Name __________________________________
Unit 4 - Review Packet
Period _________________
Part 1: Introduction to Cell Cycle and Interphase
1. Normally DNA in the cell is found in the __________________________ (location in the cell) in long
strands called ___________________________________ .
2. Why does the DNA wrap around proteins to make chromatin? What are those proteins called?
3. When the cell is getting ready to divide, the DNA coil up into _________________________________.
4. Chromosomes are made up of two identical halves called _________________________________ that are
held together by the ______________________________________, a protein disk.
5. Genetic counselors use ___________________________________ to analyze patients’ chromosomes and
determine if they have a genetic abnormality.
6. A male has a _________ and a __________ chromosome while a female has 2 ___________ chromosomes.
7. Describe the difference between an X chromosome and a Y chromosome.
8. Why do you have 2 pairs of each chromosome?
9. Prokaryotic cells divide by a process called _________________________________________ that results in 2
identical cells.
10. Body cells in eukaryotes divide by _______________________ to grow and repair while specific other
cells in eukaryotes divide by ___________________________ to produce gametes.
11. List the three stages of the cell cycle in order starting after a cell splits.
1.
2.
3.
List the phases of interphase in order and a brief description of what happens in each phase. Why
would a cell enter a G0 phase?
12. Explain the difference between chromatin, chromosome and chromatid. What phase of the cell
cycle has each form of DNA?
Mrs. Rippin
Page 1 of 8
9/19/13
Part 2: Mitosis
1. Explain the role of the spindle, the centromere and the centrioles in mitosis.
Spindle:
Centromere:
Centrioles:
2. Mitosis is the division of the ______________________ while cytokinesis is the division
of the _______________________.
3. How does cytokinesis differ in a plant cell versus an animal cell?
For the descriptions below, write the phase of the cell cycle (not just mitosis) described. Phases may
be used more than once.
4. _______________________ Nuclear envelope begins to disappear
5. _______________________ Chromatids reach the ends of the spindle and two nuclei
reform
6. _______________________ Cell grows, more mitochondria are produced
7. _______________________ The cytoplasm divides and two new cells are formed.
8. _______________________ Centromere splits, chromatids separate and begin to move apart
9. _______________________ Spindle begins to form
10. _______________________ Chromosomes line up in the middle or equator of the spindle/cell
11. _______________________ DNA duplicates and is in the form of chromatin
12. _______________________ Chromatin coils up into chromosomes
13. _______________________ In plant cells, a new cell wall forms
14. How many chromosomes would each new cell have after a human body cell divides by
mitosis/cytokinesis? Is the new cell haploid or diploid?
15. How many chromosomes would each new cell of a diploid cell with 12 chromosomes have after it
divides by mitosis/cytokinesis? Is the new cell haploid or diploid?
16. In what phase of the cell cycle does the cell spend most of its life? ________________________________
Mrs. Rippin
Page 2 of 8
9/19/13
17. For the following pictures, identify the phase of mitosis by writing the phase on the line beneath
the picture. All 4 phases of mitosis are represented. List 1-2 things that happen in the phase
underneath the line. In the box next to each picture, write a number to place them in the correct
order.
______________________________
________________________________
Describe what is happening:
Describe what is happening:
_______________________________
_________________________________
Describe what is happening:
Describe what is happening:
18. How do proteins relate to cancer? What happens if the wrong proteins are synthesized?
19. What environmental factors contribute to cancer formation?
20. How do cancer cells differ from normal body cells? Why are these differences beneficial to cancer
cells and make them more difficult to remove?
Mrs. Rippin
Page 3 of 8
9/19/13
Part 3: Meiosis
1. What are homologous chromosomes? How do they line up in mitosis? How do they line up in
meiosis?
2. What are tetrads? Why are they necessary in meiosis, but not mitosis?
3. Why is meiosis necessary for the formation of sex cells?
4. What is crossing over? When does it occur? How does it contribute to genetic variation and thus
species variation?
