6.2.2.3. Bacteria physiology

Bacteria physiology

The bacteria, like all living beings have vital functions of nutrition, in interaction and reproduction.

Nutrition functions

Bacteria can have different types of nutrition, since they can carry out all types of metabolism. Thus, bacteria can be:

Photoautotrophs.
Photoheterotrophs.
Chemoautotrophs.
Chemoheterotrophs.

Interaction functions

Many bacteria can move by creeping, with contraction and dilation movements, or by the movement of their flagella.

They respond to environmental stimuli, such as light (phototactic photosynthetic bacteria) and chemicals (chemotacticism).

When environmental conditions are adverse, the bacterium's response consists of the formation of spores, where they reduce their metabolism, resisting temperatures of up to 80 ºC, periods of water shortage, toxic substances, etc. that would end his life. When conditions are favorable again, the spores germinate and the bacteria can already carry out their functions.

Reproduction functions

Bacterial reproduction is asexual. DNA is duplicated and bipartition takes place, in which each daughter bacterium carries its identical DNA molecule.

The mesosomes are responsible for directing the DNA replication and create the membrane will separate the two daughter cells. In bacterial colonies, all bacteria are genetically the same.

In addition, bacteria have parasexual mechanisms with which they can exchange genetic material with other bacteria of their species or even others. These processes are:

the conjugation,
the transduction and
the transformation.

Conjugation

The conjugation process occurs when a donor bacterium transmits DNA, through the pili, to another recipient bacterium.

There are two types of donor bacteria: F⁺ and Hfr (of the English high frequency of recombination or high frequency of recombination). The receptor bacteria are the F ^-.

Donor bacteria have plasmids, small DNA molecules that they can transmit by conjugation, called F factors or episomes.

The F⁺ bacteria have a free episome in the hyaloplasm, transferring only the F factor, which does not recombine with their DNA, to the recipient bacteria. This bacterium transforms into F⁺.

The bacteria Hfr have episome included in the DNA of the bacterial chromosome. Before conjugation, they have to duplicate their DNA, including the factor F. They transfer a copy of DNA that will recombine with the DNA of the recipient bacteria.

Conjugación bacteriana

By Asignatura de Microbiología (Odontología) de la Universidad de Oviedo (España) [CC BY-SA 2.5], via Wikimedia Commons

Transduction

In transduction, genetic exchange also occurs, but the intervention of a transmitting agent, a bacteriophage virus, is necessary, which provides DNA fragments from the last bacterium that has parasitized.

The genetic material of the virus is integrated into the chromosome of the donor bacteria, and it follows a lysogenic cycle. When a lytic cycle begins, it will separate from the bacterial DNA but will carry some genes that it will pass on to the recipient bacteria.

Transducción bacteriana

By Asignatura de Microbiología (Odontología) de la Universidad de Oviedo (España) [CC BY-SA 2.5], via Wikimedia Commons

Transformation

In the transformation process, the bacterium introduces DNA fragments from the lysis of other bacteria.

These parasexual mechanisms, in which genetic exchange occurs between bacteria, allow bacteria to become resistant to antibiotics, as some pathogenic bacteria coexist with symbiotic bacteria that resist them.

Transformación bacteriana

By Asignatura de Microbiología (Odontología) de la Universidad de Oviedo (España) [CC BY-SA 2.5], via Wikimedia Commons

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

Canarias, July 2010, question 9

Nutrition is one of the processes that define all living things. Bacteria are especially versatile when it comes to nutrition.

a.- Name the different nutritional processes that occur in bacteria, both in terms of the carbon source and the energy source.
b.- Another vital function is reproduction. What type of reproduction do bacteria have?
c.- Where is the genome in bacteria?

Extremadura, June 2019, option A, question 4

A. Name and briefly describe the mechanisms of gene exchange or transfer that can occur between bacteria. (1.5 points)
B. Habitual microbiota (normal flora) of the human body. Concept. Functions. (0.5 pts)

Canary Islands, June 2021, question 18

18. An artist exhibits bacterial cultures on paper money to raise awareness about biological processes and denounce world conflicts. The fact that a bacterium consumed the figure of the Queen of England or that of George Washington printed on a banknote was what most surprised and inspired Ken Rinaldo. (Source: Elpais.com)

a. Indicates where the bacterial genome is located.
b. It indicates what type of biomolecules the plasmids present in many bacterial types are made up.
c. What type of reproduction do bacteria have?
d. What do bacterial transformation and transduction have in common?

Galicia, July 2021, question 8b

With respect to bacteria, what is the mechanism of gene transfer called transduction?

