The School of Biomedical Sciences Wiki - User contributions [en]

Nucleosides

2018-12-02T14:34:25Z

180344242: corrected referencing format

Nucleosides consist of a sugar ([[Ribose|ribose]] or [[Deoxyribose|deoxyribose]]) and a [[Base|heterocyclic base]] joined by a [[Glycosidic bond|glycosidic bond]]. A nucleoside with a [[Ribose|ribose sugar]] would be known as a ribonucleoside and a nucleoside with a [[Deoxyribose sugar|deoxyribose sugar]] is known as a [[Deoxyribonucleoside|deoxyribonucleoside]]<ref>http://www.biology-online.org/dictionary/Nucleoside</ref>. [[Nucleic acid|Nucleic acid]] can be hydrolysed to produce nucelosides. Nucleosides can be [[Phosphorylation|phosphorylated]] by [[Kinase|kinases]] to produce [[Nucleotides|nucleotides]].

Nucleoside triphospates are nucleosides with 3 [[Phosphate group|phosphate groups]] attached, these are used by [[DNA Primase|DNA primase to]] synthesize [[RNA primer|RNA primers]] on the lagging strand during [[DNA replication|DNA replication]]<ref>Alberts B., Johnson A., Lewis J., Raff M., Roberts K. and Walson J. (2007) Molecular Biology of the Cell, New York: Garland. Page 268</ref> ([[ATP|ATP]], [[CTP|CTP]], [[UTP|UTP]] and [[GTP|GTP]]).

The difference between a nucleoside and a nucleotide is that a nucleotide contains a phospate group. 

=== References  ===

<references />

Huntington disease

2018-12-02T14:31:31Z

180344242: corrected referencing format

Huntington disease (HD) is an [[Autosomal dominant|autosomal dominant]] disorder that causes some of the nerve cells to degenerate<ref>NHS Choices,2012.Huntington's Disease (online) available at http://www.nhs.uk/conditions/Huntingtons-disease/Pages/Introduction.aspx (accessed 29th November 2013)</ref>. It caused by the mutation in HD [[Gene|gene]] of [[Chromosome 4|chromosome 4]]<ref>The university of UTAH, 2013. Genetic Science Learning Centre,(online) available at http://learn.genetic.utah.edu/content/disorders/whataregd/hunt/</ref>. Symptoms of Huntington's disease include changes in the way people feel emotionally, talk, think about things and how they learn<ref>Symtpoms of Huntington's disease include changes in the way people feel emotionally, talk, think about things and how they learn.</ref><ref>https://www.hda.org.uk/huntingtons-disease/what-is-huntingtons-disease</ref>.

=== References ===

<references />

Microorganism

2018-12-02T14:29:54Z

180344242: corrected referencing format and grammar

The term microorganism or microbe refers to an [[Organism|organism]] that cannot be seen with the naked eye and hence, must be viewed using an instrument such as a [[Microscope|microscope]]. The study of microorganisms is referred to as [[Microbiology|microbiology]]. Microorganisms are almost exclusively unicellular organisms, but not all unicellular organisms are microscopic, and there are some organisms that are microscopic. Microbes can include various types of [[Bacteria|bacteria]], [[Protozoa|protozoa]] and [[Fungi|fungi]], but not usually [[Virus|viruses]] as these are deemed to be non-living.

Microorganisms are found almost everywhere on Earth where liquid [[Water|water]] is present. Some microorganisms called [[Extremophiles|extremophiles]] can survive in the most hostile environments such as deserts, hot springs, the ocean floor, or at the poles.

Microorganisms are vital to ecosystems and play an important role in the [[Nitrogen cycle|nitrogen cycle]], but several [[Pathogen|pathogenic]] microorganisms can have detrimental effects on other organisms<ref>http://www.sciencedaily.com/articles/m/microorganism.htm</ref>.

=== Reference ===

<references />

Ionic bond

2018-12-02T14:27:36Z

180344242:

An ionic bond describes the [[Electrostatic|electrostatic]] force between two [[Ions|ions]] with an opposing charge. The bond forms between positive [[Cation|cations]] and negative [[Anion|anions]]. The difference in charge between these atoms then causes them to attract each other. 

An example of ionic bond formation is the ionic lattice formed by solid salts<ref>https://www.chemguide.co.uk/atoms/bonding/ionic.html</ref>.

<references />

Ionic bond

2018-12-02T14:27:16Z

180344242:

An ionic bond describes the [[Electrostatic|electrostatic]] force between two [[Ions|ions]] with an opposing charge. The bond forms between positive [[Cation|cations]] and negative [[Anion|anions]]. The difference in charge between these atoms then causes them to attract each other. 

An example of ionic bond formation is the ionic lattice formed by solid salts<ref name="1">https://www.chemguide.co.uk/atoms/bonding/ionic.html</ref>.

<references />

Angiotensin I

2018-12-02T14:24:19Z

180344242: added a link

Angiotensin I is involved in the [[Renin-Angiotensin System|Renin-Angiotensin system]], involved in controlling [[Blood pressure|blood pressure]] and regulating the Na+ concentration in the blood. It is converted from Angiotensinogen, a reaction catalysed by [[Renin|Renin]]. Angiotensin I is cleaved by the [[Angiotensin Conterting enzyme|Angiotensin Converting Enzyme]] (ACE) to produce the [[Hormone|hormone]], [[Angiotensin II|Angiotensin II]]<ref>Dow, Lindsay, Morrison (1996). Biochemistry Molecules, Cells and the Body. Addison-Wesley Publishers Ltd. . 393.</ref> . 

