Download Unit 6 ~ Learning Guide Name: INSTRUCTIONS

BCLN BIOLOGY 12 – Rev July 2014
Unit 6 ~ Learning Guide
Name:________________
INSTRUCTIONS
Complete the following notes and questions as you work through the related lessons.
You are required to have this package completed BEFORE you write your unit test. Do
your best and ask questions about anything that you don't understand BEFORE you
write the unit test.
U6L1 NOTES: INTRODUCTION (web notes and video)
YOU SHOULD WATCH THE INTRODUCTION VIDEO AND
THE DNA VS RNA VIDEO BEFORE PROCEEDING ANY FURTHER!
Protein Synthesis
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DNA replication produces an ________________________________________.
Protein synthesis ___________________ to produce _____________________.
Do not confuse these 2 processes!!!!
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BCLN BIOLOGY 12 – Rev July 2014
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DNA is the ___________________________ (or template) containing
________________________________ for the _______________________
__________________ (structural and functional).
Proteins are put together in the ___________________, but DNA never leaves
the _________________. A copy of the DNA must be made. This copy is called
_____________________________ (mRNA). Think of it this way, there has to
be some mechanism to get the message from DNA that is confined in the
nucleus to the site of protein synthesis in the cytoplasm and this is done with the
aid of a messenger molecule called messenger RNA or mRNA.
Only the genes for the specific required proteins are copied into ___________.
The process of making the mRNA from a DNA template is called
__________________________.
The newly synthesized mRNA molecule then travels into the cytoplasm where it
is _____________________ into proteins.
DNA -------------------------> mRNA ------------------------------> Protein
Transcription
Translation
U6L1 PRACTICE: INTRODUCTION
1. ________________________ is the process of making an identical strand of
DNA and occurs in the nucleus. (1 mark)
2. Protein synthesis refers to the process of using the information encoded in DNA
to make proteins and involves two steps:
a. __________________________ where DNA is used as a template to
make mRNA. (1 mark)
b. __________________________ where mRNA is used to direct the
synthesis of proteins. (1 mark)
3. Please state where in the cell the following processes occurs (3 marks):
a. Replication: ___________________________
b. Transcription: _________________________
c. Translation: __________________________
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BCLN BIOLOGY 12 – Rev July 2014
U6L2 NOTES: PROTEIN SYNTHESIS (web notes and video)
Codons
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Nitrogenous bases in DNA contain the
instructions for making proteins.
____________________________________
____________________________________
Many amino acids make up a protein.
The code for protein synthesis is transcribed
from a DNA _________________ into a
molecule called _______________________
________________ (mRNA).
Once the code is transcribed each set of 3
bases on the ____________________ is
called a ______________.
There are ______ possible combinations/codons
o there are 4 possible bases read in groups of
three…43 = 64
o However, we only have about ____ amino
acids therefore, most amino acids have more
than 1 codon. Often the codons only differ in
the last base.
Example: the codons CAA and CAG
both code for the amino acid
known as glutamine
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Duplicate codons may be a way of _________________/
________________________ the effects of mutations. The duplication of
codons is called _____________________________.
The genetic code is basically "_______________________" where the
same codons stand for the same A.A. in all living things. This suggest that
all living things ______________________________________________.
AUG which is Methionine is a ______________, whereas UAA and UAG are
_______________________. At the end of each mRNA strand there are long
chains of ____________________ bases (Adenine Tail). This is so the body
can detect that the mRNA is still functional. When enough protein is created the
Adenine tail ________________. This tells the body that this particular mRNA is
__________________________________ to produce its protein. The cell will
then ________________ the no longer functional mRNA (lysosomes will be
involved in this process)
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BCLN BIOLOGY 12 – Rev July 2014
Transcription
A. The gene in _________ is selected,
isolated and uncoiled by the enzymes
_______________. The gene codes for
the ___________________ that will
eventually be produced. The Hydrogen
bonds between the complimentary base
pairs are broken to provide the DNA
template.
