Bioinformatics Research Laboratory, IBI Biosolutions Pvt. Ltd. India

The DB-DRD4 Database Project
DB-DRD4 is a Comprehensive searchable database
for Dopamine D4 Receptor sequences.
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A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

Abnormality: a condition that is not usual or typical.

Acetylcholine: Neurotransmitter present in both the central nervous system and areas where motor nerves meet muscles (called neuromuscular junctions) i.e. it is a chemical substance released by certain neurons . It participates in the transmission of nerve impulses at different parts of the body and is found in both the central nervous system, where it passes signals between neurons, and in the peripheral nervous system, where it relays nerve impulses from motor nerves to muscles.

Acetylcholinesterase: the enzyme that breaks down the neurotransmitter acetylcholine at synapses.

Adenine: one of the bases. It contains nitrogen and participates in the formation of the nucleic acids DNA and RNA in animal and plant cells. It is often abbreviated to A.

Adenosine 3', 5' Cyclic Monophosphate (cAMP): a molecule that is formed by the enzyme adenylate cyclase from adenosine triphosphate. It is important in controlling mechanisms within a cell.

Adenosine Triphosphate (ATP): an important source of cellular energy. Energy is stored in the chemical bonds of the three phosphate groups. It is released when ATP is split into its diphosphate and monophosphate forms, e.g. during muscle contraction.

Adenylate Cyclase: the enzyme that changes adenosine triphosphate (ATP) into adenosine 3', 5' cyclic monophosphate (cAMP). It has an important role in controlling mechanisms within a cell.

Adrenaline: Messenger molecule of the nervous and endocrine systems that allows the body to react to physical and psychological stress i.e. it is a hormone released by the adrenal medulla and acts on the alpha and beta adrenergic receptors. Adrenaline makes the heart beat faster. It also makes the bronchi open and reduces the flow of the blood to the arms and legs. It is also known as epinephrine.

Agonist: An agonist is a molecule that triggers the same effects and actions as a naturally occurring molecule or hormone. It stimulates or activates cellular responses just like the natural hormone. For example, a dopamine agonist causes the same effect on cells as dopamine itself by binding to the same receptor on the surface of cells. This causes the cell to respond in the same way as it would in the presence of the real hormone.

Akinesia: absence of movement

Amino Acid: a compound that contains both an acidic group and an amino group. There are 20 biologically important amino acids that are present in proteins.

Amnesia: Temporary or permanent loss of memory i.e. it can be caused by psychological shock or a change in the brain resulting from, for example, an accident, alcoholism, or disease (such as Alzheimer's disease). There are many kinds of amnesia, some of which block only the most recent memories, such as what was eaten for lunch. Others affect long-term memories, like people's names.

Amygdala: Control centre for the emotions, half of which is located in the right hemisphere and half in the left. It is located equally between the right and left cerebral hemispheres and controls the emotions. If destroyed, feelings of violence and fear disappear as well as all emotional reactions. When it is stimulated, behaviour becomes excessive, subject to extreme violence or affection.

Anticholinergic: a class of drugs that relaxes smooth muscle; used primarily to treat tremor in Parkinson's disease.

Attention: Attention is sometimes defined as the ability to select part of the environment, focus on that part, and disregard the rest. At any point in time, there are a host of sights, sounds and stimuli in the environment which are ignored, while some subset receives attention. Attention has been conceptualized as a spotlight directed at those stimuli or thoughts currently being processed. Attention may be directed under conscious control (as when a student concentrates on memorizing his notes) or may shift according to external stimuli (as when we look to find the source of a startling noise). Divided attention refers to the ability to process multiple inputs at once, as in being able to drive a car and carry on a conversation at the same time.

ATP: see adenosine triphosphate.

B

Bacterium (plural bacteria): a microorganism that is a single cell. Bacteria have a cell wall and multiply by cell division.

Bioinformatics: Branch of computer science focused on gene and protein research means it is the branch of computer science that focuses on sub-domains of biology: research on genes and proteins . Researchers in this field must use powerful computers and special calculation methods to process the large body of complex data generated by genetics. Using these tools, it was possible to sequence the human genome.

Biotechnology: Body of methods and techniques that employ as tools the living cells of organisms or parts or products of those cells (such as, genes and enzymes) means it is the technique that involve the use of living organisms ( cells , bacteria , yeast, and others) or their parts or products as tools (for example, genes and enzymes ). They are used in a number of fields: food processing, agriculture, pharmaceutics, and medicine, among others.

