Biology Extra topics
RISC
The RNA-induced silencing complex, or RISC, is a multiprotein complex that incorporates one strand of a small interfering RNA (siRNA) or microRNA (miRNA). RISC uses the siRNA or miRNA as a template for recognizing complementary mRNA. When it finds a complementary strand, it activates RNase and cleaves the RNA. This process is important both in gene regulation by microRNAs and in defense against viral infections, which often use double-stranded RNA as an infectious vector
Vitamin C
Vitamin C is a water-soluble vitamin that is necessary for normal growth and development. Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of such vitamins in your diet. All fruits and vegetables contain some amount of vitamin C.
induced mutation
a mutation caused by exposure to a mutagen
initiation, elongation, termination translation factors
Initiation factors are proteins that bind to the small subunit of the ribosome during the initiation of translation, a part of protein biosynthesis. They are divided into three major groups: Prokaryotic initiation factors Archaeal initiation factors Termination is part of the process of transcribing RNA. In eukaryotes, a termination factor is required to release the newly made (nascent) RNA from the transcription complex.
reproduction
Reproduction (or procreation) is the biological process by which new "offspring" individual organisms are produced from their "parents". Reproduction is a fundamental feature of all known life; each individual organism exists as the result of reproduction. The known methods of reproduction are broadly grouped into two main types: sexual and asexual.
The central dogma
The central dogma of molecular biology is an explanation of the flow of genetic information within a biological system. It was first stated by Francis Crick in 1958[1] and re-stated in a Nature paper published in 1970:[2] The central dogma of molecular biology deals with the detailed residue-by-residue transfer of sequential information. It states that such information cannot be transferred back from protein to either protein or nucleic acid. This has also been described as "DNA makes RNA makes protein."[3] However, this simplification does not make it clear that the central dogma as stated by Crick does not preclude the reverse flow of information from RNA to DNA, but only the reverse flow from protein to RNA or DNA.
evolution
a change in the genetic composition of a population of organisms over time.
Linus Pauling
was an American chemist, biochemist, peace activist, author, and educator. He was one of the most influential chemists in history and ranks among the most important scientists of the 20th century.[2][3] Pauling was one of the founders of the fields of quantum chemistry and molecular biology. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. American theoretical physical chemist who became the only person to have won two unshared Nobel Prizes. His first prize (1954) was awarded for research into the nature of the chemical bond and its use in elucidating molecular structure; the second (1962) recognized his efforts to ban the testing of nuclear
Miller's experiment
was an experiment that simulated the conditions thought at the time to be present on the early Earth, and tested for the occurrence of chemical origins of life. Specifically, the experiment tested Alexander Oparin's and J. B. S. Haldane's hypothesis that conditions on the primitive Earth favored chemical reactions that synthesized organic compounds from inorganic precursors. The experiment used water (H2O), methane (CH4), ammonia (NH3), and hydrogen (H2). The chemicals were all sealed inside a sterile array of glass flasks and flasks connected in a loop, with one flask half-full of liquid water and another flask containing a pair of electrodes. The liquid water was heated to induce evaporation, sparks were fired between the electrodes to simulate lightning through the atmosphere and water vapor, and then the atmosphere was cooled again so that the water could condense and trickle back into the first flask in a continuous cycle. Within a day, the mixture had turned pink in colour,[9] and at the end of two weeks of continuous operation, Miller and Urey observed that as much as 10-15% of the carbon within the system was now in the form of organic compounds. Two percent of the carbon had formed amino acids that are used to make proteins in living cells, with glycine as the most abundant. Sugars were also formed.[10] Nucleic acids were not formed within the reaction. 18% of the methane-molecules became bio-molecules. The rest turned into hydrocarbons like bitumen.
supramolecular structure of protein
- many molecules ordered into a higher level of organization with emergent properties beyond those of the individual molecules
motion
1. The act or process of changing position or place. 2. The manner in which the body or a body part moves.
Micro RNA
A microRNA (abbr. miRNA) is a small non-coding RNA molecule (ca. 22 nucleotides) found in plants and animals, which functions in transcriptional and post-transcriptional regulation of gene expression. Encoded by eukaryotic nuclear DNA, miRNAs function via base-pairing with complementary sequences within mRNA molecules, usually resulting in gene silencing via translational repression or target degradation.The human genome may encode over 1000 miRNAs,which may target about 60% of mammalian genes and are abundant in many human cell types
miRNA
A microRNA (abbr. miRNA) is a small non-coding RNA molecule (ca. 22 nucleotides) found in plants and animals, which functions in transcriptional and post-transcriptional regulation of gene expression.[1] Encoded by eukaryotic nuclear DNA, miRNAs function via base-pairing with complementary sequences within mRNA molecules, usually resulting in gene silencing via translational repression or target degradation. strand. The passenger strand is degraded, and the guide strand is incorporated into the RNA-induced silencing complex (RISC).
