12.2.2.3.2. Life cycle of the AIDS virus

Life cycle of the AIDS virus (human immunodeficiency syndrome)

The viruses that cause AIDS in humans (HIV₁ and HIV₂) are from the group of retroviruses, having single-stranded RNA as their genetic material. Therefore, their genetic material can act as mRNA and form proteins in the cells they parasitize. For DNA synthesis, two copies of its RNA and the help of the reverse transcriptase enzyme are needed.

VIH.gif (Imagen GIF, 320 × 261 píxeles) - Escalado (0 %). (s. f.). Recuperado a partir de http://4.bp.blogspot.com/_1z5CA504lBU/TU-xsFUWg4I/AAAAAAAAACI/V3OdxwQpuns/s320/VIH

The HIV virus has proteins in its envelope that are attracted to receptors located on the membrane of a lymphocyte. When the virus binds to the receptor, other proteins in the membrane are activated that cause both membranes to fuse. This recognition is necessary for the virus to adhere to and enter the cell.
After fusing, decapsidation occurs, leaving the virus RNA free in the cytoplasm. The viral enzyme reverse transcriptase will transcribe the RNA of the virus into a double strand of DNA. At this point, it is fairly easy for mutations to occur in HIV, since reverse transcriptase often makes mistakes when moving from viral RNA to DNA.
HIV (proviral) DNA enters the nucleus of the infected cell.
The integration of viral DNA into the cell's DNA occurs thanks to the intervention of an enzyme called integrase.
RNA and proteins are produced from DNA that will allow the formation of new viruses. The provirus (viral DNA integrated into the DNA of the host cell) can be inactive for a long time without producing new copies of HIV (quiescent cells with latent virus).
Assembly: New viruses are formed with RNA, proteins, and cell membrane.
Budding: The newly assembled virus leaves the cell through the plasma membrane, surrounding itself with a fragment that will form its envelope.
The newly formed virus is immature, and the action of another enzyme, the HIV protease, is necessary for it to mature and become infectious, transforming into a mature HIV.
The AIDS virus (HIV) is a retrovirus, so its genetic material is RNA (and not DNA). In order to replicate within the host cell (T4 lymphocytes), the RNA molecule has to form double-stranded DNA with the help of the enzyme reverse transcriptase or reverse transcriptase. Once viral DNA is formed, it can form new viral particles through RNA and protein synthesis. If treatment with reverse transcriptase inhibitors is carried out, the replication of the virus is paralyzed and the viral load of the patient decreases.

By US National Institute of Health (redrawn by en:User:Carl Henderson) [Public domain], via Wikimedia Commons

Animación: Retrovirus VIH.

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

Aragon, June 2019, option A, question 4.

AIDS is caused by the HIV virus, whose genetic material is in the form of RNA. Explain the cycle of this virus. (2 points)

Aragon. September 2017, option B, question 5.

AIDS is a disease that affects humans. The cause is a virus that has its genetic material in the form of RNA. When this virus infects a cell, it can lie dormant for years. (2 points)

a. What type of reproductive cycle do you think this virus exhibits? Justify your answer. (1 point)

b. What is the name of the process that the RNA of the virus must follow to integrate into the DNA of the infected cell? Briefly explain what it consists of. (1 point)

Valencian Community, July 2017, option A, block 4, question 1.

HIV virions have RNA as their genetic material. However, when they infect a cell they make a copy of its RNA in the form of DNA (4 points).

a) What is this process called and what is the most important enzyme involved?

b) What is the importance of this process in the HIV cycle?

Asturias, June 2021, question 5B, part A

When a patient is detected with a disease caused by a retrovirus, they are treated with specific inhibitors of viral reverse transcriptase (reverse transcriptase) and, then, the amount of virus drops sharply.

a) Reasonably explain the basis for this effect. (Maximum score 1 point)

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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 » 12.2.2.3.2. Life cycle of the AIDS virus Life cycle of the AIDS virus (human immunodeficiency syndrome) The viruses that cause AIDS in humans (HIV₁ and HIV₂) are from the group of retroviruses, having single-stranded RNA as their genetic material. Therefore, their genetic material can act as mRNA and form proteins in the cells they parasitize. For DNA synthesis, two copies of its RNA and the help of the reverse transcriptase enzyme are needed. VIH.gif (Imagen GIF, 320 × 261 píxeles) - Escalado (0 %). (s. f.). Recuperado a partir de http://4.bp.blogspot.com/_1z5CA504lBU/TU-xsFUWg4I/AAAAAAAAACI/V3OdxwQpuns/s320/VIH The HIV virus has proteins in its envelope that are attracted to receptors located on the membrane of a lymphocyte. When the virus binds to the receptor, other proteins in the membrane are activated that cause both membranes to fuse. This recognition is necessary for the virus to adhere to and enter the cell. After fusing, decapsidation occurs, leaving the virus RNA free in the cytoplasm. The viral enzyme reverse transcriptase will transcribe the RNA of the virus into a double strand of DNA. At this point, it is fairly easy for mutations to occur in HIV, since reverse transcriptase often makes mistakes when moving from viral RNA to DNA. HIV (proviral) DNA enters the nucleus of the infected cell. The integration of viral DNA into the cell's DNA occurs thanks to the intervention of an enzyme called integrase. RNA and proteins are produced from DNA that will allow the formation of new viruses. The provirus (viral DNA integrated into the DNA of the host cell) can be inactive for a long time without producing new copies of HIV (quiescent cells with latent virus). Assembly: New viruses are formed with RNA, proteins, and cell membrane. Budding: The newly assembled virus leaves the cell through the plasma membrane, surrounding itself with a fragment that will form its envelope. The newly formed virus is immature, and the action of another enzyme, the HIV protease, is necessary for it to mature and become infectious, transforming into a mature HIV. The AIDS virus (HIV) is a retrovirus, so its genetic material is RNA (and not DNA). In order to replicate within the host cell (T4 lymphocytes), the RNA molecule has to form double-stranded DNA with the help of the enzyme reverse transcriptase or reverse transcriptase. Once viral DNA is formed, it can form new viral particles through RNA and protein synthesis. If treatment with reverse transcriptase inhibitors is carried out, the replication of the virus is paralyzed and the viral load of the patient decreases. By US National Institute of Health (redrawn by en:User:Carl Henderson) [Public domain], via Wikimedia Commons Animación: Retrovirus VIH. Questions that have come out in University entrance exams (Selectividad, EBAU, EvAU) Aragon, June 2019, option A, question 4. AIDS is caused by the HIV virus, whose genetic material is in the form of RNA. Explain the cycle of this virus. (2 points) Aragon. September 2017, option B, question 5. AIDS is a disease that affects humans. The cause is a virus that has its genetic material in the form of RNA. When this virus infects a cell, it can lie dormant for years. (2 points) a. What type of reproductive cycle do you think this virus exhibits? Justify your answer. (1 point) b. What is the name of the process that the RNA of the virus must follow to integrate into the DNA of the infected cell? Briefly explain what it consists of. (1 point) Valencian Community, July 2017, option A, block 4, question 1. HIV virions have RNA as their genetic material. However, when they infect a cell they make a copy of its RNA in the form of DNA (4 points). a) What is this process called and what is the most important enzyme involved? b) What is the importance of this process in the HIV cycle? Asturias, June 2021, question 5B, part A When a patient is detected with a disease caused by a retrovirus, they are treated with specific inhibitors of viral reverse transcriptase (reverse transcriptase) and, then, the amount of virus drops sharply. a) Reasonably explain the basis for this effect. (Maximum score 1 point) 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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Life cycle of the AIDS virus (human immunodeficiency syndrome)