Brain: The brain is a region of tissue located inside the skull, composed of nerve cells (neurons) and other supporting cells. The brain is the primary center for coordinating and regulating body activities. Sensory information is received via nerves and processed in the brain, and the brain is the seat of thought, memory, consciousness, judgment, reason and emotion. Motor commands are initiated and discharged through nerves to the muscles and glands, and the brain also oversees autonomic functions such as breathing, digestion, and so on.

C

Catecholamines: compounds that include adrenaline, noradrenaline and some of their metabolites.

Cell: The basic subunit of any living organism; the simplest unit that can exist as an independent living system. There are many different types of cells in complex organisms such as humans, each with specific characteristics.

Central Nervous System (CNS): the portion of the nervous system consisting of the brain and spinal cord. The nervous system coordinates the adjustments and reactions of the body to internal and external conditions and stimuli.

Cephalic: relating to the head.

Cerebellum: The cerebellum is the portion of the brain which lies behind and under the cerebral cortex. It is involved in fine control and coordination of skeletal muscles. It plays an important role in movements which require careful timing and interaction of many muscles: maintaining posture, walking, eating, playing musical instruments, tracking movements with the eyes, etc.. Individuals with cerebellar damage may still be able to walk, gesture and eat, but the movements may appear difficult and clumsy.

Cerebral Cortex: Technically, a "cortex" is an outer layer of an organ; thus, there is a cerebral cortex (in the brain) as well as an adrenal cortex (the outer layer of the adrenal gland), a renal cortex (the outer layer of the kidney), and so on. However, in common parlance, "cortex" is usually taken as a shorthand for "cerebral cortex". Likewise, the adjective "cortical" usually refers to the cerebral cortex. The cortex is often divided into large regions, called lobes, based on anatomical structure and also on function. These include the frontal lobes, the parietal lobes, the occipital lobes and the temporal lobes.

Cerebral Hemisphere: the right or left half of the brain. Each cerebral hemisphere consists of cerebral cortex and basal ganglia.

Codon: a group of three DNA or RNA nucleotide bases. Together they specify the choice of an amino acid residue during peptide synthesis. If one or more of the bases changes, a different amino acid may be specified.

Cognition: the mental processes by which an individual acquires knowledge. It includes perception, intuition and reasoning.

Cortex: The external layer of various organs esp. the gray matter covering the brain.

D

Dendrite: A branched protoplasmic process of a neuron that conducts impulses to the cell body. There are usually several to a cell. They form synaptic connections with other neurons.

Depression: Mental illness characterized by sadness, general apathy, a loss of self-esteem, feelings of guilt, and, at times, suicidal tendencies i.e it is a mental illness. People experiencing it are sad, lack interest in everyday activities and events, and feel a sense of worthlessness. A depression can be triggered by a tragic event (mourning) or have no apparent cause. Several molecules found in the brain have been associated with depression, which is why it is often treated using medications that act on the brain.

DNA (Deoxyribonucleic Acid): Molecule present in the cells of all living things, DNA forms genes, the hereditary material of the cell. DNA is a macromolecule present in the cells of all living beings. All the cells of an individual contain the same DNA, creating a specific identity for the individual. When cells divide, DNA produces an identical copy of itself. A gene is a part of an individual's DNA. In eukaryotic cells DNA is located in the nucleus. In the prokaryotes (bacteria) it occurs in the cytoplasm, and it forms a core in many viruses.

Dopamine: An inhibitor dampening activity so we stay rooted. Travels along pathways into the brain. Plays different roles: Dopamine in the basil ganglia (in brains interior) show they are critical for executing smooth and controlled movements. Lack of dopamine is a cause of Parkinson disease which a person looses the ability to initiate controlled movements. Dopamine moves into frontal lobe regulating flow of information coming in from other areas of the brain. Compromise in the flow of dopamine may cause disrupted or incoherent thought as in schizophrenia. In milder disorders, too much dopamine in the limbic system and not enough in the cortex may produce an overly suspicious personality giving to bouts of paranoia or may inhibit social interaction. A shortage of Dopamine in the frontal lobes may contribute to poor working memory. Dopamine is also thought to produce feelings of bliss (the pleasure chemical). More dopamine into the frontal lobe lessens pain and increases pleasure.

