Answer:
I think you're referring to the Metaphase...
Explanation:
During Cell Division (or, rather before!) the DNA needs to be replicated. This normally is done by DNA Polymerase, and results in two identical double strands (the "Sister Chromatids".
These chromatids are held together at the Centromere, which will be the heart of the "X"-shape. After that the DNA is packed into Chromosomes by winding it around proteins called Histones. If I remember correctly there are 5 different Histones.
This "Zipping Up" makes the chromosomes more visible.
As the two sister chromatids are still connected, the result is the X-shaped Metaphase Chromosome....
Answer:
The Miller–Urey experiment (or Miller experiment) was a chemical experiment that simulated the conditions thought at the time to be present on the early Earth, and tested the chemical origin of life under those conditions. The experiment supported Alexander Oparin's and J. B. S.
Explanation:
Answer:
The purpose of mitosis is to make more diploid cells.
Explanation:
Answer;
The substance that can enter a cell by diffusion without having to be digested is water.
Explanation;
Diffusion involves the movement of molecules from a region of high concentration to a region of low concentration, down a concentration gradient.
Water is able to diffuse through the cell membrane without being digested since it has small molecules.
One property of cell membrane is semi-permeability; it selectively allows material to enter or leave the cell. Large molecules such as starch , fat and proteins, can not enter the cell due to their size and will need to be digested to small molecules for the to gain access to the cell.
