The 64 codons in the genetic code give rise to the same amino acids in nearly all organisms.
There is very little variaion. This is evidence for a single common origin of life.

Differences in the frequency of amino acid use reflects the different genes in the two organisms.

Mitosis is division of the nucleus into two genetically identical daughter nuclei in eukaryote cells.
A diploid cell will produce two diploid daughter cells in one division of mitosis.

Chromosomes condense by supercoiling during mitosis. This makes the chromosomes visible.

The DNA replicates during interphase, not prophase.

Tissues and organs must be kept in a solution with the same osmolarity as the cytoplasm of the cells to prevent osmosis. If they were kept in pure water, osmosis would carry water into the cells and they would burst, causing damage to the cells. If the solution was hypertonic, the tissue would lose water (and gain ions).

The rER has parallel membranes covered in dots, which are ribosomes, used for making proteins, for secretion from the cell.

If you look closely at X, it points to the cell wall, outside the plasma membrane, it is close to the plasma membrane, but not touching the chloroplast.

The pale area below Y is the vacuole.

Organelle Y is a mitochondrion, you can tell this by its size, and the presence of membranes inside.

Eukaryote cells (approx. 100µm in diameter) are much larger than prokaryote cells (approx 1µm) and so the concentration of reactants in the cytoplasm would be more dilute if all the metabolism happened in the cytoplasm.

Specialist organelles, like mitochondria keep the enzymes for aerobic respiration in one place, which increases their concentration, and increases the rate of reactions.

According to cell theory, living organisms are composed of cells.
Cells come from pre-existing cells and cells are the smallest using of life.

Totipotent tem cells can divide and differentiate into all cell types this help researchers to grow them in the lab.

They can differentiate along different pathways which makes stem cells useful for therapeutic uses (e.g. Stargart's disease) because they can be grown into many different tissues.

Many transmembrane proteins are involved in transport of molecules across membranes. These can either provide a sort of molecular pore through which ions or molecules can pass (facilitated diffusion), or they can use ATP to actively move molecules, even against the concentration gradient (active transport).These are just two examples, transport can also occur by simple diffusion through the phospholipid bilayer, or by endocytosis.

Hypertonic solutions have a higher concentration of solutes, and lower water potentials than cells.

Comment: During differentiation genes may be activated or repressed causing the formation of different proteins by the ribosomes but other organelles such as mitochondria continue to function in the same way

Comment:Tissues may have one or several cell types and one or more functions

Comment: Inanimate objects can move, produce and utilise energy but the process of respiration is exclusive to living systems

Comment: There are approximately 19 cells across the image so 250/19 = 13 μm.
The magnification is not needed to be used as you are given the true width of the image on the screen.

Comment: The cells are approximately the same length as the scale bar.
This would make 70µm the closest estimate as they vary in dimensions.

It is unicellular (one cell) and a eukaryote (has a nucleus) and not autotrophic.

The cell and plant are supported by the turgor pressure of water in the vacuole acting on the rigid cell wall.

In cell 2, the chromatids are aligned on the equator (seen from above) - Metaphase. In cell 1, the chromatids are moving towards the poles - Anaphase.

The first cells must have arisen spontaneously from non-living matter, probably in volcanic vents, but the universal nature of cell ultrastructure and of the genetic code makes it likely that this only happened once.