Biology, Eighth Edition (Raven)

Chapter 19: Cellular Mechanisms of Development

Control of the Cell Cycle

What makes a cell successful? Cells are the fundamental unit of life and they need to accomplish the same goals as entire organisms. Cells must take in material, perform metabolic functions, and release products. Cells must also grow and reproduce. Control of both growth and reproduction of cells is necessary for organisms to function. Uncontrolled growth and reproduction results in cancer. Cellular growth and reproduction are controlled through the cell cycle, a precise series of events that organizes growth, genetic replication, and cell division into specific time periods in the life of a cell.

View the animation below, then complete the quiz to test your knowledge of the concept.


1.	The success of DNA replication is assessed during the ______ phase.

		A)	G₁
		B)	M
		C)	C
		D)	S
		E)	G₂

2.	The cell cycle is regulated by checkpoints during the _______ phases.

		A)	G₁, S and G₂
		B)	G₁, S and C
		C)	G₁, G₂, and M
		D)	G₁, S and M
		E)	G₁, S, G₂ and M

3.	A eukaryotic cell that receives a “go-ahead” signal at the G1 checkpoint of the cell cycle will

		A)	complete the cycle and divide.
		B)	move directly into the M phase.
		C)	move directly into the G₂ phase.
		D)	enter a resting stage.
		E)	stop growing.

4.	Preparation for cell division occurs in the G₂ phase.

		A)	True
		B)	False

5.	After cytokinesis, the cell enters the G₁ phase.

		A)	True
		B)	False