5C (SS) - Cat. 1 STAAR Questions

During the cell cycle, proteins called cyclins bind to enzymes that send signals for the cell to progress through stages of cell replication. At the end of this cycle, the cyclins degrade to prevent further signaling for the cell to divide. Uncontrolled production of cyclins will most likely result in —

• the formation of tumors

• the immediate death of the cell

• the transfer of cyclins to other cells

• the formation of haploid cells

When cells lose their ability to regulate the cell cycle, they can divide at an accelerated rate and form a mass of cells. This mass of cells is referred to as —

• a tumor

• an embryo

• a gland

• an organ

What is the role of mRNA in expressing specialized structures?

• Making energy available for cellular activities

• Creating bonds to form biomolecules

• Producing sugars that assist with replication

• Providing information to form proteins

From a single fertilized ovum undergoing a series of rapid cell divisions, a human infant develops. The embryonic cells become specialized for a variety of functions. Which of these statements best describes how different cell types develop?

• Each cell type contains only the active parts of the DNA needed for that cell type.

• Each cell type has only one chromosome containing the DNA needed for that cell type.

• Each cell has an identical copy of DNA with enzymes controlling the expression of specific genes, leading to a variety of cells.

• Each cell has multiple copies of DNA that are affected in different ways by the environment to change the function of the cell at regular intervals.