Point mutations occur when a single nucleotide in the DNA sequence is changed. This can lead to different types of mutations at the protein level including nonsense, missense, and silent mutations. Nonsense mutations result in a premature stop codon. Missense mutations result in a different amino acid being incorporated. Silent mutations do not change the amino acid. While most mutations are harmful, some can be beneficial by allowing organisms to adapt to environmental changes and increase chances of survival.

1. Point Mutation Christopher Tristan G. Sunga
Master Teacher I
Gregorio Perfecto High School

2. Prayer
Let us remember that we are in the
holy presence of God.
In the name of the Father, and of the
Son, and of the Holy Spirit. Amen.
I will continue, O my God, to do all my
actions for the love of You!
St. John Baptist de La Salle, pray for us
Live Jesus in our Hearts, Forever.dd text

3. Attendance

4. Content Standards
The Learners demonstrate understanding of mutations
that occur in sex cells as being heritable.

5. Learning Competencies
• The learners should be able to: 6. explain how mutations may cause
changes in the structure and function of a protein (S10LT-IIIe38);

6. This Photo by Unknown author is licensed under CC BY-NC-ND.
Eliciting
Prior
Knowledge
Guess the AA!
Determine the amino acid using the
mRNA codon Chart and tRNA based
on the given mRNA codon

7. AUC
Amino Acid
tRNA
UAG Isoleucine

8. CCC
Amino Acid
tRNA
GGG Proline

9. GGC
Amino Acid
tRNA
CCG Glycine

10. GAG
Amino Acid
tRNA
CUC Glutamic
Acid

11. AUC
Amino Acid
tRNA
UAC Isoleucine
What will happen if the second and third bases of the codon AUC will be
changed to A?
What will be the resulting amino acid?
AAA
Lysine

12. Essential Question:
What will happen if something is
changed in the codon sequence?

13. Explore: Group Activity:
Work on the table below using Google Slides. Use the instructions
provided.
No Mutation Point Mutation
A B C
D E
DNA level TTC (4) (8) (12) (16)
mRNA (1) (5) (9) (13) (17)
tRNA (2) (6) (10) (14) (18)
Protein level (3) (7) (11) (15) (19)

14. Instructions
Fill in the missing data on the table provided in the next slides. Use the clues
provided for each number. Edit the table in order to write your answers.
1) Determine mRNA of TTC
(2) Determine tRNA of TTC
(3) Determine amino acid at protein level of TTC
(4) Change the third base of TTC to T
(5) Determine mRNA of (4)
(6) Determine tRNA of (4)
(7) Determine amino acid at protein level of (4)

15. Instructions:
(8) Change the first base of TTC to A
(9) Determine mRNA of (8)
(10) Determine tRNA of (8)
(11) Determine amino acid at protein level of (8)
(12) Change the second base of TTC to C
(13) Determine mRNA of (12)
(14) Determine tRNA of (12)
(15) Determine amino acid at protein level of (12)

16. Instructions:
(16) Change the second base of TTC to G
(17) Determine mRNA of (16)
(18) Determine tRNA of (16)
(19) Determine amino acid at protein level of (16)

17. Guide Questions:
1. What happened to the protein in (7) when the third base of TTC was
changed to T? Is this amino acid in the protein level the same or
different with (3)?
2. What happened to the protein in (11) when the first base of TTC was
changed to A? Is this amino acid in the protein level the same or
different with (3)? If it is different, what is the resulting amino acid in
(11)?

18. Guide Questions:
3. What happened to the protein in (15) when the first base of TTC was
changed to A? Is this amino acid in the protein level the same or
different with (3)? If it is different, what is the resulting amino acid in
(15)?
4. What happened to the protein in (19) when the first base of TTC was
changed to A? Is this amino acid in the protein level the same or
different with (3)? If it is different, what is the resulting amino acid in
(19)?

19. Presentation Rubrics
CRITERIA Content Presentation Teamwork Time Management
4
All the questions in the
worksheet are answered
correctly with further explanation
stated in a clear and organized
manner.
Information is
presented in a
well-organized
way.
All members
performed their
assigned tasks
cooperatively.
Presentation and task
finished ahead of
time.
3
All the questions in the
worksheet are answered in a
simple manner.
Information is
presented in an
organized way.
Most members
performed their
assigned tasks
cooperatively.
Presentation and task
finished on time.
2
The students failed to answer 1
question correctly and the rest of
the answers to questions lack
coherence.
Information is
presented with
minimal
organization.
The group was
able to come up
with poor quality
output due to
uncooperative
members.
Finished the
presentation and task
but exceeded with
few time.
1
The students failed to answer all
the questions correctly.
Information is
presented with
organization.
Only the leader
performed the
assigned tasks.
Did not finish the
presentation and task
on the given time.

20. Google Slide Link
• https://docs.google.com/presentation/d/1Io0BB0L2yYvtz2Qggv476v
HrrjZHLtc1TtGdwf2pzvw/edit?usp=sharing

21. Presentation
of Outputs

22. Answer key
No Mutation Point Mutations
A B C
D E
DNA
level
TTC TTT ATC TCC TGC
mRNA AAG AAA UAG AGG ACG
tRNA UUC UUU AUC UCC UGC
Protein
level
Lysine Lysine STOP Arginine Threonine

23. Mutation
changes to a DNA sequence.

24. Mutagens
• are agents that cause alteration in the
DNA and can lead to permanent
mutations in the DNA sequence
depending on the ability of an organism
to repair the damage.
• Examples of mutagens are radioactive
substances, x-rays, ultraviolet radiation,
and certain chemicals or drugs.

