Animal cells have a cell membrane. They also have organelles such as a nucleus, mitochondria, and the Golgi apparatus. However, they do not have *chloroplasts* as part of their cell structure.

Chloroplasts can only be found in photosynthetic cells such as those found in plants and green algae. Chloroplasts are organelles that contain chlorophyll, a pigment used in photosynthesis.

B

The nuclear envelope is the membrane that surrounds the nucleus. Chromatin is the substance within chromosomes that contains DNA and proteins. These substances are part of the nucleus.

Additionally, the nucleolus is a region of the nucleus responsible for the synthesis of ribosomes. Therefore, the **cytoplasm** is not a part of the nucleus since it is located outside the nucleus.

(a) Cytoplasm.

When cells are placed in a freshwater, the water molecules will move inside the cell. This happens because cells have high solute concentration (hypertonic) than the freshwater. Because of this, the water molecules will try to balance or dilute the high concentration by moving into the cells. As a result, the cells would swell and burst.

C. There would be a net movement of water into the cell.

Ribosomes are attached to the surface of the rough endoplasmic reticulum. Once the protein is produced by the ribosomes, the proteins are stored and carried through the rough ER.

E. ribosomes

Exocytosis is the transport process which allows the movement of substances and other materials from the inside of the cell to the outside of the cell.

D. Exocytosis

In endocytosis, large molecules or materials are taken or absorbed into the cell. The plant cells that absorbed the sucrose are under the process of endocytosis.

A. endocytosis

The graph shows a positive relationship between the two variables. As the concentration of sucrose increases, the cells’ rate of sucrose uptake goes up too. However, the rate of sucrose uptake slows down as the concentration goes from 10 mmol/L to 30 mmol/L.

A. take in sucrose more slowly

The sucrose uptake at 30 mmol/L and 40 mmol/L is at the same rate. It is shown by a straight line in the graph, which indicates that there are no changes in the rate of sucrose uptake.

D. The rate of sucrose uptake is constant between 30 and 40 mmol/L.