Dopamine Agonists: a class of drugs that binds to dopamine receptors and imitates the action of dopamine.Dopamine agonists such as bromocriptine (brand name Parlodel) and cabergoline (brand name Dostinex) inhibit GH release from the tumor. They work by stimulating natural receptorsof the hormone dopamine on the surface of the tumor. This sends messages into the tumor cells to stop producing GH.

Dopaminergic: a class of drugs with dopamine-like action; used to treat all symptoms of Parkinson's disease except postural instability. Also refers to systems within the brain that contain dopamine.

E

Enzyme: a protein found inside cells. It speeds up chemical reactions. Enzymes usually work in highly specific ways.

Exon: the coding sequence of a gene.

Expression: of a gene, activity. It is shown by production of RNA or protein.

Endorphins: mediate pain at receptor sites. In an injury receptors in skin make electrical signals that goes up the spinal cord to the brain. The brain then evaluates pain by releasing pain killers called endorphins which bind at opiate receptor sites of neurons to mediate pain. Endorphins effect the dopamine pathway that feeds into the frontal lobe. These pathways inhibit the flow of dopamine. Vast quantities of endorphins are released and nerves are shut off so more dopamine flows through pathway to get to frontal lobe therefore replacing pain with pleasure.

F

Fight-or-Flight Response: The "fight-or-flight" response refers to the body's natural reaction to an emergency. The body systems which are useful for facing a threat ("fight") or fleeing danger ("flight") are stimulated: blood flow is increased to the muscles, heart rate increases, respiration increases, and blood pressure increases. As a tradeoff, energy is decreased to other ongoing body functions including digestion, immune system response, ovulation, and so on.

Frontal Lobes: The frontal lobes lie at the front of the brain. They contain brain structures that are important for executive functions, such as planning, judgment and self-control. The frontal lobes are also involved in motor control, including the ability to form speech.

G

G Protein: a protein that has a role in controlling mechanisms within a cell. G proteins interact with adenylate cyclase in controlling the level of adenosine 3', 5' cyclic monophosphate (cAMP) within cells.

Gene Expression: the activity of a gene. It is shown by production of RNA or protein.

Gene: Section of DNA that represents the blueprint for the construction of a protein means it is a sequence of DNA , contained within the nucleus of our cells , that carries the 'instructions' for the manufacture of a protein. The information they hold describes the myriad characteristics of an individual (e.g. eye colour). Humans beings have approximately 30 000 genes, which amounts to only around 5% of their total DNA. Some animal and plant species have more genes than humans.

Genetic Code: a system that describes how nucleotide sequences in DNA and amino acid sequences in proteins relate to each other.

Genome: The total DNA present in the nucleus of each cell of an organism. It corresponds to all the organism's bases : A, T, C and G), our genome is a chain of 3.4 billion pearls. The genomes of two different people differ on average by one 'pearl' in one thousand.

Genomics: Science that studies the structure and function of genomes and, in particular, genes i.e. it is the study of the genome , the molecule of DNA found in the cells of a living being. DNA is like a string of four different 'pearls' (the bases) that contains the genes , the plans used to build proteins . The objective of genomics is to determine the order of these 'pearls', identify the genes and their functions (what proteins they code for), and establish the role of the remaining DNA.

Guanine: one of the bases. It contains nitrogen, and participates in the formation of the nucleic acids DNA and RNA in animal and plant cells. It is often abbreviated to G.

Guanosine 3', 5' Cyclic Monophosphate (cGMP): a molecule that is formed by the enzyme guanylate cyclase from guanosine triphosphate. It is important in controlling mechanisms within cells.

Guanosine Triphosphate (GTP): a source of cellular energy. Energy is stored in the chemical bonds of the three phosphate groups. It is released when GTP is split into its diphosphate and monophosphate forms.

Guanylate Cyclase: the enzyme that changes GTP into cGMP.

H

Helix: in genetics, a chain or coil that carries the genetic material in DNA. It is composed of nucleotides. DNA has two chains/coils that are wound around each other. This is called a 'double helix'.

Hippocampus: The hippocampus is a brain structure which lies under the medial temporal lobe, one on each side of the brain. It is sometimes grouped with other nearby structures including the dentate gyrus and called the "hippocampal formation." The hippocampus is critical for the formation of new autobiographical and fact memories. It may function as a memory "gateway" through which new memories must pass before entering permanent storage in the brain. Hippocampal damage can result in anterograde amnesia: loss of ability to form new memories, although older memories may be safe. Thus, someone who sustains an injury to the hippocampus may have good memory of his childhood and the years before the injury, but relatively little memory for anything that happened since.