Spontaneous mutations
A mutation that arises naturally and not as a result of exposure to mutagens.
peroxide
A peroxide is a compound containing an oxygen-oxygen single bond or the peroxide anion, O22-.[1] The O−O group is called the peroxide group or peroxo group. In contrast to oxide ions, the oxygen atoms in the peroxide ion have an oxidation state of −1
ribozyme
A ribozyme (from ribonucleic acid enzyme, also called RNA enzyme or catalytic RNA) is an RNA molecule that catalyzes a chemical reaction. Many natural ribozymes catalyze either the hydrolysis of one of their own phosphodiester bonds, or the hydrolysis of bonds in other RNAs, but they have also been found to catalyze the aminotransferase activity of the ribosome. Investigators studying the origin of life have produced ribozymes in the laboratory that are capable of catalyzing their own synthesis under very specific conditions, such as an RNA polymerase ribozyme. Mutagenesis and selection has been performed resulting in isolation of improved variants of the "Round-18" polymerase ribozyme from 2001. "B6.61" is able to add up to 20 nucleotides to a primer template in 24 hours, until it decomposes by hydrolysis of its phosphodiester bonds.
spliceosome
A spliceosome is a large and complex molecular machine found primarily within the nucleus of eukaryotes. Spliceosome is assembled from snRNPs and protein complexes. Spliceosome removes introns from a transcribed pre-mRNA segment. This process is generally referred to as splicing. [1] Only eukaryotes have spliceosomes and higher eukaryotes (metazoans or animals) have a second spliceosome, the minor spliceosome.
Vitamin
A vitamin is an organic compound required by an organism as a vital nutrient in limited amounts.An organic chemical compound (or related set of compounds) is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet.
Endoribonuclease
An Endoribonuclease is a ribonuclease endonuclease. It cleaves either single-stranded or double-stranded RNA, depending on the enzyme. Example includes both single proteins like RNase III, RNase A, RNase T1, and RNase H, and also complexes of proteins with RNA like RNase P and the RNA-induced silencing complex
exoribonuclease
An exoribonuclease is an exonuclease ribonuclease, which are enzymes that degrade RNA by removing terminal nucleotides from either the 5' end or the 3' end of the RNA molecule. Enzymes that remove nucleotides from the 5' end are called 5'-3' exoribonucleases, and enzymes that remove nucleotides from the 3' end are called 3'-5' exoribonucleases.
organization
An organization (or organisation) is a social entity that has a collective goal and is linked to an external environment.
Antisense RNA
Antisense RNA (asRNA) is a single-stranded RNA that is complementary to a messenger RNA (mRNA) strand transcribed within a cell. Some authors have used the term micRNA (mRNA-interfering complementary RNA) to refer to these RNAs but it is not widely used
deaminase
Any of a class of enzymes that catalyze the removal, usually by hydrolysis, of the amino group NH2 from an amino compound.
Vitamin B
B vitamins are a group of water-soluble vitamins that play important roles in cell metabolism. ou can get B vitamins from proteins such as fish, poultry, meat, eggs, and dairy products. Leafy green vegetables, beans, and peas also have B vitamins. Many cereals and some breads have added B vitamins.
