DNA MUTATION

1. Living Things and
Their Environment
Grade 10
UNIT III:

2. 𝐁𝐄𝐋𝐋-𝐑𝐈𝐍𝐆𝐄𝐑 𝐀𝐂𝐓𝐈𝐕𝐈𝐓𝐘
Read the sentence below as an analogy representing the
strand of DNA.
𝐓𝐇𝐄 𝐂𝐀𝐓 𝐀𝐓𝐄 𝐓𝐇𝐄 𝐑𝐀𝐓

3. 𝐁𝐄𝐋𝐋-𝐑𝐈𝐍𝐆𝐄𝐑 𝐀𝐂𝐓𝐈𝐕𝐈𝐓𝐘
a. THE HAT ATE THE RAT.
b. THE CCA TAT ETH ERA T.
c. THC ATA TET HER AT.
Identify the changes and describe how these changes
affect the meaning/thought of the sentence.

4. Grade 10
𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍 :
𝑪𝒉𝒂𝒏𝒈𝒆𝒔 𝒊𝒏 𝒕𝒉𝒆 𝑮𝒆𝒏𝒆𝒕𝒊𝒄 𝑪𝒐𝒅𝒆

5. Mutations are changes in genetic material
– changes in DNA Code – thus change in gene(s).
𝐖𝐡𝐚𝐭 𝐢𝐬 𝐚 𝐆𝐞𝐧𝐞 𝐌𝐮𝐭𝐚𝐭𝐢𝐨𝐧?

6. In gene mutations, the DNA code will have
a base (or more) missing, added, or exchanged
in a codon.
𝐖𝐡𝐚𝐭 𝐢𝐬 𝐚 𝐆𝐞𝐧𝐞 𝐌𝐮𝐭𝐚𝐭𝐢𝐨𝐧?

7. 𝑯𝒐𝒘 𝒄𝒐𝒎𝒎𝒐𝒏 𝒂𝒓𝒆 𝒎𝒖𝒕𝒂𝒕𝒊𝒐𝒏𝒔?
Mutations are relatively common occurrences in
the genetic material of organisms.
This can happen
spontaneously during DNA
replication or as a result of
exposure to mutagenic agents
such as radiation or certain
chemicals.

8. Mutations are not always seen. The affected gene
will still function.
 Mutations may be harmful.
 Mutations may be beneficial.
 Mutations may have no effect on
the organism.
𝑯𝒐𝒘 𝒄𝒐𝒎𝒎𝒐𝒏 𝒂𝒓𝒆 𝒎𝒖𝒕𝒂𝒕𝒊𝒐𝒏𝒔?

9. 𝑯𝒐𝒘 𝒎𝒖𝒕𝒂𝒕𝒊𝒐𝒏𝒔 𝒂𝒓𝒆 𝒊𝒏𝒉𝒆𝒓𝒊𝒕𝒆𝒅?
 Only mutations in gametes
(egg and sperm) are passed
onto offspring.
 Mutations in body cells only
affect the organism in which
they occur and are not
passed into offspring.

10. Types of Gene Mutations
 Point Mutation occurs when the base sequence of a
codon is changed.
ex. GCA is changed into GAA
 There are three types:
 Substitution
 Deletion
 Insertion
are also called frameshift mutations

11. 𝐒𝐔𝐁𝐒𝐓𝐈𝐓𝐔𝐓𝐈𝐎𝐍 𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍
Normal DNA strand: GAT – TTA - CCT
GAT – TCA - CCT
Mutated DNA strand:
THE CAT ATE THE RAT.
THE HAT ATE THE RAT.
𝑾𝒉𝒂𝒕 𝒉𝒂𝒑𝒑𝒆𝒏𝒆𝒅 𝒕𝒐 𝒕𝒉𝒆 𝑫𝑵𝑨?

