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Hansen’s disease(leprosy) is caused by the intracellular parasiteMycobacterium leprae. Infections cause demylenation of neurons, resulting in decreased sensation in peripheral appendages and body sites. Treatment is with multi-drug antibiotic therapy, and there is no universally recognized vaccine.
https://openstax.org/books/microbiology/pages/26-summary
Viral meningitisis more common and generally less severe than bacterial menigitis. It can result from secondary sequelae of many viruses or be caused by infections of arboviruses.
https://openstax.org/books/microbiology/pages/26-summary
Various types ofarboviral encephalitisare concentrated in particular geographic locations throughout the world. These mosquito-borne viral infections of the nervous system are typically mild, but they can be life-threatening in some cases.
https://openstax.org/books/microbiology/pages/26-summary
Zika virusis an emerging arboviral infection with generally mild symptoms in most individuals, but infections of pregnant people can cause the birth defect microcephaly.
https://openstax.org/books/microbiology/pages/26-summary
Poliois typically a mild intestinal infection but can be damaging or fatal if it progresses to a neurological disease.
https://openstax.org/books/microbiology/pages/26-summary
Rabiesis nearly always fatal when untreated and remains a significant problem worldwide.
https://openstax.org/books/microbiology/pages/26-summary
Transmissible spongiform encephalopathiessuch asCreutzfeldt-Jakob diseaseandkuruare caused by prions. These diseases are untreatable and ultimately fatal. Similar prion diseases are found in animals.
https://openstax.org/books/microbiology/pages/26-summary
Neuromycosesare uncommon in immunocompetent people, but immunocompromised individuals with fungal infections have high mortality rates. Treatment of neuromycoses require prolonged therapy with antifungal drugs at low doses to avoid side effects and overcome the effect of the blood-brain barrier.
https://openstax.org/books/microbiology/pages/26-summary
Some protist infections of the nervous systems are fatal if not treated, includingprimary amoebic meningitis,granulomatous amoebic encephalitis,human African trypanosomiasis, andneurotoxoplasmosis.
https://openstax.org/books/microbiology/pages/26-summary
The various forms of ameobic encephalitis caused by the different amoebic infections are typically fatal even with treatment, but they are rare.
https://openstax.org/books/microbiology/pages/26-summary
African trypanosomiasisis a serious but treatable disease endemic to two distinct regions in sub-Saharan Africa caused by the insect-borne hemoflagellateTrypanosoma brucei.
https://openstax.org/books/microbiology/pages/26-summary
Neurocysticercosisis treated using antihelminthic drugs or surgery to remove the large cysts from the CNS.
https://openstax.org/books/microbiology/pages/26-summary
Biology is the science of life. All living organisms share several key properties such as order, sensitivity or response to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and energy processing. Living things are highly organized following a hierarchy that includes atoms, molecules, ...
https://openstax.org/books/concepts-biology/pages/1-chapter-summary
Biology is the science that studies living organisms and their interactions with one another and their environments. Science attempts to describe and understand the nature of the universe in whole or in part. Science has many fields; those fields related to the physical world and its phenomena are considered natural sc...
https://openstax.org/books/concepts-biology/pages/1-chapter-summary
A hypothesis is a tentative explanation for an observation. A generally accepted scientific theory is thoroughly tested and confirmed explanation for a set of observations or phenomena. A scientific law is a description, often in the form of a mathematical formula, of the behavior of an aspect of nature under certain c...
https://openstax.org/books/concepts-biology/pages/1-chapter-summary
Science can be basic or applied. The main goal of basic science is to expand knowledge without any expectation of short-term practical application of that knowledge. The primary goal of applied research, however, is to solve practical problems.