=== Reference ===

<references />

Esterification

2018-12-02T14:23:26Z

180344242: corrected referencing format

Esterification is when an [[Alcohol|alcohol]] and a [[Carboxylic acid|carboxylic acid]] react together in order to create an [[Ester|ester]]. It can also be created when either [[Acyl chlorides|acyl chlorides]] and [[Alcohol|alcohols]] react, or when acid anhydrides and [[Alcohol|alcohols]] react<ref>http://www.chemguide.co.uk/organicprops/alcohols/esterification.html</ref>.

The [[Ester|ester]] is named by counting the carbons on the [[Alkyl|alkyl]] chain as the first part of the name, followed by counting the carbons on the carboxyl chain for the second part of the name<ref>http://www.chemguide.co.uk/basicorg/conventions/names2.html#top</ref>.

For example: CH3COOCH2CH2CH2 is named propyl ethanoate. As this is comprised from [[Propanol|propanol]] and [[Ethanoic acid|ethanoic acid]].

=== References ===

<references />

Semi-conservative replication

2018-12-02T14:22:11Z

180344242: corrected referencing format

Semi-conservative replication is the mechanism by which [[DNA|DNA]] replicates in [[Cell|cells]]. The parent strand splits in two and uses itself as a template to form a second [[Complementary strand|complementary strand]]. The exposed bases on the single-stranded DNA complementary base pair to [[Nucleotides|nucleotides]]. A ([[Adenine|Adenine]]) pairs with T ([[Thymine|Thymine]]) and C ([[Cytosine|Cytosine]]) pairs with G ([[Guanine|Guanine]])<ref>Alberts et al. Molecular biology of the cell fifth edition 2007. Page 266</ref>. Together the template strand and the complementary strand bond together to form a new double strand of DNA. One parent double strand of DNA will thus become two daughter double strands of DNA<ref>Hartl, D and Jones, E (2009). Genetics- Analysis of genes and genomes. 7th ed. Sudbury: Jones and Bartlett Publishers, Inc. 192.</ref>.

The new strand of [[DNA|DNA]] is made in the 5' to 3' direction as a deoxyribonucleotide is added to the 3' OH end of the chain which is catalysed by [[DNA polymerase|DNA polymerase]]<ref>Alberts et al. Molecular biology of the cell fifth edition, 2007. Page 268</ref>.

The term "semi-conservative" refers to the fact that each of the daughter double helixes contains one conserved strand from the parent DNA, as well as one newly synthesised strand<ref>http://www.nature.com/scitable/topicpage/Semi-Conservative-DNA-Replication-Meselson-and-Stahl-421</ref>.[[Image:Semi-conservative replication.gif]]

=== References ===

<references />

Trigeminal nerve

2018-12-02T14:19:18Z

180344242: added a link

The trigeminal nerve is the fifth cranial [[Nerves|nerve]] located in the [[Brain|brain]]. It posses sensory and motor components and is the major sensory nerve for the face. As well as this, it provides the nerves for the muscles of mastication<ref name="Trigeminal nerve definition">1. Crossman A, Neary D. Neuroanatomy. New York: Churchill Livingstone Elsevier; 2015.</ref>.

=== References ===

<references />

Colour blindness

2018-12-02T14:17:38Z

180344242: Added a link

The type of colour blindness are blue, green and red, which is caused by a defect in [[Cone cells|cone cells]]. The most usual form is red-green colour blindness (also known as Deuteranopia) affecting 7-10% of males. Red-green colour blindness is an [[X-linked recessive disorder|X-linked recessive disorder]] in which both men and women can get the disease, although it is much more common in males. In order for this disease to occur it requires an affected male and either a [[Homozygous|homozygous recessive]] or [[Heterozygous|heterozygous mother]]. Affected males have normal sons but carrier daughters (or affected daughters depending on the mothers [[Genotype|genotype]]) proving that the disorder is inherited by the [[X chromosome|X chromosome]]. Affected heterozygous mothers will pass condition to 50% of daughters and sons. Son's are more likely to [[Inheritance|inherit]] the disease as the recessive [[Allele|allele]] cannot be masked<ref>Reference: Alberts et al (2008) The Molceular Biology of The Cell, 5th Edition. New York: Garland Science.</ref>.

=== References ===

<references />

Deoxyribose sugar

2018-12-02T14:16:15Z

180344242: changed referencing format

Deoxyribose is a 5-sugar ring, with a similar composition as that of [[Ribose|ribose]]. The main difference in composition between the two lies in the lack of [[Hydroxyl group|hydroxyl]] (OH-) and introduction of a [[Hydrogen|hydrogen]] [[Atom|atom]] that takes its place on the second [[Carbon|carbon]] atom.

The deoxyribose sugar featured in [[DNA|DNA]] boasts a composition of 5 carbons and 3 oxygens and makes up the sugar-phosphate backbone which helps to hold the [[Purine|purines]] and [[Pyrimidine|pyrimidines]] (linked by [[Hydrogen bonds|hydrogen bonds]]) in the DNA double helix shape<ref>Hallick, Richard, B. Introduction to DNA Structure. 1995. Introduction to DNA Structure. [ONLINE] Available at: http://www.blc.arizona.edu/Molecular_Graphics/DNA_Structure/DNA_Tutorial.HTML. [Accessed 01 December 2011].</ref><ref>Luvkar, Vipul, Ribose Vs Deoxyribose. 2011. Ribose Vs Deoxyribose. [ONLINE] Available at: http://www.buzzle.com/articles/ribose-vs-deoxyribose.html. [Accessed 01 December 2011].</ref>. 