Hormone: A chemical substance produced by a gland or tissue and transported by the blood to act on a distant organ or tissue. A hormone is a molecule produced by a gland or tissue. Usually transported by the blood, a hormone affects an organ or other tissue located at a distance. For example, the pancreas produces insulin, which regulates the level of sugar throughout the organism. Hormones are "messengers" that, in concert with the nervous system, coordinate the activities of billions of cells in the human body.

Hypothalamus: Part of the brain that orchestrates the play between the nervous and endocrine systems. The human body reacts quickly to its environment through the nervous system , and more gradually by way of the endocrine system . Located at the base of the brain , the hypothalamus is the intermediary between the two systems; some of the neurons contained in the hypothalamus secrete neuro hormones , substances that influence the secretion of other hormones.

I

Immune System: The immune system normally provides continuous surveillance of body processes and acts to remedy imbalances or abnormalities. It protects the body from the effects of invasion by microorganisms (e.g. germs) and governs the removal of damaged cells from body tissue. It also discovers and disposes of abnormal cells that continually arise within the body. Immune system failure can lead to vulnerability to infection, and can also allow tumor cells to grow unchecked. Immune system overactivity can cause allergic symptoms.

Intron: a section of DNA occurring in a gene. A change in the intron does not affect the structure of that gene. It is also known as an intervening sequence.

Ion Channel: Protein embedded in the cell membrane forming a canal through which specific ions can enter and exit the cell. It is a kind of tunnel that runs through the membrane of ions travel into or out of the cell (mainly sodium, potassium, calcium, and chloride ions). Ion channels are selective and do not remain constantly open. They allow certain ions to pass through while denying access to others.

L

Lobes of the Brain: The cerebral cortex in the brain is divided into several large zones, called lobes, based on anatomical structure and division of function. See listed as individual lobes: temporal lobes, medial temporal lobes, occipital lobes, parietal lobes, frontal lobes.

M

Mammal: one of a group of highly evolved vertebrates. The females of this group secrete milk, which is used to feed their newborn.

Medial Temporal Lobes: The medial temporal lobes are the brain areas lying on the inner side of each temporal lobe. ("Medial" means "towards the middle" of the brain). This area of the brain includes several areas that are critical for new memory formation, including the hippocampus.

Membrane: A very thin barrier that surrounds a cell or the small structures found inside the cell. A membrane is a very thin envelope that surrounds and protects a cell . It controls the exchanges between the cell and the exterior environment: the membrane allows the passage of certain substances and prevents the passage of others. The small structures within the cell (the organelles) are also enclosed by membranes.

Memory: Memory refers to the storage, retention and recall of information including past experiences, knowledge and thoughts. Memory for specific information can vary greatly according to the individual and the individual's state of mind. It can also vary according to the content of the information itself; thus information which is novel or exciting tends to be better remembered than information which is uninteresting or ordinary. Failure of memory can normally result from failure to adequately store the memory in the first place, failure to retain the information (forgetting), and failure to retrieve the information later.

Memory Loss: Memory loss can refer to a specific instance of forgetting or, more generally, to an overall impairment in memory ability compared to what is expected from a healthy individual. See also: Memory, Age-Associated Memory Impairment and Amnesia.

Metabolism: The biochemical reactions that occur within a living organism and the energy exchanges and transformations that accompany them. Metabolism designates the full catalogue of biochemical reactions that occur in a living organism, as well as the energy exchanges and transformations that accompany them. It includes reactions for the synthesis and degradation of molecules.

Micro-organism: Any living organism that is too small to be seen by the naked eye such as bacteria, viruses, protozoa, single-celled algae, and many types of fungi.

Molecule: Basic building block of matter, whether inert or living. A molecule is an assembly of atoms always arranged in the same architecture. Molecules are the basic units of both living and non-living matter. Most molecules within living beings, like DNA and protein , although large (macromolecules ), do not differ in a fundamental way from the molecules of inert matter.

MAO-B inhibitor: A class of drug that blocks an enzyme that breaks down dopamine, allowing it to be at the receptor longer; used to treat all symptoms of Parkinson's disease.

N

Nerve Impulse: Electrical event that propagates along the neurons i.e. it is the nerve impulse is an electrical occurrence that travels down a neuron . This electrical signal transmits commands from the brain to the motor nerves, and carries sensory messages from sensory nerves (skin, ears, nose, eyes, taste buds) to the brain. The transmission of nerve impulses from neuron to neuron is performed by neurotransmitters .

