cellular

Virus

...ading and taking over other cells as they lack the cellular machinery for self reproduction. The term virus ...uses 3.1 Viruses as tools for exploring basic cellular processes 3.2 Viruses as tools for genetic engineering 4 Viral size, structure and, anatomy ...

Virus classification

...cause one of the two strands of DNA in which all cellular life forms store their genetic information is re... The taxonomy of viruses is similar to that of cellular organisms: Order ( -virales ) Family ( -viridae ) Subfamily ( -virinae ) Genus ( -virus )...

Vesicle

...ilayer . Vesicles store, transport , or digest cellular products and wastes . This biomembrane enclosing the vesicle is the same as that of the outer (cellular) membrane. Thus, because of the separation, the intravesicular environment can be made to be different from the cytosolic environment. Vesic...

Vacuole

..., water follows. This pressure is also helpful for cellular elongation: when the cell wall is degraded (not en...t it pushes all the cell's cytoplasm against the cellular membrane, and thus keeps the chloroplasts closer to light. The different roles of the central v...

Transmembrane receptor

... this way they play a unique and important role in cellular communications and signal transduction . Many transmembrane receptors are composed of two or more protein subunits which operate collectively and may dissociate when ligands bind, fall off, or at another stage of their "activation" cycles. ...

Tobacco mosaic virus

...radius of ~4nm and is protected from the action of cellular enzymes by the coat protein. There are three RNA nucleotides per protein monomer. The amino acid sequence of TMV's coat protein has been published in "American Chemical Society's Chemical Abstracts" in 1972 as a single word, Acetylseryltyrosylse...

Tobacco mosaic virus

...radius of ~4nm and is protected from the action of cellular enzymes by the coat protein. There are three RNA nucleotides per protein monomer. The amino acid sequence of TMV's coat protein has been published in "American Chemical Society's Chemical Abstracts" in 1972 as a single word, Acetylseryltyrosylse...

Mitosis

...ecruiting microtubules (which may be thought of as cellular ropes or poles) and forming mitotic spindles . By...llowed by cytokinesis or cleavage , where the cellular membrane pinches off between the two newly separated nuclei, to form two new daughter cells. At this...

Systems biology

...ationalise this in terms of the relevantmolecular, cellular and physiological control mechanisms. Multidisciplinary studies The studies that need to be undertaken by systems biology resear...

Synapse

... and occurs through an unusually rapid process of cellular secretion : Within the pre-synaptic nerve terminal, vesicles containing neurotransmitter sit "docked" and ready at the synaptic membrane. The arriving action potential produces an influx of calcium ions through voltage-dependent, calcium-selectiv...

Stoma

...uard cells that surround the opening and involves cellular sodium - potassium pumps. Dicotyledons usually have more stomata on the lower epidermis than the upper epidermis. As these leaves are held horizontally, upper epidermis is directly illuminated. Less number of stomata on the upper epidermis can...

Starch

...ants starch for storage is produced in specialized cellular organs, amyloplasts. Starch is often found in the fruit , seeds , or tubers of plants . The four major resources for starch production and consumption in the USA are corn , potatoes , rice , and wheat . As an additive for food proce...

Signal transduction

...s . Sensing in all forms of life depends, at the cellular level, on signal transduction. Contents show...hat converts the extracellular signal to an intra cellular one. Intracellular signalling molecules in eukaryotic cells include heterotrimeric G protein , ...

Semen

... blood , semen consists of two compartments, the cellular compartment ( spermatozoa ) and noncellular compartment ( seminal plasma ). It contains the sperm , which sometimes results in pregnancy following vaginal sex with a female . Semen is a whitish , milky fluid, very viscous , containing wat...

Blood plasma

...h a density designed to sit between the liquid and cellular layers in the tube after centrifugation, making separation more convenient. Tests of coagulation (such as the INR and APTT ) require all clotting factors to be preserved. Serum, therefore, is inappropriate for these tests. A citrated evacuated ...