=== References ===

<references />

Leprosy

2018-12-02T14:12:21Z

180344242: added links and corrected reference format

Leprosy is a disease which affects the [[Skin|skin]] and [[Mucous membranes|mucous membranes]] which causes the skin's surface to form lumps and discolouration.  It is caused by an intracellular infection by the bacteria ''[[Mycobacterium leprae.|Mycobacterium leprae.]]  ''The body responds in two different ways to this [[Infection|infection]] which causes different outcomes:

#[[Tuberculoid leprosy|Tuberculoid leprosy]] - the body produces a strong TH1 response which kills a lot of the bacteria and the disease progresses slowly.
#[[Lepromatous leprosy|Lepromatous leprosy]] - the body produces a strong TH2 antibody response which leaves a lot of [[Macrophages|macrophages]] infected with the bacteria as [[Antibodies|antibodies]] are not a good response to an intracellular infection.  As a result this form of leprosy is fatal.

Adenine

2018-12-02T14:11:09Z

180344242: Added links and corrected reference format

Adenine is one of the four nitrogen-containing base pairs found in [[DNA|DNA]], the others being [[Cytosine|Cytosine]] (C), [[Guanine|Guanine]] (G) and [[Thymine|Thymine]] (T). It is one of the purine bases along with guanine. Both cytosine and thymine are pyrimidines. Adenine has a [[Molecular weight|molecular weight]] of ~135 g/mol. In [[DNA|DNA]] it provides stability to the [[Double_helix|double helix ]]by forming two [[Hydrogen bonds|hydrogen bonds]] with [[Thymine|thymine]], which is adenine's complementary base pair. However in [[RNA|RNA]] it forms [[Hydrogen bonds|hydrogen bonds]] with [[Uracil|uracil]] instead of [[Thymine|thymine]]. [[Purines|Purines]] are 6-membered rings attatched to a 5-membered ring with nitrogens at positions 1, 3, 7 and 9 on the rings.

Adenine plays an important role in cellular organisms in the form of [[ATP|ATP]], an energy-rich molecule used during proccesses such as [[Respiration|respiration]] and other chemical reactions within the cell<ref>http://www.chem.duke.edu/~jds/cruise_chem/Exobiology/adenine.html</ref>.

=== References ===

<references />

T-tubules

2018-11-15T19:12:09Z

180344242: Added a link

T-tubules (also transverse tubules) are invaginations of the [[Muscle|muscle]] membrane ([[Sarcolemma|sarcolemma]]) which penetrate deep into the [[Muscle fibre|muscle fibre]]. [[Action potential|Action potentials]] inside t-tubules triggers [[Calcium|Ca]][[Calcium|2+]] release from terminal cisternae of the [[Sarcoplasmic reticulum|sarcoplasmic reiticulum]], which in turn will produce a [[Contraction|contraction]]. The arrangement of T-tubules and their sizes are vary depending on the muscle type.

Mediator

2018-11-15T19:10:52Z

180344242: added a link

Mediator itself is a large complex consisting of approximately 22 [[Polypeptides|polypeptides]]. This large structure is formed from 3 domains: the head, middle and tail which as unit can either exist on its own or associated with [[RNA polymerase II|RNA polymerase II]] via the c-terminal domain.

=== Function ===

The main function of the mediator complex is to interact with upstream activators on the mRNA, as well as with RNA Polymerase II to initiate [[Transcription|transcription]]. Activators cannot activate transcription independently ''[[In_vitro|In vitro]], ''and so the mediator complex is believed to aid the initiation of transcription via interactions with activators at certain locations on the mediator complex. These mediator-activator interactions, along with other transcription factors, aid the recruitment and assembly of the pre-initiation complex (PIC)<ref>Poss Z., Ebmeier C., Taatjes D. (2013) Critical Views in Biochemistry and Molecular Biology, Volume 38, Page 575-608.</ref>. 

=== Discovery of Mediator ===

Mediator was first wrote about in a 1990 paper by Kelleher, Flanagan and Kornberg titled 'A novel mediator between activator proteins and the RNA polymerase II transcription apparatus'<ref name="Original 1990 paper by Kelleher, Flanagan and Kornberg">https://www.sciencedirect.com/science/article/pii/0092867490906858?via%3Dihub</ref>. They found a gene activator protein in yeast which aided ''In vitro'' transcription of the genetic material. This research led to a Nobel Prize in Chemistry for Kornberg in 2006<ref name="Kornberg's Nobel Prize announcement page">https://www.nobelprize.org/prizes/chemistry/2006/prize-announcement/</ref>.

=== References ===

<references />

Spleen

2018-11-15T19:09:00Z

180344242: added a link

The spleen is a [[Lymphatic organ|lymphatic organ]] found in all [[Vertebrates|vertebrates]]. It is similar in structure to a large [[Lymph node|lymph node]]. The spleen serves as a [[Blood|blood]] storage organ, storing blood during [[Digestion|digestion]] and releasing it when it is finished.

The spleen also makes and destroys [[Erythrocytes|erythrocytes]] (red blood cells). Aging red blood cells are filtered out and broken down, just as in the liver; new red blood cells are generated just as in the [[Bone marrow|bone marrow]]<ref>http://www.daviddarling.info/encyclopedia/S/spleen.html</ref>.

