How to use Cell-division in a sentence
They are prominent during cell-division, but many disappear in.
The increasing temperature raises the rate of animal metabolism, while the higher alkalinity is a stimulus to cell-division.
In pathological cell-division it happens occasionally that the segmentation of the cytoplasm is delayed beyond that of the mitotic network.
Contrary, however, to the experience of others, he has never found that the attraction-spheres play an important part in direct cell-division, or, indeed, that they exert any influence whatever upon the mechanism of the process.
The body thus formed ment of is called the embryo, and this develops into the adult Primary plant, not by continued growth of all its parts as in an animal, but by localization of the regions of cell-division and growth, such a localized region being called a growing-point.Advertisement
On germination of the seed the radicle first grows out, increasing in size as a whole, and soon adding to its tissues by cell division at its apical growing-point.
On the ether hand, a survey of the facts of cellular embryology which were accumulated in regard to a variety of classes within a few years of Kovalevsky's work led to a generalization, independently arrived at by Haeckel and Lankester, to the effect that a lower grade of animals may be distinguished, the Protozoa or Plastidozoa, which consist either of single cells or colonies of equiformal cells, and a higher grade, the Metazoa or Enterozoa, in which the egg-cell by " cell division " gives rise to two layers of cells, the endoderm and the ectoderm, surrounding a primitive digestive chamber, the archenteron.
The immediate result was, as pointed out above, a reconstruction of the classification of animals upon a genealogical basis, and an investigation of the individual development of animals in relation to the steps of their gradual building up by cell-division, with a view to obtaining evidence of their genetic relationships.
The centrosomes which play so important a part in cell division may be found either lying within or at one side of the nucleus in the vegetative condition of the cell.
Although the methods of cell-division prevailing in normal structures are maintained generally in those which are pathological, yet certain modifications of these methods are more noticeable in the latter than in the former.Advertisement
Thus in the neoplasmata direct cell-division is more the rule than in healthy parts.
In Sirogonium there is cell-division in the parent-cell prior to conjugation; and as two segments are cut off in the case of the active gamete, and only one in the case of the passive gamete, there is a corresponding difference of size, marking another step in the sexual differentiation.
Much of the character of organisms is due to various symmetries, radial, bilateral, metameric and so forth, and these symmetries arise, partly at least, from the mode of growth by cell division and the marshalling of groups of cells to the places where they are destined to proliferate.
It is by no means certain that even the higher rate is greater than that exhibited by a tropical bamboo which will grow over a foot a day, or even common grasses, or asparagus, during the active period of cell-division, though the phenomenon is here complicated by the phase of extension due to intercalation of water.
And that idea is reinforced by the fact that three of the known MCPH proteins are found in the centrosome during cell division.Advertisement
V. cholerae builds only one flagellum per cell, suggesting that there must be a close coupling between flagellum biogenesis and cell division.
The BLM protein plays a role in helping ensure that chromosomes are copied properly during cell division.
A special kind of cell division takes place in making germ cells, called meiosis.
The apical meristem is an area of a plant where cell division takes place at a rapid rate.
Mitosis The most common form of cell division is called mitosis The most common form of cell division is called mitosis.Advertisement
This is imperative if cell mitosis is to continue, as cell division will only occur if cells are kept at body temperature.
Research Interests Our group studies the control of cell division when mammalian oocytes undergo meiosis.
Once this cap reaches a certain length, cell division stops and the cell becomes senescent.
In the Laminariaceae this tissue is formed by cell division at what is called an -intercalary growing point, i.e.
Resting on the dividing upper sphere are the eight-shaped " directive corpuscles," better called " praeseminal outcast cells or apoblasts," since they are the result of a cell-division which affects the egg-cell before it is impregnated, and are mere refuse, destined to disappear.Advertisement
Nor is motility by means of cilia known in the group. In the unicellular forms, cell-division involves multiplication of the plant.
In a similar way we must be careful, in our wonder at the marvellous rapidity of cell-division and growth of bacteria, that we do not exaggerate the significance of the phenomenon.
A corneal abrasion heals by the movement of neighboring epithelial cells, which slide over the wounded area, and through a cell division process called mitosis, which fill in the abraded area with new epithelial cells.
It encodes for (controls) the production of a protein that plays a role in regulating cell division following DNA damage.
In the first stage, four to 20 weeks gestation, rapid cell division and multiplication (hyperplasia) occurs as the embryo grows into a fetus.Advertisement
As cell division continues, a fluid-filled cavity called a blastocoele forms in the center of the group of cells, with the outer shell of cells called trophoblasts and an inner mass of cells called embryoblasts.
Chemicals are added to prompt the cells to go through normal development, up to the point where the chromosomes are most visible, prior to cell division.
Nondisjunction-An event that takes place during cell division in which a chromosome pair does not separate as it should.
The result is an abnormal number of chromosmes in the daughter cells produced by that cell division.
It performs certain functions during cell division.Advertisement
It is needed for good vision, cell division and differentiation, bone growth and reproduction.
While a baby is developing in the womb, cell division occurs rapidly.
After birth, this same fast cell division continues for many weeks to enable a child to grow quickly.
It will also play a vital role in cell division and immune system function.
In some cases all the eggs in a capsule develop; in other cases one egg only in a capsule (Neritina), or a small proportion (Purpura, Buccinum), advance in development; the rest are arrested either after the first process of cell-division (cleavage) or before that process.Advertisement
If in its extension to contain the new formations within it the embryo-sac remains narrow, endosperm formation proceeds upon the lines of a cell-division, but in wide embryo-sacs the endosperm is first of all formed as a layer of naked cells around the wall of the sac, and only gradually acquires a pluricellular character, forming a tissue filling the sac. The function of the endosperm is primarily that of nourishing the embryo, and its basal position in the embryo-sac places it favourably for the absorption of food material entering the ovule.
In Zygogonium, although no cell-division takes place, the gametes consist of a portion only of the contents of a cell, and this is regularly the case in Mesocarpaceae, which occupy the highest grade among Conjugatae.