Drosha
Drosha is a Class 2 RNase III enzyme responsible for initiating the processing of microRNA (miRNA), or short RNA molecules naturally expressed by the cell that regulate a wide variety of other genes by interacting with the RNA-induced silencing complex (RISC) to induce cleavage of complementary messenger RNA (mRNA) as part of the RNAi pathway. A microRNA molecule is synthesized as a long RNA primary transcript known as a pri-miRNA, which is cleaved by Drosha to produce a characteristic stem-loop structure of about 70 base pairs long, known as a pre-miRNA.[1] Drosha exists as part of a protein complex called the Microprocessor complex, which also contains the double-stranded RNA binding protein Pasha (also called DGCR8),[2] which is essential for Drosha activity and is capable of binding single-stranded fragments of the pri-miRNA that are required for proper processing
growth
Growth refers to a positive change in size, often over a period of time
homochirality
Homochirality describes a property of some materials made up of chiral units. A substance is said to be homochiral if all the constituent units are molecules of the same chiral form (enantiomer). In biology homochirality is a common property of amino acids and sugars.
Human accelerated regions (HARs)
Human accelerated regions (HARs), first described in August 2006, are a set of 49 segments of the human genome that are conserved throughout vertebrate evolution but are strikingly different in humans. They are named according to their degree of difference between humans and chimpanzees (HAR1 showing the largest degree of human-chimpanzee differences). Found by scanning through genomic databases of multiple species, some of these highly mutated areas may contribute to human-specific traits. Others may represent loss of function mutations, possibly due to the action of biased gene conversion [2][3] rather than adaptive evolution.
free radical
In chemistry, a radical (more precisely, a free radical) is an atom, molecule, or ion that has unpaired valence electrons or an open electron shell, and therefore may be seen as having one or more "dangling" covalent bonds.
non coding DNA strand
In genomics and related disciplines, noncoding DNA sequences are components of an organism's DNA that do not encode protein sequences. Some noncoding DNA is transcribed into functional noncoding RNA molecules (e.g. transfer RNA, ribosomal RNA, and regulatory RNAs), while others are not transcribed or give rise to RNA transcripts of unknown function. The amount of noncoding DNA varies greatly among species. For example, over 98% of the human genome is noncoding DNA,[2] while only about 2% of a typical bacterial genome is noncoding DNA.
Translation
In molecular biology and genetics, translation is the process in which cellular ribosomes create proteins. It is part of the process of gene expression. In translation, messenger RNA (mRNA) produced by transcription is decoded by a ribosome complex to produce a specific amino acid chain, or polypeptide, that will later fold into an active protein.
molecular chaperones and chaperonins
In molecular biology, molecular chaperones are proteins that assist the non-covalent folding or unfolding and the assembly or disassembly of other macromolecular structures, but do not occur in these structures when the structures are performing their normal biological functions having completed the processes of folding and/or assembly. Chaperonins are proteins that provide favourable conditions for the correct folding of other proteins, thus preventing aggregation. Newly made proteins usually must fold from a linear chain of amino acids into a three-dimensional form. Chaperonins belong to a large class of molecules that assist protein folding, called molecular chaperones.[1] The energy to fold proteins is supplied by adenosine triphosphate (ATP).
Directional selection
In population genetics, directional selection is a mode of natural selection in which an extreme phenotype is favored over other phenotypes, causing the allele frequency to shift over time in the direction of that phenotype. Under directional selection, the advantageous allele increases as a consequence of differences in survival and reproduction among different phenotypes. The increases are independent of the dominance of the allele, and even if the allele is recessive, it will eventually become fixed.
ontogeny
Ontogeny (also ontogenesis or morphogenesis) is the origin and the development of an organism: for example, from the fertilized egg to mature form. In time frame, it can cover the study of an organism's lifespan. The word ontogeny comes from the Greek ὄντος, ontos, present participle singular of εἶναι, "to be"; and from the suffix -geny, which expresses the concept of "mode of production".[1] In more general terms, ontogeny is defined as the history of structural change in a unity, which can be a cell, an organism, or a society of organisms, without the loss of the degree and type of organization which allow that unity to exist.[2] More recently, the term ontogeny has been used in cell biology to describe the development of various cell types within an organism.
oparin's hypothesis
Oparin suggested that the organic compounds could have undergone a series of reactions leading to more and more complex molecules. He proposed that the molecules formed colloid aggregates, or 'coacervates', in an aqueous environment. The coacervates were able to absorb and assimilate organic compounds from the environment in a way reminiscent of metabolism. They would have taken part in evolutionary processes, eventually leading to the first lifeforms. It is one of the theories for the origin of life. It is based on the "primordial soup" idea that the early earth had all the ingredients for the formation of pre-biotic compounds like amino acids, etc. It is actually known as Oparin-Haldane hypothesis.
