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Chapter Four Review
Name: ________________________________
1. In what way is the nucleus like a black box in a plane?
The nucleus is like a black box because there are still unknown processes occurring and we are not
able to see all the activity that is happening inside the nucleus.
2. Explain why DNA is required in every cell?
DNA is required in every cell because DNA contains the genes that code for the proteins the cell
requires to perform its functions.
3. DNA has a complex structure. Complete the table outlining its different parts. Use the
following words: adenine, sugar, double helix, guanine, phosphate, cytosine, twisted
ladder, thymine, nitrogenous bases.
The DNA molecule has a
Sides are made of:
double helix
phosphate
adenine
shape that resembles a(n)
sugar
pairs with
Rungs are made of:
thymine
cytosine
twisted ladder
nitrogenous bases
pairs with
guanine
4. Complete the table that outlines the role of proteins in cells.
What is the function of proteins in cells?
How are proteins and the DNA base sequence related?
Enzymes, hormones, structural proteins.
The order of the bases determines the type of protein
that will be produced.
5. The sequence of one side of a DNA molecule is GACCTGACAAGT. Complete the table
using the proper base pairs to determine the other side of the DNA.
G
A
C
C
T
G
A
C
A
A
G
T
C
T
G
G
A
C
T
G
T
T
C
A
Science 9 ● Biology● Review
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6. The structures below are involved in making proteins. Describe the role of each structure
during the process.
Structure
Function
Nucleus
Receives a chemical signal to make a protein and has the DNA.
Chromosomes
DNA (in chromosomes) has the information for the protein.
Ribosome
Proteins are made in the ribosome.
Vesicle
Carry the protein.
Endoplasmic Reticulum
Transports the protein from the ribosome and packages it in a
vesicle.
Golgi Body
Sorts and repackages the protein and releases it a vesicle.
Nuclear Pore
Allows the RNA to exit the nucleus to find the ribosome.
RNA
A messenger from the nucleus to the ribosome.
7. A(n) m u t a t i o n happens when the sequence of bases in DNA is modified. Substances
or factors which cause modifications to the DNA are called (an) m u t a g e n s . There are
three ways in which this can occur. When bases are added to the sequence it is a(n)
a d d i t i o n , when they are removed it is a d e l e t i o n , and when they are switched out
for another base it is a(n)s u b s t i t u t i o n .
Science 9 ● Biology● Review
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8. Describe how each of the following mutations can affect an organism.
Type of gene mutation
Effect on the organism
Example
Positive
Benefits the organism
Resistance to viruses or fungi.
Neutral
No effect on the organism
White coat of Spirit Bear.
Negative
Harms the organism
Sickle cell anemia or cystic
fibrosis.
9. Order the following steps for the production of proteins.
2
The DNA message for a specific protein is copied into a small molecule called RNA.
7
The Golgi body repackages the protein for transport out of the cell.
4
The RNA message is delivered to the ribosome, and the ribosome makes the protein.
8
A vesicle forms off the end of the Golgi body to carry the protein to the cell membrane.
1
The nucleus receives a chemical signal to make a specific protein.
5
The manufactured protein enters the endoplasmic reticulum.
9
The vesicle attaches to the cell membrane, and its protein contents are released out of the
cell.
6
A vesicle forms at the endoplasmic reticulum and carries the protein to the Golgi body.
3
RNA leaves through the nuclear pore.
10. Some occupations pose greater risks of mutation to DNA than others.
occupations that pose a risk and explain why.
Occupation
Reason for risk
Answers
Answers
will
will
vary.
vary.
Science 9 ● Biology● Review
Give three
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