Nervous System: The organ system consisting of the encephalon (brain, cerebellum, and brain stem), spinal cord, and nerves means it comprises the central and peripheral nervous systems. The central nervous system includes the encephalon (brain , brain stem ) and spinal cord; the peripheral system contains the body’s other nerves. Made of billions of interconnected nerve cells , the nervous system is a vast communication network linking all body parts and allowing us to interact with our environment.

Nucleotide: a compound that has a base that contains nitrogen. The base is linked to a sugar-phosphate backbone. Nucleic acids (DNA and RNA) are made of long chains of linked nucleotides.

Neuron: Nerve cells that make up the nervous system and allow different parts of the body to communicate with each other i.e. neurons are the main cells of the nervous system and there are about 100 billion of them in the brain . Thanks to their numerous branch-like processes, they interconnect forming a massive network of "wires" that extend throughout the entire body. By sending messages across this network, the different parts of the human body interact and communicate with each other.

Neurological effects: Effects to nervous system especially regarding structure, functions, and abnormalities.

Neurosciences: Branches of scientific and clinical knowledge dealing with the nervous system and its disorders. The word "neurosciences" encompasses all the disciplines dealing with the nervous system and its various disorders. This can span from the study of chemical mechanisms in the brain (the function of brain molecules ) to behavioral research. To illustrate, studies of how nerve impulses are triggered and those of the brain areas involved in language are all a part of the neurosciences.

Neurotransmitter: Chemical substance released from the end of a neuron during the propagation of a nerve impulse; it relays information from one neuron to another. A neurotransmitter, sometimes called a neuromediator, is a chemical substance that transmits information from one neuron to another by crossing the space between two adjacent neurons (the synapse). Released at the end of a neuron during the propagation of a nerve impulse.

O

Occipital Lobes: The occipital lobes lie at the rear of the brain, above the cerebellum. They contain brain areas which are important for visual processing.

Organism: any living animal or plant, protozoan, bacterium or virus.

P

Parietal Lobes: The parietal lobes lie at the top of the brain, on each side of the midline. They contain brain structures that are involved in processing sensory information, such as where on the surface of the body a touch stimulus occurred.

Parkinson's disease: It destroys dopamine-producing neurons in the substantia nigra, and causes motor symptoms (dyskinesia, tremor, rigidity) as well as cognitive symptoms. The motor symptoms can be treated by drugs that increase brain dopamine levels.

Phospholipid: a molecule containing phosphate and lipid. It is an important part of biological membranes.

Phosphoprotein: a protein containing phosphorous. The phosphate group is bound to the amino acids serine, threonine or tyrosine.

Postsynaptic Receptor: Sensor located on neurons to which neurotransmitters bind. A postsynaptic receptor is a sensor on the surface of a neuron . It captures messenger molecules from the nervous system - neurotransmitter s - and thereby functions in transmitting information from one neuron to another. Each neurotransmitter binds to just one specially constructed receptor that it recognizes based on the receptor's overall structure - like a key within a lock.

Protein: Macromolecules present in all living beings, essential for the life of the cell, as well as the entire organism. Their functions are greatly varied i.e it is a macromolecule present in all living beings. Indispensable for the life of the cell and the entire organism, proteins are constructed by our cells through DNA and the genetic code . From those that make up our hair (keratin) to those that defend us against microbes (antibodies), proteins have a wide variety of functions and responsibilities.

Proteomics: A new science researching total protein expression in different living organisms. It is a new science that focuses on the study of proteins : their roles, their structures, their localisation, their interactions, and other factors (the study of proteins falls in the domain of chemistry). Proteomics analyses, for example, the proteins of human fat cells , corn leaves, or an organism like the bacteria.

R

Receptor: Communication relay located in the cell or on its membrane. To communicate, a cell sends chemical ( protein ) or electrical messengers. The signals carried by these messengers are detected by communication relays (receptors) situated inside other cells or on the membranes of other cells. These relays then transmit the message received, unleashing a specific reaction in the organism (secretion of a hormone , for example).

Repression: In psychology, repression refers to a refusal to keep potentially distressing ideas in mind. As a result of this repression, the ideas are submerged in the unconscious, from where they may continue to influence behavior. Repression was postulated by Freud, and one function of psychoanalysis is to try and uncover repressed memories and help the patient deal with -- rather than repressing -- this disturbing information.