https://openstax.org/books/concepts-biology/pages/1-chapter-summary
applied science : a form of science that solves real-world problems
https://openstax.org/books/concepts-biology/pages/1-key-terms
atom : a basic unit of matter that cannot be broken down by normal chemical reactions
https://openstax.org/books/concepts-biology/pages/1-key-terms
basic science : science that seeks to expand knowledge regardless of the short-term application of that knowledge
https://openstax.org/books/concepts-biology/pages/1-key-terms
biology : the study of life
https://openstax.org/books/concepts-biology/pages/1-key-terms
biosphere : a collection of all ecosystems on Earth
https://openstax.org/books/concepts-biology/pages/1-key-terms
cell : the smallest fundamental unit of structure and function in living things
https://openstax.org/books/concepts-biology/pages/1-key-terms
community : a set of populations inhabiting a particular area
https://openstax.org/books/concepts-biology/pages/1-key-terms
control : a part of an experiment that does not change during the experiment
https://openstax.org/books/concepts-biology/pages/1-key-terms
deductive reasoning : a form of logical thinking that uses a general statement to predict specific results
https://openstax.org/books/concepts-biology/pages/1-key-terms
descriptive science : a form of science that aims to observe, explore, and find things out
https://openstax.org/books/concepts-biology/pages/1-key-terms
ecosystem : all living things in a particular area together with the abiotic, nonliving parts of that environment
https://openstax.org/books/concepts-biology/pages/1-key-terms
eukaryote : an organism with cells that have nuclei and membrane-bound organelles
https://openstax.org/books/concepts-biology/pages/1-key-terms
evolution : the process of gradual change in a population that can also lead to new species arising from older species
https://openstax.org/books/concepts-biology/pages/1-key-terms
falsifiable : able to be disproven by experimental results
https://openstax.org/books/concepts-biology/pages/1-key-terms
homeostasis : the ability of an organism to maintain constant internal conditions
https://openstax.org/books/concepts-biology/pages/1-key-terms
hypothesis : a suggested explanation for an event, which can be tested
https://openstax.org/books/concepts-biology/pages/1-key-terms
hypothesis-based science : a form of science that begins with a specific explanation that is then tested
https://openstax.org/books/concepts-biology/pages/1-key-terms
inductive reasoning : a form of logical thinking that uses related observations to arrive at a general conclusion
https://openstax.org/books/concepts-biology/pages/1-key-terms
life science : a field of science, such as biology, that studies living things
https://openstax.org/books/concepts-biology/pages/1-key-terms
macromolecule : a large molecule typically formed by the joining of smaller molecules
https://openstax.org/books/concepts-biology/pages/1-key-terms
molecule : a chemical structure consisting of at least two atoms held together by a chemical bond
https://openstax.org/books/concepts-biology/pages/1-key-terms
natural science : a field of science that studies the physical world, its phenomena, and processes
https://openstax.org/books/concepts-biology/pages/1-key-terms
organ : a structure formed of tissues operating together to perform a common function
https://openstax.org/books/concepts-biology/pages/1-key-terms
organ system : the higher level of organization that consists of functionally related organs
https://openstax.org/books/concepts-biology/pages/1-key-terms
organelle : a membrane-bound compartment or sac within a cell
https://openstax.org/books/concepts-biology/pages/1-key-terms
organism : an individual living entity
https://openstax.org/books/concepts-biology/pages/1-key-terms
peer-reviewed article : a scientific report that is reviewed by a scientist’s colleagues before publication
https://openstax.org/books/concepts-biology/pages/1-key-terms
phylogenetic tree : a diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both
https://openstax.org/books/concepts-biology/pages/1-key-terms
physical science : a field of science, such as astronomy, physics, and chemistry, that studies nonliving matter
https://openstax.org/books/concepts-biology/pages/1-key-terms
population : all individuals within a species living within a specific area
https://openstax.org/books/concepts-biology/pages/1-key-terms
prokaryote : a unicellular organism that lacks a nucleus or any other membrane-bound organelle
https://openstax.org/books/concepts-biology/pages/1-key-terms
science : knowledge that covers general truths or the operation of general laws, especially when acquired and tested by the scientific method
https://openstax.org/books/concepts-biology/pages/1-key-terms
scientific law : a description, often in the form of a mathematical formula, for the behavior of some aspect of nature under certain specific conditions
https://openstax.org/books/concepts-biology/pages/1-key-terms
scientific method : a method of research with defined steps that include experiments and careful observation
https://openstax.org/books/concepts-biology/pages/1-key-terms
scientific theory : a thoroughly tested and confirmed explanation for observations or phenomena
https://openstax.org/books/concepts-biology/pages/1-key-terms
tissue : a group of similar cells carrying out the same function
https://openstax.org/books/concepts-biology/pages/1-key-terms
variable : a part of an experiment that can vary or change
https://openstax.org/books/concepts-biology/pages/1-key-terms
Matter is anything that occupies space and has mass. It is made up of atoms of different elements. All of the 92 elements that occur naturally have unique qualities that allow them to combine in various ways to create compounds or molecules. Atoms, which consist of protons, neutrons, and electrons, are the smallest uni...