Second messenger

... that can diffuse both through cytosol and across cellular membranes. These intracellular messengers have some properties in common: They can be synthesized/released and broken down again in specific reactions by enzymes. Some (like Ca 2+ ) can be stored in special organelles and quickly released ...

RNA

...terial of some RNA viruses and is involved in some cellular processes, such as RNA interference . Transfer RNA (tRNA) is a small class of RNA molecules that present specific amino acids to the ribosome during translation , the anticodon of the tRNA paits with the codon of on the mRNA Messenger R...

Retrovirus

...RNA templates, and it was subsequently adopted by cellular organisms due to the increased chemical stability of DNA. The following genera are included here: Genus Alpharetrovirus ; type species: Avian leucosis virus Genus Betaretrovirus ; type species: Mouse mammary tumour virus Genus Gammare...

Reverse genetics

... antisense oligos. While RNAi acts by directing cellular systems to degrade target messenger RNA (mRNA), Mo... the target mRNA without requiring the activity of cellular proteins and without necessarily accelerating mRNA degradation. Morpholinos are effective is system...

Replication

...a form of self-replication because it requires the cellular apparatus to perform that replication. Semiconservative replication is the particular mechanism of DNA replication, of several mechanisms that were originally hypothesised, that was found to be actually used in cells. In computer science , r...

Proton pump

...n ATPase and in the ATPase proton pumps of other cellular membranes, ATP itself powers this transport. The F 0 F 1 ATP synthase of mitochondria and the CF 1 ATP synthetase of chloroplasts, in contrast, usually conduct protons from high to low concentration across the membrane while drawing energy from ...

Proton-motive force

...of CO 2 . In prokaryotes , it exists across the cellular membrane of the organism....

Proteomics

... protein interactions on the atomic, molecular and cellular levels Protein modification . Almost all proteins are modified from their pure translated amino-acid sequence, so-called post-translational modification. Specialized methods have been developed to study phosporylation (phosphoproteomics) and glyco...

Proteolysis

...irected degradation ( digestion ) of proteins by cellular enzymes called proteases or by intramolecular digestion. Proteolysis is used by the cell for several purposes. They include Removal of N-terminal methionine residues after translation . Removal of the signal sequence of peptides afte...

Proteome

... several different types of biological systems. A cellular proteome is the collection of proteins found in...e complete set of proteins from all of the various cellular proteomes. This is very roughly the protein equivalent of the genome . The term "proteome" has also...

Protein

...ction performed by a cell, including regulation of cellular functions such as signal transduction and metabolism .For example, protein catabolism requires only a few enzymes termed proteases . Mechanisms of protein regulation Various molecules and ions are able to bind to specific sites on proteins....

Prophase

...ruiting microtubules (which may be thought of as cellular ropes or poles) and forming a mitotic spindle between them. By increasing the length of the spindle (growing the microtubules), the centrioles push apart to opposite ends of the cell nucleus. See also prometaphase metaphase anaphase t...

Prion

...tein X" hypothesis) is that an as-yet unidentified cellular enzyme (Protein X) catalyzes the conversion of Pr...lonies of this fungus can merge together and share cellular contents such as nutrients and cytoplasm. A natural system of protective "incompatibility" protein...

Plant

...nd . The best preserved examples, from which their cellular construction has been described, have been found at this locality. The preservation is so perfect that sections of these ancient plants show the individual cells within the plant tissue. The Devonian period also saw the evolution of what many believe...

Plant

...nd . The best preserved examples, from which their cellular construction has been described, have been found at this locality. The preservation is so perfect that sections of these ancient plants show the individual cells within the plant tissue. The Devonian period also saw the evolution of what many believe...

Physiology

...uatic habitats , water must be stored within their cellular environments. In organisms such as these, dehydration becomes a major issue. Dehydration in humans can occur during elevated physical activity. Within the field of exercise physiology , studies have been conducted that show the effects of de...

