Chapter 22, Problem 22.77P

Consider the following sequence of DNA: $\text{3’-TTA CGG-5’}$.

1. What dipeptide is formed from this DNA after transcription and translation?
2. If a mutation converts CGG to CGT in DNA, what dipeptide is formed?
3. If a mutation converts CGG to CCG in DNA, what dipeptide is formed?
4. If a mutation converts CGG to AGG in DNA, what dipeptide is formed?

Interpretation Introduction

(a)

Interpretation:

Dipeptide formed from DNA 3' TTA CGG 5' after transcription and translation should be identified.

Concept Introduction:

Transcription − Copying of information stored as a deoxyribo nucleotide sequence of DNA into a ribonucleotide sequence of RNA.

Translation −Copying of information stored as a ribonucleotide sequence of RNA into an amino acid sequence of a peptide chain.

Genetic code − DNA and RNA transform genetic information of the living cells through triplet code, which is a sequence of three nucleotides on DNA or RNA molecules codes for a specific amino acid in protein synthesis.

Answer to Problem 22.77P

Dipeptide is Asn-Ala.

Explanation of Solution

Nucleotides are the monomer molecules for both DNA and RNA molecules. DNA has deoxyribo nucleotides and RNA has ribonucleotides.

DNA molecules consist of 2 DNA strands, which binds with base pairs as below.

Adenine (A) pairs with Thymine (T).

Cytosine (C) pairs with Guanine (G).

In RNA;

Adenine (A) pairs with Uracil (U). Cytosine (C) pairs with Guanine (G).

Codons are written from 5 prime end (5) to 3 prime end (3) of mRNA. mRNA has a base sequence which is complementary to the template DNA strand. Adenine (A) pairs with Uracil (U) in mRNA or Thymine (T) in DNA; by using two H bonds and Cytosine (C) pairs with Guanine (G) by using three H bonds. Therefore; mRNA sequence can be represented as below,

 

Codons are written from 5 prime end (5') to 3 prime end (3') of mRNA. There is a specific sequence of nucleotides for each amino acid. Below mentioned table represent the relationship between nucleotides and amino acids.

The Genetic Code- Triplets in Messenger RNA

 

According to the above table; one amino acid has several triplets, but triplet code is unique for amino acid. For Asparagine amino acid (Asn) there are 2 different but unique codons, which are AAU and AAC. Likewise, for each amino acid there are several triplets. Therefore, for a particular amino acid sequence there can be different triplet codes. AAU is unique for asparagine amino acid and GCC is unique for alanine amino acid.

Asn-Ala is the dipeptide which can be obtained from 3' TTA CGG 5' template DNA strand.

Interpretation Introduction

(b)

Interpretation:

Dipeptide formed from mutated DNA 3' TTA CGT 5' after transcription and translation should be identified.

Concept Introduction:

Transcription − Copying of information stored as a deoxyribo nucleotide sequence of DNA into a ribonucleotide sequence of RNA.

Translation − Copying of information stored as a ribonucleotide sequence of RNA into an amino acid sequence of a peptide chain.

Genetic code − DNA and RNA transform genetic information of the living cells through triplet code, which is a sequence of three nucleotides on DNA or RNA molecules codes for a specific amino acid in protein synthesis.

Mutation is an alteration of a sequence of nucleotides in DNA.

Answer to Problem 22.77P

Dipeptide is Asn-Ala.

Explanation of Solution

Nucleotides are the monomer molecules for both DNA and RNA molecules. DNA has deoxyribo nucleotides and RNA has ribonucleotides.

DNA molecules consist of 2 DNA strands, which binds with base pairs as below.

Adenine (A) pairs with Thymine (T).

Cytosine (C) pairs with Guanine (G).

In RNA;

Adenine (A) pairs with Uracil (U). Cytosine (C) pairs with Guanine (G).