Piwi-interacting RNA (piRNA)
Piwi-interacting RNA (piRNA) is the largest class of small non-coding RNA molecules expressed in animal cells.[1][2] piRNAs form RNA-protein complexes through interactions with piwi proteins. These piRNA complexes have been linked to both epigenetic and post-transcriptional gene silencing of retrotransposons and other genetic elements in germ line cells, particularly those in spermatogenesis.[3] They are distinct from microRNA (miRNA) in size (26-31 nt rather than 21-24 nt), lack of sequence conservation, and increased complexity
Polyribosome
Polyribosomes (or polysomes) also known as ergosomes are a cluster of ribosomes, bound to a mRNA molecule
RNA polymerase
RNA polymerase (RNAP or RNApol), also known as DNA-dependent RNA polymerase, is an enzyme that produces RNA. In cells, RNAP is necessary for constructing RNA chains using DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses. RNA polymerase I (also called Pol I) is, in higher eukaryotes, the enzyme that only transcribes ribosomal RNA (but not 5S rRNA, which is synthesized by RNA Polymerase III), a type of RNA that accounts for over 50% of the total RNA synthesized in a cell. RNA polymerase II (also called RNAP II and Pol II) is an enzyme found in eukaryotic cells. It catalyzes the transcription of DNA to synthesize precursors of mRNA and most snRNA and microRNA.[2][3] A 550 kDa complex of 12 subunits, RNAP II is the most studied type of RNA polymerase. A wide range of transcription factors are required for it to bind to upstream gene promoters and begin transcription.
Small Cajal body-specific RNAs
Small Cajal body-specific RNAs (scaRNAs) are a class of small nucleolar RNAs (snoRNAs) that specifically localise to the Cajal body, a nuclear organelle involved in the biogenesis of small nuclear ribonucleoproteins (snRNPs or snurps). ScaRNAs guide the modification (methylation and pseudouridylation) of RNA polymerase II transcribed spliceosomal RNAs U1, U2, U4, U5 and U12.
Small nuclear RNA
Small nuclear ribonucleic acid (snRNA), also commonly referred to as U-RNA, is a class of small RNA molecules that are found within the nucleus of eukaryotic cells. The length of an average snRNA is approximately 150 nucleotides. They are transcribed by either RNA polymerase II or RNA polymerase III, and studies have shown that their primary function is in the processing of pre-mRNA (hnRNA) in the nucleus. They have also been shown to aid in the regulation of transcription factors (7SK RNA) or RNA polymerase II (B2 RNA), and maintaining the telomeres.
Small nucleolar RNAs (snoRNAs)
Small nucleolar RNAs (snoRNAs) are a class of small RNA molecules that primarily guide chemical modifications of other RNAs, mainly ribosomal RNAs, transfer RNAs and small nuclear RNAs. There are two main classes of snoRNA, the C/D box snoRNAs which are associated with methylation, and the H/ACA box snoRNAs which are associated with pseudouridylation. SnoRNAs are commonly referred to as guide RNAs but should not be confused with the guide RNAs that direct RNA editing in trypanosomes.
primordial soup/ pizza
The Primordial Soup Theory suggest that life began in a pond or ocean as a result of the combination of chemicals from the atmosphere and some form of energy to make amino acids, the building blocks of proteins, which would then evolve into all the species. The Primordial Soup Theory states that Life began in a warm pond/ocean from a combination of chemicals that forms amino acids, which then make proteins. This is suppose to happen at least 3.8 billion to 3.55 billion years ago. The Russian Chemist A.I. Oparin and English Geneticist J.B.S. Haldane first conceived of this idea. Both developed this theory independently in 1920. In this theory, the basic building blocks of life came from simple molecule which formed in the atmosphere (w/o oxygen). This was then energized by lightning and the rain from the atmosphere created the "organic soup". The first organisms would have to be simple heterotrophs in order to survive by consuming other organisms for energy before means of photosynthesis. They would become autotrophs by mutation. Evidence now suggest the first organisms were autotrophs. Biochemist Robert Shapiro has summarized the "primordial soup" theory of Oparin and Haldane in its "mature form" as follows:[1] The early Earth had a chemically reducing atmosphere. This atmosphere, exposed to energy in various forms, produced simple organic compounds ("monomers"). These compounds accumulated in a "soup", which may have been concentrated at various locations (shorelines, oceanic vents etc.). By further transformation, more complex organic polymers - and ultimately life - developed in the soup.
