Subject/Course Title: Biology 15 16
Unit Title/Skill Set: 5. DNA, RNA and Protein Synthesis--11 Days
Overview: This unit examines the role of nucleic acids and cellular organelles in
the production of proteins and the resultant expression of phenotype.
Unit Essential Question(s): How do organisms use DNA and RNA to make
proteins? What factors affect gene expression?
Unit Competencies—What students need to be able to do (skills) as Do Now’s.
2. Explain the structural relationships between DNA, genes, and chromosomes.
4. Describe how DNA replication results in the transmission and/or conservation of the genetic
information.
8. Describe the role of the nucleus, ribosomes, ER, and Golgi apparatus in the production and processing
of proteins.
9. Describe how genetic mutations alter DNA sequence and may or may not affect phenotype.
10. Explain the unified process of protein synthesis.
Unit Concepts—What students need to know as Guided Reading
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Structure of DNA
o Components of a nucleotide
o Base-pair rule (Chargaff’s Rule)
Structure of eukaryotic chromosomes
Semi-conservative/DNA replication process
Similarities and differences between DNA and RNA
Types of RNA
Transcription uses DNA to make RNA
Translation uses RNA to make a protein
Role of ribosomes, endoplasmic reticulum and Golgi apparatus in assembling, transporting, packaging
and modifying different proteins
Phenotype as a function of gene expression (DNA to protein to phenotype)
Different types of gene mutations
Possible effect of mutation (change in the DNA sequence) on phenotype
Environmental influences on phenotype
NUCLEIC ACIDS: DNA, RNA, and PROTEIN SYNTHESIS SYLLABUS
1.
2.
3.
4.
5.
Every reading assignment is expected to be completed BEFORE you come to class. Confused about the
reading? Prepare questions to ask in class AS YOU READ.
Be a Scout and Be Prepared…Reading quizzes may be given at ANY time.
Homework is due ON THE DUE DATE (Sectionals—Turn in on the due date…Field trips and
illnesses—turn in on your first day back.).
Do Now’s are to be completed in class and turned in THAT BLOCK. (Absent??—Turn in first day
back. Questions on the reading that goes with the Do Now??—Turn in written question specifying
what you don’t understand. Be specific. Don’t say, “I don’t get it”.)
Vocabulary understanding is necessary. Attend to the words at the beginning of each chapter, or words
that you encounter that are new to you.
6. **In order for you to participate in structured activities and labs, you must have
your Guided Reading up-to-date as well as your vocabulary.
7.
DAY
Labs are to be read beforehand.
5
Vocabulary
DNA replication-structure/function
HOMEWORK/DUE
Read: 9.2, 9.3, 10.1 p. 207-14,
10.2 p. 219-20
Watch Videos: 1 and 2
Activity: Nucleotide cha-cha
otherwise known as line dancing
in the hall
Watch: remaining videos
Activity: DNA base bonds,
nucleotides
Activity: DNA Chutes Ladders
Activity: Replication
Rock/Paper/Scissors
6
Vocabulary
DNA transcription
DUE: Reading corrections
Activity: Transcription Jeopardy
7
Vocabulary
Reading the AA Table
Translation to proteins, ER, Golgi
Activity: Translation Penny
Toss
8
Lab: The Genetic Code/Stellar Thread
DUE: Bgram
9
Mutations
Amoeba Sisters video
Putting It Together
Activity: Random Acts of
Mutations, Sickle Cell
Activity: Amoeba Sisters HO
Activity: Cut the strips, make
models
1-3
4
LESSON
Guided Reading—self-scored
DNA history
DNA components/structure/function
Relationship between DNA, genes, and
chromosomes
Vocabulary
DNA-structure/function
10-11 Lab: CHNOPS
DUE THE NEXT DAY: Protein Synthesis CHNOPS Lab
Test sometime, somewhere, somehow, good luck. TBA
Animation resources: You may also locate these on the server in my distribution box
under Nucleic Acids
Amoeba Sisters Youtube: Find the one(s) on DNA vs RNA and Protein Synthesis (we’re
doing the worksheet that goes with this):
DNA structure and Function-- https://www.youtube.com/watch?v=_POdWsii7AI
DNA Replication-- https://www.youtube.com/watch?v=dKubyIRiN84
DNA Replication: The Cell’s Extreme Team Sport-https://www.youtube.com/watch?v=5qSrmeiWsuc&list=PLwL0Myd7Dk1F0iQPGrjehze3
eDpco1eVz&index=9
Why RNA is Just as Cool as DNA-- https://www.youtube.com/watch?v=0ElozX1k8M&index=19&list=PLwL0Myd7Dk1F0iQPGrjehze3eDpco1eVz
Protein Synthesis and the Lean, Mean Ribosome Machines-https://www.youtube.com/watch?v=h5mJbP23Buo&index=20&list=PLwL0Myd7Dk1F0i
QPGrjehze3eDpco1eVz
Other soures:
http://www.phschool.com/science/biology_
place/labbench/index.html
http://www.wwnorton.com/college/biology/discover
bio4/_core/ch/08/animations.aspx
http://www.bozemanscience.com/
Interactive site
http://www.dnai.org/
DNA/RNA/PROTEIN SYNTHESIS VOCABULARY
1. Chromosomes-A single piece of coiled DNA and associated proteins found in
linear forms in the nucleus of eukaryotic cells and circular forms in the cytoplasm
of prokaryotic cells; contains genes that code for traits. Each species has its own
number of chromosomes.