12. 𝐒𝐔𝐁𝐒𝐓𝐈𝐓𝐔𝐓𝐈𝐎𝐍 𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍
 In this type of mutation, one nucleotide base is
replaced by another. For example, a thymine (T)
may be substituted with a cytosine (C) in the DNA
sequence.
Normal DNA strand: GAT – TTA - CCT
GAT – TCA - CCT
Mutated DNA strand:

13. 𝐓𝐘𝐏𝐄𝐒 𝐒𝐔𝐁𝐒𝐓𝐈𝐓𝐔𝐓𝐈𝐎𝐍 𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍
 SILENT MUTATION is
when a single base
pair gets swapped out
on the DNA, but the
mutated RNA
sequence produces
the same amino acid.

14. 𝐓𝐘𝐏𝐄𝐒 𝐒𝐔𝐁𝐒𝐓𝐈𝐓𝐔𝐓𝐈𝐎𝐍 𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍
 MISSENSE is when a
nucleotide gets
changed, resulting in a
different amino acid in
the protein. This is the
type of mutation that
causes sickle cell
anemia.

15. 𝐓𝐘𝐏𝐄𝐒 𝐒𝐔𝐁𝐒𝐓𝐈𝐓𝐔𝐓𝐈𝐎𝐍 𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍
 NONSENSE is the worst type of substitution
mutation. This type of mutation occurs when a base
change causes an early stop codon.

17. 𝐈𝐍𝐒𝐄𝐑𝐓𝐈𝐎𝐍 𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍
Mutated DNA strand: GAT – TTA - GGG - CCT
Normal DNA strand: GAT – TTA - CCT
THE CAT ATE THE RAT.
THE CCA TAT ETH ERA T.
𝑾𝒉𝒂𝒕 𝒉𝒂𝒑𝒑𝒆𝒏𝒆𝒅 𝒕𝒐 𝒕𝒉𝒆 𝑫𝑵𝑨?

18. 𝐈𝐍𝐒𝐄𝐑𝐓𝐈𝐎𝐍 𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍
 An insertion mutation occurs when an extra
nucleotide base is added to the DNA sequence.
This can lead to a shift in the reading frame and
alter the subsequent amino acid sequence.
Mutated DNA strand: GAT – TTA - GGG - CCT
Normal DNA strand: GAT – TTA - CCT

19. 𝐃𝐄𝐋𝐄𝐓𝐈𝐎𝐍 𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍
Mutated DNA strand: GA – TTA - CCT
Normal DNA strand: GAT – TTA - CCT
THE CAT ATE THE RAT.
THC ATA TET HER AT.
𝑾𝒉𝒂𝒕 𝒉𝒂𝒑𝒑𝒆𝒏𝒆𝒅 𝒕𝒐 𝒕𝒉𝒆 𝑫𝑵𝑨?

20. 𝐃𝐄𝐋𝐄𝐓𝐈𝐎𝐍 𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍
 A deletion mutation involves the removal of one or
more nucleotide bases from the DNA sequence.
Like insertion mutations, deletions can also cause a
shift in the reading frame and result in a different
protein product.
Mutated DNA strand: GA – TTA - CCT
Normal DNA strand: GAT – TTA - CCT

21. 𝐈𝐧𝐝𝐢𝐯𝐢𝐝𝐮𝐚𝐥 𝐀𝐜𝐭𝐢𝐯𝐢𝐭𝐲
Directions: Read the following scenarios and identify the
type of point mutation that is occurring in each case.
A DNA sequence originally reads:
ATG CTA GGC TAC GCA
After a mutation, the DNA sequence becomes: ATG
CTA GAC TAC GCA SUBSTITUTION

22. 𝐈𝐧𝐝𝐢𝐯𝐢𝐝𝐮𝐚𝐥 𝐀𝐜𝐭𝐢𝐯𝐢𝐭𝐲
Directions: Read the following scenarios and identify the
type of point mutation that is occurring in each case.
A DNA sequence originally reads:
TAC GAT CGA TCG
After a mutation, the DNA sequence becomes: TAC
GAT CGA TCG T INSERTION

