the process whereby solutes are transported through the phloem. Unlike xylem, phloem is essentially a chain of living cells. The most widely accepted explanation for translocation of substances in the phloem is the Münch pressure flow hypothesis. The proposed mechanism is as follows: a high concentration of solute ( e.g., sugars) is loaded into cells of the phloem, presumably by active transport, at locations, such as a leaf, where sugars are produced by photosynthesis. The high solute concentration in the phloem cell creates an osmotic gradient which draws water into the phloem. The resulting high turgor pressure causes flow to occur. If the dissolved sugars or other chemicals carried along with the sugars are removed from the phloem at another place in the tree for use (a sink such as a root or fruit), the decline in concentration of sugar causes water to move out of the phloem cells. Because water is moving in at a source and out at a sink, there is a mass flow of water and substances in the phloem.
mutation that moves a portion of a chromosome to a new location, generally on a different chromosome.
1. the process by which protein is moved across a cell membrane. 2. the process by which DNA fragments move between chromosomes.
an exchange of material between or within chromosomes, and can involve any chromosome.
1). Genetic. Change in position of a segment of a chromosome to another location in the same or a different chromosome. 2). Physiological. The movement of assimilates (carbohydrates or nutrients) from one plant organ to another in response to stress or ontogeny. 3). Breakage and reunion of chromatid at a different point of the chromosome.
trans, across + locare, to put or place] (1) An aberration in chromosome structure resulting from an error in meiosis or from mutagens; attachment of a chromosomal fragment to a nonhomologous chromosome. (2) During protein synthesis, the third stage in the elongation cycle when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport via phloem of food in a plant.
The process whereby the genetic code present on the m-RNA molecule directs the order of the specific amino acids during protein synthesis or transfer of solutes or other materials such as pesticides from one part of a plant to another.
Removal to another place. In genetics, the shifting of a segment or fragment of one chromosome into another part.
An abnormality of chromosomes in marrow or lymph node cells, which occurs when a piece of one chromosome breaks off and sticks to the end of another chromosome. In a balanced translocation, each of two chromosomes have a piece broken off and the lost piece sticks to the broken end of the other chromosome. The gene at which the break occurs is altered. This is one form of a somatic mutation in which may transform the gene into an oncogene or cancer-causing gene.
chromosomal abnormality which occurs when chromosomes break and the fragments rejoin to other chromosomes.
(trans-lo-KAE-shun) Rearrangement of a chromosome in which a segment is moved from one location to another, either within the same chromosome or to another chromosome
Change in position of a length of genetic material within a chromosome
A process in which 2 or more chromosomes break, and the broken parts of the chromosomes switch places. This forms new hybrid chromosomes with often abnormal functions.
switching of a segment of a chromosome to another chromosome.
A chromosomal defect that results in a change in the position of a chromosomal segment within the genome. It does not change the total number of genes present.
A chromosomal mutation caused by the exchange of genetic material among non-homologous chromosomes. A barrier to reproduction with organisms with normal (non-inversion) chromosome because it inhibits the pairing of homologous chromosomes during fertilization and meiosis.
(genetics) an exchange of chromosome parts; "translocations can result in serious congenital disorders"
a change in chromosome configuration in which chromosomes are attached to each other (Robertsonian) or pieces of different chromosomes have been interchanged (reciprocal)
a chromosome rearrangement in which part of a chromosome breaks off and then reattaches to a different chromosome
a condition where a fragment of one chromosome is broken off and is then attached to another
a mutation in which, typically, a piece of DNA from one chromosome is exchanged with a piece of DNA from another chromosome
a piece of one chromosome stuck to another
a rearrangement of chromosome segments between two different chromosomes
a type of chromosomal rearrangement
the transfer of part of one chromosome to another part of the same chromosome or to a different chromosome.
An abnormal rearrangement of the DNA in a chromosome.