2. Deoxyribonucleic Acid (DNA) A biological macromolecule that codes for the
genetic information for traits (carried in proteins) in living organisms. It can make
copies (replication) of itself and copies onto RNA.
3. DNA Replication-The process in which DNA makes a duplicate copy of itself
from a template (pattern).
4. Golgi Apparatus-An organelle found in eukaryotic cells responsible for the final
stages of processing proteins for release by the cell.
5. Mutation-A permanent change of genetic material (ie: chromosomal mutation or
gene mutation) that may be passed to offspring.
6. Nucleus-A membrane-bound organelle in eukaryotic cells functioning to maintain
the genetic material and, through the expression of that material, controlling and
regulating cellular activities (homeostasis).
7. Protein Synthesis-The process in which amino acids are arranged in a linear
sequence through the process of transcription of DNA and to RNA and the
translation of RNA to a doubly twisted polypeptide molecule with a specific
shape which determines its function.
8. Ribosome-A cellular structure composed of RNA and proteins that is the site of
protein synthesis in eukaryotic AND prokaryotic cells.
9. Semiconservative Replication-The process in which the DNA molecule uncoils
and separates into two strands. Each original strand becomes a template (pattern)
on which a new strand is constructed, resulting in two DNA molecules identical to
the original DNA molecule.
10. Transcription-The process in which a strand of messenger RNA (mRNA) is
synthesized by using the genetic information found on a strand of DNA acting as
a template.
11. Translation-The process in which the messenger RNA (mRNA) molecule on a
ribosome is encoded to produce a sequence of amino acids for protein synthesis.
DNA NUCLEOTIDES and BASE BONDING STRATEGIES
1. Write in the blank below: the number of weak H bonds holding the complementary
base pairs together.
2. Write in the blank above: the four nucleotides (substitute the first letter of each base
instead of the letter ‘B’).
DNA Chutes and Ladders Questions
1. Name three scientists responsible for discovering the structure of DNA.
2. What are the three components of a nucleotide?
3. What two components of a nucleotide never change?
4. What component of a nucleotide changes?
5. What are the four DNA bases and how do they pair?
6. Wilkins and Franklin are known for…
7. Watson and Crick are known for…
8. Explain the significance of the physical structure of each DNA base.
9. How can every living thing share the same four bases in their DNA and still have
so much variety?
10. What is the result of a single error in DNA bases?
REPLICATION ROCK/PAPER/SCISSORS QUESTIONS
1. What is the process called whereby a new copy of DNA is made?
2. What is the reason that DNA makes a copy of itself?
3. The ending, ‘ase’ refers to any molecule (usually an enzyme) that breaks bonds.
What do you think DNA helicase does?