23. 𝐈𝐧𝐝𝐢𝐯𝐢𝐝𝐮𝐚𝐥 𝐀𝐜𝐭𝐢𝐯𝐢𝐭𝐲
Directions: Read the following scenarios and identify the
type of point mutation that is occurring in each case.
A DNA sequence originally reads:
GCA TGA CGT TAC
After a mutation, the DNA sequence becomes: GCA
TGA CGT TGC SUBSTITUTION

24. 𝐈𝐧𝐝𝐢𝐯𝐢𝐝𝐮𝐚𝐥 𝐀𝐜𝐭𝐢𝐯𝐢𝐭𝐲
Directions: Read the following scenarios and identify the
type of point mutation that is occurring in each case.
A DNA sequence originally reads:
AGT CTA GGC TAC GCA
After a mutation, the DNA sequence becomes: AGT
CTA GGC TAC GA DELETION

25. 𝐐𝐔𝐈𝐙
Directions: Read the following items and
choose the letter of the correct answer.

26. 1. Which of the following is true about DNA mutation?
a. DNA mutation is a process of DNA replication.
b. DNA mutation is a process of DNA repair.
c. DNA mutation is a process of DNA recombination.
d. DNA mutation is a process of genetic alteration in
which there is a change in the nucleotide sequence of
DNA.

27. 2. Which type of point mutation involves the
substitution of one nucleotide base with another?
a. Insertion c. deletion
b. Substitution d. duplication
3. What is the term for mutations that do not result in
a change in the amino acid sequence?
a. Silent mutation c. Nonsense mutation
b. Missense mutation d. Frameshift mutation

28. 4. A DNA sequence originally reads: ATG CTA GGC TAC
GCA. After a mutation, the DNA sequence becomes: ATG
CTA GAC TAC GCA. What type of point mutation
occurred?
a. Insertion c. deletion
b. Substitution d. duplication

29. 5. What is the consequence of a frameshift mutation?
a. No change in the amino acid sequence
b. Substitution of one amino acid for another
c. Creation of a premature stop codon
d. Alteration of the reading frame and amino acid
sequence

30. DNA
Mutation
Alterations or Changes in the genetic material
Point Mutation Frameshift Mutation
Substitution Insertion Deletion
Silent Mutation Nonsense Mutation
Missense Mutation
Occurs when the base sequence
of a codon is changed.
Occurs when an extra nucleotide
base is added to DNA sequence.
Involves removal of one or more
nucleotide bases from DNA
sequence.

32. Original DNA Sequence: TAC - ACC - TTG - GCG - ACG - ACT
mRNA Sequence: AUG - UGG - AAC - CGC - UGC - UGA
Amino Acid Sequence: MET - TRP - ASN - ARG - CYS - (STOP)
Mutated DNA Sequence #1: TAC - ATC - TTG - GCG - ACG - ACT
What’s the mRNA sequence? ______________________________
What will be the amino acid sequence? ________________________
Will there likely be effects? ___________
What kind of mutation is this? _____________________________
AUG - UAG - AAC - CGC - UGC - UGA
Methionine - Stop
YES
Substitution - Nonsense Mutation

33. Original DNA Sequence: TAC - ACC - TTG - GCG - ACG - ACT
mRNA Sequence: AUG - UGG - AAC - CGC - UGC - UGA
Amino Acid Sequence: MET - TRP - ASN - ARG - CYS - (STOP)
Mutated DNA Sequence #2: TAC - GAC - CTT - GGC - GAC - GAC T
What’s the mRNA sequence? ______________________________
What will be the amino acid sequence? ________________________
Will there likely be effects? ___________
What kind of mutation is this? _____________________________
AUG - CUG - GAA - CCG - CUG - CUG - A
METHIONINE - LEUCINE -GLUTAMIC ACID – PROLINE
YES
INSERTION - FRAME SHIFT