Phosphorylation

...lying phosphorylation can be very complex. In some cellular signalling pathways, a protein A phosphorylates B, and B phosphorylates C, but A also phosphorylates C directly, and B can phosphorylate D, which may in turn phosphorylate A. Types of phosphorylation See also protein kinase for more details ...

Peroxisome

...H 2 O 2 (hydrogen peroxide, a toxic byproduct of cellular metabolism ) to H 2 O and O 2 , with 4H 2 O 2 → 4H 2 O + 2O 2 . In humans, high numbers of peroxisomes can be found in the liver, where toxic byproducts are known to accumulate. All of the enzymes found in a peroxisome are imported from the c...

Passive transport

...cial carrier proteins that are embedded within the cellular membrane. A lot of large molecules, such as glucos...be bonded to a receptor site and moved through the cellular membrane. Bear in mind, however, that facilitated diffusion is a passive process, and the solutes st...

Oxidative phosphorylation

...n cells . It is the final metabolic pathway of cellular respiration , after glycolysis and the citric acid cycle . The process takes place at a biological membrane . In prokaryotes this is the plasma membrane , and in eukaryotes it is the inner of the two mitochondrial membranes . NADH and...

Oswald Avery

...r of genes. S strain bacteria first had the large cellular structures removed. Then they were treated with protease enzymes , which removed the proteins from the cells before the remainder was placed with R strain bacteria. The R strain bacteria transformed, meaning that proteins didn't carry the genes ...

Nucleotide

... group . Nucleotides also play important roles in cellular energy transport and transformations (notably ATP and NAD+/NADH ), and in enzyme regulation (see for example, protein kinase ). The nucleobase can be a purines or pyrimidines , the sugar can be deoxyribose in DNA or ribose in RNA, and th...

Nondisjunction

...occur in the meiosis I or meiosis II phases of cellular reproduction. This is a cause of several medical conditions, including: Down Syndrome - trisomy of chromosome 21 Patau Syndrome - trisomy of chromosome 13 Edward Syndrome - trisomy of chromosome 18 Turner Syndrome - only one X chro...

Neuroscience

...els of study, from the molecular level through the cellular level (individual neurons ), the level of relativ...e - In principle, there is no distinction between cellular and molecular biology of the brain and of any other organ. However, there are so many differences b...

Neuron

...ells. The dendrite , a short, branching arbor of cellular extensions. Each neuron has very many dendrites with profuse dendritic branches. These structures form the main information receiving network for the neuron. Axon and dendrites alike are typically only about a micrometre thick, while the soma is ...

Nicotinamide adenine dinucleotide

...ly in glycolysis and the citric acid cycle of cellular respiration . It forms NADP with the addition of a phosphate group to the 2' position of the nucleotide through an ester linkage. NADP is produced in the preliminary cycles of photosynthesis , and is used in the later Calvin cycle of photosynthe...

Nicotinamide adenine dinucleotide

...ly in glycolysis and the citric acid cycle of cellular respiration . It forms NADP with the addition of a phosphate group to the 2' position of the nucleotide through an ester linkage. NADP is produced in the preliminary cycles of photosynthesis , and is used in the later Calvin cycle of photosynthe...

Nicotinamide adenine dinucleotide

...ly in glycolysis and the citric acid cycle of cellular respiration . It forms NADP with the addition of a phosphate group to the 2' position of the nucleotide through an ester linkage. NADP is produced in the preliminary cycles of photosynthesis , and is used in the later Calvin cycle of photosynthe...

Morphogenesis

...logy along with the control of cell growth and cellular differentiation . Morphogenesis is concerned with ...lei of the syncytial blastoderm converting it to a cellular blastoderm. Wingless morphogen The expression patterns of the final class of segmentation...

Molecular evolution

...als, or viruses , or can occur deliberately under cellular control during the processes such as meiosis or hypermutation . Mutations are considered the driving force of evolution , where less favorable (or deleterious ) mutations are removed from the gene pool by natural selection , while more favorabl...