4. The resulting DNA strand from replication is an exact ___ of the original strand.
5. An important function of DNA polymerase is to check the new strand for ____.
6. What kind of bond is formed between the bases?
7. A gene is a series of bases that code for a single ______?
8. What are replication forks?
9. Explain what a complementary base pair is. Give an example.
10. A virus that invades bacteria and makes the bacteria produce more viruses are
called…
TRANSCRIPTION JEOPARDY GAME QUESTIONS
1. The process of transcription copies the DNA code onto…
2. Three differences between DNA and mRNA are…
3. Thymine in DNA is replaced by ___ in mRNA.
4. DNA is found ONLY in the nucleus, but mRNA is made in the nucleus and then
goes to the…
5. In the first step of transcription, DNA unwinds, the Hydrogen bonds between
bases break and the DNA separates. Then…
6. What are the base pairing in mRNA?
7. RNA polymerase does what in transcription?
8. Explain how a template works in transcription.
9. How are prokaryotes different from eukaryotes during transcription?
10. What is the function of mRNA?
Penny Toss Translation
1. A codon is to mRNA as a ______ is to tRNA.
2. Ribosomes function as a(n) ________________________ for proteins.
3. The role of the ER is to _________________________________.
4. Golgi apparatus functions in _________________, __________________,
_____________________, and ________________different proteins.
5. The ‘essential’ building blocks of proteins are ___________________, and
come from the _____________that you eat.
6. ______________help to form peptide bonds between adjacent amino acids.
7. After the long chain of aa’s are formed, the chain ____________________ and
____________________which will determine its function.
8. The genetic code for making proteins is described as being nearly ___________
as all living things use the same series of ___________ in groups of three known
as a ____________.
9. In order for a ribosome to begin making a protein, ___________must be present
in the codon.
10. In order for a ribosome to stop making a protein, a ‘stop’ codon is needed. What
disease may occur if there is a missing stop?
Putting It Together
CHNOPS Lab
Constructing a Model of Protein Synthesis
PRE-LAB DISCUSSION
Genes are the units that determine inherited characteristics, such as hair color and
blood type. Genes are lengths of DNA molecules that determine the structure of
polypeptides (the building blocks of proteins) that our cells make. The sequence of
nucleotides in DNA determines the sequence of amino acids in polypeptides, and thus the
structure of proteins.
In a process called transcription, which takes place in the nucleus of the cell,
messenger RNA (mRNA) reads and copies the DNA’s nucleotide sequences in the form
of a complementary RNA molecule. Then the mRNA carries this information in the form
of a code to the ribosomes, where protein synthesis takes place. The code, in DNA or
mRNA, specifies the order in which the amino acids are joined together to form a
polypeptide. The code words in mRNA, however, are not directly recognized by the
corresponding amino acids. Another type of RNA called transfer RNA (tRNA) is needed
to bring the mRNA and amino acids together. As the code carried by mRNA is “read” on
a ribosome, the proper tRNAs arrive in turn and give up the amino acids they carry to the
growing polypeptide chain. The process by which the information from DNA is
transferred into the language of proteins is known as translation.
In this investigation, you will simulate the mechanism of protein synthesis and
thereby determine the traits inherited by fictitious organisms called CHNOPS. CHNOPS,
whose cells contain only one chromosome, are members of the kingdom Animalia. A
CHNOPS chromosome is made up of eight genes (A, B, C, D, E, F, G and H), each of
which is responsible for a certain trait.
PROCEDURE
1. To determine the trait for Gene A of your CHNOPS, first you must transcribe the
DNA into mRNA.
2. Then, you must write the nucleotides of tRNA that are complementary to mRNA.
3. Use the chart in Figure 1 to find the corresponding amino acid sequence.
Remember to use the mRNA sequence and not the tRNA sequence in this chart!
4. Using figure 2, find the trait that matches the amino acid sequence. To save
space, you may abbreviate each amino acid. Record this information in the
appropriate place.
5. Repeat steps 1 through 4 for the remaining genes (B through F).
6. Create two additional traits for your CHNOPS and give their initial DNA
sequence, mRNA codon, tRNA anticodon, and the amino acid sequence. Start
with a trait listed in Figure 2 and work backwards to fill in the information for
Genes G and H.