B. Free-floating ___________________ join
complementary to the selected gene on
the DNA template. The enzyme RNA
__________________ assists with this.
Remember these two important points:
-The DNA strand is called the _______________
- ***Uracil always joins to Adenine when forming the ________. There is
no __________ in RNA.
Thymine is only found in
DNA***
C. The enzyme ___________ glues the alternating sugar-phosphate backbone
together.
D. Enzymes
break
the
_____________ bond that
is
temporarily
formed
between
the
newly
synthesized
mRNA
molecule and the DNA
template and then the
mRNA is released from the
DNA template. We now
have an _________ strand.
E. The __________________
joins back together and the
mRNA passes through the nuclear envelope through the nuclear pores into the
cytoplasm.
F. DNA recoils back up into its _____________________ with the help of enzymes.
YOU SHOULD WATCH THE TRANSCRIPTION VIDEO
BEFORE PROCEEDING ANY FURTHER!
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BCLN BIOLOGY 12 – Rev July 2014
Translation
G. STEP 1: ___________________ - mRNA becomes
associated with a ________________ in the
cytoplasm which is made up of ribosomal RNA
(rRNA) and proteins. When the mRNA comes near
the two ribosomal subunits, the large subunit
__________________ to the mRNA. The first
tRNA's anticodon* then __________________ and
binds to the mRNA before the small subunit can
attach. Once both subunits are attached a
functional complex is formed. Note that each tRNA
_________________________________________
__________________________ that is determined
based on its anticodon.
* anticodon = a set of 3 nucleotides at the "base" of the tRNA that will bind to a
complimentary mRNA codon
H. STEP 2: _______________________ - A second tRNA comes in, compliments
and binds to the second mRNA codon. The ribosome then assists in transferring
the amino acid from the ____________________________________________
__________________, forming a peptide bond between the amino acids in the
process.
The
ribosome
then
moves
down
the
mRNA
by
_____________________, the first (now empty tRNA) is released and recycled
such that it can pick up another amino acid. Meanwhile, a third complimentary
tRNA binds to the third mRNA codon and the amino acid transfer, peptidebonding, chain elongation process is continued so on and so forth.
I. STEP 3: __________________________ - The ribosome continues to
read/translate the mRNA strand and a _______________________ chain grows
until a _____________________________ is reached. Once the terminator
codon is reached the finished polypeptide (protein) is released. The mRNA will
then be read by more ribosomes (mass production of identical proteins) or
___________________.
Many ribosomes may be found together,
____________________________. This group of ribosomes is called a
____________________________.
YOU SHOULD WATCH BOTH OF THE TRANSLATION VIDEOS AND
THE CODON CHARTS VIDEO BEFORE PROCEEDING ANY FURTHER!
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BCLN BIOLOGY 12 – Rev July 2014
Codon Charts
Please use the codon chart provided to answer the following where the template
DNA strand is: TTA TGC TCC TAA
1. What is the complimentary DNA sequence to the above template sequence?
2. What is the complimentary mRNA sequence to the above template sequence?
3. What amino acid sequence does the above template sequence code for?
4. In order, what would be the sequences of the tRNA anticodons necessary to
translate the above template sequence?
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BCLN BIOLOGY 12 – Rev July 2014
Mutations: Any change in the DNA of an Organism.
Truths about Mutations:
• Most are minor
• Many are harmful
• Some are lethal
• Very few are helpful
• Which types of mutations are these?
Types of Mutations:
• Germ Mutation - occurs in gametes (egg or sperm cells)
• Somatic Mutation - occur in body cells
• Chromosomal Mutations:
1. ___________________________________________________________
___________________________________________________________
2. ___________________________________________________________
___________________________________________________________
3. ___________________________________________________________
___________________________________________________________
4. ___________________________________________________________
__________________________________________________________.
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BCLN BIOLOGY 12 – Rev July 2014
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Gene Mutations:
5. Point mutations - a change in a single nitrogen base in DNA.
6. Frame-shift mutation - the addition or deletion of a nitrogen base, causing
the gene sequence to read out of sequence.
Causes of Mutation
Can arise _________________ (due to an unknown cause) or they may be caused by
an ______________.
