Question

1. place a number beside the term according to its description below :

introns___

m-RNA ____

protein ____

ribosomes ____

DNA ____

r-RNA ____

RNA-polymerase ____

t-RNA _______

A---T, C--G ______

DNA-polymerase ____

A--U, C--G ______

RNA ____

exons______

triplet code _____

1. enzyme which takes care of making any type of RNA on the base of DNA information.

2. nucleic acid which carries information taken from DNA about order of amino acids

3. complementary base pairing in DNA

4. nucleic acid to bring amino acids for protein synthesis and recognize their codes( taxi and translator )

5. what is produced in result of translation

6. enzyme that takes care of DNA duplication ( and chromosomes duplication in S stage )

7. nucleic acid made of 2 strands kept by hydrogen bonds, twisted ladder, part of chromosome, it's where genes are located

8. nucleic acid which is part of ribosomes

9. non-coding parts of DNA, removed from RNA after transcription

10. made of 2 subunits, has A and P sites, assembling bench for making protein

11. A--U, C--G complementary base pairing in RNA

12. protein-coding portions of DNA

13. three nucleotides of RNA which call for particular amino acid, also STOP or START signals

14. single-stranded nucleic molecule, made on the base of DNA in result of transcription

2. Making protein...use your knowledge about complementary base pairing and complete the following exercise about transcription and translation( assume that for making m-RNA, second strand of DNA is used!!!)

first strand of DNA : TAC --- AAA---TTA ---CCG ---CCC---TTG---GGG---TTT

second strand : ___________________________________________________________________________

m-RNA : ___________________________________________________________________________

amino acids: ____________________________________________________________________________

anticodons: ____________________________________________________________________________

3. Can these triplets -- TAC , TTT, TGG, GTA-- be anticodons? ___ Why? __________

4. If in DNA 22% of guanine, what would be % of thymine ____, adenine ____, cytosine ____?

5. Does DNA participate directly in translation? ____ Why? ______

6. Mutations can be result of base substitution. Use DNA molecule given in #2 exercise. But now change ( due to mutations! ) second triplet of the first strand of DNA from AAA to AAG, and the last triplet on the first strand of DNA from TTT into TTG. Complete trascription and translation only for affected triplets.

DNA first strand: ______________ _____________ as a result of two mutations,

second strand : _____________ ______________

m-RNA : ______________ _________________

amino acids: ______________ _________________

--- which mutation is silent (= mute, neutral )? _____ why? ______

-- which mutation is so-called missense ? _____ why? _______

Answer 1

introns :- non-coding parts of DNA, removed from RNA after transcription

m-RNA  :- nucleic acid to bring amino acids for protein synthesis and recognize their codes( taxi and translator )

protein  :- what is produced in result of translation

ribosomes  :- nucleic acid which carries information taken from DNA about order of amino acids

DNA  :- nucleic acid made of 2 strands kept by hydrogen bonds, twisted ladder, part of chromosome, it's where genes are located

r-RNA  :- nucleic acid which is part of ribosomes

RNA-polymerase  :- enzyme which takes care of making any type of RNA on the base of DNA information.

t-RNA  :- made of 2 subunits, has A and P sites, assembling bench for making protein

A---T, C--G :- complementary base pairing in DNA

DNA-polymerase  :-  enzyme that takes care of DNA duplication ( and chromosomes duplication in S stage )

A--U, C--G :- complementary base pairing in RNA

RNA :- single-stranded nucleic molecule, made on the base of DNA in result of transcription

exons :- protein-coding portions of DNA

triplet code  :- three nucleotides of RNA which call for particular amino acid, also STOP or START signals

2.

second strand :- ATG --- TTT---AAT ---GGC ---GGG---AAC---CCC---AAA

m-RNA :- UAC --- AAA---UUA ---CCG ---CCC---UUG---GGG---UUU

amino acids :- Tyr --- Lys---Leu ---Pro ---Pro---Leu---Gly---Phe

anticodons :- UAC --- UUU---AAU ---CCG ---CCC---UUG---GGG---UUU

3. Yes because the three unpaired nucleotides, called an anticodon.The anticodon of any one tRNA fits perfectly into the mRNA codon that codes for the amino acid attached to that tRNA.

4. A+G+T+C =100 % ............equation1

and here A=T and G=C

We know that G= 22% therefore C= 22%

Putting the above values in equation1

we get,

A+22+T+22 = 100

A+T+44 =100

A+T = 100-44

A+T = 56, ................equation 2

we know A=T .............equation 3

Therefore

A+A =56 ................ from equation 2 and 3

A= 28

therefore A= 28% T=28% G=22% and C=22%

5. DNA does not directly participate in translation. because The genetic information in DNA is used as a basis to create mRNA by transcription and further mRNA enter translation and act as template.

6.

DNA first strand :-  AAG and TTG as a result of two mutations,

second strand :- TTC and AAC

m-RNA : AAG and UUG

amino acids: Lys and leu respectively

mutation from AAA to AAG is neutral because both the codon code for lysine so at the end there will be no changes in amino acid sequence.

a missense mutation is a point mutation in which a single nucleotide change results in a codon that codes for a different amino acid. In above condition the mutation from TTT into TTG result in change in amino acid that is it will code for Phe and Leu respectively

NOTE :- For reference the table is given as follows.

The amino acid sequence is determined using the mRNA only .

During transcription the mRNA undergoes transcription from 5' to 3' end so it becomes completentary to the template strand.