RNA: This molecule is present in the cells of all living beings and plays an essential role in the synthesis of proteins i.e it is a molecule present in the cells of all living beings and is essential for the synthesis of proteins . There are different types of RNA, including messenger RNA (mRNA), and transfer RNA (tRNA). mRNA transmits information encoded in DNA, while tRNA uses this information to manufacture proteins.

S

Schizophrenia: It is a disorder associated with abnormally high levels of brain dopamine; symptoms may include disordered thought, hallucinations and social withdrawal. These symptoms may be ameliorated by drugs that decrease brain dopamine levels.

Serotonin: a chemical, 5-hydrozytryptamine (5-HT), present in blood platelets, the gastrointestinal tract, and certain regions of the brain. It plays an important role in blood clotting, stimulating a strong heart beat, initiating sleep, fighting depression (prescription drugs that treat depression raise the brain's levels of serotonin) and causing migraine headaches in susceptible individuals (because of its ability to constrict blood vessels or cause them to spasm). Serotonin is synthesized from the amino acid L-tryptophan. Serotonin (and, therefore, L-tyrptophan) also serves as a precursor for the pineal hormone melatonin, which regulates the body's clock.

Stress: In medical terms, stress refers to events that cause a reaction in the body. These events may be physical (e.g. accident or injury) or psychological (e.g. fear, grief, joy). For example, situations perceived as dangerous or threatening may result in the body's "fight-or-flight" response, in which hormones are released that prepare the body to face a threat or run away from it.

Substantia nigra: The substantia nigra is a region of the brain which contains neurons that produce the neurotransmitter dopamine. It is black in appearance, giving rise to the name ("substantia nigra" is Latin for "black substance".) Neurons in the substantia nigra travel to brain areas which are important for motor control as well as to the frontal lobes, which are important for attention and executive function. Parkinson's disease is a disorder that involves progressive death of neurons in the substantia nigra, leading to motor and cognitive symptoms.

Synapse: The point of junction between two neurons in a neural pathway, where the termination of the axon of one neuron comes into close proximity with the cell body or dendrites of another. At this point, where the relationship of the two neurons is one of contact only, the impulse traveling in the first neuron initiates an impulse in the second neuron. Synapses are polarized, i.e., the impulses pass in one direction only. They are susceptible to fatigue, offer a resistance to the passage of impulses, and are markedly susceptible to the effects of oxygen deficiency, anesthetics, and other agents, including therapeutic drugs and toxic chemicals.

T

Temporal Lobes: The temporal lobes of the brain are located on each side of the brain. They are so-named because they lie under the temples. They contain brain areas which are important for auditory processing, including the ability to understand spoken words. They also contain structures such as the hippocampus which are important for new memory formation.

Traumatic Brain Injury: Traumatic brain injury is brain injury resulting from external physical damage or wound, such as a blow to the head. This differentiates it from brain injury caused by disease (e.g. Alzheimer's disease, encephalitis, AIDS, etc.).

Thalamus: A large ovoid mass of gray matter at the base of the brain, the chief center for transmission of sensory impulses to the cerebral cortex.

V

Variable number tandem repeats (VNTR): Linear arrangement of multiple copies of short repeated DNA sequences that vary in length and are highly polymorphic, making them useful as markers in linkage analysis or A segment of DNA that consists of repetitions of a fixed sequence of consecutive DNA base pairs a constant number of times in any one individual and that is widely used for identification purposes in forensic medicine because the number of repetitions of the fixed sequence within the segment varies from individual to individual.

Virus: A virus is a small organism which can infect other biological organisms.Viruses can only reproduce by invading and taking over cells as they lack the cellular machinery for self reproduction.They cause diseases in human beings, animals, plants and bacteria.Examples of human diseases caused by viruses include the common cold, influenza, small pox, AIDS, and cold sores.

Z

Zinc finger domain (zinc finger motifs): Motifs in DNA- and RNA-binding proteins whose amino acids are folded into a single structural unit around a zinc atom. In the classic zinc finger, one zinc atom is bound to two cysteines and two histidines. In between the cysteines and histidines are 12 residues which form a DNA binding fingertip. By variations in the composition of the sequences in the fingertip and the number and spacing of tandem repeats of the motif, zinc fingers can form a large number of different sequence specific binding sites.

  
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