endosymbiotic theory
The endosymbiotic theory states that several key organelles of eukaryotes originated as symbioses between separate single-celled organisms. According to this theory, mitochondria and plastids (e.g. chloroplasts), and possibly other organelles, represent formerly free-living bacteria that were taken inside another cell as an endosymbiont. Molecular and biochemical evidence suggest that the mitochondrion developed from proteobacteria (in particular, Rickettsiales, the SAR11 clade,[1][2] or close relatives) and the chloroplast from cyanobacteria.
laws of thermodynamics
The first law, also known as Law of Conservation of Energy, states that energy can not be created or destroyed; it can only be redistributed or changed from one form to another. The second law of thermodynamics says that the entropy of any isolated system not in thermal equilibrium almost always increases. The third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature approaches zero.
huntingtin gene
The huntingtin gene, also called HTT or HD (Huntington disease) gene, is the IT15 ("interesting transcript 15") gene which codes for a protein called the huntingtin protein.[2] The gene and its product are under heavy investigation as part of Huntington's disease clinical research. It is variable in its structure, as the many polymorphisms of the gene can lead to variable numbers of glutamine residues present in the protein. In its wild-type (normal) form, it contains 6-35 glutamine residues. However, in individuals affected by Huntington's disease (an autosomal dominant genetic disorder), it contains greater than 36 glutamine residues (highest reported repeat length is about 250).[3] Its commonly used name is derived from this disease; previously, the IT15 label was commonly used. The mass of huntingtin protein is dependent largely on the number of glutamine residues it has, the predicted mass is around 350 kDa. Normal huntingtin is generally accepted to be 3144 amino acids in size. The exact function of this protein is not known, but it plays an important role in nerve cells. Within cells, huntingtin may be involved in signaling, transporting materials, binding proteins and other structures, and protecting against programmed cell death (apoptosis). The huntingtin protein is required for normal development before birth.[4] It is expressed in many tissues in the body, with the highest levels of expression seen in the brain.
mRNA stability
The stability of mRNAs may be controlled by the 5' UTR and/or 3' UTR due to varying affinity for RNA degrading enzymes called ribonucleases and for ancillary proteins that can promote or inhibit RNA degradation.
tobacco mosaic virus
Tobacco mosaic virus (TMV) is a positive-sense single stranded RNA virus that infects plants, especially tobacco and other members of the family Solanaceae. The infection causes characteristic patterns, such as "mosaic"-like mottling and discoloration on the leaves (hence the name). TMV was the first virus to ever be discovered. Two scientists contributed to the discovery of the first virus, Tobacco mosaic virus. Ivanoski reported in 1892 that extracts from infected leaves were still infectious after filtration through a Chamberland filter-candle. Bacteria are retained by such filters, a new world was discovered: filterable pathogens. However, Ivanovski probably did not grasp the full meaning of his discovery. Beijerinck, in 1898, was the first to call 'virus', the incitant of the tobacco mosaic. He showed that the incitant was able to migrate in an agar gel, therefore being an infectious soluble agent, or a 'contagium vivum fluidum' and definitively not a 'contagium fixum' as would be a bacteria. Ivanovski and Beijerinck brought unequal but decisive and complementary contributions to the discovery of viruses. Since then, discoveries made on Tobacco mosaic virus have stood out as milestones of virology history
Translation (initiation, elongation, translocation)
Translation proceeds in four phases: initiation, elongation, translocation and termination (all describing the growth of the amino acid chain, or polypeptide that is the product of translation). Amino acids are brought to ribosomes and assembled into proteins. In activation, the correct amino acid is covalently bonded to the correct transfer RNA (tRNA). The amino acid is joined by its carboxyl group to the 3' OH of the tRNA by an ester bond. When the tRNA has an amino acid linked to it, it is termed "charged". Initiation involves the small subunit of the ribosome binding to the 5' end of mRNA with the help of initiation factors (IF). Termination of the polypeptide happens when the A site of the ribosome faces a stop codon (UAA, UAG, or UGA). No tRNA can recognize or bind to this codon. Instead, the stop codon induces the binding of a release factor protein that prompts the disassembly of the entire ribosome/mRNA complex.