5. Describe how the following phases are different in meiosis and mitosis:
A) mitosis prophase and meiosis I prophase
B) mitosis metaphase and meiosis I metaphase
6. How do the two phases of meiosis in question #5 contribute to genetic and species variation?
7. A human body cell contains ___________ chromosomes, but a human sex cell (gamete) contains
____________ chromosomes.
8. What is the difference between a haploid cell and a diploid cell? Which type is a body cell? Which
type is an egg or sperm cell?
9. Define genetic recombination.
10. When a human egg and sperm combine, a ________________________ forms with 46 chromosomes.
11. List 3 ways that meiosis differs from mitosis.
Mrs. Rippin
Page 4 of 8
9/19/13
Part 4: DNA Structure and Replication
1. Describe the contribution made by each of the following scientists:
Watson and Crick:
Rosalind Franklin:
2. Describe the structure of DNA. Draw a sketch of an individual nucleotide as part of your
description. Label each part.
3. What is the main function of DNA?
4. Why does the DNA need to replicate? When does replication occur?
5. What are the base pairs? (Which nitrogen bases pair together in DNA?) What rule applies to base
pairing?
6. Which of the nitrogen bases are purines? Which are pyrimidines?
7. What enzyme catalyzes DNA replication?
8. What is a replication fork? Why are they necessary?
9. What types of errors can occur in replication? How can they be corrected?
10. What happens to the cell if replication errors are not corrected?
11. If one side of the DNA is ATTCGGATA, what would the other side be?
Mrs. Rippin
Page 5 of 8
9/19/13
12. What is gene expression? How do proteins control an organism’s appearance, behavior, and
ultimately all cell processes?
13. Why is RNA necessary? Where is it made?
14. What two processes make up gene expression?
Part 5: RNA and Transcription
1. What makes up the DNA code?
2. The alphabet codes for words, DNA codes for _______________________________________, which make
up _________________________.
3. A) What do you call each group of three nucleotides? B) What does each group code for?
4. Groups of three are used because DNA needs to code for ____________ amino acids.
5. The start codon is _____________ and codes for the amino acid _______________________________.
6. The stop codons are _________, _________, and __________. They indicate the stopping points in the
amino acid sequence.
7. List 3 differences and 3 similarities between RNA and DNA. You may use a chart.
8. Describe the process of transcription. Try to do this without notes first and use your own words.
You do not need to know the names of each stage, just describe what happens.
Mrs. Rippin
Page 6 of 8
9/19/13
9. Write the correct RNA sequence for the DNA sequence below. (One side of the DNA strand is
represented.)
TACCGCACCTAA
_________________________________________________________
10. The enzyme _________________________________ is used in _______________________________, the process by
which DNA is used to make RNA.
11. Explain the role of mRNA, tRNA and mRNA.
mRNA:
tRNA:
rRNA:
12. Explain, briefly, how each type of RNA is modified after transcription.
mRNA:
tRNA:
rRNA:
12. Explain how mistakes can be made in transcription.
Part 6: Translation
1. What is the purpose of translation?
2. Describe the process of translation. Try to do this without notes first and use your own words. You
do not need to know the names of each stage, just describe what happens.
Mrs. Rippin
Page 7 of 8
9/19/13
3. Explain the role of each of the three types of RNA in the process of translation:
mRNA:
tRNA:
rRNA:
4. What does the ribosome bind to at the start of translation?
5. Explain the role of anticodons.
6. Write the amino acid sequence that would results from the following mRNA sequence:
AUG
CCC
GUU
AUU
UGA
7. What is a gene?
8. Describe errors that occur in translation. What happens as a result of these errors?
9. Which is more likely to cause problems, replication errors or translation/transcription errors?
Why?
10. Most errors in any of the 3 processes are caught and fixed by __________________________.
11. What happens to the amino acid sequence after it leaves the ribosome?
12. How many genes are in the human genome? How many chromosomes? How many base pairs?
(Find the answers in your book!)
Mrs. Rippin
Page 8 of 8
9/19/13