=== References ===

<references />

Carbohydrate structure

2018-11-15T19:08:10Z

180344242: added links and corrected reference format

Carbohydrates are [[Molecule|molecules]] which consist of [[Carbon|carbon]] [[Atom|atoms]], [[Oxygen|oxygen]] atoms and [[Hydrogen|hydrogen]] atoms. Sometimes [[Nitrogen|nitrogen]] and [[Sulphur|sulphur]] atoms can be present too. The empirical formula of carbohydrates is (CH2O)n. All carbohydrates consist of an [[Aldehyde|aldehyde]] or [[Ketone|ketone]] molecule with at least one [[Hydroxyl group|hydroxyl group]] attached. [[Monosaccharides|Monosaccharides]] are the simplest carbohydrates, they are aldehydes or ketones with at least two hydroxyls attached.

Carbohydrates have many [[Isomer|isomers]] due to them containing numerous [[Chiral centre|chiral centres]]. [[Stereoisomer|Stereoisomers]] are isomers with the same atoms but with a different arrangement of atoms in space. Carboydrates can form D or L isomers, called [[Enantiomers|enantiomers]].

Chiral centres occur when an [[Alpha carbon|alpha carbon]] has four different groups attached to it. The two compounds are called stereoisomers and are mirror images of each other for example Beta – D – [[Glucose|glucose]], and Beta – L – Glucose are stereoisomers and rotate the plane of polarised light in opposite directions. The D isomer rotates the plane of polarised light clockwise and so is dextrorotatory, and the L isomer rotates the plane of polarised light anticlockwise and so is laevorotatory<ref name="null">Berg J., Tymoczko J., Stryer L., Biochemistry 7th Edition 2012. New York. WH Freeman. page 330-335</ref>.

=== References ===

<references />

Viagra

2018-11-15T19:05:34Z

180344242: added links and corrected reference format

Viagra is the trademark name for the drug [[Sildenafil|sildenafil]], which was developed by the pharmaceutical company Pfizer. It is used to treat erectile dysfunction in males<ref>Francis, Sharron H., Corbin, Jackie D. (2005). Sildenafil: efficacy, safety, tolerability and mechanism of action in treating erectile dysfunction. Expert opinion on drug metabolism and toxicology. 1 (2), p283-293.</ref>. Initially, it was widely used to relieve the symptoms of [[Angina|angina]]. The [[Molecular formula|molecular formula]] for Viagra is C22H30N6O4S and the elimination [[Half life|half-life]] is approximately 3 to 4 hours.

=== Mechanism of action ===

[[Acetylcholine|Acetylcholine]] is released by nerves in the walls of penile [[Blood vessels|blood vessels which]] causes [[Nitric oxide|nitric oxide]] (NO) to be released by [[Endothelial cells|endothelial cells]] in the vessel lining. NO binds to the enzyme [[Guanylyl cyclase|guanylyl cyclase]] in the [[Smooth_muscle_cells|smooth muscle cells]] of the [[Blood vessel|blood vessel]] which catalyses the production of [[CGMP|cyclic GMP]] (cGMP) from [[GTP|GTP]]. The smooth muscle cells respond to this by relaxing which allows the blood vessel to dilate.

[[CGMP|cGMP]] is quickly degraded by [[CGMP phosphodiesterase|cGMP phosphodiesterase]]. This enzyme hydrolyses cGMP to [[GMP|GMP]]. Viagra works to [[Competitive inhibitors|competitively inhibit]] [[CGMP phosphodiesterase|cGMP phosphodiesterase]] so that [[Intracellular|intracellular]] levels of cGMP remain high, meaning penile blood vessels are dilated for a longer period of time<ref>Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P (2008). Molecular Biology of the Cell. 5th ed. New York: Garland Science. p888-889.</ref>.

=== References ===

<references />

Testosterone

2018-11-15T19:04:13Z

180344242: added links and corrected reference format

Testosterone (systematic name being 17beta-Hydroxyandrost-4-en-3-one) is a [[Steroids|steroid]] [[Sex hormone|sex hormone]]. It is a nongaseous [[Signal moleculre|signal molecule]] that is both [[Hydrophobic|hydrophobic and]] small<ref>Alberts, Johnson, Lewis, Raff, Roberts and Walter. (2008) 'Molecular Biology of the Cell' 5th Edition. New York: Garlands Science. p 889</ref>.

In males, it is produced in the testicles and promotes male secondary sexual characteristics such as increased muscle growth, a deeper voice, production of [[Sperm|sperm]] and development of sexual characteristics<ref>The Reproductive System at a Glance By Linda J. Heffner, Danny J. Schust P.17</ref>.

Like other steroid hormones, the precursor to these chemicals is [[Cholesterol|cholesterol]]. More specifically, testosterone is an [[Androgen hormone|androgen hormone]], one of the five major classes of steroid hormones, which also includes: progestagens, glucocorticoids, mineralocorticoids and estrogens<ref>Berg,J.M, Tymoczko, J.L, Gatto, G.J.Jr, Stryer, L. Biochemistry Eighth Edition. 2015</ref>. Conversion of cholesterol to testosterone follows a number of steps and intermediate products: The starting reaction for any steroid hormone is the interaction between cholesterol and the cholesterol-side-chain-cleavage enzyme (P450scc). This results in the production of pregnenolone. From here, this is where differentiation of the hormones occurs. For the production of testosterone, pregnenolone interacts with the P450c17 enzyme and produces 17alpha-Hydroxy-pregnenolone. Further interaction with P450c17 results in dehydroepiandrosterone (DHEA). From here, DHEA can either: react with 3beta-HSD2 enzyme and produce androst-4-ene 3,17-dione or react with 17beta-HSD3 enzyme and produce androst-5-ene 3beta, 17beta-diol. Finally, from here the androst-4-ene 3,17-dione can react with 17beta-HSD3 enzyme and produce testosterone. On the other hand, androst-5-ene 3beta, 17beta-diol reacts with the 3beta-HSD2 enzyme and result in testosterone, which has an end number of 19C<ref>Norman, A.W, Henry, H.L. Hormones Third Edition. 2015 p.47</ref>.

