1. Keystone Review – Characteristics of Life (Cells)
D – All the activities help keep the internal conditions of a cell constant.
A – Both prokaryotes contain ribosomes that assemble proteins from mRNA.
D – Prokaryotic cells are much smaller than eukaryotic cells
D – The plasma membrane’s role is to determine which substances can enter and exit the cell
B – DNA is found in the nucleus in an eukaryotic cell.

2. Keystone Review – Characteristics of Life (Cells)
Identify structure 1 and describe its main function.
Structure 1 is the cell wall, and its role is to support and provide protection for the cell. For example, a plant cell will not burst if it is place in a hypotonic environment.

3. Keystone Review – Characteristics of Life (Cells)
Identify structure and describe its main function.
Structure 3 is the central vacuole, and its role is to store materials such as water and nutreints.

4. Keystone Review – Characteristics of Life (Cells)
A wilted houseplant is watered. Explain how structures 1 and 3 work together to cause a change in the plant.
A plant wilts because it lost water. When the plant is watered, the water is stored in the central vacuole and this organelle expands. This places pressure against the cell wall, which remains rigid. This pressure within the plant cell causes the plant to remain upright.