(synonym: chromosome rearrangement) A chromosome alteration in which a whole chromosome or segment of a chromosome becomes attached to or interchanged with another whole chromosome or segment, the resulting hybrid segregating together at meiosis; balanced translocations (in which there is no net loss or gain of chromosome material) are usually not associated with phenotypic abnormalities, although gene disruptions at the breakpoints of the translocation can, in some cases, cause adverse effects, including some known genetic disorders; unbalanced translocations (in which there is loss or gain of chromosome material) nearly always yield an abnormal phenotype
TRANZ-lo-KAY-shun Exchange of genetic material between nonhomologous chromosomes. 301
A chromosome rearrangement in which the chromosomes are not arranged in the typical set of 23 pairs. Even if the correct amount of genetic material is present, an individual with a chromosome translocation is at increased risk for having problems such as difficulty conceiving or maintaining a pregnancy. Chromosome translocations are often inherited.
The transfer of chromosomal material between chromosomes.
This occurs when a piece of one chromosome breaks off and attaches to another, different chromosome. When no material is lost or gained the translocation is said to be 'balanced' and the individual is not affected. An 'unbalanced' translocation results in the loss or gain of genetic material which may result in a genetic disorder.
The rearrangement of genetic material within the same chromosome or the transfer of a segment of one chromosome to another one. People with balanced translocations do not always manifest genetic syndromes, but may be carriers of genetic syndromes and can have children with unbalanced translocations. Can occur with any chromosomal anomaly syndrome.
A mutation in which a large segment of one chromosome breaks off and attaches to another chromosome. See also: mutation
The fusion or exchange of material between chromosomes. When there is no gain or loss of material, the translocation is said to be balanced; when there is gain or loss, resulting in trisomy or monosomy for a particular chromosome segment, it is said to be unbalanced.
The movement of a segment from one chromosome to another without altering the number of chromosomes. 2) the movement of þuids through the phloem from one part of a plant to another, with the direction of movement depending on the pressure gradients between source and sink regions. PICTURE
a mutation in which a chromosomal piece becomes attached to another chromosome.
detachment of a piece of one chromosome and reattachment to another chromosome during segregation; can cause abnormally long and short chromosomes.
trans, across + locare, to place) 1. The movement of nutrients or products of metabolism from one location to another. 2. Change in position of a segment of a chromosome to another, non-homologous chromosome.
Results from an exchange of segments in non-homologous chromosomes.
a chromosome aberration which results in a change in position of a chromosomal segment within the genome, but does not change the total number of genes present
of a chromosome describes a rearrangement in which part of a chromosome is detached by breakage and then becomes attached to some other chromosome. Return to text.
A type of chromosomal mutation where a piece of a chromosome is moved to an abnormal position on the same or a different (usually) chromosome. This type of mutation may or may not have phenotypic consequences depending on whether or not the genetic material in the moved DNA is able to function normally.
a chromosome alteration involving a change in position of a chromosome piece (or pieces) and the gene sequences it contains.
Movement of a chromosome fragment to another place. Translocations are common in sarcomas and leukaemias. For example Ewing's sarcoma is characterised a t(11;22) translocation which fuses the EWS gene on chromosome 22 with the FLI1 gene on chromosome 11. See also: Chromosome.
A process in which a bit of genetic material from one chromosome swaps places with a bit from another chromosome. In CML, a piece (called "abl") from chromosome 9 is translocated onto a segment (called "bcr") on chromosome 22, creating the bcr-able oncogene.
Pertaining to a novel chromosome formed by breakage and reunion of DNA molecules into a non-wild-type configuration.
A type of chromosome aberration in which a sequence of DNA from one chromosome is moved to another chromosome.
Transfer of part of a chromosome to a different position especially on a nonhomologous chromosome.
Breakage and removal of a large segment of DNA from one chromosome, followed by the segment's attachment to a different chromosome.
The relocation of a chromosomal segment to a different position in the genome.
The repositioning of a segment of a chromosome from its usual site to another in the genome (either on the same chromosome or another one).
The movement or reciprocal exchange of large chromosomal segments, typically between two different chromosomes
when the location of specific chromosome material moves to another chromosome.
A type of aberration characterized by fragmentation of a chromosome and transfer of the broken-off portion to another chromosome, often of a different pair.
A number of the chromosomal mutations called translocations, A balanced transloctation where a segment of DNA abnormally becomes attached to the wrong chromosome, which results in two nonhomologous chromosomes being able to cross over, something which normally can occur only between homologous chromosomes.An unbalanced translocation A genetic translocation that results in the loss of a part of a chromosome or causes other genome damage. (09 Oct 1997)