=== References ===

<references />

Carbon dioxide

2018-11-15T19:00:30Z

180344242:

[[Carbon_dioxide|Carbon dioxide]] is a chemical compound consisting of two [[Oxygen|oxygen]] [[Atom|atoms]] [[Covalent_Bonds|covalently]] linked to a central [[Carbon|carbon]] [[Atom|atom]], and so can be represented with the chemical formula CO2.

Carbon dioxide is essential for the process of [[Photosynthesis|photosynthesis]] which occurs in the [[Chloroplasts|chloroplasts]] of plants. This is a process in which the carbon dioxide from the air (around 0.0360% of the air is carbon dioxide<ref>http://www.eoearth.org/article/Atmospheric_composition</ref>: produced by [[Respiration|respiration]] by living organisms, as well as by the combustion of fossil fuels, is utilised by the plants to produce the [[Sugar|sugars]] they require to grow. Plants may also store this sugar in the form of [[Starch|starch]].

Carbon dioxide is constantly recycled in a cycle, being produced by respiration and used in photosynthesis 

=== References ===

<references />

Microscope

2018-11-15T18:58:43Z

180344242: corrected referencing format

A microscope is an instrument used primarily by scientists to examine things which are too small to see without the microscope<ref>https://en.wikipedia.org/wiki/Microscope</ref>. 

=== References: ===

<references />

Transferases

2018-11-15T18:56:51Z

180344242: added links and corrected reference format

Transferases are a group of [[Enzymes|enzymes]] which [[Catalyse|catalyse]] the transfer of, i.e. remove a functional group from one [[Molecule|molecule]] to another e.g [[Methyl|methyl]], [[Phosphate group|phosphate]], [[Amino group|amino]] groups<ref>Marks D B., Marks A D., Smith C M., (1996) Basic Medical Biochemistry: A clinical Approach, 1st edition, Philadelphia; Baltimore: Lippincott Williams and Wilkins</ref>.

This type of reaction that occurs is called a group transfer reaction and an example of this is [[Nucleotide monophosphate kinase|nucleotide monophosphate kinase]], also abbreviated to NMP kinase<ref>Jeremy M. Berg et al. Biochemistry, 6th edition, 2007, W.H Freeman and Company, New York. Chapter 8 – Metabolism: Enzymes, Basic Concepts and Kinetics, page 237</ref>.

=== References ===

<references />

Oxidation number

2018-11-15T18:51:40Z

180344242: added links

The oxidation number of an [[Atom|atom]] represents how many [[Electron|electrons]] it has lost, gained or shared. In an uncombined [[Element|element]] the [[Oxidation|oxidation]] state is always zero because no electrons have been transferred. For a [[Monoatomic ion|monoatomic ion]], the oxidation state is equal to its charge. For an ion with more than one atom the sum of the atoms oxidation states is equal to the overall charge. In a [[Covalent|covalently bonded]] atom, the oxidation number depends on the [[Electronegativity|electronegativity]] of the atoms it is sharing electrons with. Oxidation number increases when atoms are oxidised, and decreases when they are reduced during [[Redox reaction|redox reactions]].

Glycolipid

2018-11-15T18:50:18Z

180344242: added links

Glycolipids are sugar- containing lipids and in an animal [[Cell|cell]] these [[Lipids|lipids]] are derived from [[Sphingosine|sphingosine]]. The [[Amino group|amino group]] of the [[Sphingosine|sphingosine]] backbone is acylated by a [[Fatty acid|fatty acid]]. The identity unit of a [[Glycolipid|glycolipid]] is linked to the primary [[Hydroxyl group|hydroxyl group]] of the sphingosine backbone and one or more [[Sugars|sugars]] are attached to this group. [[Cerebroside|Cerebroside]] is the simplest [[Glycolipid|glycolipid]] and it contains a single sugar residue which is either [[Glucose|glucose]] or [[Galactose|galactose]]. More complex glycolipids contain a branched chain of several sugars <ref>J.Berg, J.L Tymoczko, L.Stryer (2007), 6th Edition, Basingstoke: W.H. Freeman and Company</ref>.

=== References ===

<references />

Natural killer cell

2018-11-15T18:49:17Z

180344242: added links

Natural Killer Cells (NK Cells) are [[White blood cells|white blood cells]] and are part of the [[Innate immune response|innate immune response]]. They contain [[Cytotoxic granules|cytotoxic granules]] containing [[Enzymes|enzymes]] which aid host rejection of [[Tumour|tumours]] and virus-infected cells. They are activated by IFNα, IFNβ, IL12 and produce IFNγ to control infection while the adaptive response begins.

NK Cells have inhibitory and activating receptors on their cell surface. Inhibitory receptors recognise [[MHC Molecules|MHC 1]] receptors on host cells and this "switches off" the NK Cell, preventing it from killing. The reason that NK Cells can kill [[Cancer|cancer]] cells and infected cells is because they often lose their MHC 1, leaving them vulnerable to NK Cell killing.

Start Codon

2018-11-15T18:47:35Z

180344242: edited referencing format

The start codon for any [[Polypeptide chain|polypeptide chain]] is not always AUG at some circumtances, which codes for [[Methionine|Methionine]]. tRNAMet is bound to AUG and begins polypeptide synthesis<ref>Daniel L. Hartl and Maryellen Ruvolo (2012) Genetics: Analysis of genes and genomes. 8th Edition. USA: Jones and Bartlett Learning, p.26</ref>.

