Order of bases
in DNA Order of bases in
mRNA (codon) Order of bases in
tRNA (anticodon) Amino Acid Coded into Proteins
TAG AUC
CAT
GUC CCA
Methionine Valine ACU
ACA UGU
AAA
GAA CUU
Genetic code Table
Q22. Why is the specific base pairing essential to the processes of
transcription and translation. ________________________________
Q23. How many codon/s codes for one amino acid?
_______________________________________________________
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Activity 6
Chromie Change
In this activity the learners will illustrate and differentiate the kinds of chromosomal mutations.
Teaching Tips:
• Introduce the lesson using guided inquiry to activate learners’ prior knowledge.
• Establish the motivation for mutation lesson.
1. How do errors in base pairing of the DNA change the DNA sequence? (Different protein that is usually non-functional or with altered function will be made).
2. What do you call these changes? (Mutation)
3. What might cause a mutation to occur? (Mutations may be caused by mutagens in the form of radiation, chemicals, extremes of temperature, and even viral infection).
• Determine the number of groups in your class for the activity. Ideally, about ten (10) learners or less per group.
• Explain the procedure of the activity. Make sure that the learners will be able to follow the steps and come up with the expected output.
• Check on the groups from time to time, see to it that the learners are able to do it correctly.
• Remind them to answer the guide questions.
• Lead learners to the answers of guide questions.
• Guide the students in filling out the table below. Refer to the possible answers in the table.
Broke a part Broke a part, reversed and reinserted it into
thechromosome
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3. Which condition/s do you think either loss or gain of genetic material.
Q24. Translocation occurs when a piece of chromosome breaks off and attaches to another chromosome. An inversion involves the breakage of a chromosome in two places in which the resulting piece of DNA is reversed and re-inserted into the chromosome. Deletion refers to the loss of a segment of DNA or chromosome.
Changes that affect the structure of chromosomes can cause problems with growth, development, and function of the body’s systems.
These changes can affect many genes along the chromosome and disrupt the proteins made from these genes.
Q25. The normal genetic content of the chromosome may be affected. Many diseases are caused by the effects of inherited genes. In most cases, there is only a small difference between the DNA sequence in the defective gene and a normal one. This difference is enough to cause serious and often fatal diseases.
Q26. Gain or loss of chromosome material results in chromosomal mutations or aberrations; may also result to Down’s syndrome, Klinefelter’s Syndrome, or Turner’s Syndrome. However, Cri-du-chat Syndrome is due to loss of chromosome.
Q27. The possible effects of chromosomal mutations are medical problems, problems on growth and development, genetic disorders, and even death.
• Assess the learners’ understanding by showing a drawing of the four kinds of chromosomal mutations. Let learners analyze and identify the type of chromosomal mutation.
• Show a normal male and female karyotype and some examples of karyotypes of chromosomal abnormalities, e.g. Down’s Syndrome, Cri-du-chat, Klinefelter’s syndrome and Turner’s syndrome. Let learners compare the normal karyotype with the karyotype of affected individuals. Let them identify which set of homologous chromosomes are affected.
• Conclude the lesson by asking learners if their knowledge of molecular genetics may affect their lives. Ask for some volunteers and listen to their thoughts and ideas.
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• Point out to the learners that in agriculture, traits of plants and animals could be modified by targeted or random mutations and that not all mutations are harmful.
• Mention to the learners the concept about genetic engineering. In recombinant DNA technology, scientists have developed methods to move genes from one species into another. This process uses restriction enzymes to cleave one organism’s DNA into fragments and other enzymes to splice the DNA fragment into a plasmid or viral DNA. Transgenic organisms are able to manufacture genetic products alien to themselves using recombinant DNA. Genetic engineering has already been applied to bacteria, plants, and animals. These organisms are engineered to be of use to humans.
• Access additional resources about genetic engineering on this link www.worldofteaching.com
• Cite the work of Luther Burbank, an American horticulturist who introduced more than 200 varieties of fruit. The teacher can tell the learners that he developed pomato (tomato/potato), plumcot (plum/
apricot), and the white raspberry. The teacher can localize examples.
