The Cell Cycle
What process allows multicellular organisms to grow?
Cell division (mitosis and cytokinesis)
When one body cell divides, how many new cells are produced?
Two
What disease can develop when cells divide uncontrollably?
Cancer
What molecule stores a cell’s genetic instructions?
DNA
What does DNA replication do?
Makes a copy of DNA
During which part of the cell cycle does a cell grow, copy its DNA, and prepare for division.
M Phase or Interphase
Interphase
What process divides a cell’s nucleus?
Mitosis
Do healthy cells follow signals that tell them when to stop dividing?
Yes
DNA looks like a twisted ladder. What is this shape called?
A double helix
Does DNA replication happen before or after a cell divides?
Before
During which part of interphase is DNA copied: G₁, S, or G₂?
S phase
What process divides the cytoplasm, separating the cell into two cells?
Cytokinesis
What is a change in the DNA sequence called?
A mutation
Which DNA base pairs with adenine (A)?
Thymine (T)
During replication, the two DNA strands separate. What does each original strand help build?
A new matching strand
Why must a cell copy its DNA before it divides?
So each new cell receives a complete set of DNA.
Do the two cells produced by normal mitosis usually have the same or different genetic information?
The same
What do cell cycle checkpoints check for: problems in the cell or food in the stomach?
Problems in the cell
Which DNA base pairs with cytosine (C)?
Guanine (G)
If one DNA strand reads A–T–G–C, what is the complementary strand?
T–A–C–G
A cell has damaged DNA. Should it continue dividing or stop for repairs?
Stop for repairs.
You scrape your knee. How does cell division help the injury heal?
It produces new cells to replace damaged cells.
Why can uncontrolled cell division harm nearby healthy tissue?
Extra cells can crowd or damage healthy tissue.
What three parts make up a DNA nucleotide?
A sugar, a phosphate group, and a nitrogen base
After replication, each DNA molecule contains how many original strands and how many new strands?
One original strand and one new strand