the first cell of a human is called zygote.
the first cell of a human is called zygote.
what is the first cell of a human called?
zygote
in flowering plants, the "ovule" (from latin "ovulum" meaning small egg) is a complex structure born inside ovaries. the ovule initially consists of a stalked, integumented "megasporangium" (also called the "nucellus"). typically, one cell in the megasporangium undergoes meiosis resulting in one to four megaspores. these develop into a megagametophyte (often called the embryo sac) within the ovule. the megagametophyte typically develops a small number of cells, including two special cells, an egg cell and a binucleate central cell, which are the gametes involved in double fertilization. the central cell, once fertilized by a sperm cell from the pollen becomes the first cell of the endosperm, and the egg cell once fertilized become the zygote that develops into the embryo. the gap in the integuments through which the pollen tube enters to deliver sperm to the egg is called the micropyle. the stalk attaching the ovule to the placenta is called the funiculus.
gynoecium
the dual-cell voltage clamp technique is a specialized variation of the two electrode voltage clamp, and is only used in the study of gap junction channels. gap junctions are pores that directly link two cells through which ions and small metabolites flow freely. when two cells in which gap junction proteins are expressed either endogenously or via injection of mrna, a junction channel will form between the cells. since two cells are present in the system, two sets of electrodes are used. a recording electrode and a current injecting electrode are inserted into each cell, and each cell is clamped individually (each set of electrodes is attached to a separate apparatus, and integration of data is performed by computer). to record junctional conductance, the current is varied in the first cell while the recording electrode in the second cell records any changes in v for the second cell only. (the process can be reversed with the stimulus occurring in the second cell and recording occurring in the first cell.) since no variation in current is being induced by the electrode in the recorded cell, any change in voltage must be induced by current crossing into the recorded cell, through the gap junction channels, from the cell in which the current was varied.
voltage clamp