7. Using all the inherited traits, sketch your CHNOPS in the space provided.
Figure 1
First
Base
U
C
A
G
U
Phenylalanine
Phenylalanine
Leucine
Leucine
Leucine
Leucine
Leucine
Leucine
Isoleucine
Isoleucine
Isoleucine
Methionine
(start)
Valine
Valine
Valine
Valine
Second Base
C
A
Serine
Tyrosine
Serine
Tyrosine
Serine
Stop
Serine
Stop
Proline
Histidine
Proline
Histidine
Proline
Glutamine
Proline
Glutamine
Threonine
Asparagine
Threonine
Asparagine
Threonine
Lysine
Threonine
Lysine
Alanine
Alanine
Alanine
Alanine
Aspartate
Aspartate
Glutamate
Glutamate
G
Cysteine
Cysteine
Stop
Tryptophan
Arginine
Arginine
Arginine
Arginine
Serine
Serine
Arginine
Arginine
Glycine
Glycine
Glycine
Glycine
Figure 2
Amino Acid Sequence
Tyrosine – Alanine – Tyrosine
Lysine – Leucine
Proline – Alanine – Alanine
Histidine – Arginine
Tryptophan – Proline – Isoleucine
Threonine – Serine – Serine
Tyrosine – Glutamate - Aspartate
Lysine – Arginine – Serine – Leucine
Valine – Isoleucine
Serine – Alanine
Trait
Hairless
Hairy
Plump
Skinny
Four-legged
Two-legged
Long nose
Short nose
No freckles
Freckles
Proline – Serine – Phenylalanine - Glycine
Proline – Serine – Glycine
Methionine – Tryptophan – Stop
Cysteine – Methionine – Alanine
Methionine – Phenylalanine – Valine
Valine – Glycine – Cysteine
Asparagine – Threonine – Methionine
Cysteine – Aspartate - Stop
Blue skin
Orange skin
Short legs
Long legs
Long tail
Short tail
Spots
Stripes
Third
Base
U
C
A
G
U
C
A
G
U
C
A
G
U
C
A
G
CHNOPS A
Gene A
DNA A C C G G T T
AT
mRNA
_____________________
tRNA
_____________________
Amino Acid
Sequence
___________________
Trait
______________________
Gene D
GGA CGC
Gene B
Gene C
DNA A G C C G A
mRNA
_____________________
tRNA
_____________________
Amino Acid
Sequence
___________________
Trait
______________________
DNA
TTT AAC
mRNA
_____________________
tRNA
_____________________
Amino Acid
Sequence
___________________
Trait
______________________
Gene E
GGG AGG AAA
DNA
C
GA
mRNA
_____________________
tRNA
_____________________
Amino Acid
Sequence
___________________
Trait
______________________
DNA
CCC
mRNA
_____________________
tRNA
_____________________
Amino Acid
Sequence
___________________
Trait
______________________
Gene G
Gene H
DNA
mRNA
_____________________
tRNA
_____________________
Amino Acid
Sequence
___________________
Trait
______________________
DNA
mRNA
_____________________
tRNA
_____________________
Amino Acid
Sequence
___________________
Trait
______________________
Gene F
ATG CTC
DNA
C
TA
mRNA
_____________________
tRNA
_____________________
Amino Acid
Sequence
___________________
Trait
______________________
** Draw your CHNOPS
on a blank sheet of
paper.
Use color.
Label each gene with its
letter.
CHNOPS B
Gene G
Gene H
DNA
DNA
mRNA _____________________
mRNA _____________________
tRNA _____________________
Amino Acid
Sequence ___________________
tRNA _____________________
Amino Acid
Sequence ___________________
Trait ______________________
Trait ______________________
CHNOPS C
Gene G
Gene H
DNA
DNA
mRNA _____________________
mRNA _____________________
tRNA _____________________
Amino Acid
Sequence ___________________
tRNA _____________________
Amino Acid
Sequence ___________________
Trait ______________________
Trait ______________________
CHNOPS D
Gene G
Gene H
DNA
DNA
mRNA _____________________
mRNA _____________________
tRNA _____________________
Amino Acid
Sequence ___________________
tRNA _____________________
Amino Acid
Sequence ___________________
Trait ______________________
Trait ______________________
______Score
CHNOPS DQ’s
Name_____________________ Date_______Blk__
ANALYZE AND CONCLUDE
1. Compare and contrast translation and transcription.
Transcription
Both
Translation
2. What is the specific site for transcription in the cell?
_____________________________
3. What is the specific site for translation in the cell?
_______________________________
4. How many tRNA nucleotides form an anticodon that will attach to the mRNA
codon? ____________
5. Suppose you knew the makeup of specific proteins in a cell. How could you
determine the particular DNA code that coded for them? (Think about it, you did
this in this lab.)
CHNOPS DQ’s. Cont.
6. How could one change in a DNA nucleotide alter the formation of the translated
protein? For example, if we changed or removed the nucleotide in bold from the
following DNA strand, how would that affect the formation of the protein?
