Name _____________________________________________
Review Questions for the Cell Cycle and DNA Quiz:
What do hydrogen bonds do?
What does DNA stand for?
What do the centrioles do? When do they appear in the cell?
What unwinds and unzips the DNA molecule? How does it unzip and unwind the DNA molecule?
What molecules are the rungs of the DNA ladder made of?
Pair up the nitrogen bases...
What is the shape of DNA?
What molecule helps the new nitrogen base pairs attach to the exposed nitrogen base pairs?
What stage of the cell cycle takes the longest? What happens in that stage?
Why do the chromosomes line up across the middle of the cell during metaphase? Why might this be
important?
Why do you think the chromatin condenses into chromosomes during Mitosis?
What is the purpose of mitosis? What is the purpose of interphase? What is the purpose of
cytokinesis?
What do the spindle fibers do? When do they appear in the cell?
**Answers to these questions and the questions from class are available on my website**
Quiz Format: Multiple Choice, Diagrams, Short-Answer Questions
On the quiz, be prepared to:
-Look at an image of a cell and identify the phase that it is in (Interphase, Prophase,
Metaphase, Anaphase, Telophase, or Cytokinesis) and explain what is occurring in each
phase.
-Label a diagram of DNA and explain how its structure ensures that exact copies of DNA are
made during replication.
Good Resources: Cell Cycle Booklet. Website: Power Points, Videos, and Guided Notes. The HW
Reading and Questions on the Cell Cycle, Mitosis, and DNA.
Answer to Review Questions for the Cell Cycle and DNA Quiz: Answers for the questions in BOLD
What do hydrogen bonds do?
They hold the nitrogen base pairs together in the rungs of the DNA molecule.
What does DNA stand for?
Deoxyribose nucleic acid
What do the centrioles do? When do they appear in the cell?
Produce spindle fibers that attach to each chromosome at the centromere and pull the
chromosomes apart. They appear in the cell during G2 of Interphase.
What unwinds and unzips the DNA molecule? How does it unzip and unwind the DNA molecule?
An enzyme called DNA Helicase unwinds and unzips the molecule by breaking the
hydrogen bonds between the base pairs.
What molecules are the rungs of the DNA ladder made of?
Nitrogen bases and hydrogen bonds
Pair up the nitrogen bases...
Adenine – Thymine
Cytosine – Guanine
What is the shape of DNA?
Double helix, spiral staircase, twisted ladder
What molecule helps the new nitrogen base pairs attach to the exposed nitrogen base pairs?
An enzyme called DNA Polymerase
What stage of the cell cycle takes the longest? What happens in that stage?
Interphase takes the longest; it is comprised of 3 phases: G1, S, and G2. During G1, the
cell grows to its full size and carries out all of its life functions. During S, the cell makes
copies of its DNA through a process call replication. During G2 the cell makes final
preparations for divisions, most importantly it produces centrioles during this phase.
Why do the chromosomes line up across the middle of the cell during metaphase? Why might this be
important?
They line up across the middle so that they can ensure that each daughter cell receives
a full copy of DNA, so each daughter cell must receive 1 sister chromatid from each pair.
Lining up down the middle of the cell ensures that the sister chromatids will be split in half
and pulled in the right direction during anaphase.
Why do you think the chromatin condenses into chromosomes during Mitosis?
Mitosis is nuclear division – meaning that the DNA must be evenly divided into the two
new daughter cells. When it is all stretched out as chromatin (noodles) it is not organized.
When the chromatin condenses into chromosomes, this helps to keep the DNA organized so
that it can be evenly divided. Think about it like packing a suitcase: the cell is going on a trip
during cellular division and it needs to take its DNA with it. During Interphase, the DNA is out
and about tell the cell what to do (much like the clothes in your room). When it is time for
mitosis, the DNA gets “packed” into the chromosomes (much like you packing up clothes in a
suitcase for a trip). When the cell is done splitting and two new daughter cells are formed, the
DNA stretches out (just like the clothes come out of your suitcase when you arrive at your
desitnation).
What is the purpose of mitosis? What is the purpose of interphase? What is the purpose of
cytokinesis?
-Mitosis: nuclear division. Divide the DNA in half and create two new nuclei for the
daughter cells
-Interphase: perform life functions of the cell (BIG 7), copy the DNA (Replication), and
produce structures necessary for division (centrosomes).
-Cytokinesis: cellular division. When the parent cell splits into the 2 daughter cells.
What do the spindle fibers do? When do they appear in the cell? Spindle fibers are produced by the centrosomes. They attach to chromosomes at the
centromeres during metaphase. During anaphase, they pull the sister chromatids apart and to
opposite ends of the cell.