Mutation is an alteration of a sequence of nucleotides in DNA. When mutation happens at a particular position of a DNA molecule, that mutation goes through mRNA and translate a wrong peptide.

Mutations can be classified based on the change that results in a DNA molecule. There are three types of mutations which can be classified as follows;

1. Point mutations − A substitution of one nucleotide for another nucleotide.
2. Deletion mutations − One or more nucleotides is lost from a particular DNA molecule.
3. Insertion mutations − One or more nucleotides is added to a DNA molecule.

Codons are written from 5 prime end (5) to 3 prime end (3) of mRNA. mRNA has a base sequence which is complementary to the template DNA strand. Adenine (A) pairs with Uracil (U) in mRNA or Thymine (T) in DNA; by using two H bonds and Cytosine (C) pairs with Guanine (G) by using three H bonds. Therefore; mRNA sequence can be represented as below,

 

Codons are written from 5 prime end (5') to 3 prime end (3') of mRNA. There is a specific sequence of nucleotides for each amino acid. Below mentioned table represent the relationship between nucleotides and amino acids.

The Genetic Code- Triplets in Messenger RNA

 

According to the above table; one amino acid has several triplets, but triplet code is unique for amino acid. For Asparagine amino acid (Asn) there are 2 different but unique codons, which are AAU and AAC. For, Alanine (Ala) there are 4 different but unique codons, which are GCU, GCC, GCA and GCG. Likewise, for each amino acid there are several triplets. Therefore, for a particular amino acid sequence there can be different triplet codes. AAU is unique for asparagine amino acid and GCA is unique for alanine amino acid. Though there is a mutation in the strand, in this example same peptide is generated as the non-mutated peptide.

Asn-Ala is the dipeptide which can be obtained from 3' TTA CGT 5' mutated template DNA strand.

Interpretation Introduction

(c)

Interpretation:

Dipeptide formed from mutated DNA 3' TTA CCG 5' after transcription and translation should be identified.

Concept Introduction:

Transcription − Copying of information stored as a deoxyribo nucleotide sequence of DNA into a ribonucleotide sequence of RNA.

Translation − Copying of information stored as a ribonucleotide sequence of RNA into an amino acid sequence of a peptide chain.

Genetic code − DNA and RNA transform genetic information of the living cells through triplet code, which is a sequence of three nucleotides on DNA or RNA molecules codes for a specific amino acid in protein synthesis.

Mutation is an alteration of a sequence of nucleotides in DNA.

Answer to Problem 22.77P

Dipeptide is Asn-Gly.

Explanation of Solution

Nucleotides are the monomer molecules for both DNA and RNA molecules. DNA has deoxyribo nucleotides and RNA has ribonucleotides.

DNA molecules consist of 2 DNA strands, which binds with base pairs as below.

Adenine (A) pairs with Thymine (T).

Cytosine (C) pairs with Guanine (G).

In RNA;

Adenine (A) pairs with Uracil (U). Cytosine (C) pairs with Guanine (G).

Mutation is an alteration of a sequence of nucleotides in DNA. When mutation happens at a particular position of a DNA molecule, that mutation goes through mRNA and translate a wrong peptide.

Mutations can be classified based on the change that results in a DNA molecule. There are three types of mutations which can be classified as follows;

1. Point mutations − A substitution of one nucleotide for another nucleotide.
2. Deletion mutations − One or more nucleotides is lost from a particular DNA molecule.
3. Insertion mutations − One or more nucleotides is added to a DNA molecule.

Codons are written from 5 prime end (5) to 3 prime end (3) of mRNA. mRNA has a base sequence which is complementary to the template DNA strand. Adenine (A) pairs with Uracil (U) in mRNA or Thymine (T) in DNA; by using two H bonds and Cytosine (C) pairs with Guanine (G) by using three H bonds. Therefore; mRNA sequence can be represented as below,

 

Codons are written from 5 prime end (5') to 3 prime end (3') of mRNA. There is a specific sequence of nucleotides for each amino acid. Below mentioned table represent the relationship between nucleotides and amino acids.