A factor that increases the chance of a mutation is called a ________________
Environmental Mutagens
1. Chemical - food additives
• _______________________________________________
• _______________________________________________
• _______________________________________________
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BCLN BIOLOGY 12 – Rev July 2014
2. Radiation - (__________________________________
____________________________________________)
• The greater the exposure the greater the risk.
• Suspected mutagens are tested on bacteria and
other organisms such as Fruit Flies, and then
mammals (rats, mice). If mutations (such as cancer)
develop, the government restricts its use.
• Mutagens that lead to an increased chance of cancer
are called _____________________.
Examples of Mutations
1. DOWN' SYNDROME - A chromosomal translocation
• part of chromosome #21 becomes attached to another
chromosome (#'s 12, 14, 15, or 22)
• also have 2 normal chromosome #21
2. SICKLE-CELL ANEMIA
• substitution of a base to produce a different amino
acid.
• results in abnormal hemoglobin molecules.
• prevalent in African American (10% carry the trait)
• causes decreased ability for the blood to carry
oxygen
• 2 chromosomes: 1 normal and 1 sickle actually protects from Malaria
• if both chromosomes are sickle, the condition is fatal
3. CANCER - a somatic mutation (affects an individual's body cells)
• results in uncontrolled growth of abnormal body cells that fail to stay in the organ
where they arose.
4. HEMOPHILIA - a germ cell mutation (a mutation of the original sex cells)
• passed on to the individual from a previous generation.
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BCLN BIOLOGY 12 – Rev July 2014
U6L2 PRACTICE: PROTEIN SYNTHESIS
1. Why is the genetic code considered "universal"? (1 mark)
2. Please complete the following table.
example. (8 marks)
Replication has been filled out as an
Replication
Overall Process
DNA  DNA
Location
nucleus
Key Enzymes
helicase,
DNA polymerase,
ligase
Additional Notes
involves making a
new copy of the
entire genome for the
purposes
of
cell
division
Transcription
Translation
3. Please list the steps of translation and provide a brief description of each step. (6
marks)
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BCLN BIOLOGY 12 – Rev July 2014
4. If an enzyme is composed of 687 amino acids, how many bases would the
mature mRNA that encoded for it have? (1 mark)
5. The codon table allows you to determine the amino acid sequence of a
polypeptide based on the________________ sequence. (1 mark)
6. Use a codon table to determine the amino acid sequence encoded for by the
following mRNA sequence. (2 marks)
mRNA: AUG GAA GCU ACG
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BCLN BIOLOGY 12 – Rev July 2014
7. Use a codon table to determine the amino acid sequence encoded for by the
following DNA sequence. (3 marks)
DNA: CCG CTC TTA CTT
8. What would be the sequence of the 4 tRNAs' anticodons, in order, that would be
used to translate the following DNA sequence into a protein? (2 marks)
DNA: CGG TTG TGT TAG
9. A mutagen causes a base pair to be removed from a gene that codes for a
protein within a cell. Name the type of mutation and the likely effect of this
mutation on protein synthesis. (3 marks)
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BCLN BIOLOGY 12 – Rev July 2014
10. Choose ONE of the following topics to research and write a paragraph about. (10
marks)
A. Some theories state that mutations are involved in the evolution of life on
Earth. Assuming this is true, describing the difference that a somatic
mutation versus a germ mutation would have on future generations.
B. Using internet resources, research one disorder in animals caused by a
mutation. Include:
 name of disorder
 description of symptoms/effects of disorder
 specifics of the type of mutation that causes the disorder
 a diagram/picture of the effects of the disorder
C. Using internet resources, research gene therapy. Include:
 a basic description of what gene therapy is
 some examples of disorders that may be treated by gene
therapy
 a description of some of the challenges/limitations face by
the field of gene therapy
~ END OF BIOLOGY 12 UNIT 6 LEARNING GUIDE ~
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BCLN BIOLOGY 12 – Rev July 2014
UNIT 6 ANSWER KEY
U6L1 PRACTICE: INTRODUCTION
1. ________________________ is the process of making an identical strand of DNA and occurs in
the nucleus. (1 mark)
2. Protein synthesis refers to the process of using the information encoded in DNA to make proteins
and involves two steps:
a. __________________________ where DNA is used as a template to make mRNA. (1
mark)
b. __________________________ where mRNA is used to direct the synthesis of proteins.