Explain (step by step).
DNA :
TACTCAATTCACGCT
Random Acts of Mutations
Mutations Worksheet
(staff.fcps.net/einman/biology/MutationsWS.doc)
Deletion, Insertion & Substitution
There are several types of mutation:
 DELETION (a base is lost/deleted)
 INSERTION (an extra base is added/inserted)
--- Deletion & insertion may cause what’s called a FRAMESHIFT mutation,
meaning the reading “frame"
changes, thus changing the amino acid sequence
from this point forward
 SUBSTITUTION (one base is substituted for another)
--- If a substitution changes the amino acid, it’s called a MISSENSE
mutation
--- If a substitution does not change the amino acid, it’s called a SILENT
mutation
--- If a substitution changes the amino acid to a “stop,” it’s called a
NONSENSE mutation
Complete the boxes below. Classify each as Deletion, Insertion or Substitution
AND as either
frameshift, missense, silent or nonsense (Hint: Deletion & Insertion will always be
frameshift).
Original DNA Sequence:
T A C A C C T T G G C G A C G A C T…
mRNA Sequence:
Amino Acid Sequence:
Mutated DNA Sequence #1
T A C A T C T T G G C G A C G A C T…
What’s the mRNA sequence?
he chan
What will be the amino acid sequence?
Will there likely be effects?
What type of mutation is this? ________________________________
Mutated DNA Sequence #2
T A C G A C C T T G G C G A C G A C T…
What’s the mRNA sequence?
What will be the amino acid sequence?
Will there likely be effects?
What type of mutation is this? ________________________________
chan
Mutated DNA Sequence #3
T A C A C C T T A G C G A C G A C T…
What’s the mRNA sequence?
chan
What will be the amino acid sequence?
Will there likely be effects?
What type of mutation is this? ________________________________
Mutated DNA Sequence #4
T A C A C C T T G G C G A C T A C T…
What’s the mRNA sequence?
chan
What will be the amino acid sequence?
Will there likely be effects?
What type of mutation is this? _________________________________
Original DNA Sequence:
T A C A C C T T G G C G A C G A C T…
mRNA Sequence:
Amino Acid Sequence:
Mutated DNA Sequence #5
T A C A C C T T G G G A C G A C T…
What’s the mRNA sequence?
What will be the amino acid sequence?
Will there likely be effects?
What type of mutation is this? _________________________________
1. Which type of mutation is responsible for new variations of a trait?
2. Which type of mutation does not result in an abnormal amino acid sequence?
3. Which type of mutation stops the translation of an mRNA molecule?
chan
Sickle Cell Anemia
Sickle cell anemia is the result of a type of mutation in the gene that codes for
part of the hemoglobin molecule. Recall that hemoglobin carries oxygen in your red
bloods cells. The mutation causes these red blood cells to become stiff & sickleshaped when they release their oxygen. The sickled cells tend to get stuck in blood
vessels, causing pain and increased risk of stroke, blindness, damage to the heart &
lungs, and other conditions.
--- Analyze the DNA strands below to determine what amino acid is changed AND
what type of mutation occurred
Normal hemoglobin DNA
C A C G T A G A C T G A G G A C T C…
Normal hemoglobin mRNA
Normal hemoglobin AA sequence
---------------------------------------------------------------------------------------------Sickle cell hemoglobin DNA
C A C G T A G A C T G A G G A C A C…
Sickle cell hemoglobin mRNA
Sickle cell hemoglobin AA sequence
4. What type of mutation is this? Please explain why.
-----------------------------------------------------------------------------------------------------------------
DNA, RNA and Protein Synthesis Do Now Answers
________Score
Name____________________________
Day Rephrase the question in complete sentences. Use punctuation.
2
4
8
9
10
Unit V DNA/RNA/Protein Synthesis Guided Reading OL/LS 15-16
__________Score
Name______________________________
Read: 9.2 The Structure of DNA
1. Make a small portion of the model (Fig. 4) of the double helix shape below in the
space on the left.
Make the model 8 base pairs long.
Use four different colors for bases.
Use circles to represent the bases.
Make a key to identify the bases.
Make the bonds double or triple.
2. Name five scientists and their part in the DNA discovery.
1.
2.
3.
4.
5.