Many polypeptides, however, have the [[Methionine|methionine]] cleaved off after translation is complete, so AUG [[Codon|codon]] will not always be present in base sequences and not counted as in total number of [[Amino acid|amino acid]] as start and stop codon are not counted as amino acid at the end of the reaction of binding [[Protein|protein]].  

=== References ===

<references />

Autonomic Nervous System

2018-11-15T18:46:47Z

180344242: edited referencing format

The autonomic nervous system (also known as the visceral nervous system<ref>Silverthorn, D.U. (2010) Human Physiology an Integrated Approach (5th ed.) San Francisco: Pearson Education, Inc. publishing as Pearson Benjamin Cummings. Page 249</ref>) can be referred to as the vegetative nervous system<ref>Silverthorn, D.U. (2010) Human Physiology an Integrated Approach (5th ed.) San Francisco: Pearson Education, Inc. publishing as Pearson Benjamin Cummings. Page 386</ref> as its functions are not under voluntary control. It is part of the [[Peripheral nervous system|peripheral nervous system which]] consists of efferent neurones in which impulses from the [[Central nervous system|central nervous system travel]] to their targets (usually muscles and glands)<ref>Silverthorn, D.U. (2010) Human Physiology an Integrated Approach (5th ed.) San Francisco: Pearson Education, Inc. publishing as Pearson Benjamin Cummings. Page 249</ref>.

The autonomic nervous system can be divided into the [[Sympathetic nervous system|sympathetic]] and [[Parasympathetic nervous system|parasympathetic]] systems, which can be recognised according to the chemical neurotransmitters they use<ref>Silverthorn, D.U. (2010) Human Physiology an Integrated Approach (5th ed.) San Francisco: Pearson Education, Inc. publishing as Pearson Benjamin Cummings. Page 249 and 386</ref>. The targets of autonomic neurones are [[Muscle|smooth muscle, cardiac muscle]], many [[Exocrine glands|exocrine glands]], a few [[Endocrine glands|endocrine glands]], lymphoid tissues and some [[Adipose tissue|adipose tissue]]<ref>Silverthorn, D.U. (2010) Human Physiology an Integrated Approach (5th ed.) San Francisco: Pearson Education, Inc. publishing as Pearson Benjamin Cummings. Page 249 and 386</ref>. The autonomic system is important in the body as it maintains [[Homeostasis|homeostasis]]<ref>Silverthorn, D.U. (2010) Human Physiology an Integrated Approach (5th ed.) San Francisco: Pearson Education, Inc. publishing as Pearson Benjamin Cummings. Page 387</ref>. 

The [[Autonomic_Nervous_System|autonomic nervous system]] is the portion of the nervous system that regulates and controls visceral functions such as heart rate, temperature regulation during [[Homeostasis|homeostasis]], digestion and [[Blood pressure|blood pressure]].  Although the autonomic nervous system is a functionally distinct system of its own it is composed of the central nevous system and the peripheral nervous system, the autonomic nervous system carries nerve impulses to glands, [[Muscle|smooth muscle]] and [[Muscle|cardiac muscle]] and is under involuntary, subconcious control. Visceral sub concious control is achieved by reflex arcs which is a nerve pathway in the body taken by an [[Action potential|action potential]] that leads to a rapid involuntary respoonse to a stimulus. The autonomic nervous system can be further sub divided into the sympathetic nervous system which stimulates effectors and so speeds up any activity. It acts like an emergency controller so helps the body cope with essful situations by heightening our awareness and preparing us for activity (fight or flight response). It is also divided into the [[Parasympathetic nervous system|parasympathetic nervous system]], which inhibits effectors and so slows down any activity, it controls activities under normal resting conditions.  

=== References ===

<references />

Carbaminohemoglobin structure

2018-11-15T18:34:12Z

180344242: corrected referencing format

Carbaminohaemoglobin, is a [[Molecules|molecule]] of [[Haemoglobin|haemoglobin]] which binds to a [[Carbon dioxide|CO2]] [[Molecule|molecule]] reversibly. [[Amide|Amide]] linkages form between the [[Terminal amino groups|terminal amino groups]] found on the constituent [[Polypeptide chain|polypeptide]] chains which form the structure of haemoglobin. This allows one molecule of haemoglobin to transport 4 molecules of CO2<ref name="Carbon dioxide transport">Smith N. Carbon Dioxide &amp;amp;amp; Oxygen Transport. [Online].; 2001 [cited 2015 November 15th. Available from: http://www.diatronic.co.uk/nds/webpub/homepage.htm.</ref>.

=== References ===

<references />

Troponin I

2018-11-15T18:25:04Z

180344242: added links

Troponin is an accessory [[Protein|protein]] found in [[Thin filaments|thin filaments]] (also known as actin filaments). Thin filaments are structural components of a repeating unit called the [[Sarcomere|sarcomere]]. These thin filaments play an important role in [[Muscle_contraction|muscle contraction]]. Troponin consists of three sub-units; [[Troponin T|troponin T]], I and [[Troponin C|C]]. When the muscle is at rest the T and I sub-units bind to [[Tropomyosin|tropomyosin]] and [[Actin|actin]] resulting in an inhibitory process that prevents [[Myosin|myosin]] heads from binding to actin. When the concentration of [[Calcium_ions|calcium ions]] raises in the [[Cytoplasm|cytoplasm]], due to the influx from the [[Sarcoplasmic reticulum|sarcoplasmic reticulum]], the calcium ions bind to [[Troponin C|troponin C]]<ref>Alberts, B. et al., 2008. Molecular Biology of the Cell, Fourth Edition 5th Edition., New York, USA: Garland Publishing Inc.</ref>. This binding causes troponin I to release its hold on actin, which allows tropomyosin to move back to its normal position. Consequently, the [[Myosin|myosin]] binding site is uncovered, allowing myosin heads to bind to [[Actin|actin]] and form a [[Cross_bridge|cross bridge]], triggering contraction<ref>Alberts,Bruce et al. (2002) Molecular biology of the cell 4th ed. (chapter 16 pg 962-965). New York, Garland Science.</ref>.

