 9.6.3. Expressiveness and genetic penetrance 9.7. Sex-linked inheritance 9.7.1. Y-linked inheritance 9.7.2. X-linked inheritance 9.8. Heredity influenced by sex 9.9. Bibliography 10. Molecular genetics 10.1. DNA as hereditary material 10.2. DNA replication 10.2.1. The need for DNA replication 10.2.2. First hypotheses about DNA duplication 10.2.3. Meselson and Stahl experiment 10.2.4. The sense of growth of the new strands 10.2.5. Mechanism of DNA replication 10.2.5.1. Replication in prokaryotes 10.2.5.2. Replication in eukaryotes 10.2.6. Error correction 10.2.7. Enzymes involved in replication 10.3. Gene concept 10.4. "One gene-one enzyme" theory 10.5. Transcription 10.5.1. Mechanism of transcription 10.5.1.1. Transcription in prokaryotes 10.5.1.2. Eukaryotic transcription 10.6. Translation or protein biosynthesis 10.6.1. The genetic code 10.6.2. Mechanism of translation of RNA to proteins 10.6.2.1. Translation in eukaryotes 10.7. Regulation of gene expression 10.8. Bibliography 11. Genetics and evolution 11.1. Mutations 11.2. Types of mutations 11.2.1. Gene or point mutation 11.2.2. Chromosomal or structural mutation 11.2.3. Mutation at the genomic level 11.3. Causes of mutations 11.4. Evolutionary implications of mutations 11.5. Metabolic implications of mutations 11.6. Bibliography 12. Microbiology and biotechnology 12.1. Microbiology 12.2. Viruses 12.2.1. Viral morphology 12.2.2. Viral physiology 12.2.2.1. Lytic cycle 12.2.2.2. Lysogenic cycle 12.2.2.3. Cycles of viruses of special interest 12.2.2.3.1. Flu virus life cycle 12.2.2.3.2. Life cycle of the AIDS virus 12.3. Other acellular forms 12.3.1. Viroids 12.3.2. Prions 12.4. Biotechnology 12.5. Bibliography 13. Immunology 13.1. Infection concept 13.2. Defense mechanisms against infections 13.2.1. Nonspecific mechanisms 13.2.1.1. Primary barriers: external defenses 13.2.1.2. Secondary barriers: internal defenses 13.2.2. Specific mechanisms 13.3. Immunity and immune system 13.3.1. Components of the immune system 13.3.2. Concept and nature of antigens 13.4. The immune response 13.4.1. Humoral immune response: the antibodies 13.4.1.1. Antibody-producing cells: B lymphocytes 13.4.1.2. Antibodies 13.4.1.2.1. Types of antibodies 13.4.1.2.2. Antigen-antibody reaction 13.4.1.3. Immune memory: primary and secondary responses 13.4.2. Cellular immune response: T lymphocytes 13.5. Types of immunity 13.5.1. Natural immunity 13.5.2. Artificial immunity 13.6. Immune system disorders 13.6.1. Autoimmunity 13.6.2. Hypersensitivity 13.6.3. Immunodeficiency 13.6.4. Transplants and the phenomenon of rejections 13.7. Bibliography « Previous \| Next » 11.3. Causes of mutations Causes of genetic mutations Mutations can be spontaneous, caused by errors in replication or fortuitous DNA damage, or induced, artificially produced by mutagenic agents. The DNA is subjected to repeated attacks of chemical or physical environment of the cell agents substances can cause natural mutations. But in addition to nature, there are also attacks produced by unhealthy social (alcohol, tobacco,...) and eating habits that have increased the number of mutagenic agents. These mutagenic agents can be classified into: Chemical mutagens: they are chemical compounds capable of abruptly altering DNA structures, such as: Alkylating agents, such as mustard gas, which alter replication by introducing radicals methyl, ethyl, ... Intercalating agents, such as acridine orange and benzopyrene. Benzopyrene that binds to DNA preventing base pairing. Deaminating agents. Analogs of puric and pyrimidine bases. Nitrous acid that accelerates the transformation of cytosine into uracil. Dioxins that are carcinogens. Physical mutagens: these are radiations that can alter the sequence and structure of DNA. *Non-ionizing radiation: For example, ultraviolet radiation* that originates dimers of pyrimidine (generally thymine), which distort the double helix of DNA and prevent its replication and cell division or form free radicals. By derivative work: Mouagip (talk)DNA_UV_mutation.gif: NASA/David HerringThis vector graphics image was created with Adobe Illustrator. (DNA_UV_mutation.gif) [Public domain], via Wikimedia Commons Vídeo: Radiación UV y mutación del ADN. *Ionizing radiation (X-rays, gamma), break the phosphodiester bonds, altering the DNA chains. For example, gamma* and alpha radiation. The ultrasound also produce structural chromosomal variations. Biological mutagens: are those "living" organisms that can alter the sequences of the genetic material of their host, such as: viruses, bacteria and fungi. Examples are transposons (autonomous DNA fragments). Factors that are not mutagenic agents but that determine whether or not a mutation will take place: temperature, oxygen pressure, aging. The 37 ºC of temperature causes, for example, that the human cells lose every day about 5000 puric bases (adenine and guanine) and the transformation of cytosine into uracil and adenine into hypoxanthine. Mutagens that result from metabolized non-carcinogenic substances, for example benzopyrene is the substance resulting from liver metabolism. Questions that have come out in University entrance exams (Selectividad, EBAU, EvAU) Aragon. September 2018, option A, question 4. September 2014, option B, question 1. Mutations (2.5 points) c) Mutagens. (0.5 points) Aragon. June 2016, option B, question 4. Mutations: (2 points) b) List two mutagenic agents. (0.5 points) Andalusia, June 2017, option B, question 5. In the radiology services of the health centers there are posters that warn of the risks of x-ray examinations to pregnant women or those who may be pregnant. What is this warning based on? Give reasons for the answer [1]. Murcia, September 2018, option B, question 5. Answer the following questions: a) What are mutations? (0.6 pts) b) What is a mutagenic agent? (0.6 pts). Give an example of a physical mutagenic agent and another of a chemical agent (0.3 pts). Extremadura, July 2020, question 6 Mutations and mutagenic agents: A. Concept of mutation. (0.5 points) B. Classification of mutagenic agents. Give two examples of each type. (1.5 points) Extremadura, June 2021, question 6 6.-Regarding mutations: A. Concept of mutation. (0.5 points) B. Differentiate between gene and chromosomal mutation. (0.5 points) C. List two types of mutagenic agents and give two examples for each of them. (1 point) Navarra, June 2021, question 13 a) Cite 3 examples of mutagenic agents. b) A person is continuously exposed to mutagenic agents in such a way that he suffers a mutation in his genome. What has happened if that mutation is hereditary? c) What if that mutation is not hereditary? Asturias, July 2021, question 4b Define the concept of mutation. Name a physical and chemical mutagenic agent, indicating their action. (Maximum score 1 point) Fundamental ideas about the causes of mutations The causes of mutations can be: Spontaneous, produced by errors in replication or by fortuitous DNA damage. Induced, artificially produced by mutagenic agents. Mutagens or mutagenic agents are chemical, physical or biological agents that alter the genetic information of an organism and this increases the frequency of mutations above the natural level. Licensed under the Creative Commons Attribution Share Alike License 4.0 « Previous \| Next » These pages are semi-automatically translated from the web Biology 2nd Baccalaureate. Biología de 2º de Bachillerato (biologia-geologia.com). You can make any suggestion, question, comment, ..., in our forum 2º Bachillerato Biología - Foro de biologia-geologia.com
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Causes of genetic mutations