1. The cell wall has lignin (hard substance): to prevent the xylem vessel from collapsing and withstand high pressure.
2. The absence of protoplasm (nucleus + cytoplasm) and cross wall: to allow water to move through the lumen easily.
Hope it helped!
During metaphase 1, the spindle fibers attach to the centromeres of each chromosome. Both kinetochores of each sister chromatid pair are turned toward the same pole. And 2 members of each chromosome pair (sister chromatids) are pulled into each new cell during anaphase 1.
I think the answer you want is they are called chromatids.
synthesis phase of interphase
A universal genetic code allows "the processes of transcription and translation to produce the same proteins in all species."
To say that the genetic code is universal it means that it is read/interpreted in the same exact way in all cells. This is that the same group of three nucleotides, a codon, will always translate into the same amino acid in any cell leading to the formation of the same protein, or at least a protein with same amino acids when first formed.
Primary, Secondary, Tertiary, Quaternary <span />