The Genetic Code- Triplets in Messenger RNA

 

According to the above table; one amino acid has several triplets, but triplet code is unique for amino acid. For Asparagine amino acid (Asn) there are 2 different but unique codons, which are AAU and AAC. For, Glycine (Gly) there are 4 different but unique codons, which are GGU, GGC, GGA and GGG. Likewise, for each amino acid there are several triplets. Therefore, for a particular amino acid sequence there can be different triplet codes. AAU is unique for asparagine amino acid and GGC is unique for glycine amino acid. Hence, because of the mutation in the strand, in this example resulting peptide from the mutated template DNA is different from the non-mutated peptide.

Asn-Gly is the dipeptide which can be obtained from 3' TTA CCG 5' mutated template DNA strand.

Interpretation Introduction

(d)

Interpretation:

Dipeptide formed from mutated DNA 3' TTA AGG 5' after transcription and translation should be identified.

Concept Introduction:

Transcription − Copying of information stored as a deoxyribo nucleotide sequence of DNA into a ribonucleotide sequence of RNA.

Translation − Copying of information stored as a ribonucleotide sequence of RNA into an amino acid sequence of a peptide chain.

Genetic code − DNA and RNA transform genetic information of the living cells through triplet code, which is a sequence of three nucleotides on DNA or RNA molecules codes for a specific amino acid in protein synthesis.

Mutation is an alteration of a sequence of nucleotides in DNA.

Answer to Problem 22.77P

Dipeptide is Asn-Ser.

Explanation of Solution

Nucleotides are the monomer molecules for both DNA and RNA molecules. DNA has deoxyribo nucleotides and RNA has ribonucleotides.

DNA molecules consist of 2 DNA strands, which binds with base pairs as below.

Adenine (A) pairs with Thymine (T).

Cytosine (C) pairs with Guanine (G).

In RNA;

Adenine (A) pairs with Uracil (U). Cytosine (C) pairs with Guanine (G).

Mutation is an alteration of a sequence of nucleotides in DNA. When mutation happens at a particular position of a DNA molecule, that mutation goes through mRNA and translate a wrong peptide.

Mutations can be classified based on the change that results in a DNA molecule. There are three types of mutations which can be classified as follows;

1. Point mutations − A substitution of one nucleotide for another nucleotide.
2. Deletion mutations − One or more nucleotides is lost from a particular DNA molecule.
3. Insertion mutations − One or more nucleotides is added to a DNA molecule.

Codons are written from 5 prime end (5) to 3 prime end (3) of mRNA. mRNA has a base sequence which is complementary to the template DNA strand. Adenine (A) pairs with Uracil (U) in mRNA or Thymine (T) in DNA; by using two H bonds and Cytosine (C) pairs with Guanine (G) by using three H bonds. Therefore; mRNA sequence can be represented as below,

 

Codons are written from 5 prime end (5') to 3 prime end (3') of mRNA. There is a specific sequence of nucleotides for each amino acid. Below mentioned table represent the relationship between nucleotides and amino acids.

The Genetic Code- Triplets in Messenger RNA

 

According to the above table; one amino acid has several triplets, but triplet code is unique for amino acid. For Asparagine amino acid (Asn) there are 2 different but unique codons, which are AAU and AAC. For, Serine (Ser) there are 6 different but unique codons, which are UCU, UCC, UCA, UCG, AGU and AGC. Likewise, for each amino acid there are several triplets. Therefore, for a particular amino acid sequence there can be different triplet codes. AAU is unique for asparagine amino acid and UCC is unique for serine amino acid. Hence, because of the mutation in the strand, in this example resulting peptide from the mutated template DNA is different from the non-mutated peptide.

Asn-Ser is the dipeptide which can be obtained from 3' TTA AGG 5' mutated template DNA strand.