Vitamin A
Vitamin A is a fat-soluble vitamin. Two different types of vitamin A are found in the diet. Preformed vitamin A is found in animal products such as meat, fish, poultry and dairy foods. The other type, pro-vitamin A is found in plant-based foods such as fruits and vegetables. The most common type of pro-vitamin A is beta-carotene. Vitamin A helps form and maintain healthy skin, teeth, skeletal and soft tissue, mucus membranes, and skin. It is also known as retinol because it produces the pigments in the retina of the eye. Vitamin A promotes good vision, especially in low light. It may also be needed for reproduction and breast-feeding.
Vitamin D
Vitamin D helps the body absorb calcium. Calcium and phosphate are two minerals that are essential for normal bone formation. Throughout childhood, your body uses these minerals to produce bones. If you do not get enough calcium, or if your body does not absorb enough calcium from your diet, bone production and bone tissues may suffer. The body makes vitamin D when the skin is directly exposed to the sun. That is why it is often called the "sunshine" vitamin. Most people meet at least some of their vitamin D needs this way. Very few foods naturally contain vitamin D. As a result, many foods are fortified with vitamin D. Fortified means that vitamins have been added to the food. Fatty fish (such as tuna, salmon, and mackerel) are among the best sources of vitamin D. Beef liver, cheese, and egg yolks provide small amounts. Mushrooms provide some vitamin D. The vitamin D content is also being boosted by exposure to some commercially available mushrooms to ultraviolent light.
Vitamin E
Vitamin E is an antioxidant that protects body tissue from damage caused by substances called free radicals. Free radicals can harm cells, tissues, and organs. They are believed to play a role in certain conditions related to aging. The body also needs vitamin E to help keep the immune system strong against viruses and bacteria. Vitamin E is also important in the formation of red blood cells and it helps the body use vitamin K. It also helps widen blood vessels and keep blood from clotting inside them. Cells use vitamin E to interact with each other and carry out many important functions. The best way to get the daily requirement of vitamin E is by eating food sources. Vitamin E is found in the following foods: Vegetable oils (such as wheat germ, sunflower, safflower, corn, and soybean oils) Nuts (such as almonds, peanuts, and hazelnuts/filberts) Seeds (such as sunflower seeds) Green leafy vegetables (such as spinach and broccoli) Fortified breakfast cereals, fruit juices, margarine, and spreads. Fortified means that vitamins have been added to the food. Check the Nutrition Fact Panel on the food label.
Vitamin H
Vitamin H, more commonly known as biotin, is part of the B complex group of vitamins. All B vitamins help the body to convert food (carbohydrates) into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly. Your body needs biotin to metabolize carbohydrates, fats, and amino acids, the building blocks of protein. Biotin is often recommended for strengthening hair and nails and it's found in many cosmetic products for hair and skin. Biotin is consumed from a wide range of food sources in the diet, but few are particularly rich sources. Foods with a relatively high biotin content include Swiss chard, raw egg yolk (however, the consumption of avidin-containing egg whites with egg yolks minimizes the effectiveness of egg yolk's biotin in one's body), liver, Saskatoon berries, and leafy green vegetables. Like all B vitamins, it is a water-soluble vitamin, meaning the body does not store it. However, bacteria in the intestine can make biotin. It is also available in small amounts a number of foods. Biotin is also important for normal embryonic growth, making it a critical nutrient during pregnancy.
Vitamin K
Vitamin K is known as the clotting vitamin, because without it blood would not clot. Some studies suggest that it helps maintain strong bones in the elderly. The best way to get the daily requirement of vitamin K is by eating food sources. Vitamin K is found in the following foods: Green leafy vegetables, such as kale, spinach, turnip greens, collards, Swiss chard, mustard greens, parsley, romaine, and green leaf lettuce Vegetables such as Brussels sprouts, broccoli, cauliflower, and cabbage Fish, liver, meat, eggs, and cereals (contain smaller amounts) Vitamin K is also made by the bacteria that line the gastrointestinal tract.