Mitosis

...ecruiting microtubules (which may be thought of as cellular ropes or poles) and forming mitotic spindles . By...llowed by cytokinesis or cleavage , where the cellular membrane pinches off between the two newly separated nuclei, to form two new daughter cells. At this...

Mitochondrion

...tosol . Mitochondria are sometimes described as " cellular power plants ", because their primary function i... mitochondria is to convert organic materials into cellular energy in the form of ATP , mitochondria play an important role in many important metabolic tasks...

Mitochondrion

...tosol . Mitochondria are sometimes described as " cellular power plants ", because their primary function i... mitochondria is to convert organic materials into cellular energy in the form of ATP , mitochondria play an important role in many important metabolic tasks...

Actin

...ents ), which like the other two components of the cellular cytoskeleton form a three-dimensional network inside an eukariotic cell . Actin filaments provide mechanical support for the cell, determine the cell shape, enable cell movements (through pseudopods ); and participate in certain cell junctions,...

Microbiology

...lls to study protein-protein interactions within a cellular environment. See also Archaea Bacterium Biochemistry Eukaryote Genetics Geomicrobiology Immunology Medicine Prokaryote Virology Important publications in microbiology Return to Biology , ...

Meiosis

... Meiosis (a Greek word meaning "decrease") is a cellular process that forms the basis for sexual reproduct...kept together by recombination nodules ), there is cellular growth and genetic transcription (and so chromosomes are seen less condensed) Diakinesis : chrom...

Max Delbr

...duce in "one step ", rather than exponentially as cellular organisms do. In 1941, he married Mary Bruce, with whom he had four children. In 1942, he and Salvador Luria demonstrated that bacterial resistance to virus infection is caused by random mutation and not adaptive change. For that, they we...

Mathematical biology

...egel, Modeling dynamic phenomena in molecular and cellular biology . C.U.P., 1984. ISBN 052127477X F. Hopp...4468 A. Goldbeter, Biochemical oscillations and cellular rhythms . C.U.P., 1996. ISBN 0521599466 E. Renshaw, Modelling biological populations in space an...

Long-term potentiation

...erje Lmo in 1966 and is commonly regarded as the cellular basis of memory . Contents showTocToggle("s...tory activity (or "trace") tends to induce lasting cellular changes that add to its stability.... When an axon of cell A is near enough to excite a cell B and r...

Lipid

...ous compartment, which is essentially the basis of cellular membranes. Micelles and bilayers separate out from the polar milieu by a process known as the "hydrophobic effect." When dissolving a nonpolar substance in a polar environment, the polar molecules (i.e. water in an aqueous solution) become more orde...

Citric acid cycle

...l living cells that utilize oxygen as part of cellular respiration . In these aerobic organisms , the citric acid cycle is a metabolic pathway that forms part of the break down of carbohydrates , fats and proteins into carbon dioxide and water in order to generate energy. It is the second of...

Jean-Baptiste Lamarck

...as much more plausible before the discovery of the cellular mechanisms for genetic transmission. (Darwin, incidentally, acknowledged his theory would remain somewhat incomplete if the mechanism for inheritance could not be discovered.) In botany, his auctorial abbreviation is Lam . See also: Trofim L...

Ion channel

...s open in response to internal solutes and mediate cellular responses to second messengers . Stretch-activated channels open or close in response to mechanical forces that arise from local stretching or compression of the membrane around them; for example when their cells swell or shrink. Such channels a...

Insulin

...on 2 Structure and production 3 Actions on cellular and metabolic level 4 Regulatory action on blo...he muscular layer of the arteries . Actions on cellular and metabolic level The actions of insulin on the global human metabolism level include: cellula...

Immunology

...Many components of the immune system are actually cellular in nature and not associated with any specific or... into scientic theory. The study of molecular and cellular components that comprise the immune system, including their function and interaction, is the central...