https://openstax.org/books/concepts-biology/pages/2-chapter-summary
Water has many properties that are critical to maintaining life. It is polar, allowing for the formation of hydrogen bonds, which allow ions and other polar molecules to dissolve in water. Therefore, water is an excellent solvent. The hydrogen bonds between water molecules give water the ability to hold heat better tha...
https://openstax.org/books/concepts-biology/pages/2-chapter-summary
The pH of a solution is a measure of the concentration of hydrogen ions in the solution. A solution with a high number of hydrogen ions is acidic and has a low pH value. A solution with a high number of hydroxide ions is basic and has a high pH value. The pH scale ranges from 0 to 14, with a pH of 7 being neutral. Buff...
https://openstax.org/books/concepts-biology/pages/2-chapter-summary
Living things are carbon-based because carbon plays such a prominent role in the chemistry of living things. The four covalent bonding positions of the carbon atom can give rise to a wide diversity of compounds with many functions, accounting for the importance of carbon in living things. Carbohydrates are a group of m...
https://openstax.org/books/concepts-biology/pages/2-chapter-summary
Lipids are a class of macromolecules that are nonpolar and hydrophobic in nature. Major types include fats and oils, waxes, phospholipids, and steroids. Fats and oils are a stored form of energy and can include triglycerides. Fats and oils are usually made up of fatty acids and glycerol.
https://openstax.org/books/concepts-biology/pages/2-chapter-summary
Proteins are a class of macromolecules that can perform a diverse range of functions for the cell. They help in metabolism by providing structural support and by acting as enzymes, carriers or as hormones. The building blocks of proteins are amino acids. Proteins are organized at four levels: primary, secondary, tertia...
https://openstax.org/books/concepts-biology/pages/2-chapter-summary
Nucleic acids are molecules made up of repeating units of nucleotides that direct cellular activities such as cell division and protein synthesis. Each nucleotide is made up of a pentose sugar, a nitrogenous base, and a phosphate group. There are two types of nucleic acids: DNA and RNA.
https://openstax.org/books/concepts-biology/pages/2-chapter-summary
acid : a substance that donates hydrogen ions and therefore lowers pH
https://openstax.org/books/concepts-biology/pages/2-key-terms
adhesion : the attraction between water molecules and molecules of a different substance
https://openstax.org/books/concepts-biology/pages/2-key-terms
amino acid : a monomer of a protein
https://openstax.org/books/concepts-biology/pages/2-key-terms
anion : a negative ion formed by gaining electrons
https://openstax.org/books/concepts-biology/pages/2-key-terms
atomic number : the number of protons in an atom
https://openstax.org/books/concepts-biology/pages/2-key-terms
base : a substance that absorbs hydrogen ions and therefore raises pH
https://openstax.org/books/concepts-biology/pages/2-key-terms
buffer : a solution that resists a change in pH by absorbing or releasing hydrogen or hydroxide ions
https://openstax.org/books/concepts-biology/pages/2-key-terms
carbohydrate : a biological macromolecule in which the ratio of carbon to hydrogen to oxygen is 1:2:1; carbohydrates serve as energy sources and structural support in cells
https://openstax.org/books/concepts-biology/pages/2-key-terms
cation : a positive ion formed by losing electrons
https://openstax.org/books/concepts-biology/pages/2-key-terms
cellulose : a polysaccharide that makes up the cell walls of plants and provides structural support to the cell
https://openstax.org/books/concepts-biology/pages/2-key-terms
chemical bond : an interaction between two or more of the same or different elements that results in the formation of molecules
https://openstax.org/books/concepts-biology/pages/2-key-terms
chitin : a type of carbohydrate that forms the outer skeleton of arthropods, such as insects and crustaceans, and the cell walls of fungi
https://openstax.org/books/concepts-biology/pages/2-key-terms
cohesion : the intermolecular forces between water molecules caused by the polar nature of water; creates surface tension
https://openstax.org/books/concepts-biology/pages/2-key-terms
covalent bond : a type of strong bond between two or more of the same or different elements; forms when electrons are shared between elements
