Cell Cycle: Interphase & DNA Replication

Open Ended

Reflect on what you observed in the video in relation to cell replication during the development of the salamander. Describe what occurred to the cells as they replicated and what happened to the salamander as the cells replicated? Why do you think the cell cycle may be important?

Multiple Choice

Which of the following statements best explains why the cell cycle is important for the growth of an organism?

• During the cell cycle, the DNA helicase “unzips” the DNA molecule along weak hydrogen bonds which allows for the transfer of genetic information.

• The nuclear membrane disappears during the cell cycle so that cells can expand.

• Mitosis and meiosis allow for genetic mutations to occur within daughter cells and gametes.

• Multicellular organisms require cellular division for the replacement and repair of cells and tissues.

Multiple Choice

A tumor suppressor gene, or anti-oncogene, is a gene that protects a cell from one step on the path to cancer.  When this gene mutates to cause a loss or reduction in its functions, a cell can progress to cancer, usually in combination with other genetic changes.

What is the main function of tumor-suppressor genes in the cell cycle?

• Disrupt the G2 phase.

• Inhibit or prevent uncontrolled cell division.

• Stop mutations from occurring in DNA code.

• Regulate the amount of energy needed during cell division.

Multiple Choice

Which phase in the cell cycle of eukaryotes ensures that everything is ready for DNA replication that occurs during the S phase?

• Mitosis

• G2 Gap Phase

• G1 Growth Phase

• Cytokinesis

Multiple Choice

Look at the diagram.

Which of the following stages best describes the pre-mitotic phase where the cell checks for errors and makes needed repairs?

• G2 stage

• G1 stage

• Telophase

• Anaphase

Multiple Choice

What is the first step of DNA replication?

• DNA helicase “unzips” the DNA molecule along weak hydrogen bonds.

• DNA polymerase adds free nucleotides to form the new strands of DNA.

• DNA ligase joins fragments of growing strands of DNA.

• Two semiconservative daughter DNA molecules are formed.