=== References ===

<references />

Folic acid

2018-11-15T18:23:06Z

180344242: referencing format edits, added links and corrected spelling

Folic acid, also cmmonly known as folate, falls into the family of B vitamins, B9 to be exact. Folic acid is crucial for proper brain function and plays an important role in mental and emotional health. Folate aids in the production of [[DNA|DNA]] and RNA,  and is especially important when cells and tissues are growing rapidly, such as in infancy, adolescence, and pregnancy. Folic acid also works closely with [[Vitamin_B12|vitamin B12]] to help make [[Red_blood_cells|red blood cells]] and help [[Iron|iron]] work properly in the body.

It is common for one to have low levels of folate in their body. Some contributing factors to this include alcoholism, inflammatory bowel disease, celiac disease and certain medication. A lack of folate body on a typical being can result in poor growth, tongue inflammation, gingivitis, loss of appetite, shortness of breath, diarrhea, irritability, forgetfulness, and mental sluggishness. 

A daily amount of 400 mg would be sufficicient to meet daily requirements. Folate supplements which reach this requirement are a must espcially for women who intend to have a child in the near future to prevent [[Neural Tube Defect|Neural Tube Defects]] (NTD) as NTD occurs shortly after conception. Impregnanted women should ideally consume 600 mg of folate per day<ref>University of Maryland Medical Center - http://umm.edu/health/medical/altmed/supplement/vitamin-b9-folic-acid#ixzz3K7f1xSp2</ref>.  

=== References ===

<references />

Charge

2018-11-15T18:14:58Z

180344242: added a link

Electrical charge is a property of matter. It is measured using the [[SI units|SI unit]], the [[Coulomb|coulomb]] (C). From a biological stand-point, this is most useful when referring to the charge of [[Ions|ions]] or [[Molecules|molecules]] (like Mg2+ ions having a 2+ charge, or DNA having partial negative charge).

If any object with a charge is placed in a magnetic field they will experience a force (be that repulsive or attractive). This force is proportional to the strength of the magnetic field and the size of the charge.

If two charged objects come together, they will also experience a force, as stated previously. This is called the coulomb force and is mathematically described as so: 

F = q1q2/4π(ε0)r2 <ref name="null">R. Nave. Electric Forces. Available from:http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elefor.html. Date accessed: 18/10/16</ref>

Where F = Force

q1 and q2 = respective charges

ε0 = Permittivity of free space (8.85x10-12 Fm-1)

r = distance between centre of objects   

Charge is an exploitable property when working with DNA. The [[Phosphate backbone|phosphate backbone]] of [[DNA|DNA]] carries a partial negative charge which, in the presence of an electric field, can migrate down a gel. This is the concept of [[Gel electrophoresis|gel electrophoresis]]. Smaller fragments of DNA will migrate further down the gel, towards the [[Anode|anode]], than larger fragments. Using a [[DNA ladder|DNA ladder]] of predetermined sizes of DNA, you can work out the size of unknown fragments using the distance they have moved down the gel.<ref>University of Waikato. Gel Electrophoresis. Available at:http://biotechlearn.org.nz/themes/dna_lab/gel_electrophoresis. Date accessed: 18/10/16</ref>

=== References ===

<references />

Transmission electron microscopes

2018-11-15T18:10:27Z

180344242: Added a link

This is a type of [[Microscope|microscope]] that utilizes [[Electrons|electrons]] when forming an image for a specimen. The [[Electrons|electrons]] are transmitted through the specimen to produce a high-resolution 2-D image of the specimen, as they hit a fluorescent screen<ref>Young Scientists Journal. 2015. Transmission Electron Microscope. [ONLINE] Available at: https://ysjournal.com/transmission-electron-microscope/. [Accessed 16 October 2018].</ref>.

=== References ===

<references />

Sodium chloride

2018-11-15T18:07:00Z

180344242: Corrected reference format and added a link

Sodium chloride (chemical formula NaCl) is an inorganic salt formed by the [[Ionic bond|ionic bonding]] of sodium and chloride ions. 

It has a [[Molecular_weight|molecular weight]] of 58.44 g/mol and a solubility in water of 360 g/l<ref name="1.">http://www.chemicalbook.com/ChemicalProductProperty_EN_CB4104636.htm</ref>. 

It is the largest dissolved constituent of seawater and is mass produced by the evaporation of seawater in salt farms or by the mining of rock salt<ref name="2.">http://www.madehow.com/Volume-2/Salt.html</ref>.

Sodium chloride produced in this way will always containt impurities from other [[Ions|ions]] in seawater.

Pure sodium chloride can be produced by reacting [[Sodium|sodium]] metal with [[Chlorine|chlorine]] gas<ref name="3.">http://www.angelo.edu/faculty/kboudrea/demos/sodium_chlorine/sodium_chlorine.htm</ref>.