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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 » 6.2.2.3. Bacteria physiology Bacteria physiology The bacteria, like all living beings have vital functions of nutrition, in interaction and reproduction. Nutrition functions Bacteria can have different types of nutrition, since they can carry out all types of metabolism. Thus, bacteria can be: Photoautotrophs. Photoheterotrophs. Chemoautotrophs. Chemoheterotrophs. Interaction functions Many bacteria can move by creeping, with contraction and dilation movements, or by the movement of their flagella. They respond to environmental stimuli, such as light (phototactic photosynthetic bacteria) and chemicals (chemotacticism). When environmental conditions are adverse, the bacterium's response consists of the formation of spores, where they reduce their metabolism, resisting temperatures of up to 80 ºC, periods of water shortage, toxic substances, etc. that would end his life. When conditions are favorable again, the spores germinate and the bacteria can already carry out their functions. Reproduction functions Bacterial reproduction is asexual. DNA is duplicated and bipartition takes place, in which each daughter bacterium carries its identical DNA molecule. The mesosomes are responsible for directing the DNA replication and create the membrane will separate the two daughter cells. In bacterial colonies, all bacteria are genetically the same. In addition, bacteria have parasexual mechanisms with which they can exchange genetic material with other bacteria of their species or even others. These processes are: the conjugation, the transduction and the transformation. Conjugation The conjugation process occurs when a donor bacterium transmits DNA, through the pili, to another recipient bacterium. There are two types of donor bacteria: F⁺ and Hfr (of the English high frequency of recombination or high frequency of recombination). The receptor bacteria are the F ^-. Donor bacteria have plasmids, small DNA molecules that they can transmit by conjugation, called F factors or episomes. The F⁺ bacteria have a free episome in the hyaloplasm, transferring only the F factor, which does not recombine with their DNA, to the recipient bacteria. This bacterium transforms into F⁺. The bacteria Hfr have episome included in the DNA of the bacterial chromosome. Before conjugation, they have to duplicate their DNA, including the factor F. They transfer a copy of DNA that will recombine with the DNA of the recipient bacteria. By Asignatura de Microbiología (Odontología) de la Universidad de Oviedo (España) [CC BY-SA 2.5], via Wikimedia Commons Transduction In transduction, genetic exchange also occurs, but the intervention of a transmitting agent, a bacteriophage virus, is necessary, which provides DNA fragments from the last bacterium that has parasitized. The genetic material of the virus is integrated into the chromosome of the donor bacteria, and it follows a lysogenic cycle. When a lytic cycle begins, it will separate from the bacterial DNA but will carry some genes that it will pass on to the recipient bacteria. By Asignatura de Microbiología (Odontología) de la Universidad de Oviedo (España) [CC BY-SA 2.5], via Wikimedia Commons Transformation In the transformation process, the bacterium introduces DNA fragments from the lysis of other bacteria. These parasexual mechanisms, in which genetic exchange occurs between bacteria, allow bacteria to become resistant to antibiotics, as some pathogenic bacteria coexist with symbiotic bacteria that resist them. By Asignatura de Microbiología (Odontología) de la Universidad de Oviedo (España) [CC BY-SA 2.5], via Wikimedia Commons Questions that have come out in University entrance exams (Selectividad, EBAU, EvAU) Canarias, July 2010, question 9 Nutrition is one of the processes that define all living things. Bacteria are especially versatile when it comes to nutrition. a.- Name the different nutritional processes that occur in bacteria, both in terms of the carbon source and the energy source. b.- Another vital function is reproduction. What type of reproduction do bacteria have? c.- Where is the genome in bacteria? Extremadura, June 2019, option A, question 4 A. Name and briefly describe the mechanisms of gene exchange or transfer that can occur between bacteria. (1.5 points) B. Habitual microbiota (normal flora) of the human body. Concept. Functions. (0.5 pts) Canary Islands, June 2021, question 18 18. An artist exhibits bacterial cultures on paper money to raise awareness about biological processes and denounce world conflicts. The fact that a bacterium consumed the figure of the Queen of England or that of George Washington printed on a banknote was what most surprised and inspired Ken Rinaldo. (Source: Elpais.com) a. Indicates where the bacterial genome is located. b. It indicates what type of biomolecules the plasmids present in many bacterial types are made up. c. What type of reproduction do bacteria have? d. What do bacterial transformation and transduction have in common? Galicia, July 2021, question 8b With respect to bacteria, what is the mechanism of gene transfer called transduction? 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Bacteria physiology

Nutrition functions

Interaction functions

Reproduction functions

Conjugation

Transduction

Transformation