The G2 checkpoint of cell division prevents the cell from entering the mitotic or dividing phase until all chromosomes have accurately been replicated. Other answers: "Prevents sister chromatids from separating before each chromatid is secured to a spindle microtubule" refers to the spindle or M checkpoint. "Initiates the cell division process if conditions are favorable" and "Ensures that the cell has matured to a sufficient state before beginning synthesis" refer to functions of the restrictive or G1 checkpoint. "Ensures that each daughter cell has received the correct number of chromatids after cell division" is incorrect since there is no checkpoint in cell division to error check the results of mitosis.

During interphase, you have G_1, or gap 1, in which the cell grows. Then you have S phase, in which the cell synthesizes its DNA. Finally, you have G_2, or gap 2, in which the cell continues to grow again.

The Na+/K+ pump is active transport and therefore requires ATP. Since the pump is moving ions against its concentration gradient, it requires ATP to change the conformation of the pump to release the ions. All of the other forms of transport are either diffusion (moving down its concentration gradient) or facilitated diffusion (moving down its concentration gradient with the help of a channel or carrier). 

Good tip: Pumps are used for active transport while carrier proteins or channels are used for facilitated diffusion which is a type of passive transport.

Cells do not arise from nonliving substances, though scientists used to believe they did. Through several experiments by many different scientists, it became clear that indeed all cells arise from preexisting cells.

Amino acids are the building blocks of proteins, so when they are put together in a chain, you will get a protein.

A macromolecule made of amino acids is a protein. Lactase, the enzyme that aids in lactose digestion, is the only protein on the list. Sucrose and glucose are carbohydrates. Deoxyribonucleic acid is DNA, a nucleic acid. Triglycerides are a type of lipid.   

Note: You can identify an enzyme (which is a protein) by the fact that its name ends in "-ase."

Glucose and fructose are monomeric saccharides, or monosaccharides. The carbon to hydrogen to oxygen  ratio exists in a 1:2:1 pattern indicative of a monomeric saccharide. The molecular formula of glucose and fructose is . Maltose is a disaccharide composed of two molecules of glucose.

The disaccharide maltose is formed by the dehydration synthesis reaction of two glucose monomers. When simply adding the two glucose monomers together, it may be thought that the summation of the two  will be the chemical formula of maltose. However, this does not account for the dehydration synthesis reaction in which one oxygen atom and two hydrogen atoms disappear. After accounting for these molecules the chemical formula for maltose will be represented by .

Glycogen, starch, and cellulose are all polysaccharides composed of many glucose monomers linked together.

The sugar polymer form in which plants store energy is starch, whereas with animals, it is glycogen. While the other answers may in fact be sugar molecules involved in energy metabolism, they do not represent the primary sugar polymer storage molecule. Therefore the correct form of storage for plants is starch. And the correct form of storage for animals is glycogen.