=== References ===

<references />

Sodium hydroxide

2018-11-15T18:04:15Z

180344242: added links

Sodium hydroxide (NaOH) is a common inorganic [[Compound|compound]] with a [[Molecular weight|molecular weight]] of 39.997 g/mol, formed from Na+ and OH- [[Ion|ions]]. It has a [[Melting_point|melting point]] of 318oC, a [[Boiling_point|boiling point]] of 1390oC and a density of 2.13 g/mL<ref>Chemspider.com. (2018). Sodium hydroxide | HNaO | ChemSpider. [online] Available at: http://www.chemspider.com/Chemical-Structure.14114.html [Accessed 20 Oct. 2018].</ref>. Typically a white crystalline odorless solid at room temperature, it forms sodium hydroxide solution in [[Water|water]]. Highly corrossive, NaOH can induce severe burns on differents parts of the body such as the [[Skin|skin]]. Some applications include [[Electroplating|electroplating]] and oxide coating<ref>PubChem, Sodium hydroxide, Accessed on 19 October 2017, Available at https://pubchem.ncbi.nlm.nih.gov/compound/sodium_hydroxide#section=Top</ref>. 

=== Reference ===

<references />

Coenzyme A

2018-11-15T17:59:18Z

180344242: Added a link

Coenzyme A's functionalty depends on the presence of a [[Cofactor]], which is a non protein group, that enables the [[Enzyme|enzyme]] to function. Coenzyme A carries an [[Acetyl_group|Acetyl group]] to become [[Acetyl-CoA|Acetyl Coenzyme A]] (Acetyl CoA) <ref>Alberts, B et al. (2008). Molecular Biology of the Cell. 5th ed. US: Garland Science. p83-84</ref><ref>Hames, D et al. (2005) Biochemistry, 3rd ed.UK Taylor and Francis p88</ref>.

=== References: ===

<references />

Central Dogma

2018-11-15T17:55:23Z

180344242: Corrected reference format and added a link

‘The Central Dogma’ of molecular biology is the term used to describe how the genetic information stored within [[DNA|DNA]] is first encoded into [[RNA|RNA]] and then used to produce functional [[Proteins|proteins]] within the [[Cell|cell]]<ref>Becker, W., Hardin, J., Bertoni, G. and Kleinsmith, L.J. (2012) Becker’s World of the Cell. 8th Edition. San Francisco: Pearson Benjamin Cummins. (p. 645)</ref>. Although [[DNA|DNA]] contains all the genetic information needed to produce proteins, it uses RNA as an intermediary molecule to transfer the information, thus RNA molecules are often referred to as the ‘messenger’ molecules ([[MRNA|mRNA]]), transferring the genetic information from DNA in order to produce proteins<ref>Hartl, D.L. and Ruvolo, M. (2012) Genetics. 8th Edition. Burlington, MA: Jones &amp;amp;amp;amp;amp;amp;amp; Bartlett Learning. (pp. 22-23).</ref>.

The central dogma was a theory first postulated by [[Francis Crick|Francis Crick]] in 1970 and to this day, is still widely accepted. The basic idea for the hypothesis can be written as follows: Polynucleotides and polypeptides use RNA as an intermediate in their two-component system, or more simply: DNA ---> RNA ---> Protein<ref>Crick F. The central dogma of molecular biology Nature Published 08/08/1970 Cited 05/12/2017 227(5258):561–563</ref>. The idea relies on the ability of the polynucleotides to encode proteins using their genetic information and the polypeptides' [[Catalysis|catalytic activity]] which includes [[Enzyme|enzymes]] able to synthesise DNA. Thus, the central dogma can be said to be based on the two processes: [[Transcription|Transcription]] and [[Translation|Translation]].

[[DNA|DNA]] contains very specific sequences of nucleotides which can act as a template for a strand of [[RNA|RNA]] to be produced through the process of transcription. The resulting strand of RNA then codes for a very specific sequence of [[Amino acid|amino acids]]. These can be joined together in the [[Ribosome|ribosome]] of the [[Cell|cell]] to produce a [[Polypeptide chain|polypeptide chain]] in a process known as translation. Hence, all the information that is needed to make proteins initially comes from DNA molecules<ref>Hartl, D.L. and Ruvolo, M. (2012) Genetics. 8th Edition. Burlington, MA: Jones &amp;amp;amp;amp;amp;amp;amp; Bartlett Learning. (pp. 22-23).</ref>.

The two processes go hand in hand and furthermore, the whole central dogma theory is founded upon the irreversibility of the translation process. Crick hypothesised the theory after the discovery of [[Reverse transcriptase|reverse transcriptase]] as the discovery of such an enzyme made it clear that, without very complicated molecular machinery, it is impossible to go from a protein to nucleic acids<ref>Eugene V. Koonin Why the Central Dogma: on the nature of the great biological exclusion principle Published 16/09/2016 Cited 05/12/2017 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4573691/</ref>.

However, w[[Nucleic_acids]]hilst this concept is true for the majority of our [[Genes|genes]], recent studies have shown that not every gene found in [[DNA|DNA]] codes for a protein. In fact, some sequences of [[DNA|DNA]] can code for various types of RNA<ref>National Centre for Biotechnology Information (2007) Central Dogma of Biology: Classic View. Available at: http://www.ncbi.nlm.nih.gov/Class/MLACourse/Modules/MolBioReview/central_dogma.html (Accessed: 28/11/14)</ref>.

The Central Dogma is also essential to the [[RNA world|RNA World]] Hypothesis.

=== References ===

<references />