coding DNA strand
When referring to DNA transcription, the coding strand is the DNA strand which has the same base sequence as the RNA transcript produced (although with thymine replaced by uracil). It is this strand which contains codons, while the non-coding strand contains anti codons.
homeostasis
a tendency to equilibrium or stability in the normal physiological states of the organism
Enol
an organic compound in which one carbon of a double-bonded pair is also attached to a hydroxyl group, thus a tautomer of the ketone form
phosphatidylcholine
are a class of phospholipids that incorporate choline as a headgroup. They are a major component of biological membranes and can be easily obtained from a variety of readily available sources, such as egg yolk or soybeans, from which they are mechanically or chemically extracted using hexane. Phosphatidylcholine is a major constituent of cell membranes and pulmonary surfactant, and is more commonly found in the exoplasmic or outer leaflet of a cell membrane. It is thought to be transported between membranes within the cell by phosphatidylcholine transfer protein (PCTP).[3] Phosphatidylcholine also plays a role in membrane-mediated cell signaling and PCTP activation of other enzymes
Huntington's disease
is a neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and psychiatric problems. It typically becomes noticeable in mid-adult life. HD is the most common genetic cause of abnormal involuntary writhing movements called chorea, which is why the disease used to be called Huntington's chorea. It is much more common in people of Western European descent than in those of Asian or African ancestry. The disease can affect both men and women. The disease is caused by an autosomal dominant mutation in either of an individual's two copies of a gene called Huntingtin, which means any child of an affected person typically has a 50% chance of inheriting the disease. Physical symptoms of Huntington's disease can begin at any age from infancy to old age, but usually begin between 35 and 44 years of age. Through genetic anticipation, the disease may develop earlier in life in each successive generation
Keto
prefix indicating possession of the carbonyl (:C:O) group:
RNA cell hypothesis
proposes that a world filled with life based on ribonucleic acid (RNA) predates the current world of life based on deoxyribonucleic acid (DNA) and protein. RNA, which can both store information like DNA and act as an enzyme like proteins, may have supported cellular or pre-cellular life. Some hypotheses as to the origin of life present RNA-based catalysis and information storage as the first step in the evolution of cellular life. The RNA world is proposed to have evolved into the DNA and protein world of today. DNA, through its greater chemical stability, took over the role of data storage while protein, which is more flexible in catalysis through the great variety of amino acids, became the specialized catalytic molecules. The RNA world hypothesis suggests that RNA in modern cells, in particular rRNA (RNA in the ribosome which catalyzes protein production), is an evolutionary remnant of the RNA world.
monophyletic life
relating to or characterized by descent from a single ancestral group of animals or plants
respiration
respiration (often confused with breathing) is defined as the transport of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction. This is in contrast to the biochemical definition of respiration, which refers to cellular respiration: the metabolic process by which an organism obtains energy by reacting oxygen with glucose to give water, carbon dioxide and ATP (energy). Although physiologic respiration is necessary to sustain cellular respiration and thus life in animals, the processes are distinct: cellular respiration takes place in individual cells of the organism, while physiologic respiration concerns the bulk flow and transport of metabolites between the organism and the external environment.
bioluminescence
the production of light by living organisms as a result of the oxidation of a light-producing substance (luciferin) by the enzyme luciferase: occurs in many marine organisms, insects such as the firefly, etc
excitability
the property of a cell that enables it to react to irritation or stimulation, such as the ability of a nerve or muscle cell to react to an electric stimulus.
Louis Paster
was a French chemist and microbiologist who is well known for his discoveries of the principles of vaccination, microbial fermentation and pasteurization. He is remembered for his remarkable breakthroughs in the causes and preventions of diseases, and his discoveries have saved countless lives ever since. He reduced mortality from puerperal fever, and created the first vaccines for rabies and anthrax. His medical discoveries provided direct support for the germ theory of disease and its application in clinical medicine. He is best known to the general public for his invention of the technique of treating milk and wine to stop bacterial contamination, a process now called pasteurization. He is regarded as one of the three main founders of bacteriology, together with Ferdinand Cohn and Robert Koch, and is popularly known as the "father of microbiology"
Albert Szent-György
was a Hungarian physiologist who won the Nobel Prize in Physiology or Medicine in 1937.[1] He is credited with discovering vitamin C and the components and reactions of the citric acid cycle.