34. Original DNA Sequence: TAC - ACC - TTG - GCG - ACG - ACT
mRNA Sequence: AUG - UGG - AAC - CGC - UGC - UGA
Amino Acid Sequence: MET - TRP - ASN - ARG - CYS - (STOP)
Mutated DNA Sequence #3: TAC - ACC - TTA - GCG - ACG - ACT
What’s the mRNA sequence? ______________________________
What will be the amino acid sequence? ________________________
Will there likely be effects? ___________
What kind of mutation is this? _____________________________
AUG - UGG - AAU - CGC - UGC - UGA
METHIONINE-TRYPTOPHAN-ASPARAGINE-
ARGININE - CYS - (STOP)
No
Substitution - Silent Mutation

35. Original DNA Sequence: TAC - ACC - TTG - GCG - ACG - ACT
mRNA Sequence: AUG - UGG - AAC - CGC - UGC - UGA
Amino Acid Sequence: MET - TRP - ASN - ARG - CYS - (STOP)
Mutated DNA Sequence #4: TAC - ACC - TTG - GGA - CGA - CT
What’s the mRNA sequence? ______________________________
What will be the amino acid sequence? ________________________
Will there likely be effects? ___________
What kind of mutation is this? _____________________________
AUG - UGG - AAC - CCU - GCU - GA
METHIONINE-TRYPTOPHAN-ASPARAGINE- PROLINE
- ALANINE
Yes
DELETION – FRAME SHIFT

36. Grade 10
𝐌𝐔𝐓𝐀𝐓𝐈𝐎𝐍 :
𝑨𝒃𝒏𝒐𝒓𝒎𝒂𝒍𝒊𝒕𝒊𝒆𝒔 𝒊𝒏
𝑪𝒉𝒓𝒐𝒎𝒐𝒔𝒐𝒎𝒂𝒍 𝑺𝒕𝒓𝒖𝒄𝒕𝒖𝒓𝒆

38. Chromosomal Mutation
 Chromosomal mutations involve changes
in the number or structure of
chromosomes.

39. 𝐖𝐡𝐚𝐭 𝐢𝐬 𝐚 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞?
 A syndrome is a set of medical signs and symptoms
which are correlated with each other and often
associated with
a particular disease or disorder.

40. 𝐊𝐚𝐫𝐲𝐨𝐭𝐲𝐩𝐢𝐧𝐠
 Karyotyping is a test to examine chromosomes in a
sample of cells. This test can help identify genetic
problems as the cause of a disorder or disease.

41. 𝐂𝐫𝐢-𝐝𝐮-𝐜𝐡𝐚𝐭 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞
𝐃𝐨𝐰𝐧 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞
𝐄𝐝𝐰𝐚𝐫𝐝𝐬 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞

42. 𝐂𝐫𝐢-𝐝𝐮-𝐜𝐡𝐚𝐭 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞
 “Cri du chat” is caused by the
deletion of part of the short arm
of chromosome 5. “Cri du chat”
is French, and the condition is so
named because affected babies
make high-pitched cries that
sound like a cat.

44.  Down’s syndrome is usually
caused by an extra copy of
chromosome 21(trisomy 21).
 Characteristics include decreased
muscle tone, stockier build,
asymmetrical skull, slanting eyes
and mild to moderate mental
retardation.
𝐃𝐨𝐰𝐧 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞

46. 𝐄𝐝𝐰𝐚𝐫𝐝𝐬 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞
 Edwards syndrome, which is
the second most common
trisomy after Down’s syndrome,
is a trisomy of chromosome
18.
 Symptoms include mental and
motor retardation and
numerous congenital
anomalies causing serious
health problems.

