Sperm-cells sentence example
These sacs contain the developing sperm cells or eggs, and are with very few exceptions universal in the group. The testes are more commonly thus involved than are the ovaries.
Weismann has also ingeniously argued from the structure of the egg-cell and sperm-cell, and from the way in which, and the period at which, they are derived in the course of the growth of the embryo from the egg - from the fertilized egg-cell - that it is impossible (it would be better to say highly improbable) that an alteration in parental structure could produce any exactly representative change in the substance of the germ or sperm-cells.
The gametophyte or prothallial generation is thus extremely reduced, consisting of but little more than the male and female sexual cells - the two sperm-cells in the pollen-tube and the egg-cell (with the synergidae) in the embryo-sac. At the period of fertilization the embryo-sac lies in close proximity tube has penetrated, the separating cell-wall becomes absorbed, and the male or sperm-cells are ejected into the embryosac. Guided by the synergidae one male-cell passes into the oosphere with which it fuses, the two nuclei uniting, while the other fuses with the definitive nucleus, or, as it is also called, the endosperm nucleus.
Calocoma the body-cells may be eight or even ten in number and the sperm-cells twice as numerous.
In Microcycas 16 sperm-cells are produced.Advertisement
The process by which the chromosomes divide during the production of egg and sperm cells is termed meiosis.
All of the cells of the body excluding the egg and the sperm cells are called the somatic cells.
In other cases, one parent has two normal RB1 genes in every somatic cell, but some egg or sperm cells contain a changed or missing RB1 gene.
Offspring would be at increased risk since some of the egg or sperm cells could have the changed/deleted RB1 gene.
Normally, FSH and LH help the immature sperm cells grown and develop.Advertisement
In Klinefelter syndrome, there are few or no sperm cells.
An autosomal dominant form of VWD can be inherited from either parent or can occur as a spontaneous gene mutation (change) in the embryo that is formed when the egg and sperm cells come together during fertilization.
Male sperm cells contain either an X or a Y; if the sperm with the Y chromosome fertilizes an egg, the baby will be male.
In a very rare number of Down syndrome cases (about 1-2%), the original egg and sperm cells are completely normal.