https://openstax.org/books/concepts-biology/pages/2-key-terms
denaturation : the loss of shape in a protein as a result of changes in temperature, pH, or exposure to chemicals
https://openstax.org/books/concepts-biology/pages/2-key-terms
deoxyribonucleic acid (DNA) : a double-stranded polymer of nucleotides that carries the hereditary information of the cell
https://openstax.org/books/concepts-biology/pages/2-key-terms
disaccharide : two sugar monomers that are linked together by a glycodsidic bond
https://openstax.org/books/concepts-biology/pages/2-key-terms
electron : a negatively charged particle that resides outside of the nucleus in the electron orbital; lacks functional mass and has a charge of –1
https://openstax.org/books/concepts-biology/pages/2-key-terms
electron transfer : the movement of electrons from one element to another
https://openstax.org/books/concepts-biology/pages/2-key-terms
element : one of 118 unique substances that cannot be broken down into smaller substances and retain the characteristic of that substance; each element has a specified number of protons and unique properties
https://openstax.org/books/concepts-biology/pages/2-key-terms
enzyme : a catalyst in a biochemical reaction that is usually a complex or conjugated protein
https://openstax.org/books/concepts-biology/pages/2-key-terms
evaporation : the release of water molecules from liquid water to form water vapor
https://openstax.org/books/concepts-biology/pages/2-key-terms
fat : a lipid molecule composed of three fatty acids and a glycerol (triglyceride) that typically exists in a solid form at room temperature
https://openstax.org/books/concepts-biology/pages/2-key-terms
glycogen : a storage carbohydrate in animals
https://openstax.org/books/concepts-biology/pages/2-key-terms
hormone : a chemical signaling molecule, usually a protein or steroid, secreted by an endocrine gland or group of endocrine cells; acts to control or regulate specific physiological processes
https://openstax.org/books/concepts-biology/pages/2-key-terms
hydrogen bond : a weak bond between partially positively charged hydrogen atoms and partially negatively charged elements or molecules
https://openstax.org/books/concepts-biology/pages/2-key-terms
hydrophilic : describes a substance that dissolves in water; water-loving
https://openstax.org/books/concepts-biology/pages/2-key-terms
hydrophobic : describes a substance that does not dissolve in water; water-fearing
https://openstax.org/books/concepts-biology/pages/2-key-terms
ion : an atom or compound that does not contain equal numbers of protons and electrons, and therefore has a net charge
https://openstax.org/books/concepts-biology/pages/2-key-terms
ionic bond : a chemical bond that forms between ions of opposite charges
https://openstax.org/books/concepts-biology/pages/2-key-terms
isotope : one or more forms of an element that have different numbers of neutrons
https://openstax.org/books/concepts-biology/pages/2-key-terms
lipids : a class of macromolecules that are nonpolar and insoluble in water
https://openstax.org/books/concepts-biology/pages/2-key-terms
litmus paper : filter paper that has been treated with a natural water-soluble dye so it can be used as a pH indicator
https://openstax.org/books/concepts-biology/pages/2-key-terms
macromolecule : a large molecule, often formed by polymerization of smaller monomers
https://openstax.org/books/concepts-biology/pages/2-key-terms
mass number : the number of protons plus neutrons in an atom
https://openstax.org/books/concepts-biology/pages/2-key-terms
matter : anything that has mass and occupies space
https://openstax.org/books/concepts-biology/pages/2-key-terms
monosaccharide : a single unit or monomer of carbohydrates
https://openstax.org/books/concepts-biology/pages/2-key-terms
neutron : a particle with no charge that resides in the nucleus of an atom; has a mass of 1
https://openstax.org/books/concepts-biology/pages/2-key-terms
nonpolar covalent bond : a type of covalent bond that forms between atoms when electrons are shared equally between atoms, resulting in no regions with partial charges as in polar covalent bonds
https://openstax.org/books/concepts-biology/pages/2-key-terms
nucleic acid : a biological macromolecule that carries the genetic information of a cell and carries instructions for the functioning of the cell
https://openstax.org/books/concepts-biology/pages/2-key-terms