• (Optional)Have students think about a hybrid fruit, vegetable, flower or animals that they might like to breed. Let them draw pictures of their hybrid organisms considering the qualities that they would like their hybrid organisms to have.
• You may use the given sample rubric for this task or you may create your own rubric.
Suggested website for hybrid fruits and vegetables:
(www.buzzle.com/articles/hybrid-fruits-and-vegetables.html)
KEY CONCEPT TO EMPHASIZE:
• A mutation is a change in the base sequence of DNA. Mutations may affect only one gene, or they may affect whole chromosomes.
• Mutations in eggs or sperm effect future generations by producing offspring with new characteristics.
• Mutations in body cells affect only the individual and are not passed on to the offspring.
• When DNA from two different species are joined together, it is called recombinant DNA. This process uses restriction enzymes to cleave one organism’s DNA into fragments and other enzymes to splice the DNA fragment into a plasmid or viral DNA.
Note: The teacher can acces the LRMDS(BEAM) material of DepEd from which Activity 6 was adapted.
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Name: _______________________________ Date: ________________
Grade: _____________ Teacher: _________________________________
RUBRIC
andcreative use of materials, madeunderstanding Piece was not
created at all Piece was created but
Effort Did not finish the work in a
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SUMMARY
• DNA is the genetic material of organisms. A DNA is a double helix molecule composed of two complementary strands of deoxyribonucleotides units.
The complementary base pairs of the DNA are held by hydrogen bonds.
• The central dogma of the transfer of genetic information states that the sequence involved in the expression of hereditary characteristics is from DNA to RNA to proteins.
• Genes are segments of DNA that may code for RNA or proteins.
• Most sequences of three bases in the DNA of a gene code for a single amino acid in a protein.
• Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).
• There are three major types of RNA in the cell and their functions:
1. mRNA carries the information from DNA to the ribosomes.
2. tRNA translates the genetic message carried by the mRNA through protein synthesis.
3. rRNA forms the structural component of the ribosome.
• Ribosomal RNA serves as the site for attachment of mRNA and tRNA and for protein synthesis
• Translation is a process which the order of bases in mRNA of amino acids is synthesized/converted/decoded into a protein. It occurs in a ribosome of the cytoplasm.
• A mutation is a change in the base sequence of DNA. Mutations may affect only one gene, or they may affect whole chromosomes.
• Mutations in eggs or sperm may affect future generations by transmitting these changes in the offsprings. Mutations in non-sex (somatic) cells only are not hereditary.
• When DNA from two different species are joined together, it is called recombinant DNA. This process uses restriction enzymes to cleave one organism’s DNA into fragments and other enzymes to splice the DNA fragment into a plasmid or viral DNA.
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Answers to Summative Assessment:
A. 1. (a) TTACGGTCACCA 2. (a) (c) UUACGGUCACCA 3. (b) AAUGCCAGUGGU B. 4. UGG
5. 66. Aspartic acid 7. U & A
C. Arrange the following steps in protein synthesis from first to last (1-6).
1 A. Transcription
3 B. tRNA – amino acid units link to mRNA 4 C. Amino acid separate from tRNA
5 D. Polypeptide chain assembled 2 E. mRNA links to ribosome
6 F. Stop codon encountered in mRNA
D. Given the list of amino acids, determine the sequence of bases in the codon of the mRNA that codes for these amino acids. Use the table for the Genetic Code
1. AUG 6. AAU/AAC
2. UUA/UUG/CUU/ 7. GUU/GUC/GUA/GUG CUC/CUA/CUG
3. AGA/AGG 8. GGU/GGC/CGA/GGG
4. ACU/ACC/ACA/ACG 9. GAU/GAC
5. AAA/AAG 10. GAA/GAG
E. AUG UUA AGA ACU AAA AAU GUU GGU GAU GAA
Note: The teacher should consider that there are other possible answers to be presented by students since one amino acid maybe coded by several codons.
DNA Template