(1 mark)
3. Please state where in the cell the following processes occurs (3 marks):
a. Replication: ___________________________
b. Transcription: _________________________
c. Translation: __________________________
U6L2 PRACTICE: PROTEIN SYNTHESIS
1. Why is the genetic code considered "universal"? (1 mark)
= because the same codons code for the same amino acids in all living things
2. Please complete the following table. Replication has been filled out as an example. (8 marks)
Replication
Transcription
Translation
Overall Process
DNA  DNA
DNA  mRNA
mRNA  protein
Location
nucleus
nucleus
cytosol
Key Enzymes
helicase,
DNA polymerase,
ligase
RNA polymerase
ribosomes
Additional Notes
involves making a
new copy of the
entire genome for the
purposes
of
cell
division
forms immature
mRNA that must
then be processed
to become mature
and exit to cytosol
requires additional
assistance from
rRNA (part of the
ribosome) and
tRNAs which
transfer amino acids
to the growing aa
chain
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BCLN BIOLOGY 12 – Rev July 2014
3. Please list the steps of translation and provide a brief description of each step. (6 marks)
Step 1. = Initiation where small ribosome subunit binds to start codon of mRNA,
the initiator tRNA binds complimentary to the mRNA's start codon and then the
large ribosomal subunit binds to the complex such that the initiator tRNA is located
in the P site of the ribosome.
Step 2. = Elongation where a second tRNA binds complimentary to the mRNA's
second codon such that the second tRNA is located in the A site of the ribosome.
The ribosome catalyzes the transfer of the amino acid from the tRNA in the P site
to the tRNA in the A site, forming a peptide bond between the two amino acids.
The ribosome then shifts down the mRNA by a single codon such that the empty
tRNA is now in the E site of the ribosome and the tRNA with the growing amino acid
chain is now in the P site of the ribosome and the A site is now open and available
for a new complimentary tRNA. The empty tRNA exits the E site to be recycled
while a new, complimentary tRNA comes into the A site and the entire process is
repeated.
Step 3. = Termination where the ribosome encounters a termination codon (stop
codon) on the mRNA. A release factor will complimentary bind to the mRNA stop
codon such that it is in the A site of the ribosome, when the ribosome goes to
transfer the amino acid changing to this release factor it cannot do so and the amino
acid chain polypeptide/protein) is released from the ribosomal complex. All other
components are released from the complex and may be recycled and used again to
produce more copies of the protein.
4. If an enzyme is composed of 687 amino acids, how many bases would the mature mRNA that
encoded for it have? (1 mark)
= each codon is coded for by 3 bases so…3 x 687 = 2061 bases
5. The codon table allows you to determine the amino acid sequence of a polypeptide based on
the________________ sequence. (1 mark)
6. Use a codon table to determine the amino acid sequence encoded for by the following mRNA
sequence. (2 marks)
mRNA: AUG GAA GCU ACG
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BCLN BIOLOGY 12 – Rev July 2014
7. Use a codon table to determine the amino acid sequence encoded for by the following DNA
sequence. (3 marks)
DNA: CCG CTC TTA CTT
8. What would be the sequence of the 4 tRNAs' anticodons, in order, that would be used to translate
the following DNA sequence into a protein? (2 marks)
DNA: CGG TTG TGT TAG
9. A mutagen causes a base pair to be removed from a gene that codes for a protein within a cell.
Name the type of mutation and the likely effect of this mutation on protein synthesis. (3 marks)
= If a single base pair from a gene is removed it is known as a deletion and a frame
shift mutation. As the entire reading frame of the gene is shifted, the entire code
downstream of the mutation will be translated incorrectly likely leading to a
completely non-functional protein. If this protein is essential for cellular function
the cell and potentially the organism will die.
10. Choose ONE of the following topics to research and write a paragraph about. (10 marks)
Answers will vary.
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