25. Point Mutation
• It is the type mutation in
DNA or RNA wherein
one single nucleotide
base is deleted, added
or altered. This can lead
to substitution
mutation.
• There are three types of
substitution mutation.
• These are nonsense,
missense and silent
mutation.

26. Answer key
No Mutation Point Mutations
A B C
D E
DNA
level
TTC TTT ATC TCC TGC
mRNA AAG AAA UAG AGG ACG
tRNA UUC UUU AUC UCC UGC
Protein
level
Lysine Lysine STOP Arginine Threonine
NON-SENSE

27. Nonsense Mutation
• results in the formation of a stop codon due to the substitution
of one nitrogenous base.
• Remember, stop codons are special nitrogenous bases that stop
the translation stage in protein synthesis. These are ATC, ATT, or
ACT in DNA, and UAG, UAA, or UGA in mRNA.
• They are usually located at the end of messenger RNA
nucleotide base sequence.
• However, when a substitution mutation causes it to appear in
another place, it will suddenly stop the translation process to
amino acid and will fail to produce the correct protein.

28. Nonsense Mutation

29. Answer key
No Mutation Point Mutations
A Non-Sense C
D E
DNA
level
TTC TTT ATC TCC TGC
mRNA AAG AAA UAG AGG ACG
tRNA UUC UUU AUC UCC UGC
Protein
level
Lysine Lysine STOP Arginine Threonine
MISSENSE

30. Missense Mutation
• When one nitrogenous base of the DNA is replaced and
the result is an altered codon but does not form a stop
codon
• This will create a different amino acid in protein
synthesis.
Example:
DNA: CAT to mRNA : GUA to tRNA CAU (Valine)
If CAT is changed into:
CCT to mRNA: GGA to tRNA: CCU (Glycine)

31. Missense Mutation

32. Missense
Mutation
•Conservative mutation: When
the new amino acid formed has
the same properties of the one
that was supposed to be
produced.
•Non-conservative: When the
new amino acid formed has
different properties of the one
that was supposed to be
produced.

33. Answer key
No Mutation Point Mutations
A Non-Sense Missense
Conservative Non-
Conservative
DNA
level
TTC TTT ATC TCC TGC
mRNA AAG AAA UAG AGG ACG
tRNA UUC UUU AUC UCC UGC
Protein
level
Lysine Lysine STOP Arginine Threonine

34. Answer key
No Mutation Point Mutations
A Non-Sense Missense
Conservative Non-
Conservative
DNA
level
TTC TTT ATC TCC TGC
mRNA AAG AAA UAG AGG ACG
tRNA UUC UUU AUC UCC UGC
Protein
level
Lysine Lysine STOP Arginine Threonine
SILENT

35. Silent Mutation
• happens when a nitrogenous base is altered but the
same amino acid is produced.
• Remember, many codons can code for the same amino
acid.
Example:
GGC and GGU can both code for glycine.
If C is changed to an U, the same amino acid will be
produced and therefore, the amino acid will not be
changed.

36. Silent
Mutation

37. Application: Mutations in
our Body
Sickle-Cell Anemia
• group of inherited red blood cell
disorders.
• In someone who has SCD, the red
blood cells become hard and sticky
and look like a C-shaped farm tool
called a “sickle”.
• The sickle cells die early, which
causes a constant shortage of red
blood cells.
• Also, when they travel through small
blood vessels, they get stuck and clog
the blood flow.
• This can cause pain and other serious
problems such infection, acute chest
syndrome and stroke.

38. Application: Mutations in our Body
Cancer
• When a tumor
suppressor gene
mutates, cells grow
uncontrollably. And
they may eventually
form a tumor.

39. Application: Mutations
in our Body
Cystic Fibrosis
• Cystic fibrosis is caused
by mutations in the gene
that produces the cystic
fibrosis transmembrane
conductance regulator
(CFTR) protein.

40. History Integration: Hiroshima
Bombing 1945
• The two atomic bombs dropped on Japan in 1945
killed and maimed hundreds of thousands of
people, and their effects are still being felt today.
• In the years that followed, many of the survivors
would face leukemia, cancer, or other terrible
side effects from the radiation.
• Five to six years after the bombings, the
incidence of leukemia increased noticeably
among survivors. After about a decade, survivors
began suffering from thyroid, breast, lung, and
other cancers at higher than normal rates.
• Reference: https://www.icanw.org/hiroshima_and_nagasaki_bombing
s

41. Health
Integration:
COVID-19 variants
• Viruses like SARS-CoV-2
continuously evolve
as changes in the genetic
code (genetic mutations)
occur during replication
of the genome.
• Reference: https://www.c
dc.gov/coronavirus/2019-
ncov/variants/variant-
classifications.html

42. Computer Integration: Malware Mutation

43. Essential Question:
What will happen if something is changed in the codon sequence?

44. Can MUTATIONS be beneficial?
They lead to new versions of proteins that help organisms adapt to changes in their
environment.
It is essential for evolution to occur. They increase an organism’s changes of surviving or
reproducing, so they are likely to become more common over time.
Mutations in many bacteria that allow them to survive in the presence of antibiotic drugs. The
mutations lead to antibiotic-resistant strains of bacteria.
A unique mutation is found in people in a small town in Italy. The mutation protects them from
developing atherosclerosis, which is the dangerous buildup of fatty materials in blood vessels.
The individual in which the mutation first appeared has even been identified.

45. Let's Assess!
QUIZIZ

46. Thank you!