Actin is a protein that helps the cell maintain its shape and polarity. It also plays a significant role in muscle contraction. A table summarizing the cellular functions of different types of proteins is shown.
Based on this information, actin is most likely --
Renin is an enzyme that catalyzes a reaction by solidifying (solid) milk. Renin was added to three different test tubes with milk. Each test tube was placed in a water bath for ten minutes. The data collected during the experiment are shown.
Which statement best explains the results of Test Tube 3?
Scientists observe the traits of cells on four microscope slides and record their observations in a table. Based on the scientists' observations, identify the cell type for each microscope slide in the table.
Move the correct answer to each box. Each answer may be used more than once.

The diagram represents the movement of three different substances across a cell membrane.
Moving which of these substances across the cell membrane requires energy from ATP?
A table comparing the characteristics of four samples is shown.
Which sample most likely contains viruses?
Which pair of statements best compares the primary functions of the carbohydrate chitin and the protein chitinase?
Materials are provided to students to build models of a prokaryotic cell, a eukaryotic cell, and a virus. The materials and the structures they represent are listed in the table shown.
Which material will students use in all three models?
In animal cells, the sodium-potassium pump moves sodium and potassium ions against a concentration gradient across the cell membrane.
What type of transport is used, AND why is this type of transport necessary?
Read the question carefully. Then enter your answers below for both parts.