3. In the following base sequence fill in the missing base based on the base-pairing rule.
A-
T-
G-
C-
Read: 9.3 The Replication of DNA
5. Replication is the process of :
_______________________________________________________
for the purpose of (there are three):
_______________________________________________________
DNA/RNA/Protein Synthesis Guided Reading
Page 2
5. Identify two enzymes during Replication, and tell the function of each.
Enzyme
Function
Enzyme
Function
6. Use the model below to color the bases according to your previous key.
In two sentences, tell what happens at the replication fork.
Define and use the word ‘nucleotide’ in your sentence.
____________________________________________________________________
____________________________________________________________________
DNA/RNA/Protein Synthesis Guided Reading
Page 3
Read: 10.1 From Genes to Proteins: Transcription
7. What are four differences between DNA and RNA? (Hint: bases, # of strands, sugar,
location.)
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
8. mRNA’s function is to
____________________________________________________(why is it
called ‘messenger’?) of making ________________________ (what macromolecule)
to the ___________________ (what organelle?) in the______________________
(location).
9. The cell needs to make proteins. The first thing that has to happen is that the DNA
in the ________________________(location) unzips a section that codes for the protein
to be made. _____________(how many) strand(s), called the ‘sense’ strand, is used as a
_______________________________(meaning the ‘pattern’) to make a copy strand.
The new strand is going to take the message of making proteins to the ribosomes in the
_______________________________and so is called ___________________________.
The Genetic Code: Three-Nucleotide ‘Words’
10. The code for proteins is really a group of ____________(how many) bases that code
for one ________________
_____________. These molecules come from the food that
you eat. Look at Fig 4. Notice that the ending of most of these molecules is___________
which is a feature they have in common, much like enzymes generally end in ‘ase’.
In order to read the chart in Fig 4, think of Battleship, or Bingo. Notice the heading
At the top on the left says, ‘First Base’. So if your sequence of bases is ‘ACG’, the first
base is ‘A’. So I look down the column U, C, A, G and locate ‘A’, the third base down.
Keep your finger there. Look across the top in the middle where it says ‘Second Base’.
My second base is ‘C’. So I look across the row and find the C, just left of middle, and
follow it down to my ‘A’ base row. The third base is ‘G’. Look across the top to the right
and see the column going down that says, ‘third base’. Locate the
DNA/RNA/Protein Synthesis Guided Reading
Page 4
base ‘G’ in the third row grouping down the page that corresponds to where my finger
was keeping my place for the first base, ‘A’. What is the amino acid that is
coded for by the base sequence ACG?
______________________________________
Look for the AUG codon. What surprise ‘amino acid’ does it code for? ______________
Logically, if there’s a start signal, there’s probably a stop signal. What are the three
‘STOP’ codons? _____________
______________
_______________
11. What do you think might happen if the ‘start’ code had a mutation?
________________________________________________________________________
12. What do you think might happen if the ‘stop’ code had a mutation?
________________________________________________________________________
Translation
13. In translation, the amino acids that are coded for in the mRNA codons, are located in
the cytoplasm (and come from the breakdown of the food that you eat). In order for the
correct amino acids to be transferred to the ribosomes/mRNA
complex, another single stranded RNA is used: _______________, which transfers to
amino acid the ribosome. tRNA drops the amino acid in place behind the previous amino
acid, then continues back to the cytoplasm for more of that particular amino acid. When
the new amino acid arrives in the correct place, a peptide bond is formed.
14. When the long string of amino acids are released from the ribosome, it is called
a chain, because that’s what it looks like. It then folds, then twists, the twists again to
form a very complex shape. It’s the complex shape that gives the protein its function.
What is the ultimate source of the protein’s complex shape?
___________________________
15. How can only four bases, in a sequence of three’s, code for such diversity?
________________________________________________________________________
DNA/RNA/Protein Synthesis Guided Reading
Page 5
Read: Mutations, p. 219-20
16. What are the five mutations and their effects?
Mutation
Effect
Watch These Videos, Answer the Questions:
17. https://www.youtube.com/watch?v=_POdWsii7AI
Why don’t the stomach genes for digestive enzymes make digestive
enzymes if they are found in your skin cells?
What is this system of gene control called?
________________________________________________________________________
________________________________________________________________________
18. https://www.youtube.com/watch?v=dKubyIRiN84
What is the problem with the 3’ to 5’ strand in replication?
________________________________________________________________________
________________________________________________________________________