49. 𝐊𝐥𝐢𝐧𝐞𝐟𝐞𝐥𝐭𝐞𝐫 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞
Klinefelter syndrome results from a chromosomal abnormality where males
have an extra X chromosome, resulting in a composition of XXY instead of
XY. This extra X chromosome leads to various physical and hormonal
differences characteristic of the syndrome.

50. 𝐓𝐮𝐫𝐧𝐞𝐫 𝐒𝐲𝐧𝐝𝐫𝐨𝐦𝐞
Turner Syndrome is a genetic disorder that affects females. It occurs when
one of the X chromosomes is partially or completely missing. This
condition can lead to a variety of physical and developmental
abnormalities.

51. 𝐐𝐮𝐢𝐳: 𝐆𝐞𝐧𝐞𝐭𝐢𝐜 𝐃𝐢𝐬𝐨𝐫𝐝𝐞𝐫𝐬
𝐓𝐞𝐬𝐭 𝐲𝐨𝐮𝐫 𝐤𝐧𝐨𝐰𝐥𝐞𝐝𝐠𝐞 𝐚𝐛𝐨𝐮𝐭 𝐠𝐞𝐧𝐞𝐭𝐢𝐜 𝐝𝐢𝐬𝐨𝐫𝐝𝐞𝐫𝐬
𝐰𝐢𝐭𝐡 𝐭𝐡𝐢𝐬 𝐪𝐮𝐢𝐳. 𝐂𝐡𝐨𝐨𝐬𝐞 𝐭𝐡𝐞 𝐜𝐨𝐫𝐫𝐞𝐜𝐭 𝐚𝐧𝐬𝐰𝐞𝐫 𝐟𝐨𝐫 𝐞
𝐚𝐜𝐡 𝐪𝐮𝐞𝐬𝐭𝐢𝐨𝐧. 𝐆𝐨𝐨𝐝 𝐥𝐮𝐜𝐤!

52. 1. Which genetic disorder is also known as Down
Syndrome?
a. Trisomy 21 c. Cat’s Cry Syndrome
b. Trisomy 18 d. Edwards Syndrome
2. Which genetic disorder is characterized by an extra
copy of chromosome 18?
a. Trisomy 21 c. Cat’s Cry Syndrome
b. Trisomy 18 d. Cri du chat syndrome

53. 3. Which genetic disorder is also known as Cat's Cry
Syndrome?
a. Edwards Syndrome c. Trisomy 21
b. Cri-du-chat syndrome d. Trisomy 18
4. Which genetic disorder is characterized by an extra
copy of the X chromosome in males?
a. Klinefelter Syndrome c. Trisomy 21
b. Turner Syndrome d. Trisomy 18

54. 5. Which genetic disorder is characterized by the
absence of one X chromosome in females?
a. Klinefelter Syndrome c. Trisomy 21
b. Turner Syndrome d. Trisomy 18

55. 𝐈𝐧𝐝𝐢𝐯𝐢𝐝𝐮𝐚𝐥 𝐀𝐜𝐭𝐢𝐯𝐢𝐭𝐲
Instructions:
Read each scenario and identify the type of mutation that
occurs.

56. 1. A DNA sequence originally reads:
ATG-CGA-CGC-TAC
After a mutation, the DNA sequence reads:
ATG-CTA-CGC-TAC
2. A DNA sequence originally reads:
TAC-GAT-AGC-CGC
After a mutation, the DNA sequence reads:
TAC-GAC-AGC-CGC
3. A DNA sequence originally reads:
CCG-TAA-GCG-ATT
After a mutation, the DNA sequence reads:
CCG-TAA-CGA-TT

57. 4. A DNA sequence originally reads:
AGC-TGA-ATG-CGT
After a mutation, the DNA sequence reads:
AGC-TGA-AAT-GCG-T
5. A DNA sequence originally reads:
AAT-GCG-TCC-GAC
After a mutation, the DNA sequence reads:
AAT-CGC-GTC-CGA-C