Download Onion Cell Scientific Diagram (sorry, it`s a bit blurry) Notice: all labels

Onion Cell Scientific Diagram (sorry, it’s a bit blurry)
Notice: all labels aligned on the right hand side. Terms spelled correctly. Ruler used in the title and
to make the labels. Diagram is simple and uses clean lines, no sketching. The only thing that is
missing is some stippling (dots) to show that the nucleus was a bit darker.
Calculations are neat and organized showing the formula, full solution and therefore statement. Does
your mitosis diagram follow these same guidelines?
Onion Lab Discussion Solutions – Read and compare your answers to the solutions. What detail are
you missing? Is it content? Scientific terms? Clarity? Connections to the labs.
1.The structures identified were the nucleus, nuclear membrane, cytoplasm and cell wall. The
nucleus was a spherical structure in the cell that was stained yellow by the iodine. It was surrounded
by the nuclear membrane. The cell wall was the outermost layer of the cell that defined the cell's
rectangular like shape. It was thicker than the nuclear membrane. The cytoplasm filled the
cell(Notice how we try to refer to observations in the lab).
2. The most obvious difference between a plant and animal cell is that a plant cell has a cell wall
giving the cells a definite, rectangular shape. The animal cell lacks a cell wall and therefore the
shape of an animal cell is not definite.
3. An onion cell is not a typical plant cell. This is because it was not green and did not contain
chloroplasts when viewed under the microscope. Most plant cells are green and contain chloroplasts
to perform photosynthesis. An example of this is the aquatic plant cell observed in class, it was green
and its cells contained chloroplasts.
4. One type of cell was visible in the Onion. The evidence was that all cells had the a similar definite
shape (see diagram), the same organelles were visible and the same approximate size.
Four structures that were likely present but that could not be seen were (any other 4 in the cell) ribosomes, mitochondria, endoplasmic reticulum, lysosomes, golgi bodies, etc.
The statement "All plant cells contain chloroplasts" is not correct. The Onion cell represents a plant
cell because it has a cell wall, a definite shape and a large vacuole (although this could not be seen).
However, because of its function it is not necessary for it to contain chloroplasts. It is more correct to
say that plants contain cells that have chloroplasts. There are different types of plant cells and
depending on their location and function they may or may not have chloroplasts. The cells in the
leaves and stem above the ground must have chloroplasts because their purpose is to
photosynthesize to make food for the entire plant. The cells in the root are not exposed to the
sunlight, therefore they cannot photosynthesize and there is no need for them to have chloroplasts.
They help to store nutrients for the plant.